U.S. patent application number 14/602611 was filed with the patent office on 2015-06-25 for method and apparatus for dispensing items.
This patent application is currently assigned to DATA DETECTION TECHNOLOGIES LTD. The applicant listed for this patent is Data Detection Technologies Ltd.. Invention is credited to AMICHAI ADAM, ODED DAVIDOVITCH, IGOR FAIB, NACHSHON KAHANA, YUVAL LICHI, ISRAEL SHNEIDERMAN, YOSSI SHOMER, ARYEH TEITELBAUM, ARI TIDHAR, ZVI WEINBERGER.
Application Number | 20150175287 14/602611 |
Document ID | / |
Family ID | 45509014 |
Filed Date | 2015-06-25 |
United States Patent
Application |
20150175287 |
Kind Code |
A1 |
TIDHAR; ARI ; et
al. |
June 25, 2015 |
METHOD AND APPARATUS FOR DISPENSING ITEMS
Abstract
A method for rapidly and accurately dispensing a predetermined
number of discrete items, the method comprising: operating a
conveyor to transport multiple items towards an imaging device,
wherein the items are arranged in a single layer and at least some
of the items are transported in parallel; operating the imaging
device to continuously capture images of an area immediately below
an end of the conveyor, so that items falling off the conveyor are
recorded in the images while in trajectory; processing the images
in real time, to continuously determine the number of falling
items; stopping the conveyor before the number of falling items has
reached the predetermined number, while continuing to determine the
number of falling items until items cease to fall off the conveyor
innertially; and automatically dispensing an additional amount of
items, to complete the predetermined number of items.
Inventors: |
TIDHAR; ARI; (Ganey Tikva,
IL) ; SHNEIDERMAN; ISRAEL; (Jerusalem, IL) ;
KAHANA; NACHSHON; (Jerusalem, IL) ; ADAM;
AMICHAI; (Betar-lllit, IL) ; TEITELBAUM; ARYEH;
(Jerusalem, IL) ; DAVIDOVITCH; ODED; (Tel Aviv,
IL) ; SHOMER; YOSSI; (Kochav Yaakov, IL) ;
LICHI; YUVAL; (Kibbutz Ramat Rachel, IL) ;
WEINBERGER; ZVI; (Jerusalem, IL) ; FAIB; IGOR;
(Jerusalem, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Data Detection Technologies Ltd. |
Jerusalem |
|
IL |
|
|
Assignee: |
DATA DETECTION TECHNOLOGIES
LTD
|
Family ID: |
45509014 |
Appl. No.: |
14/602611 |
Filed: |
January 22, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13658881 |
Oct 24, 2012 |
8972049 |
|
|
14602611 |
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Current U.S.
Class: |
700/240 |
Current CPC
Class: |
B65B 57/14 20130101;
B65G 43/08 20130101; G06M 7/02 20130101; B65B 57/20 20130101; G06M
7/04 20130101; G06T 7/0004 20130101; G06F 17/00 20130101; B65B
5/103 20130101; G06T 2207/10016 20130101 |
International
Class: |
B65B 57/20 20060101
B65B057/20; B65B 57/14 20060101 B65B057/14; G06T 7/00 20060101
G06T007/00; B65G 43/08 20060101 B65G043/08 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 1, 2011 |
GB |
1120691.9 |
Claims
1. A method for rapidly and accurately dispensing a predetermined
number of discrete items, the method comprising: operating a
conveyor to transport multiple items towards an imaging device;
operating the imaging device to continuously capture images of the
items falling off the conveyor, wherein the items are recorded
while in trajectory; processing the images in real time, to
continuously determine the number of falling items; stopping the
conveyor before the number of falling items has reached the
predetermined number; and operating a supplementary item dispenser
to automatically and discretely dispense, one by one, the exact
number of items needed to complete the predetermined number of
items.
2. The method according to claim 1, wherein the operating of the
supplementary item dispenser is performed at least partially
simultaneously with the operating of the conveyor.
3. The method according to claim 1, wherein the imaging device is
operated to continuously capture images of an area immediately
below an end of the conveyor, said area extending to an effective
portion of the width of the end of the conveyor, such that all of
the items transported and falling off the end of the conveyor are
recorded in the images.
4. The method according to claim 3, wherein the processing of the
images to continuously determine the number of falling items
comprises increasing an item count by one when an item enters or
exits said area, wherein entrance or exit is determined when a
bottom or top portion of an item, correspondingly, appears in an
image but is missing from an immediately preceding image.
5. The method according to claim 3, wherein the processing of the
images to continuously determine the number of falling items
comprises: tracking each item over consecutive images, from
entering the area until exiting said area; and increasing an item
count by one upon the exit of each tracked item, to prevent a
miscount if occasional noise appears in one or more of the
images.
6. The method according to claim 1, wherein a vertical gap is
provided between the end of the conveyor and an upper edge of the
area, to ensure that an end surface of the conveyor is not recorded
in the images.
7. The method according to claim 1, wherein the items are arranged
in a single layer on the conveyor and at least some of the items
are transported in parallel, in a direction orthogonal to a
direction of the transport, and wherein at least some of the items
falling off the conveyor are falling off in parallel, in a
direction orthogonal to a direction of the transport.
8. The method according to claim 1, wherein the total number of
falling items is smaller than the predetermined number by up to
ten.
9. An apparatus comprising: a conveyor configured to transport
multiple items from a hopper to an end of the conveyor; an imaging
device configured to continuously capture images of the items
falling off the conveyor, wherein the items are recorded in the
images while in trajectory; a counting device configured to process
the images in real time, to continuously determine the number of
falling items; an actuator configured to control operation of said
conveyor in accordance with actuator control commands; a computing
platform configured to: receive the number of falling items from
said counting device, generate an actuator control command of said
actuator control commands, the actuator control command being to
stop said conveyor before the number of falling items has reached
the predetermined number, and generate a dispenser control command
based on the number of items needed for completing the
predetermined number of items; and a supplementary item dispenser
configured, responsive to the dispenser control command, to
dispense exactly and discretely, one by one, the number of items
needed for completing the predetermined number of items.
10. The apparatus according to claim 9, wherein said counting
device comprises an image sensor and is configured to capture said
images using a predetermined number of pixel rows of said image
sensor, the predetermined number being lower than a total number of
sensor rows existing in said image sensor.
11. The apparatus according to claim 9, wherein said counting
device is configured to determine the number of falling items by
analyzing a pattern of sensor pixels affected by a falling item in
consecutive samples of the image sensor.
12. The apparatus according to claim 9, wherein said counting
device comprises an image sensor, and wherein the apparatus further
comprises at least one light source for providing light to be
reflected by the falling items onto the image sensor.
13. The apparatus according to claim 9, further comprising a lens
assembly for focusing light reflected from the falling items onto
the imaging device.
14. The apparatus according to claim 9, wherein the supplementary
dispenser is further configured to dispense the number of items
needed for completing the predetermined number of items at least
partially simultaneously with the transporting of the multiple
items by the conveyor.
15. The apparatus according to claim 9, wherein the conveyor is a
parallel transport conveyor configured to transport the multiple
items in parallel, in a direction orthogonal to a direction of the
transport.
16. The apparatus according to claim 15, wherein the imaging device
is configured to continuously capture images of an area immediately
below an end of the conveyor, and wherein at least some of the
items falling off the conveyor are falling off in parallel, in a
direction orthogonal to a direction of the transport.
17. The apparatus according to claim 9, wherein the actuator
control command is such that the number of falling items is smaller
than the predetermined number by up to ten.
18. An item dispenser comprising: a parallel transport conveyor
configured to transport items such that items fall off an end of
the conveyor at a rate of at least 50 items per second; an imaging
device configured to continuously capture images of the items
falling off the conveyor, wherein the items are recorded in the
images while in trajectory; a counting device configured to process
the images in real time, to continuously determine the number of
falling items; an actuator configured to control operation of said
conveyor in accordance with actuator control commands; a computing
platform configured to: receive the number of falling items from
said counting device, generate an actuator control command of said
actuator control commands, the actuator control command being to
stop said conveyor before the number of falling items has reached a
predetermined number, and generate a dispenser control command
based on the number of items needed for completing the
predetermined number of items; and a supplementary item dispenser
configured, responsive to the dispenser control command, to
dispense exactly the number of items needed for completing the
predetermined number of items, discretely, one by one, and at a
rate of 1-4 items per second.
19. The item dispenser according to claim 18, wherein the
supplementary dispenser is further configured to dispense exactly
the number of items needed for completing the predetermined number
of items at least partially simultaneously with the transporting of
the items by the parallel transport conveyor.
20. The item dispenser according to claim 18, wherein the actuator
control command is such that the number of falling items is smaller
than the predetermined number by up to ten.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an apparatus and method for
dispensing a multiplicity of discrete items into groups (or
"batches"), each group containing a predetermined number of the
items.
BACKGROUND OF THE INVENTION
[0002] It is frequently required to dispense items of particulate
matter into batches of known quantity. Examples include dispensing
medicinal tablets, pills, capsules, seeds, candies or the like into
bottles, sacks or other containers, sorting rough diamonds into
packages or containers of approximately equal number of samples,
such as to enable different evaluators to estimate the quality and
worth of the whole, or the like.
[0003] In some dispensing tasks, the finished container must not
contain less than the predetermined number of items. For example,
when dispensing certain pills, a full treatment cycle may have to
be provided, therefore at least the predetermined number of items
must be provided in each container.
[0004] On the other hand, the dispensed items may be expensive, so
if too many of the containers contain more than the predetermined
number of items, it translates to direct loss to the supplier of
the items or to the packing organization.
[0005] In many dispensing machines, the items are transported along
a conveyor, at the end of which they fall or are otherwise
collected into containers. Thus, if the items are put onto the
conveyor in a single file, then a simple counting or weighting
mechanism may provide satisfactory results. However, such a
mechanism is inherently slower and therefore enables the dispensing
of fewer items than if the items were freely placed on the conveyor
without posing such limitations.
[0006] Furthermore, some dispensing machines also utilize various
barriers for physically preventing items from falling off the
conveyor once the desired amount has been reached.
[0007] U.S. Pat. No. 5,473,703 to Smith, entitled "Methods and
apparatus for controlling the feed rate of a discrete object
sorter/counter", discloses a controller which adjusts the vibrator
to oscillate the feed bowl at a predetermined amplitude until the
sensor array senses a first object. The controller then adjusts the
vibrator to oscillate the feed bowl at a lower amplitude and
monitors the sensing of other objects. Time intervals between
objects being sensed are monitored and the controller adjusts the
vibrator to oscillate the feed bowl at a lower or higher amplitude
to maintain a constant feed rate. A count of objects sensed is
maintained and compared to a predetermined maximum count. When the
count of objects equals a predetermined number less than the
maximum count, the controller adjusts the vibrator to oscillate the
feed bowl at a lower amplitude to lower the feed rate. When the
count of objects equals the maximum count, the controller activates
a gate closing the chute.
[0008] U.S. Pat. No. 6,659,304 to Geltser et al., entitled
"Cassettes for systems which feed, count and dispense discrete
objects", discloses a high capacity cassette for an object counting
and dispensing system, that includes, inter alia, a structure which
feeds the discrete objects in single file toward an exit hole.
[0009] U.S. Pat. No. 6,449,927 to Hebron et al., entitled
"Integrated automated drug dispenser method and apparatus",
discloses, inter alia, singulation control, which is a process by
which drugs move through a canister in a nearly single-file
fashion. Means for singulation control is provided by the width of
the acceleration ramp and the dispensing ramp. By providing the
proper ramp width, the movement of drugs in other than a nearly
single-file fashion is prevented. The proper ramp width may in fact
be more than one width and may, for example, be a width that is
tapered from a largest width to a smallest width. It may also be
preferable to design canisters for specific drugs based on the drug
size and shape. The drug size and shape may be used to select a
proper ramp width. Singulation control may be aided by maintaining
the acceleration ramp and the dispensing ramp surfaces on which
drugs move at an angle with respect to horizontal. The angle is
selected so that the edge of the ramp surface closest to the center
of the canister is above a horizontal plane which intersects the
edge of the ramp surface farthest from the center of the
canister.
[0010] Hebron further discloses that in order to minimize the fill
time, the drive frequency is increased slowly until it approaches
the maximum detection rate of the sensor. The drug count is a
discrete integer count registered in a fixed sampling time. A
moving average is used as the basis to predict when the last drug
will fall through the sensor. As the drug count approaches the
total count, the time to terminate the fill is predicted as a
fraction of the sampling time of the counting mechanism. The
vibration of the canister or unit-of-use bin by the vibrating
dispenser is terminated when the estimated time to terminate is
reached. In the expected event that the count is short one or two
solid drugs, the drive mechanism is restarted as the last used
frequency for a short time pulse, 25 milliseconds to 100
milliseconds, for example. Then the drive mechanism is turned off
at least until the next drug count registers. If the count is still
short, this process is repeated.
[0011] European Patent Application No. 1,852,372 to Ogawa et al.,
entitled "Vibrating bowl, vibrating bowl feeder, and vacuum
deposition apparatus", discloses, inter alia, a vibrating bowl and
the like, which are capable of accurately counting the number of
objects to be fed, accurately leading objects one by one to an
external place per unit time, and aligning collectivity of objects
into a row or tier at an intermediate point on a feed passage by
simple alignment means.
[0012] U.S. Patent Application Publication No. 2005/0263537 to
Gerold et al., entitled "Automated pill-dispensing apparatus",
discloses, inter alia, a bulk storage unit useful for automatically
dispensing solid pills includes a track having a length, an
upstream end and a downstream end, the track being adapted to feed
pills along its length in a longitudinal direction when the track
is vibrated. A storage unit includes a hopper positioned over the
track and having an opening for dropping pills onto the upstream
end, the storage unit including a door movable between an open
position permitting singulated pills to drop off the downstream end
and a closed position preventing pills from dropping off the track.
The door, when close to the closed position and being moved to the
closed position, moving parallel the longitudinal direction so that
any pills handing partially off the downstream end are pushed back
onto the track as the door comes to rest in the closed
position.
[0013] U.S. Patent Application Publication No. 2010/0205002 to
Chambers, entitled "Automated pill-dispensing apparatus",
discloses, inter alia, that pills advance up a spiraling edge of a
vibratory feeding bowl and pass through a singulator. Proceeding in
a generally single file manner, each pill falls one by one off an
exit edge of the vibratory feeding bowl into an upper portion of a
pill dispensing route. As the pills pass through the upper portion,
they also pass through the light beams provided by a first and
second sensor pairs. Then the pills continue down through a lower
portion of the dispensing route, usually a dispensing chute. After
passing through the dispensing chute, the pills pass through a
dispensing neck and out of the pill dispensing device and into the
pill bottle. Once the desired number of pills has been dispensed,
the controller signals the vibratory base unit to turn off.
Moreover, a pill stop mechanism is activated by the controller to
prevent any additional pills located close to the exit edge from
falling into the upper portion of the dispensing route.
[0014] U.S. Pat. No. 6,253,953 to Ishizuka, entitled "Automatic
high-speed pill counting apparatus", discloses, inter alia, an
apparatus comprising a cylindrical pill hopper having a pill exit
and a center hole in a base plate; a rotational separative feeder
mounted in the cylindrical pill hopper and removably fitted on a
shaft borne in the center hole of the base plate, the feeder
including an upper diametrically smaller portion and a lower
diametrically larger portion having an external diameter
approximate to the internal diameter of the lower portion of the
pill hopper, a multiplicity of vertically through holes being
formed in the outer circumference of the lower diametrically larger
portion and allowed to come into alignment with the pill exit for
accommodating a plurality of pills vertically, the multiple
vertically through holes being enlarged at their lower portions, a
ring-shaped slit being formed in such a position in the outer
circumference of the lower diametrically larger portion as to
accommodate substantially one pill from the bottom; and a pill
separating plate mounted on the cylindrical pill hopper above the
pill exit and having an inwardly projected tip fitted loosely in
the slit. The apparatus can count the pills quickly and accurately
while preventing the inner wall of the cylindrical portion of the
hopper from becoming dirty and the pills from being soiled or
broken.
[0015] U.S. Pat. No. 4,382,527 to Lerner, entitled "Article
handling system with dispenser", discloses, inter alia, that in a
system for dispensing weighed or counted articles, articles are fed
from a supply hopper by a vibratory conveyor to maintain a
controlled level of articles in a bowl-shaped feeder hopper. In a
weigher embodiment, articles are initially discharged from the
feeder hopper through two discharge openings into an accumulator
bucket. A weighing unit monitors the weight of articles in the
bucket and signals a door to close one of the discharge openings as
the weight of articles in the bucket begins to approach a
predetermined weight. The weighing unit subsequently signals the
feeder hopper drive to slow its feeding action as the weight of
articles in the bucket more closely approaches the predetermined
weight. The feeder hopper discharge openings are arranged near each
other at locations where the door-controlled opening will provide a
rapid, bulk feed of articles, while the other opening will provide
a single-file trickle feed. In a counter embodiment, a feeder
hopper having a single discharge opening is used so that articles
can pass single file from the feeder hopper past a counter unit to
an accumulator bucket.
[0016] Japanese Patent No. 2,132,011 to Kazumi et al., entitled
"Granular material discharging device", discloses, in its published
English abstract, improvement of the discharge control precision by
selecting the vibration frequency in response to the load change or
a feeder based on the measured data of the load and flow speed for
each vibration frequency so that the flow speed is made constant in
a medicine quantitative discharging device using a vibration
feeder. The device includes a central processing unit which selects
the relational data among the vibration frequency, load, and flow
speed in response to the type of an inputted bulk material, e.g.,
D1. The optimum frequency corresponding to the present load is
selected from the data D1 based on the load signal SL outputted
from a weight measuring device, and the AC power source
corresponding to the frequency signal is fed to an electromagnetic
section via a D/A converting circuit, an integrating circuit, a V/F
converting circuit, and a power driving circuit; A vibration feeder
is operated at the preset frequency, and the flow speed is made
nearly constant. The discharge control precision can be improved
according to this constitution.
[0017] Some dispensing and packing machines include a counting
mechanism for determining the actual number of collected objects.
By monitoring objects interrupting the illumination of a light
source onto a pixelated array, it is possible to count objects
being poured.
[0018] Such a mechanism is disclosed, for example, in U.S. Pat. No.
5,768,327 to Pinto et al., entitled "Method and apparatus for
optically counting discrete objects". Pinto describes an object
counter including a feeding funnel having a frustroconical section,
the narrow end of which is coupled to a substantially vertical
feeding channel having a substantially rectangular cross section. A
pair of linear optical sensor arrays are arranged along adjacent
orthogonal sides of the feeding channel and a corresponding pair of
collimated light sources are arranged along the opposite adjacent
sides of the feeding channel such that each sensor in each array
receives light the corresponding light source. Objects which are
placed in the feeding funnel fall into the feeding channel and cast
shadows on sensors within the arrays as they pass through the
feeding channel. Outputs from each of the two linear optical arrays
are processed separately, preferably according to various
conservative criteria, and two object counts are thereby obtained.
The higher of the two conservative counts is accepted as the
accurate count and is displayed on a numeric display. In another
embodiment, four sensor arrays and light sources are provided. The
third and fourth sensor arrays and corresponding light sources are
located downstream of the first and second arrays. The outputs of
each of the sensor arrays are processed separately and the highest
conservative count is accepted as the accurate count and is
displayed on a numeric display.
[0019] U.S. Pat. No. 5,317,645 to Prozek et al., entitled "Method
and apparatus for the recognition and counting of discrete
objects", discloses, inter alia, an apparatus for counting discrete
objects of various sizes and shapes as they travel through the
apparatus in a disorderly flow. The apparatus includes a sensor
array which comprises a plurality of photodetectors arranged in a
linear fashion. The discrete objects are passed over the sensor
array. By utilizing the sensor array as a means for obtaining
information about the discrete objects, the apparatus samples the
sensor array at predetermined time intervals, examines the various
contours of the images produced through the sampling and based upon
predetermined criteria determines whether an image represents one
or more objects.
[0020] European Patent No. 1,083,007 to Satoru et al., entitled
"Method and apparatus for sorting granular objects with at least
two different threshold levels", discloses, inter alia, a method
and system for sorting items in different sizes, wherein granular
objects flowing in a continuous form are irradiated by light. The
resulting image element signals from a solid-state image device are
binarized by a threshold value of a predetermined luminance
brightness determined for detecting a defective portion of a
granular object of a first level, and the above image element
signals are also binarized by a threshold value of a predetermined
luminance brightness determined for detecting a defective portion
of a second level. The second level is for a tone of color heavier
than that of the first level. When a defective image element signal
is detected from the binarized image elements, an image element of
a defective granular object at the center location is specified and
the sorting signal is outputted to act on the center location of
the defective granular object corresponding to the image element at
the specified center location. A granular object having a heavily
colored portion which, even small in size, has influence to the
product value can be effectively ejected. Sorting yield is improved
by not sorting out the granular objects having a defective portion
which is small and only lightly colored thus having no influence to
the product value.
[0021] There is thus a need in the art for a dispensing apparatus
and method, which provide for dispensing a predetermined quantity
of items in each group, in an accurate, rapid and efficient
manner.
SUMMARY OF THE INVENTION
[0022] There is provided, in accordance with an embodiment, a
method for rapidly and accurately dispensing a predetermined number
of discrete items, the method comprising: operating a conveyor to
transport multiple items towards an imaging device, wherein the
items are arranged in a single layer and at least some of the items
are transported in parallel; operating the imaging device to
continuously capture images of an area immediately below an end of
the conveyor, so that items falling off the conveyor are recorded
in the images while in trajectory; processing the images in real
time, to continuously determine the number of falling items;
stopping the conveyor before the number of falling items has
reached the predetermined number, while continuing to determine the
number of falling items until items cease to fall off the conveyor
innertially; and automatically dispensing an additional amount of
items, to complete the predetermined number of items.
[0023] In some embodiments, the automatic dispensing of the
additional amount of items comprises operating a supplementary item
dispenser, to dispense exactly the number of items needed for
completing the predetermined number of items.
[0024] In some embodiments, the automatic dispensing of the
additional amount of items comprises pulsing the conveyor, wherein
the length of the pulse is determined based on an earlier
calibration stage in which a ratio of pulse length to falling items
is estimated statistically.
[0025] In some embodiments, the area immediately below the end of
the conveyor extends to an effective portion of the width of the
end of the conveyor, such that all of the items transported in
parallel and falling off the end of the conveyor in parallel are
recorded in the images.
[0026] In some embodiments, a vertical gap is provided between the
end of the conveyor and an upper edge of the area, to ensure that
an end surface of the conveyor is not recorded in the images.
[0027] In some embodiments, the processing of the images to
continuously determine the number of falling items comprises
increasing an item count by one when an item exits the area,
wherein an exit is determined when a top portion of an item appears
in an image but is missing from a consecutive image.
[0028] In some embodiments, the processing of the images to
continuously determine the number of falling items comprises
increasing an item count by one when an item enters the area,
wherein entrance is determined when a bottom portion of an item
appears in an image but is missing from an immediately preceding
image.
[0029] In some embodiments, the processing of the images to
continuously determine the number of falling items comprises:
tracking each item over consecutive images, from entering the area
until exiting the area; and increasing an item count by one upon
the exit of each tracked item, to prevent a miscount if occasional
noise appears in one or more of the images.
[0030] There is further provided, in accordance with an embodiment,
a method counting discrete items, the method comprising: providing
multiple items to be counted; operating a conveyor to transport the
items towards an imaging device, wherein the items are arranged in
a single layer and at least some of the items are transported in
parallel; operating the imaging device to continuously capture
images of an area immediately below an end of the conveyor, so that
items falling off the conveyor are recorded in the images while in
trajectory; processing the images in real time, to continuously
determine the number of falling items; and providing a total
determined number of falling items once the processing indicates
that no items have fallen for a predetermined period of time.
[0031] In some embodiments, the method further comprising
automatically stopping the conveyor once the processing indicates
that no items have fallen for a predetermined period of time.
[0032] There is further provided, in accordance with an embodiment,
an apparatus for rapidly and accurately dispensing a predetermined
number of discrete items, the apparatus comprising: a parallel
transport conveyor configured to transport multiple items, in
parallel, from a hopper to an end of the conveyor; an imaging
device configured to continuously capture images of an area
immediately below an end of the conveyor, so that items falling off
the conveyor are recorded in the images while in trajectory; a
counting device configured to process the images in real time, to
continuously determine the number of falling items; an actuator
configured to control operation of said conveyor in accordance with
actuator control commands; a computing platform configured to
receive the number of falling items from said counting device, to
generate the actuator control command to stop said conveyor before
the number of falling items has reached the predetermined number,
and to generate a dispenser control command based on the number of
items needed for completing the predetermined number of items; and
a supplementary item dispenser configured, responsive to the
dispenser control command, to dispense exactly the number of items
needed for completing the predetermined number of items.
[0033] In some embodiments, said counting device comprises an image
sensor and is configured to capture said images using a
predetermined number of pixel rows of said image sensor, the
predetermined number being lower than a total number of sensor rows
existing in said image sensor.
[0034] In some embodiments, said counting device is configured to
determine the number of falling items by analyzing a pattern of
sensor pixels affected by a falling item in consecutive samples of
the image sensor.
[0035] In some embodiments, said counting device comprises an image
sensor, and wherein the apparatus further comprises at least one
light source for providing light to be reflected by the falling
items onto the image sensor.
[0036] In some embodiments, the apparatus further comprising a lens
assembly for focusing light reflected from the falling items onto
the imaging device.
[0037] There is further provided, in accordance with an embodiment,
an item dispenser comprising: a parallel transport conveyor
configured to transport items at a rate of at least 50 items per
second; an imaging device configured to continuously capture images
of an area below an end of the conveyor, so that items falling off
the conveyor are recorded in the images while in trajectory; a
counting device configured to process the images in real time, to
continuously determine the number of falling items; an actuator
configured to control operation of said conveyor in accordance with
actuator control commands; a computing platform configured to
receive the number of falling items from said counting device, to
generate the actuator control command to stop said conveyor before
the number of falling items has reached the predetermined number,
and to generate a dispenser control command based on the number of
items needed for completing the predetermined number of items; and
a supplementary item dispenser configured, responsive to the
dispenser control command, to dispense exactly the number of items
needed for completing the predetermined number of items, at a rate
of 1-4 items per second.
[0038] There is further provided, in accordance with an embodiment,
an item dispenser comprising: a parallel transport conveyor; an
imaging device for capturing at least one image of items as they
fall off the conveyor, wherein most of the items are positioned on
substantially a same plane when captured by the imaging device; a
counting device for counting the items based on the at least one
image; and a computing platform connected to said conveyor and to
said counting device, and being configured to operate said conveyor
in a continuous mode until a desired item count of a present batch
is indicated by said counting device as nearly being reached, and
in a pulsed mode to complete at least an amount of items missing
from the desired item count, wherein the pulsed mode comprises
activation of said conveyor in at least one pulse having a length
which was pre-determined to cause a set number of items to fall off
the conveyor as a direct result of the conveyor's operation as well
as indirectly, due to inertial forces following the pulse.
BRIEF DESCRIPTION OF THE FIGURES
[0039] Exemplary embodiments are illustrated in referenced figures.
Dimensions of components and features shown in the figures are
generally chosen for convenience and clarity of presentation and
are not necessarily shown to scale. The figures are listed
below.
[0040] FIG. 1A shows a schematic illustration of a first exemplary
embodiment of a machine for dispensing items;
[0041] FIG. 1B shows a schematic illustration of a second exemplary
embodiment of a machine for dispensing items;
[0042] FIG. 2A is a flowchart of steps in a method for calibrating
a dispensing machine;
[0043] FIG. 2B is a flowchart of steps in a method for operating a
dispensing machine;
[0044] FIG. 2C is a flowchart of steps in an embodiment of a
calibration stage of an imaging mechanism used for counting falling
items;
[0045] FIG. 3A is an exemplary embodiment of the lens, sensor and
lightening equipment used for counting the items falling off a
conveyor;
[0046] FIG. 3B is an exemplary embodiment of the lens, sensor and
lightening equipment used for counting the items falling off a
sliding area;
[0047] FIG. 4A shows an exemplary snapshot of items falling off the
sliding area;
[0048] FIG. 4B is a schematic illustration of a multiplicity of
sensor lines captured during the falling of three exemplary
tablets; and
[0049] FIG. 5 shows a schematic illustration of the mode of
operation of a conveyor and a supplementary item dispenser.
DETAILED DESCRIPTION
[0050] The following description relates to rapid, accurate and
efficient dispensing of predetermined quantities of discrete items,
such as seeds, gems, medicinal tablets, pills, capsules, candies or
the like.
[0051] One technical problem addressed by the disclosed method and
apparatus relates to a situation in which it is required to
dispense substantially identical items from a container into
separate packages, each package containing the same predetermined
number of items. The dispensing has to be done at high accuracy,
such that no package contains less than the predetermined number of
elements so as to avoid customer dissatisfaction and complaints. On
the other hand, packages containing more than the predetermined
number should be rare, in order to avoid waste and financial
losses.
[0052] One technical solution is the provisioning of an apparatus
and method for dispensing a predetermined number of items.
[0053] The apparatus may include a feeder such as a hopper or a
silo which can contain a large amount of the items which are to be
dispensed. The hopper releases the items onto a conveyor activated
by an actuator, the actuator controlled by a computing platform.
The conveyor may be a conveyor belt, a vibrating conveyor, a
vibrating chute, a chute having changing inclination, or any
similar means for transporting items along a path. In some
embodiments, the items are released from the hopper in a free
manner, such that multiple items can be released simultaneously or
with minimal time difference, so that a second item begins to
release before a first item has been fully released. As a result of
the motion of the conveyor and/or its vibrations, the items become
randomly arranged on the surface of the conveyor, in a single
layer, and in a way that multiple items run in parallel (as opposed
to a single file).
[0054] The vibrations of the actuator may make the items vibrate on
the conveyor, so that each of them eventually assumes a stable
posture. For example, some items, such as medicinal tablets, may be
shaped as right circular cylinders, or a similar shape having at
least one substantially planar face. The vibrations may cause the
tablets to move such that any one of their planar sides is placed
on the conveyor, wherein usually tablets do not lean on each other,
but rather a full planar face of each tablet is placed on the
conveyor's surface. Items that do not have a planar side may assume
a relatively stable posture according to their shape, center of
gravity and the like. For example, tubular capsules with rounded
ends may lie with the tubular surface, as opposed to the head, on
the conveyor. Being symmetrical, even if a capsule rotates about
its tubular surface, it will have the same projection when viewed
from above.
[0055] As items reach the end of the conveyor, they start falling
in ballistic trajectory off the conveyor, into a container or a
track which eventually leads to a container. As the items start
falling off of the conveyor, the gaps between them tend to
increase, and items that were previously touching each other while
on the conveyor tend to separate. Accordingly, in an embodiment, an
imaging device continuously captures images of an area immediately
below the end of the conveyor ("counting area"), so that the
falling items are depicted in the images while in trajectory, when
the vast majority of items, if not all of them, are spread out and
not in contact with one another. This enables better counting of
the items during computerized analysis of the captured images.
[0056] In an alternative embodiment, the conveyor, which is
generally horizontal, ends with a sloped sliding area. The items
fall off the conveyor to the sliding area, slide across the area
and at its end fall into the container being filled or into a track
which leads to the container. The slope of the sliding area
provides for substantially the same speed function of the items
travelling along the sliding area, and thus for substantially the
same falling speed of the items at the instance they leave the
sliding area. It also provides for increased spacing between items,
and for a substantially similar trajectory once leaving the sliding
area, therefore providing a similar angle in relation to the
imaging device.
[0057] In some embodiments, excluding incidental acceleration of
the conveyor when started and deceleration when stopped, the
actuator moves the conveyor at constant characteristics, such as
speed, vibration frequency, vibration amplitude, chute inclination,
and/or the like.
[0058] The items are being counted as they fall off the conveyor
edge or off the sliding area, and once at least a predetermined
number of items have fallen into the container, the conveyor is
stopped. In some embodiments, the predetermined number is an
undershoot, i.e., smaller than the quantity of items required to be
finally dispensed, since it is taken into account that after the
conveyor has stopped, one or more items may still fall through the
counting area into the container by virtue of inertial forces. The
item(s) falling after the conveyor has stopped are counted as well,
and the total number of items in the container is determined.
[0059] In an embodiment, the system may be configured such that
even with the inertial fall, the total number of dispensed items is
in almost all cases still smaller than the final required number.
In these cases, the control system re-activates the conveyor in one
or more pulses, as necessary, so that additional items fall off and
complete the final number.
[0060] A pulse relates to a short activation, in which the conveyor
operates at its steady speed (or other characteristic) for a short
time period. Some pulses may be even so short, that the conveyor
does not even manage to reach its previous, steady speed.
Typically, a pulse may last a fraction of a second, and causes a
few items, such as, for example, 1-10 items, to fall off the
conveyor or the sliding area.
[0061] The accumulated number of dispensed items is determined
after each pulse, so as to determine whether additional pulses are
required. Once the number of dispensed items has been reached (or
exceeded) the number of required items, the container is removed,
and a new container is placed and filled in the same manner.
[0062] As an alternative to the pulse, an additional device,
referred to as a supplementary item dispenser, may be used to
complete the items still missing from the final number. The
supplementary item dispenser may include a mechanism that holds
multiple items in storage and mechanically pushes them out
discretely, one by one. This mechanism may be relatively slow,
especially when the number of missing items is, for example, 5 or
more. This slowness may, theoretically, render the entire process
inefficient, since the very fast dispensing by the conveyor seems
useless if a slow additional step is needed every time. By way of
example, the conveyor may dispense at a rate of at least
approximately 50 items per second (or, in another embodiment, at
least approximately 90 items per second), while the supplementary
item dispenser will only be able to dispense 1-4 items per
second--as experimentally verified by the inventors.
[0063] Therefore, in an embodiment, the dispensing by the conveyor
and the dispensing by the supplementary item dispenser may be
performed at least partially simultaneously, thereby mitigating or
eliminating the slowness problem. In this embodiment, two container
stations are provided: a first station below the end of the
conveyor, for receiving the falling items, and a second station at
the supplementary item dispenser, for receiving the
discretely-dispensed items. This way, while the supplementary item
dispenser completes the missing items in a container already filled
by the conveyor, other items are being dispensed into a second
container at the first station, by the conveyor. When the second
container is filled with the undershoot amount of items, it moves
to the second station for completion, and so on and so forth.
[0064] As long as the time to fill at the second station does not
exceed the time to fill at the first station, the supplementary
item dispenser will not cause any delays. If the time at the second
station is somewhat longer than at the first station, the whole
process may still be regarded as beneficial, since the majority of
the time at the second station is, still, not a waste.
[0065] The method and apparatus may require calibration for each
type of dispensing task. The calibration may depend on the
characteristics of the dispensed items, for example size, shape,
weight, friction coefficient against the conveyor or against the
sliding area, and/or the like. The calibration also depends on the
operation parameters of the apparatus, such as minimal or maximal
speed, acceleration and deceleration speed, physical dimensions
and/or the like.
[0066] Calibration comprises determining one or more parameters
related to the activation of the apparatus, such as the rate at
which the items are dispensed from the hopper onto the conveyor,
the initial length of time for which the control system activates
the conveyor so as to dispense most of the required quantity, and
the duration of pulse required to complete dispensing of the
predetermined quantity.
[0067] If a sliding area is used, the length or slope of the
sliding area may be determined as well.
[0068] In some embodiments, the length of the pulse may depend on
the number of items still missing in a container. For example, if
one or two items are missing, the apparatus may be calibrated to
activate the conveyor for one 100 millisecond pulse. However, if 20
items are missing, the pulse length may be determined to be 500
milliseconds, after which a few items may still be missing, thus
requiring another pulse. Naturally, these exemplary values may
change depending on the type of dispensed items and/or the
operation parameters of the apparatus.
[0069] In some embodiments, in which the conveyor may assume
different characteristics for each dispensing type (such as speed,
slope if relevant, vibration rate, vibration amplitude, and/or the
like), these characteristics may also be determined during the
calibration stage.
[0070] In addition to a calibration step which is performed prior
to a new type of dispensing task, calibration may also be performed
on the fly, while a dispensing task is being executed. After a
group of items has finished to dispense, the operating parameters
which characterized this group may be used to adjust the parameters
for the next group. For example, if the initial calibration had
determined that the conveyor should stop 5 items before the final
count is reached, but during the task it appears that an overshoot
of the final count occurs too often, then the later, on the fly
calibration may set the apparatus to stop the conveyor 6 items
before the final count. Similarly, other parameters may be adjusted
should any deviation from the desired result is detected at some
point. This way, especially during long dispensing tasks having a
large number of groups to dispense, there is constant control over
the dispensing, such that any deviation from the initial
calibration is prevented or at least mitigated.
[0071] The counting device employed for determining the number of
items that have fallen into the container may be implemented in a
variety of ways. In some exemplary embodiments, a method and an
arrangement may use an image sensor comprised of rows and columns
of pixels.
[0072] The sensor may be located such that the sensor rows are
oriented substantially horizontally, and the sensor columns are
inclined at a certain angle in relation to the trajectory of the
items at the counting area, for example perpendicular to the
trajectory, between 45.degree. and 90.degree., or between
90.degree. and 135.degree.. The sensor may be positioned either
above the trajectory of falling items or below the trajectory,
namely--below the conveyor (or the sliding area, if it exists).
[0073] The sensor may be controlled by a control and processing
unit associated with a computing platform. The sensor may be a
complementary metal-oxide-semiconductor (CMOS) sensor, a
charge-coupled device (CCD) sensor or any other sensor. In usual
embodiments, a lens is located between the sensor and the falling
area of the items, and one or more optional light sources such as
white Light Emitting Diodes (LEDs) may shed light on the falling
items. The LEDs may illuminate the falling area at an angle such
that only minimal light is reflected from objects other than the
falling items, and the lens focuses the light reflected from the
falling items onto the sensor. Alternatively, the LEDs may be
positioned below the trajectory, such that the sensor picks up the
shadows of the falling items.
[0074] Optionally, only a predetermined group of sensor rows, out
of the total rows of the sensor, is sampled, for example 1-20 rows,
such that collecting the values of the sensor rows may be described
as imaging the falling items through a relatively narrow planar
slit. In an alternative embodiment, the whole sensor may comprise
only a small number of pixel rows, for example 1-20 rows.
[0075] Since the falling speed of the items is substantially
uniform due to the conveyor speed or the sliding area, the sampling
rate of the sensor may be set such that light reflected from an
item falling at an average speed will be captured by at least a
predetermined number of consecutive sensor samples. The number of
pixels affected by the item on the sensor may depend on the shape
of the falling item. For example, a tablet shaped as a right
circular cylinder is likely to fall such that its planar faces
appear substantially as a circle. Thus, the sensor rows in which
the item is seen may produce a pattern in which the first and last
sensor samples in which the item is captured may contain less
affected pixels than intermediate samples.
[0076] Due to the known pattern of pixels in the sensor samples
affected by each tablet when it falls, and since usually items fall
separately since they do not lean on each other, two or more
adjacent falling items which are captured by a single sensor
samples can be distinguished using previous or consecutively
captured samples.
[0077] One technical effect of the disclosed subject matter is
providing a method and apparatus for dispensing a predetermined
number of items into a container, with high accuracy so that in
almost 100% of the cases, the package contains exactly the required
number, and the task is performed at a high efficiency so that the
available resources are utilized well.
[0078] Reference is now made to FIG. 1A, which shows a schematic
illustration of an apparatus for providing for dispensing a
predetermined number of items at high accuracy and high
efficiency.
[0079] The apparatus comprises a machine 100 communicating with and
receiving control commands from a computing platform 104. Machine
100 comprises an imaging (or "capturing") device 135 and a counting
device 136 which provides information to control and processing
unit 144. Computing platform 104 provides control commands to
machine 100.
[0080] Machine 100 comprises a reservoir, such as a hopper or silo
112, which contains a multiplicity of items 116 to be dispensed
into containers. Each container, such as container 132, is to
contain, finally, a predetermined number of items 116.
[0081] Hopper 112, shown here as one example of a reservoir, may
comprise a gate at its lower opening 114. Raising or lowering the
gate limits the number of items 116 being dispensed from hopper 112
onto conveyor 120. In some embodiments, lower opening 114 is wide
enough to allow multiple items 116 to be dispensed onto conveyor
120 in parallel. Handling multiple items concurrently provides for
fast dispensing and high yield of the method and apparatus.
However, those of skill in the art will recognize that items may be
dispensed onto conveyor 120 using other means known in the art.
[0082] Conveyor 120 may be a conveyor belt, a vibrating chute, a
chute having variable inclination angle or the like. Optionally,
conveyor 120 is of a form (hereinafter "parallel transport
conveyor") which enables transporting multiple items at least
partially in parallel, in a direction orthogonal to the transport
direction. Conveyor 120 is of such a width that multiple items fit
on its top surface in parallel.
[0083] Conveyor 120 is controlled by actuator 124, which receives
commands from computing platform 104. Actuator 124 may operate by
electrical current, hydraulic fluid pressure, pneumatic pressure or
any other energy source, and converts the energy into some kind of
motion applied to conveyor 120.
[0084] The functionality of actuator 124 depends on the nature of
conveyor 120. For example, if conveyor 120 is a conveyor belt, then
actuator 124 drives or stops the belt; if conveyor 120 is a
vibratory chute then actuator 124 starts or stops a vibration
engine; if conveyor 120 is a variable inclination chute then
actuator 124 lowers or raises one side of the chute, or the
like.
[0085] In some embodiments, actuator 124 causes vibrations in
conveyor 120, which cause the items on conveyor 120 to assume a
certain position. For example, if the dispensed items are
cylinder-shaped medicinal tablets, the vibrations may cause them to
assume a position on conveyor 120 such that one of their planar
sides rests on conveyor 120, and generally no item leans partially
or fully on another item. However, the items may occasionally touch
each other.
[0086] Items 116 proceed along or with conveyor 120 when operated,
until the conveyor's end 128.
[0087] From conveyor end 128, the items fall and reach container
132, either directly, as shown, or through a track (not shown) that
leads to the container.
[0088] In some embodiments, the speed of actuation of conveyor 120
and therefore the speed of the items placed thereon, can be for
example between about 2 cm per second and 20 cm per second, e.g., 6
cm per second.
[0089] The falling items are imaged by capture device 135 as they
travel along a virtual "counting area" 129 extending from conveyor
end 128 or slightly below it to a certain distance below, forming a
virtual convex rectangle which faces the capture device. The images
may then be analyzed by counting device 136. Counting device 136
may receive control commands, such as a command to sample a sensor
within capture device 135, from control and processing unit 164.
Control and processing unit 164 may be a part of, or otherwise
associated with computing platform 104 detailed below. Counting
device 136 may provide the imaged data to control and processing
unit 164 for counting. Control and processing unit 164 may transfer
the raw data or the counting results or intermediate results to
computing platform 104.
[0090] In some embodiments, control and processing unit 164 may be
implemented as part of computing platform 104, for example as an
application executed by computing platform 104. However, in other
embodiments, control and processing unit 164 may be implemented
separately from computing platform 104, or as a part of counting
device 136.
[0091] Counting device 136 and the operation of control and
processing unit 164 is further detailed in association with FIG. 3
and FIGS. 4A-4C below.
[0092] Computing platform 104 may comprises a processor 144.
Processor 144 may be any Central Processing Unit (CPU), a
microprocessor, an electronic circuit, an Integrated Circuit (IC)
or the like. Alternatively, computing platform can be implemented
as hardware or configurable hardware such as field programmable
gate array (FPGA) or application specific integrated circuit
(ASIC). In yet other alternatives, processor 144 can be implemented
as firmware written for or ported to a specific processor such as
digital signal processor (DSP) or microcontrollers. Processor 144
may be used for performing mathematical, logical or any other
instructions required by computing platform 104 or any of it
subcomponents.
[0093] In some embodiments, computing platform 104 may comprise an
MMI (man-machine interface) module 148. MMI module 148 may be
utilized for receiving input or providing output to and from
machine 100, counting device 140, or a user, for example receiving
specific user commands or parameters related to calibrating and
operating the apparatus, storing and retrieving information,
providing output for analyzing performance of the apparatus, or the
like.
[0094] In some exemplary embodiments, computing platform 104 may
comprise one or more storage devices such as storage device 152.
Storage device 152 may be non-transitory (non-volatile) or
transitory (volatile). For example, storage device 152 can be a
Flash disk, a Random Access Memory (RAM), a memory chip, an optical
storage device such as a CD, a DVD, or a laser disk; a magnetic
storage device such as a tape, a hard disk, storage area network
(SAN), a network attached storage (NAS), or others; a semiconductor
storage device such as Flash device, memory stick, or the like. In
some exemplary embodiments, storage device 152 may retain program
code of control component 160 detailed below operative to cause
processor 144 to perform acts associated with any of the steps of
FIG. 2 detailed below, displaying information to the user, or the
like. Storage device 152 may also retain information such as
calibration results to be used when operating the machine for a
particular type of dispensing task, number of finished containers,
the number of items in each container, or the like.
[0095] Computing platform 144 may further comprise or be associated
with one or more Input/Output (I/O) devices 156 communicating with
MMI module 148, such as a terminal, a display, a keyboard, an input
device or the like, to interact with the system, to provide
instructions for calibrating the machine or the like.
[0096] Computing platform 144 may also execute control component
160 for determining and generating control commands to be provided
to actuator 124, optionally during calibration, and optionally
during operation, for example in accordance with counts received
from counting device 136.
[0097] Control component 160 can be implemented as one or more sets
of interrelated computer program instructions, which may be
developed using any programming language and under any development
environment. The computer program instructions may be stored on
storage 152 and provided to processor 144 or any other programmable
processing apparatus to produce a machine, such that the
instructions, which execute via the processor, create means for
implementing the functions specified in the flowcharts or block
diagrams.
[0098] The computer program instructions may also be stored on a
computer-readable non-transitory medium to produce an article of
manufacture. The steps performed by control component 160 are
further detailed in association with FIG. 2 below.
[0099] It will be appreciated that computing platform 144 can be
provided remotely from machine 100, as part of machine 100, or in
any combination thereof
[0100] Reference is now made to FIG. 1B, which shows a schematic
illustration of another embodiment of an apparatus for providing
for dispensing predetermined number of items at high accuracy and
high efficiency.
[0101] As in FIG. 1A, the apparatus comprises machine 100, hopper
or silo 112 with a gate at its lower opening 114, conveyor 120,
actuator 124, computing platform 104, capture device 135, counting
device 136, and container 132.
[0102] Items 116 are released onto conveyor 120, and proceed along
or with conveyor 120 when operated, until the conveyor's end
128.
[0103] From conveyor end 128, the items fall onto and along slope
134. It will be appreciated that slope 134, in some embodiments,
may be made of a rough material so that the items do not accelerate
along slope 134, but their speed is maintained due to the friction.
However, the friction coefficient between slope 134 and the items
is such that the friction does not hold the items from sliding, and
does not cause the items to roll, thus keeping unchanged the side
of the item that touches slope 134.
[0104] Slope 134 causes the items to assume a substantially uniform
speed as they fall off end 138 of slope 134, as well as continue
their free fall at a similar trajectory, such that their angle in
relation to capture device 135 is similar.
[0105] In some embodiments, the speed of conveyor 120 and therefore
the speed of the items placed thereon, can be for example between
about 2 cm per second and 20 cm per second, e.g., 6 cm per second.
The speed of the items sliding along slope 134 may increase
relatively to the speed of conveyor 120 and may get to between
about 20 cm per second and about 2 meters per second, depending on
the material of slope 134 and its angle.
[0106] At end 138 of slope 134, the items fall and reach container
132. Capture device 135 is positioned and set so as to capture the
items as they fall off end 138 of slope 134, unlike the setting of
FIG. 1A at which the items are captured as they travel along a
virtual "counting area" 139 extending from end 138 of slope 134 or
slightly below it to a certain distance below, forming a virtual
convex rectangle which faces the capture device. The images are
analyzed and machine 100 is controlled and activated in
substantially the same manner as in the embodiment of FIG. 1A.
[0107] Referring now to FIGS. 2A and 2B, showing a flowchart of
steps in methods for calibrating and operating a dispensing
machine, such as the one shown in FIG. 1, to provide high accuracy
and high efficiency dispensing of items, thus yielding high
throughput.
[0108] FIG. 2A shows a flowchart of steps in an embodiment of a
calibrating stage 200 of a dispending machine. Calibrating stage
200 may be performed upon the manufacturing of the apparatus, so
that the apparatus may be provided out of the factory with preset
calibrations for various types of items and/or other parameters.
Additionally or alternatively, calibrating stage 200 may be
performed by the end-user before each type of a dispensing job. The
user may also save these calibrations for later use.
[0109] On step 208, the conveyor is activated for a first time
interval. In some embodiments, the first time interval is long
enough so as to reach a substantially uniform rate of falling
items, after the initial, incidental acceleration period (which
typically lasts a fraction of a second) of the conveyor has been
completed.
[0110] On step 212, the number of items that have fallen into the
container is determined. The fallen items include also the items
that have fallen due to inertial forces after the conveyor has
stopped. A register may be made of the number of items that have
fallen innertially. It will be appreciated that step 212 can be
performed at least partially concurrently with step 208, since
items may be counted as they fall, and/or after the conveyor has
stopped.
[0111] On step 216, a first function is determined, which relates
to the throughput of the system during continuous activation, and
associates a number of items falling during and due to the
operation of the conveyor with the time period for which it is
required to operate the conveyor. The first function may be
referred to as a continuous throughput function, and described
analytically as a look-up table, as a part-wise function or in any
other manner. Optionally, the first function is divided into two
parts: The first part indicates a linear correlation between the
conveyor's operation time and the number of items falling during
that time. The second part, on the other hand, is indicative of the
number of items which are expected to fall, due to inertial forces,
after the conveyor had stopped. Naturally, the number of items
falling innertially is not dependent on the conveyor's operation
time, but rather on its operational characteristics such as speed,
frequency of vibration, amplitude of vibration, inclination and/or
the like. By way of example, if the conveyor is operated with a
certain set of operational characteristics for a period of X
seconds, the number of falling items would be f(x)+c, wherein f(x)
denotes the number of items falling during exactly the X seconds,
and c denotes the number of items falling innertially,
afterwards--which is a constant being independent of X.
[0112] Optionally, similar to the way c is defined in the first
function, any acceleration and/or deceleration periods of the
conveyor may be accounted for using another constant value,
again--since these acceleration/deceleration periods are also not
dependent on the length of X. Accordingly, the first part of the
function may be actually divided into two sub-parts, one denoting
the number of items falling (or not) during the
acceleration/deceleration periods, and the other defining the
number of items falling during X less the acceleration/deceleration
periods--namely, during the portion of X in which the conveyor
already operates with its desired operational characteristics.
[0113] On step 220, the conveyor is activated and operated for a
second time interval, referred to as a pulse time interval, which
is substantially shorter than the first time interval, typically
lasting fractions of a second but optionally, in some embodiments,
more than that. On step 224, the number of items to have fallen
during and due to said operation is determined similarly to step
212 above, including the account for inertial falls and
acceleration/deceleration periods. A pulse may relate to a short
time interval in which the conveyor operates at its steady speed
(or other characteristic) for a time period which is relatively
short.
[0114] Steps 220 and 224 may be repeated one or more times, since
the effect of the acceleration/deceleration periods on the number
of falling items when activating the conveyor for short periods of
time may be high, since the acceleration/deceleration periods are
quite long in relation to the total pulse time.
[0115] On step 228, a second function is determined, which relates
to the throughput of the system in pulse activations,
again--accounting for the constant acceleration/deceleration
periods and inertial falls. The function may be referred to as a
pulse throughput function, and may associate a number of items
falling during and due to the activation of the conveyor with the
time period for which it is required to activate the conveyor. The
function may be described analytically as a look-up table as a
part-wise function or in any other manner.
[0116] In some embodiments, the first and second functions can be
determined as a single, possibly part-wise, function.
[0117] The first and second functions may be determined upon
multiple activations rather than a single activation each. Thus,
the functions may be determined statistically while optionally
employing analytical methods.
[0118] In some embodiments, the first and second functions are
determined and later used when the conveyor operates under constant
characteristics, excluding on the acceleration and deceleration
times, such as speed, vibration frequency, vibration amplitude, or
the like.
[0119] Determining the first function, comprising steps 208, 212
and 216, and determining the second function, comprising steps 220,
224 and 228, can be performed in reverse order.
[0120] It will also be appreciated that the first and second
functions may be item- and setting-dependent, i.e., dispensing
different items may yield different functions. In addition, other
parameters of the machine may be determined, such as the conveyor
speed, frequency, the height of the hopper gate, or the like.
[0121] Reference is now made to FIG. 2B, which shows a flowchart of
steps in an embodiment of a dispensing stage 204 of a dispensing
machine.
[0122] On step 232, the conveyor is activated for a period of time
determined such that the number of items falling due to activation
approaches, but doesn't reach, the number of items it is required
to dispense in each container. The duration is determined in
accordance with the first throughput function determined on step
216 of the calibration stage. In some embodiments, the period of
time is determined such that in the majority of cases, the
container will contain less than the required number of items. The
reasoning for that is that it is generally desired to have fewer
items, which is correctable by adding items, than having too many
items dispensed.
[0123] On step 236, the number of items that have fallen into the
container is determined. The number of items also includes the
items that have fallen due to inertial forces after the conveyor
has stopped. It will be appreciated that in some embodiments the
items are counted as they fall, which happens when the conveyor is
in motion and some time afterwards.
[0124] On step 240, it is determined whether items are still
missing in the container to complete the entire quantity that has
to be dispensed.
[0125] If no items are missing, which may be a rare occasion, then
on optional step 242, the throughput functions or parameters
thereof as set on calibration steps 200, such as the values of
particular points in the throughput functions, are updated based on
the number of items that have fallen during the initial operation
and the one or more pulses. Similarly, if the number of missing
items becomes, in time, lower or higher than the number earlier set
in the calibration step or in previous groups dispensed, the values
of particular points in the throughput functions, are updated based
on the number of items that have fallen during the initial
operation and the one or more pulses. The updated parameters may be
employed when dispensing further groups of items or in later
activations. It will be appreciated that the on-the-fly update of
the calibration parameters can be performed after dispensing items
into one container, after a number of containers have been
dispensed, after a full dispensing task was completed, or the like.
Repeatedly updating the functions or parameters enhances the
accuracy and thus the throughput of the method and apparatus.
[0126] Whether the calibration parameters have been updated on the
fly or not, the container is removed, and the next container is
placed on step 244.
[0127] If items are still missing, two options are available, in
two embodiments or in a unified embodiment: In the first option, on
step 248, the required duration is determined for a pulse length,
such that the items that will fall due to the pulse will approach
or complete the required number of items. The duration is
determined in accordance with the second throughput function
determined on step 228 on the calibration stage.
[0128] In some embodiments, if the number or percentage of items
missing in the container exceeds a predetermined value, for example
more than 10% or 10 items of the items are missing, the pulse
length may be determined such that the total number of fallen items
after the pulse may still not complete the required number in many
of the cases, and another pulse may be required, which may provide
higher accuracy. Namely, if too many items are missing, then a
single, long pulse may be inaccurate and inferior to a number of
shorter pulses. If, however, the number of missing items is lower
than the threshold, then the pulse length may be determined such
that the total number of items after the pulse will equal the
required number.
[0129] In alternative embodiments, only pulses of one or more
predetermined lengths may be enabled, such that if items are
missing from the container, one of the predetermined lengths can be
selected. If only one such predetermined length is enabled, step
248 can be omitted.
[0130] Thus, on step 252 the conveyor may be activated for the
determined or predetermined pulse length.
[0131] On step 256 the number of fallen items is determined
similarly to step 236 above, and control returns to step 240.
[0132] Depending on the usage and nature of the items to be
dispensed, in some embodiments, a single activation of the conveyor
would be enough to ensure that in large enough percentage of the
cases, the number of dispensed items is within satisfactory range
from the required number. If, however, greater accuracy is
required, then one or more pulses would be required to achieve the
goal so that no over shooting occurs.
[0133] In the second option employed when items are still missing
in step 240, a supplementary item dispenser may be utilized to
dispense the missing items. Interim reference is now made to FIG.
5, which depicts this option. Firstly, a conveyor 502 is used to
rapidly dispense a relatively large number of items, for example
tens, hundreds or thousands of items in one operation. Conveyor 502
is stopped as the number of items 506 in a container 504 almost
reaches the desired final number, such that even after the inertial
fall, a few items (for example 1-10) will still be missing.
Container 504 is then transported, using automatic means, from
station A near the conveyor to station B near a supplementary item
dispenser 508. Supplementary item dispenser 508 then dispenses the
missing items 510 into container 504, typically at a much slower
rate than the throughput of conveyor 502. While supplementary item
dispenser 508 operates, conveyor 502 is operated again, to fill
another container. This process continues until the desired amount
of containers have been filled to completion.
[0134] Reference is now made to FIG. 2C, which shows a flowchart of
steps in an embodiment of a calibration stage of an imaging
mechanism used for counting falling items.
[0135] On step 260, the moving element such as the conveyor is
activated for a time interval.
[0136] On step 264, one or more items are captured of items falling
off the sliding area, by a multiplicity of images taken at a
default or a previously set imaging rate. Each image comprises one
or more pixel lines of a light sensitive sensor of the imaging
mechanism.
[0137] On step 268, the number of samples in which each falling
item is captured is determined, automatically or by an operator
examining the samples.
[0138] On step 272, which may be performed together with step 268
or separately, the number of pixels each falling item affects in
each sample is determined. For example, a cylindrical tablet having
a round cross section may affect fewer pixels on the first and last
sensor rows on which it is captured than the number of pixels it
affects on intermediate rows.
[0139] On step 276, if required, the capturing rate is adjusted, so
that the number of samples in which each falling item is captured
in, and the number of pixels it affects in each sample enables the
detection and distinction of all items with high accuracy.
[0140] For example, if the capturing rate is such that each item is
captured in at most one sample, this may not suffice and a higher
rate may be required. If, on the other hand, each captured item is
captured in more than enough samples to detect and distinguish
between falling items, a lower capturing rate may be used in order
to lower the computational complexity. In one embodiment, a typical
capturing rate may be between 25-100 frames per second. In another
embodiment, the typical capturing rate may be between 101-200
frames per second. In yet a further embodiment, the typical
capturing rate may be between 201-400 frames per second
[0141] It will be appreciated that steps 260, 264, 268, 272 and 276
may be repeated for different times relatively to the activation
pulse. For example, items that have fallen off due to inertial
forces after the moving element has stopped may have different
speed than elements that have fallen during steady activation of
the moving element. Thus, the imaging rate of the counting device
may vary in accordance with the activation state of the moving
element.
[0142] On step 280, the required capture rate, or capture rate
scheme if different activation phases require different capturing
rates, may be determined and used for capturing items during
dispensing.
[0143] It will be further appreciated that items of different
shapes may require different imaging rates. For example, for
imaging larger items which are viewed by each sensor line for
longer periods of time may be imaged using slower capturing rate,
while smaller items may require higher imaging rate.
[0144] For items having a less even shape, such as a cylinder
having an elliptical cross section or any other shape, some further
analysis may be performed, since the items may assume different
positions and appear in varying patterns and varying number of
samples, depending on their position relatively to the sensor. In
such cases, the capturing rate may be set to an average or another
combination of the imaging rates acceptable for different positions
of the items.
[0145] Reference is now made to FIG. 3A, showing an embodiment of a
capturing device as used with the embodiment of FIG. 1A above. The
capturing device captures images of items such as items 116 as they
fall off end 128 of conveyor 120. The capturing device 135
comprises sensor 300, which may be a CMOS, a CCD or any other
imaging sensor. The sensor may be implemented as a one- or
two-dimensional collection of pixel sensors, each pixel containing
a photodetector and an amplifier. If sensor 300 comprises a
two-dimensional array, the rows or columns of the pixel sensors may
or may not be aligned.
[0146] The sensor may be positioned such that its face is at an
angle of between about 45.degree. and about 135.degree., e.g.
90.degree. to a tangent to the trajectory of the falling items, at
the virtual counting area.
[0147] Sensor 300 may be located such that its central area, e.g.,
one or more central rows, are closest to end 128 of conveyor 120.
In some exemplary embodiments, the central area of sensor 300 may
be located at a distance of between about 20 cm and about 40 cm
from the central area of end 128.
[0148] Capturing device 135 may further comprise one or more light
sources such as light sources 306 and 308 which shed light
constantly or intermittently on the falling items.
[0149] In embodiments wherein light is shed intermittently, the
pulse length and frequency of the LEDs may be selected such that
enough light will be reflected from each item to activate the
sensor.
[0150] Light sources 306 and 308 are optionally positioned such
that light will not be reflected or only minimally reflected from
other objects except the items that have fallen off end 128.
[0151] Capturing device 135 may further comprise a lens 312 for
focusing the light reflected from the falling items onto sensor
300. Lens 312 is optionally a lens assembly, which may, in some
embodiments, provide also an optical zoom function.
[0152] The images sampled by sensor 300 may be transferred to image
control and processing unit 164, which may perform the counting and
report the number to computing platform 144, or transfer the raw
sensor data to be processed by computing platform 144.
[0153] Reference is now made to FIG. 3B, showing an embodiment of
capturing device 135 as used with the embodiments shown in FIG. 1B
above. As in FIG. 3A above, capturing device 135 comprises a sensor
300, light sources 306 and 308, and lens 312. However, sensor 300
is positioned such that it captures images of items as they fall
off end 138 of slope 134.
[0154] Sensor 300 may be located such that its central area, e.g.,
one or more central rows, are closest to end 138 of slope 134. In
some exemplary embodiment, the central area of sensor 300 may be
located at a distance of between about 20 cm and about 40 cm from
the central area of end 138.
[0155] Due to inertial forces, items fall off end 138 in
substantially the same posture in which they slid along slope 134.
Thus, sensor 300 may be substantially parallel to a planar face of
items falling off end 138 of slope 134, and substantially parallel
to the continuation of the plane of slope 134.
[0156] Light sources 306 and 308 may shed light constantly or
intermittently on the falling items, and may be positioned such
that light will not be reflected or only minimally reflected from
slope 134 but only from the items that have fallen off end 138,
such as item 118.
[0157] Referring now to FIG. 4A showing an illustration of multiple
items falling off end 128 of conveyor 120 in the embodiment of FIG.
1A, or off end 138 of slope 134 in the embodiment of FIG. 1B. Since
the items generally assume a stable posture on conveyor 120 and do
not lean on one another, together with their speed being
substantially uniform, only in rare cases tables are imaged as
partially or fully overlapping. Thus, when considering consequent
relatively narrow horizontal slices of FIG. 4A, each falling item
can be detected. Even if two or more items are adjacent to one
another, they can still be separated since as they tip over the
edge thee gaps between the items increase to enable counting.
[0158] Referring now to FIG. 4B, showing a consecutive sequence of
samples of a sensor line. As mentioned, one or more lines of the
sensor may be utilized. Hence, the case shown in this figure is the
most general one, which shows only a single line of pixels. Sample
420, taken at time To comprises a narrow sequence 444 of pixels
affected by a lower edge of a first item consisting of sequences
444, 448, 450, 452 and 454, while samples 422, 424, 426 and 428,
taken at times T.sub.1, T.sub.2 and T.sub.3, respectively, show
wider sequences 448, 450, and 452 of item 408, respectively, and
sample 428 taken at time T.sub.4 also shows again a narrow sequence
454 of pixels affected by item 408.
[0159] Similarly, sequences 458, 460, 462, 464 and 468 of samples
424, 426, 428, 430 and 432, respectively, taken at times T.sub.2,
T.sub.3, T.sub.4, T.sub.5 and T.sub.6 respectively, wherein the
sequences are created by the light reflected from a second item,
and sequences 470, 472, 474, 478 and 480 of samples 432, 434, 436,
438 and 440, respectively, taken at times T.sub.5, T.sub.6,
T.sub.7, T.sub.8 and T.sub.9 respectively, wherein the sequences
are created by the light reflected from a third item.
[0160] Using the known pattern of affected pixels created by a
falling item on consecutive capturing of a sensor line, the
sequence of sensor line samples taken at times T.sub.0 to T.sub.9
are analyzed, and the three items are detected and counted. For
example, distinguishing and counting the right cylindrical shapes
may be based on the lower number of affected pixels at their end
samples, and higher number at intermediate samples.
[0161] It will be appreciated that even if items may fall at
different speeds, the general pattern may still be valid although
it may slightly change. For example, if an item falls at a higher
speed, its central part may appear in fewer than three samples, or
its narrower first or last sample may be missing. Thus, in some
embodiments, the pattern may be searched for with some
flexibility.
[0162] It will also be appreciated that if two or more items seem
adjacent on the sensor, the number of items may be determined by
dividing the number of affected pixels by the maximal estimated
number of pixels affected by a single item, and rounding the result
to the higher number. Some measurements have shown that in about 1%
of the cases two items may seem adjacent, while in significantly
smaller percentage three or more items are adjacent, therefore such
division may provide satisfactory results.
[0163] Using a single sensor, and sampling a single sensor line, or
a number of sensor lines, such as 20 sensor lines, provides for
cost reduction, as well as efficient detection of the falling
items. The efficient detection can be used for increasing the
detection speed, thus enabling the counting of more items per time
unit. In other embodiments, however, two or more sensors may be
used.
[0164] The analysis of the sensor lines can be performed by control
and processing mechanism 164 of FIG. 1, or by computing platform
104.
[0165] In some further analysis, image analysis techniques may be
used for determining whether a falling item is whole or broken,
according to its various projections on the sensors. If this
feature is provided, broken items can be either ignored or removed
from the item stream so that the container will comprise at least
the required number of proper items. Alternatively, the entire
packaged unit 132 may be discarded.
EXAMPLES
[0166] The disclosure provides a method and apparatus for
dispensing items into containers and counting the number of
dispensed items, such that each container has a predetermined
number of items. The method enables high accuracy so that exactly
the required number of items is dispensed in high percentage of the
cases. The method also enables for efficient counting of the items
being dispensed into the container, so that relevant control
commands can be provided to conveyor 120 to move or stop.
[0167] In instances where the number of items dispensed is slightly
smaller than the required number of items, for example between
about one item and about ten items are missing, then the rest of
the items may be dispensed into the container using a different,
possibly slower machine, so as not to reduce the container filling
speed of the disclosed machine.
[0168] Experimental results have shown that the disclosed method
can account for a counting error which is less than one item in
fifty thousand (50,000), such that if, for example, each container
is to contain 100 items, less than one in 500 packages will have
the wrong number of items. These results, which are surprising
given the high dispensing rate of the present method and apparatus,
may be attributed, inter alia, to one or more parameters such as
the imaging device configuration, its position and direction, the
calibration stage with its two functions, the utilization of the
conveyor and/or the supplementary item dispenser, as well as other
parameters discussed above.
[0169] The experimental results have also provided for correct
counting of up to ten cylindrical tablets falling substantially
simultaneously off a conveyor having width of about 70 mm.
[0170] While the disclosure has been described with reference to
exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the disclosure. In addition, many modifications may be made to
adapt a particular situation, material, step or component to the
teachings without departing from the essential scope thereof
Therefore, it is intended that the disclosed subject matter not be
limited to the particular embodiment disclosed as the best mode
contemplated for carrying out this invention, but only by the
claims that follow.
[0171] In the description and claims of the application, each of
the words "comprise" "include" and "have", and forms thereof, are
not necessarily limited to members in a list with which the words
may be associated.
* * * * *