U.S. patent application number 13/729862 was filed with the patent office on 2013-05-23 for method for measuring three-dimension shape of target object.
This patent application is currently assigned to KOH YOUNG TECHNOLOGY INC.. The applicant listed for this patent is KOH YOUNG TECHNOLOGY INC.. Invention is credited to Se Hyun HAN, Hee Tae KIM, Min Young KIM, Seung Jun LEE, Byung Min YOO.
Application Number | 20130128280 13/729862 |
Document ID | / |
Family ID | 38282411 |
Filed Date | 2013-05-23 |
United States Patent
Application |
20130128280 |
Kind Code |
A1 |
KIM; Min Young ; et
al. |
May 23, 2013 |
METHOD FOR MEASURING THREE-DIMENSION SHAPE OF TARGET OBJECT
Abstract
A method of measuring a 3D shape, which can measure a 3D shape
of target objects on a board by searching a database for bare board
information when a measuring object is not set to a normal
inspection mode or by performing bare board teaching when the board
is supplied from a supplier having not the bare board information
is provided. The method of measuring a 3D shape includes operation
S100 of measuring a brightness of a first illumination source 41a,
operation S200 of measuring a phase-to-height conversion factor,
operation S300 of determining whether the measurement is performed
in a normal inspection mode, operation S400 of measuring a 3D shape
of a board 62 according to the normal inspection mode, operation
S500 of determining whether bare board information about the board
62 is included, operation S600 of performing bare board teaching
when the bare board information is excluded, operation S700 of
measuring the 3D shape of target objects on the board 62 when the
bare board information is included or bare board teaching
information is generated, and operation S800 of analyzing whether
the board 62 is normal or abnormal by using 3D shape information.
Therefore, the 3D shape of target objects on the board may be more
readily measured.
Inventors: |
KIM; Min Young; (Seoul,
KR) ; KIM; Hee Tae; (Yonginsi, KR) ; YOO;
Byung Min; (Ansan-si, KR) ; HAN; Se Hyun;
(Asan-si, KR) ; LEE; Seung Jun; (Seoul,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KOH YOUNG TECHNOLOGY INC.; |
Seoul |
|
KR |
|
|
Assignee: |
KOH YOUNG TECHNOLOGY INC.
Seoul
KR
|
Family ID: |
38282411 |
Appl. No.: |
13/729862 |
Filed: |
December 28, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12453321 |
May 7, 2009 |
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|
13729862 |
|
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|
11656458 |
Jan 23, 2007 |
7545512 |
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12453321 |
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Current U.S.
Class: |
356/601 |
Current CPC
Class: |
G06T 7/521 20170101;
G01B 11/28 20130101; G01B 11/2531 20130101 |
Class at
Publication: |
356/601 |
International
Class: |
G01B 11/28 20060101
G01B011/28 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 26, 2006 |
KR |
10-2006-0008479 |
Jan 26, 2006 |
KR |
10-2006-0008480 |
Claims
1. A method of measuring a three-dimensional shape, comprising:
transferring a target object having a conductive pad on which a
solder is not formed by controlling a table transfer device;
illuminating a pattern light onto the target object having the
conductive pad on which a solder is not formed; acquiring a pattern
image of the pattern light illuminated onto the target object
having the conductive pad on which a solder is not formed;
calculating height of the conductive pad by using the acquired
pattern image; transferring a target object having a conductive pad
on which a solder is formed by controlling the table transfer
device; illuminating a pattern light onto the target object having
the conductive pad on which the solder is formed; acquiring a
pattern image of the pattern light illuminated onto the target
object having the conductive pad on which the solder is formed;
calculating a height of the solder by using the acquired pattern
image; calculating a height of the solder in which the height of
the pad is excluded; and calculating a volume, a height
distribution and a center of gravity of the solder.
2. The method of claim 1, wherein calculating a height of the
solder by using the acquired pattern image comprises: calculating a
histogram by using the acquired pattern image; calculating a
reference plane by using the calculated histogram; and calculating
the height of the solder that is relative to the reference
plane.
3. The method of claim 1, wherein illuminating a pattern light onto
the target object having the conductive pad on which a solder is
not formed and illuminating a pattern light onto the target object
having the conductive pad on which the solder is formed comprises
switching off any one of a plurality of first illumination sources
and switching on a remaining first illumination source.
4. The method of claim 3, wherein calculating a height of the
solder by using the acquired pattern image comprises unifying
heights respectively measured by the first illumination
sources.
5. The method of claim 1, further comprising: illuminating a second
illumination source onto the target object and capturing an image
thereof; acquiring a particular shape from the captured image; and
searching a database for a target object information having a shape
that is substantially identical to the acquired particular
shape.
6. The method of claim 1, wherein calculating a volume, a height
distribution and a center of gravity of the solder comprises
calculating an eccentricity for judging whether the solder is
separated from the conductive pad by using the center of
gravity.
7. A method of measuring a three-dimensional shape, comprising:
illuminating a pattern light generated from an illumination source
onto a target object including a conductive pad and a solder;
acquiring a pattern image of the pattern light by a camera; and
calculating a volume, a height distribution and a center of gravity
of the solder by using the acquired pattern image.
8. The method of claim 7, wherein calculating a volume, a height
distribution and a center of gravity of the solder by using the
acquired pattern image comprises calculating an eccentricity for
judging whether the solder is separated from a center of the
conductive pad by using the center of gravity.
Description
RELATED APPLICATIONS
[0001] This application is a Continuation patent application of
co-pending application Ser. No. 11/656,458, filed on 23 Jan. 2007.
The entire disclosure of the prior application, Ser. No.
11/656,458, from which an oath or declaration is supplied, is
considered a part of the disclosure of the accompanying
Continuation application and is hereby incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] A method of measuring a 3D shape, which can measure 3D shape
of target objects on a board by searching a database for bare board
information when inspection option is set to the teaching-based
inspection mode or by performing bare board teaching when the board
from a supplier having not the bare board information is
inspected.
[0004] 2. Description of the Related Art
[0005] A method of measuring a 3D shape according to a conventional
art will be described with reference to FIG. 1.
[0006] FIG. 1 is a flowchart illustrating a method of measuring a
3D shape according to the conventional art. Referring to FIG. 1, to
measure a 3D shape of a measuring object, in operation S10, a
grating pattern illumination is emitted towards a reference surface
by emitting a light generated from an illumination source (not
shown) towards a grating device (not shown) to acquire a reference
phase corresponding to the reference surface. In operation S11, a
grating is moved by a fine pitch using a piezoelectric actuator
(not shown) and emitted towards the reference surface and a grating
pattern image is acquired using a charged coupled device (CCD)
camera and a grabber (not shown). In operation S12, when the
grating pattern image is acquired by the grabber, a bucket
algorithm is applied to the grating pattern image. In operation
S13, the reference phase with respect to the reference surface is
acquired.
[0007] In operation S15, when the reference phase corresponding to
the reference surface is acquired, a measuring object is placed on
a moving table and a light generated from the illumination source
is emitted towards a measuring surface of the measuring object to
acquire a phase of the measuring object. In operation S16, the
grating is moved by a fine interface using the piezoelectric
actuator to apply the bucket algorithm, and the grating pattern
image reflected from the measuring surface is acquired via the CCD
camera and the grabber. In operation S17, the bucket algorithm is
applied to the grating pattern image. In operation S18, an object
phase of the measuring object is acquired.
[0008] When the object phase is acquired, the object phase is
deducted from the reference phase in operation S21, and a moire
phase is acquired in operation S21. When the moire phase is
acquired, the moire phase is unwrapped in operation S22, and actual
height information of the measuring object is acquired by using a
result of unwrapping. Through the above-described operations, the
3D shape of the measuring object is acquired.
[0009] However, the conventional 3D shape measuring method has a
problem in that an operator may feel tired a lot, and a
productivity may be reduced since each of measuring conditions is
manually calculated and then measurement is performed when a
totally new measuring object, not an ongoing measuring object, is
measured.
SUMMARY OF THE INVENTION
[0010] An objective of the present invention is to provide a method
of measuring a 3D shape which can measure 3D shape of target
objects according to the normal inspection mode when a measuring
object is set to the normal inspection mode, and also can measure
the 3D shape of target objects on the board by searching a database
for bare board information when the inspection option is set to the
teaching-based inspection mode or by performing bare board teaching
when the board is inspected from a supplier having not the bare
board information, and thereby can improve a productivity of
electronic board manufacturing line.
[0011] Another objective of the present invention is to improve the
measurement quality of the 3D shape of target objects by measuring
their 3D shape with a regular brightness of an illumination source
at each illumination level, which is predefined prior to the
machine operation.
[0012] To accomplish the above objects of the present invention,
there is provided a method of measuring a 3 dimensional (3D) shape,
the method including: measuring a brightness of a first
illumination source by controlling via a central control unit a
module control unit and an image acquisition unit; measuring a
phase-to-height conversion factor by controlling via the central
control unit the module control unit and the image acquisition unit
after the brightness measuring process of the first illumination
source is completed; determining whether the measurement is
performed in a normal inspection mode after the brightness of the
first illumination source and the phase-to-height conversion factor
are measured and calculated; measuring a 3D shape of a board
according to the normal inspection mode by controlling, via the
central control unit, the module control unit and the image
acquisition unit when it is the normal inspection mode as a result
of the determination; searching a database and determining, via the
central control unit, whether bare board information about the
board is in the database when it is not the normal inspection mode
as a result of the determination; performing bare board teaching by
controlling, via the central control unit, the module control unit
and the image acquisition unit when the bare board information is
not in the database; measuring the 3D shape of the board according
to a teaching-based inspection mode by controlling, via the central
control unit, the module control unit and the image acquisition
unit when the bare board information is in the database or when
bare board teaching information is generated by performing the bare
board teaching; and analyzing via the central control unit whether
3D shape of target objects on the board is normal or abnormal by
using the measured 3D shape information of the objects according to
the normal inspection mode and the teaching-based inspection
mode.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The above and other objects, features and advantages of the
present invention will become apparent from the following
description of a preferred embodiment given in conjunction with the
accompanying drawings, in which:
[0014] FIG. 1 is a flowchart illustrating a method of measuring a
3D shape according to a conventional art;
[0015] FIG. 2 is a diagram illustrating a 3D shape measuring system
for a 3D shape measuring method according to the present
invention;
[0016] FIGS. 3A through 3C illustrate a configuration of a board, a
bare board, and a calibration target;
[0017] FIG. 4 is a flowchart illustrating a method of measuring a
3D shape according to the present invention;
[0018] FIG. 5 is a flowchart illustrating an operation of measuring
a brightness of a first illumination source shown in FIG. 4;
[0019] FIG. 6 is a flowchart illustrating an operation of measuring
a phase-to-height conversion factor shown in FIG. 4;
[0020] FIGS. 7A and 7B are flowcharts illustrating an operation of
measuring a 3D shape of a board according to a normal inspection
mode shown in FIG. 4;
[0021] FIGS. 8A and 8B are flowcharts illustrating a bare board
teaching operation shown in FIG. 4; and
[0022] FIGS. 9A and 9B are flowcharts illustrating an operation of
measuring a 3D shape of a board according to a teaching-based
inspection mode shown in FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Preferred embodiments of the present invention will be
described in detail with reference to the accompanying
drawings.
[0024] FIG. 2 is a diagram illustrating a 3D shape measuring system
for a 3D shape measuring method according to the present invention.
As shown in FIG. 2, the 3D shape measuring apparatus includes a
central control unit 10, a module control unit 20, an image
acquisition unit 30, at least one pattern projector 40, a second
illumination source 50, an X-Y table 61, a table moving device 60,
and a camera 70. Hereinafter, a configuration of each element will
be described.
[0025] A charge coupled device (CCD) camera or a complementary
metal oxide semiconductor (CMOS) camera is utilized for the camera
70. A second illumination source 50, an optical filter 71, and a
lens 72 are provided below the camera 70. A plurality of light
emitting diodes (LEDs) formed in a shape of a circle or a circular
lamp is utilized for the second illumination source 50, and the
second illumination source 50 is utilized as an illuminator to
measure particular shape of specific locations on a board 62 or a
bare board 63 which corresponds to a measuring object.
[0026] The table moving device 60 drives the X-Y table 61 which is
positioned below the camera 70 and thereby moves the board 62, the
bare board 63, or a calibration target 64 to predefined measurement
locations so that the camera 70 may take images of the board 62,
the bare board 63 or the calibration target 64.
[0027] At least one pattern projector 40 of the 3D shape measuring
system, which is indicated by a solid line and a dotted line as
shown in FIG. 2, is provided. Each of the at least one pattern
projector 40 is provided to be inclined in one side or another side
of the camera 70 which takes images of the board 62, the bare board
63 or the calibration target 64. In this instance, the pattern
projector 40 includes an illumination part 41, a grating moving
device 42, a grating device 43, and a lens 44. The illumination
part 41 includes a first illumination source 41a and a plurality of
lenses 41b and 41c. An illumination generated from the first
illumination source 41a passes through the plurality of lenses 41b
and 41c, and is emitted toward the grating device 43 and then
toward the board 62, the bare board 63 or the calibration target
64.
[0028] The image acquisition unit 30 receives the image taken by
the camera 70 and transmits the received image to the central
control unit 10. The module control unit 20 includes a table
controller 21, a grating controller 22, and an illumination
controller 23. The illumination controller 23 controls the first
illumination source 41a of the illumination part 41 or the second
illumination source 50, the grating controller 22 controls the
grating moving device 42, and the table controller 21 controls the
table moving device 60.
[0029] The central control unit 10 includes a control board 11, an
image processing board 12, and an interface board 13. The central
control unit 10 transmits/receives a control signal or control
information to the module control unit 20 and the image acquisition
unit 30 via the interface board 13, the image processing board 12
processes an image received from the image acquisition unit 30, and
the control board 11 generally controls the 3D shape measuring
apparatus of the present invention. Also, the central control unit
10 searches a database 80 for bare board information of a new board
supplier or stores the bare board information which is acquired in
a teaching-based inspection mode.
[0030] Hereinafter, a method of measuring 3D shape of target
objects on the board 62 by using the 3D shape measuring system
constructed as above will be described with reference to FIGS. 2
through 4.
[0031] FIG. 2 is a diagram illustrating a 3D shape measuring system
for a 3D shape measuring method according to the present invention,
FIGS. 3A through 3C illustrate a configuration of a board, a bare
board, and a calibration target, and FIG. 4 is a flowchart
illustrating a method of measuring a 3D shape according to the
present invention.
[0032] As shown in FIGS. 2 through 4, an initial setup operation of
the 3D shape measuring system according to the present invention is
performed before measuring the 3D shape. For the initial setup
operation, in operation S100, the central control unit 10 controls
the module control unit 20 and the image acquisition unit 30 to
measure a brightness of the first illumination source 41a. In
operation S200, when the brightness of the first illumination
source 41a is completely measured, the central control unit 10
controls the module control unit 20 and the image acquisition unit
30 to measure a phase-to-height conversion factor. Through
operations S100 and S200, the initial setup operation of the 3D
shape measuring system is completed.
[0033] In operation S300, after the brightness of the first
illumination source 41a and the phase-to-height conversion factor
are measured for the initial setup operation of the 3D shape
measuring system, the central control unit 10 determines whether
the measurement is performed in a normal inspection mode. When an
operator selects a normal inspection mode or a teaching-based
inspection mode, by using input information via an input device,
such as a keyboard (not shown), or by using an job program
pre-installed in the 3D shape measuring system, the central control
unit 10 recognizes and determines the selected mode.
[0034] In operation S400, when the central control unit 10
determines it is the normal inspection mode in operation S300, the
central control unit 10 controls the module control unit 20 and the
image acquisition unit 30 to measure the 3D shape of target objects
on the board 62 according to the normal inspection mode.
Conversely, when the central control unit 10 determines it is not
the normal inspection mode in operation S300, the central control
unit performs operation S500 of searching the database 80 for bare
board information of the board 62.
[0035] In operation S510 of operation S500, the table controller 21
of driving the table moving device 60 controls the X-Y table 61 to
move the board 62 to a measurement location. In operation S520,
when the board 62 is moved to the measurement location, the central
control unit 10 controls the illumination controller 23 to switch
on the second illumination source 50. In operation S530, when the
second illumination source 50 is switched on and thereby the camera
70 takes a picture of the board 62 and the image acquisition unit
acquires an image, the central control unit 10 calculates location
information about a particular part of the board 62. In this
instance, the particular part of the board 62 or the bare board 63
indicates a mark (not shown) which can be distinguishable for each
manufacturer or each product adopting the board 62 or the bare
board 63. In operation S540, when the location information about
the particular part of the board 62 is calculated, the central
control unit 10 searches the database 80 for bare board information
which is identical to the image information of the particular part.
In operation S550, it is determined whether the database 80
contains the bare board information about the board 62 to be
currently measured.
[0036] In operation 600, when the database 80 excludes the bare
board information in operation S500, the central control unit 10
controls the module control unit 20 and the image acquisition unit
30 to perform a bare board teaching.
[0037] In operation 700, when the database 80 includes the bare
board information in operation S500 or bare board teaching
information is generated in operation S600, the central control
unit 10 controls the module control unit 20 and the image
acquisition unit 30 to measure the 3D shape of target objects on
the board 62. When the 3D shape of the board 62 is measured in each
of operations S400 and S700, the central control unit 10 analyzes
whether the board 62 is normal or abnormal by using information
about the measured 3D shape in operation S800 and thereby badness
of a solder 62e, which is formed on the board 62 after measuring
the 3D shape of the board 62, is determined. As described above,
since the 3D shape of target objects on the board 62 is measured
according to the normal inspection mode or the teaching-based
inspection mode, the 3D shape of target objects on the board may be
more readily and efficiently acquired.
[0038] Hereinafter, operations S100, S200, S400, S600, and S700 in
a method of measuring a 3D shape according to the present invention
will be sequentially described in detail
[0039] As shown in FIGS. 2 through 5, in operation S110 of
operation S100, the central control unit 10 sets a range of an
illumination adjustment command value and then a brightness of the
first illumination source 41a is adjusted by the illumination
controller 23 of the module control unit 20 according to the set
adjustment command value.
[0040] The calibration target 64 is utilized to adjust the
brightness of the first illumination source 41a. As shown in FIG.
3C, the calibration target 64 includes a plane surface 64a and a
stepped difference 64b, and is formed in a gray color. Also, the
calibration target 64 is applied when measuring the brightness of
the first illumination source 41a or calculating the
phase-to-height conversion factor in the initial setup operation
for measuring the 3D shape. In operation S111, to measure the
brightness of the first illumination source 41a using the
calibration target 64, the table controller 21 of the module
control unit to drive the table moving device 60 drives the X-Y
table 61 and the calibration target 64 is moved to a measurement
location. In this instance, the measurement location indicates a
location where the camera 70 may take an image of the calibration
target 64.
[0041] In operation S112, when the calibration target 64 is moved
to the measurement location, the first illumination source 41a is
switched on by the illumination controller 23 of the module control
unit 20. In operation S113, when the first illumination source 41a
is switched on, the central control unit 10 sets the ranges of the
illumination adjustment command value. In this instance, when a
user inputs information about the adjustment command value using an
input device, such as a keyboard (not shown), and the like, the
central control unit 10 recognizes the input information and sets
the range of the adjustment command value. In operation S114, when
the range of the illumination adjustment command value is set, the
central control unit 10 controls the illumination controller 23 to
adjust the brightness of the first illumination source 41a
according to the set adjustment command value.
[0042] In operation S120, when the brightness of the first
illumination source 41a is adjusted, the grating controller 22 of
the module control unit 20 to drive the grating moving device 42
moves the grating device 43 an N number of times and the camera 70
takes an image of the calibration target 64 for each movement and
the image acquisition unit 30 acquires the image of the calibration
target 64. In operation S130, when the image acquisition unit 30
acquires N images of the calibration target 64, the acquired image
is received via the image processing board 12 and the interface
board 13 of the central control unit 10 and average-process of the
received images is performed, and an average image is calculated.
In this instance, the average image process acquires an average
image where a grating pattern is eliminated from the N number of
images taken by the camera 70 every time the grating device 43 is
moved the N number of times to acquire the image of the calibration
target 64. In the present invention, the image of the calibration
target 64 is acquired by moving the grating device 43 at least four
times and the average image process is performed.
[0043] In operation S140, when the average image of the calibration
target 64 is calculated, the central control unit 10 sets a
representative brightness value of the calculated average image to
an illumination brightness of a corresponding illumination
adjustment command value. In operation S150, when the illumination
brightness is set, the central control unit 10 determines whether
the adjustment command value is maximum. When the illumination
adjustment command value is maximum within the set range of the
adjustment command value, the central control unit 10 determines
the brightness adjustment of the first illumination source 41a is
completed.
[0044] In operation S160, when the illumination adjustment command
value is maximum, the central control unit 10 defines the
illumination brightness corresponding to each adjustment command
value. In operation S170, when the illumination brightness
corresponding to each adjustment command value is defined, the
central control unit 10 generates the illumination brightness
corresponding to each adjustment command value into an illumination
index table. In this instance, the illumination index table defines
the illumination brightness according to each adjustment command
value. Therefore, when measuring the 3D shape of the board 62 or
the bare board 63 by using the first illumination source 41a, the
illumination brightness may be linearly adjusted by using the
brightness index table, and thus the measurement quality of a 3D
shape may be improved.
[0045] When a plurality of first illuminations sources 41a is
provided as indicated by a solid line and a dotted line as shown in
FIG. 2, in operation S161 of operation S160, the central control
unit 10 determines whether the plurality of first illumination
sources 41a is provided. In operation S162, when the plurality of
first illumination sources 41a is provided, any one of the
plurality of first illumination sources 41a is switched off and any
one of remaining first illumination sources 41a is switched on.
Specifically, when any one of the plurality of first illumination
sources 41a indicates the first illumination source 41a indicated
by the solid line in FIG. 2, the remaining first illumination
source 41a is indicated by the dotted line in FIG. 2.
[0046] In operation S163, when the remaining first illumination
source 41a is switched on, the central control unit 10 determines
whether the adjustment command value of the remaining first
illumination source 41a is maximum. In operation S164, when the
adjustment command value of the remaining first illumination source
41a is maxim, the central control unit 10 compares the illumination
brightness values corresponding to each of the adjustment command
value of any one of the plurality of first illumination sources 41a
and the adjustment command value of the remaining first
illumination source 41a, and selects a smaller illumination
brightness value between them as the brightness of the total
illumination system according to each adjustment command value. In
operation S165, when the illumination brightness of the total
illumination system corresponding to each adjustment command value
is determined, the central control unit 10 calculates new
adjustment command value of each first illumination corresponding
to the selected illumination brightness of the total illumination
system, and then redefines the illumination adjustment command
values of the plurality of first illumination sources 41a
corresponding to the selected illumination brightness of the total
illumination system. Through the above-described operations, the
illumination brightness defined for each adjustment command value
is generated into the illumination index table.
[0047] In operation S200, when the brightness measurement of the
first illumination source 41a is completed, the central control
unit 10 controls the module control unit 20 and the image
acquisition unit 30 to measure the phase-to-height conversion
factor. As shown in FIGS. 2 through 4 and FIG. 6, operation S210 of
controlling, by the central control unit 10, the illumination
controller 23 of the module control unit 20 to adjust the
brightness of the first illumination source 41a according to the
selected adjustment command value of the total illumination system
is performed.
[0048] More specifically, to adjust the brightness of the first
illumination source, in operation S211, the table controller 21 of
driving the table moving device drives the X-Y table 61 and thus
the calibration target 64 is moved to the measurement location. In
operation S212, when the calibration target 64 is moved to the
measurement location, the first illumination source 41a is switched
on by the illumination controller 23. In operation S213, when the
first illumination source 41a is switched on, the central control
unit 10 selects an adjustment command value. In operation S214,
when the adjustment command value is selected, the central control
unit 10 controls the illumination controller 23 to adjust the
brightness of the first illumination source 41a to the illumination
brightness corresponding to the selected adjustment command
value.
[0049] In operation S220, when the first illumination source is
adjusted, the central control unit 10 determines whether a
measurement portion of the calibration target 64 corresponds to a
plane surface 64a. Whether the measurement portion of the
calibration target 64 corresponds to the plane surface 64a is
determined by the central control unit 10 by using the image, taken
by the camera 70, in a state where the second illumination source
50 is switched on. When the measurement portion of the calibration
target 64 does not correspond to the plane surface 64a, the central
control unit 10 drives the table moving device 60 to move the plane
surface 64a of the calibration target 64 to a focus location of the
camera 70 or the plane surface 64a is manually moved by the
operator.
[0050] In operation S230, when the measurement portion of the
calibration target 64 corresponds to the plane surface 64a, the
central control unit 10 sets the plane surface 64a of the
calibration target 64 as an inspection area. In operation S240,
when the plane surface 64a of the calibration target 64 is set as
the inspection area, the grating controller 22 of driving the
grating moving device 42 moves the grating device 43 the N number
of times, emits a grating pattern illumination towards the plane
surface 64a for each movement and takes an image of the calibration
target via the camera 70, which is reflected from the plane surface
64a. The image acquisition unit 30 acquires the taken images of the
plane surface 64a. In operation S250, when the image acquisition
unit 30 acquires the images of the plane surface 64a, the central
control unit 10 acquires a phase map of the plane surface 64a by
using an N-bucket algorithm and the acquired images, and also
stores the phase map of a first reference surface m. Information,
such as the phase map of the first reference surface m, is stored
in a storage device (not shown), such as a hard disk that connects
with the control board 11 of the central control unit 10, and the
like.
[0051] When the phase map of the first reference surface m of the
plane surface 64a is stored, operation S220 is re-performed. In
operation S260, when the measurement portion does not correspond to
the plane surface 64a, the central control unit 10 sets a stepped
difference 64b of the calibration target 64 as the inspection area.
In operation S270, when the stepped difference 64b is set as the
inspection area, the grating controller 22 of driving the grating
moving device 42 moves the grating device 43 the N number of times,
emits a grating pattern illumination towards the stepped difference
64b for each movement and takes an image of the calibration target
64 via the camera 70, which is reflected from the stepped
difference 64b. The image acquisition unit 30 acquires the taken
images of the stepped difference 64b. In operation S280, when the
image acquisition unit 30 acquires the images of the stepped
difference 64b, the central control unit 10 acquires a phase map of
the stepped difference 64b by using an N-bucket algorithm and the
acquired images.
[0052] In operation S290, when the phase map of each of the plane
surface 64a and the stepped difference 64b are acquired in each of
operations S250 and S280, the phase-to-height conversion factor of
each pixel is calculated and stored by using the acquired phase
maps. In this instance, the phase-to-height conversion factor is
required to convert a phase into a height value when calculating a
phase of each point by using the N-bucket algorithm and then
calculating the height value of a corresponding point by using the
calculated phase. To calculate the phase-to-height conversion
factor of each pixel, the central control unit 10 calculates a
relative height phase of the stepped difference 64b with respect to
the first reference surface m by using phase information about the
first reference surface m and the phase map of the stepped
difference 64b. When the relative height phase of the stepped
difference 64b is calculated, the central control unit 10
calculates the phase-to-height conversion factor by using the
relative height phase of the stepped difference 64b, pattern period
information of the stepped difference 64b, and a known height of
the stepped difference 64b of the calibration target 64.
[0053] Operation 5290 is performed with respect to each of the
plurality of first illumination sources 41a when the plurality of
first illumination sources 41a as indicated by the solid line and
the dotted line in FIG. 2 is provided. More specifically, when the
plurality of first illumination sources 41a is provided, in
operation 5291, the phase-to-height conversion factor of each pixel
is calculated by using the phase map, which is acquired according
to the grating pattern illumination generated from any one of the
first illumination sources 41a.
[0054] In operation 5292, when the phase-to-height conversion
factor of each pixel is calculated, the central control unit 10
determines whether the plurality of first illumination sources 41a
is provided. In operation 5293, when the phase-to-height conversion
factor of each pixel according to any one of the plurality of first
illumination sources 41a is calculated, the central control unit 10
controls the illumination controller 23 of the module control unit
20 to switch off any one of the plurality of first illumination
sources 41a where the phase-to-height conversion factor is
calculated, and switch on a remaining first illumination source
41a.
[0055] In operation S294, when the remaining first illumination
source 41a is switched on, the central control unit 10 determines
whether the phase-to-height conversion factor of each pixel
according to the grating pattern illumination from the remaining
first illumination source 41a is calculated. In operation S295,
when the phase-to-height conversion factor of each pixel is
calculated, the central control unit 10 stores the phase-to-height
conversion factor of each pixel according to each of the plurality
of first illumination sources 41a.
[0056] When the phase-to-height conversion factor of each pixel was
not calculated, the central control unit 10 returns to operation
S210 of controlling the illumination controller 23 of the module
control unit 20 to adjust the brightness of the first illumination
source 41a according to the selected adjustment command value.
[0057] When the illumination index table is generated and the
phase-to-height conversion factor is calculated, operation S400 of
measuring the 3D shape of target objects on the board 62 according
to the normal inspection mode is performed. More specifically, in
operation S410 of operation S400, as shown in FIGS. 2 through 4 and
FIGS. 7A and 7B, the table controller 201 of driving the table
moving device 60 drives the X-Y table 61, and the board 62 is moved
to the measurement location.
[0058] In operation S420, when the board 62 is moved to the
measurement location, the central control unit 10 controls the
illumination controller 23 to adjust the brightness of the first
illumination source 41a according to the selected adjustment
command value. In operation S430, when the brightness of the first
illumination source 41a is adjusted, the central control unit 10
controls the module control unit 20 and the image acquisition unit
30 to acquire the phase map of the board 62, and calculates the
relative height phase with respect to a first reference surface m.
In operation S440, when the relative height phase with respect to
the first reference surface m is calculated, the central control
unit 10 calculates a phase histogram by using the relative height
phase with respect to the first reference surface m, and calculates
the 3D shape of target objects on the board 62 by using the
calculated phase histogram.
[0059] In operation S442 of operation S440 in FIG. 7A, when a
single first illumination source 41a is provided, and in this
instance, the relative height phase with respect to the first
reference surface m of the board 62 according to the grating
pattern illumination generated from the first illumination source
41a is calculated, the central control unit 10 calculates a phase
histogram by using the relative height phase with respect to the
first reference surface m. In operation S443, when the phase
histogram is calculated, the central control unit 10 separates a
second reference surface n and a solder 62e from the calculated
phase histogram, and calculates a centroid of the second reference
surface n and the solder 62e.
[0060] In this instance, the method of calculating the centroid of
the second reference surface n and the solder 62e initially
separates the second reference surface n and the solder 62e by
using pre-stored dimensional information of the board 62. When the
second reference surface n is calculated, the central control unit
10 separates the solder 62e by using the calculated second
reference surface n. When the second reference surface n and the
solder 62e are separated, the central control unit 10 calculates
the centroid of the second reference surface n and the solder 62e
by using a centroid method.
[0061] In operation S444, when the centroid of the second reference
surface n and the solder 62e is calculated, the central control
unit 10 calculates a representative height of the solder 62e by
using the centroid of the second reference surface n and the
centroid of the solder 62e. In operation S445, when the
representative height of the solder 62e is calculated, the central
control unit 10 calculates a volume, a height distribution, and an
positional offset of the solder 62e by using the calculated
representative height.
[0062] Hereinafter, performing operation S440 in FIG. 7B when the
plurality of first illumination sources 41a is provided will be
described in detail.
[0063] In operation S441, when the plurality of first illumination
sources 41a is provided, and the relative height phase with respect
to the first reference surface m of the board 62 according to the
grating pattern illumination generated from any one of the
plurality of first illumination sources 41a and the relative height
phase with respect to the first reference surface m of the board 62
according to the grating pattern illumination generated from the
remaining first illumination source 41a are calculated, the central
control unit 10 calculates a combined height phase where noise is
removed from the relative height phase with respect to the first
reference surface m according to each of the plurality of first
illumination sources 41a, and stores the calculated combined height
phase.
[0064] In operation S442, when the combined height phase is stored,
the central control unit 10 calculates a phase histogram by using
the stored combined height phase, which is the same as when only
the single first illumination source 41a is provided. In operation
S443, the central control unit 10 separates the second reference
surface n and the solder 62e from the calculated phase histogram,
and calculates the centroid of the second reference surface n and
the solder 62e. Next, as described above, in operation S444, the
central control unit 10 calculates the representative height of the
solder 62e by using the centroid of the second reference surface n
and the centroid of the solder 62e. In operation S445, when the
representative height of the solder 62e is calculated, the central
control unit 10 calculates a volume, a height distribution, and an
positional offset of the solder 62e by using the calculated
representative height.
[0065] In this instance, the height distribution of the solder 62e
is calculated based on the second reference surface n, and the
volume of the solder 62e is calculated by multiplying the
phase-to-height conversion factor of each pixel and phase
information of the solder 62e, and summing up the results of the
multiplications. Also, the positional offset of the solder 62e is
calculated depending upon how far the solder 62e is located from
the center of a conductive pad 62d by using location information of
the solder 62e which is calculated by using the volume of the
solder 62e. Based on the calculated volume, height, distribution
and positional offset information of solder, the goodness and
badness of the board is determined automatically.
[0066] In operation S600, when the bare board information is
excluded in operation 5500, the central control unit 10 controls
the module control unit 20 and the image acquisition unit 30 to
perform a bare board teaching.
[0067] As shown in FIGS. 2 through 4, and FIGS. 8A and 8B, the bare
board 63 is moved to the measurement location in operation S600.
Specifically, in operation S610, the table controller 21 of driving
the table moving device 60 drives the X-Y table 61 whereby the bare
board 63 is moved to the measurement location. To distinguish the
bare board 63 from the board 62, the bare board 63 includes a base
plate 62a, a conductive pattern 62b, a solder mask 62c, and the
conductive pad 62d.
[0068] In operation S620, when the bare board 63 is moved to the
measurement location, the central control unit 10 controls the
illumination controller 23 to adjust the brightness of the first
illumination source 41a according to the selected adjustment
command value. In operation S630, when the brightness of the first
illumination source 41a is adjusted, the central control unit 10
controls the module control unit 20 and the image acquisition unit
30 to acquire the phase map of the bare board 63, and calculates
the relative height phase with respect to the first reference
surface m. In this instance, the first reference surface m
indicates the base plate 62a of the bare board 63, and is
calculated by using pre-given bare board information.
[0069] In operation S640, when the relative height phase with
respect to the first reference surface m is calculated, the central
control unit 10 stores location information and image information
about a particular part of the bare board 63, as bare board
information, in the database 80.
[0070] In this instance, operation S640 may be performed in a
different way with respect to when only a single first illumination
source 41a is provided and when a plurality of first illumination
sources 41a is provided. Initially, performing operation S640 when
the single first illumination source 41a is provided will be
described. In operation S642, when the relative height phase with
respect to the first reference surface m is calculated, the central
control unit 10 stores the relative height phase with respect to
the first reference surface m as height phase information of the
bare board 63. In operation S643, when the height phase information
is stored, the central control unit 10 determines whether teaching
with respect to all areas of the bare board 63 is completed. In
operation S644, when the teaching with respect to all areas of the
bare board 63 is completed, the central control unit 10 controls
the illumination controller 23 of the module control unit 21 to
switch off the first illumination source 41a and switch on the
second illumination source 50. In operation S645, when the second
illumination source 50 is switched on, the central control unit 10
controls the image acquisition unit 30 to acquire the image with
respect to the particular part of the bare board 63 using the
camera 70, and stores the acquired image, and also calculates
location information with respect to the particular part of the
bare board 63, and stores the calculated location information and
the image information in the database 80.
[0071] Hereinafter, performing operation S640 when the plurality of
first illumination sources 41a is provided will be described. In
this instance, in operation S641, when the relative height phase
with respect to the first reference surface m of the bare board 63
according to any one of the plurality of first illumination sources
41a and the relative height phase with respect to the first
reference surface m of the bare board 63 according to a remaining
first illumination sources 41a are calculated, the central control
unit 10 calculates the combined height phase where noise is removed
from the relative height phase with respect to each first reference
surface m. Operations after calculating the combined height phase
are identical when only the single first illumination source 41a is
provided. In operation S642, when the combined height phase is
calculated, the central control unit 10 stores the calculated
combined height phase as height phase information.
[0072] In operation S643, when the height phase information is
stored, the central control unit 10 determines whether teaching
with respect to all areas of the bare board 63 is completed. In
operation S644, when the teaching with respect to all areas of the
bare board 63 is completed, the central control unit 10 controls
the illumination controller 23 of the module control unit 21 to
switch off the plurality of first illumination sources 41a and
switch on the second illumination source 50. In this instance, all
of the plurality of first illumination sources 41a is switched off.
Also, in operation S645, when the second illumination source 50 is
switched on, the central control unit 10 controls the image
acquisition unit 30 to acquire the image with respect to the
particular part of the bare board 63 using the camera 70, and
stores the acquired image, and also calculates location information
with respect to the particular part of the bare board 63, and
stores the calculated location information in the database 80.
[0073] Hereinafter, operation 5700 of measuring the 3D shape of
target objects on the board 62 according to a teaching-based
inspection mode when the bare board information is included in
operation S500 will be described with reference to FIGS. 2 through
4, and FIGS. 9A and 9B.
[0074] In operation S710 of operation S700, bare board information
corresponding to the board 62 is read from the database 80. In
operation S720, when the bare board information of the board 62 is
read, the central control unit 10 controls the illumination
controller 23 of the module control unit to switch off the second
illumination source 50 when the second illumination source 50 is
switched on. In operation S730, when the second illumination source
50 is switched off, the table controller 21 of driving the table
moving device 60 drives the X-Y table 61 whereby the board 62 is
moved to the measurement location.
[0075] In operation S740, when the board 62 is moved to the
measurement location, the central control unit 10 controls the
illumination controller 23 to adjust the brightness of the first
illumination source 41a according to the selected adjustment
command value. In operation S750, when the brightness of the first
illumination source 41a is adjusted, the central control unit 10
controls the module control unit 20 and the image acquisition unit
30 to acquire the phase map of the board 62 and calculates the
relative height phase with respect to the first reference surface
m. In operation 5760, when the relative height phase with respect
to the first reference surface m is calculated, the central control
unit 10 calculates the phase histogram by using the relative height
phase with respect to the first reference surface m, and calculates
the 3D shape of the board 62.
[0076] In this instance, operation S760 may be performed in a
different way with respect to when only a single first illumination
source 41a is provided and when a plurality of first illumination
sources 41 is provided.
[0077] Initially, performing operation S760 when only the single
first illumination source 41a is provided will be described. In
operation S762, when the relative height phase with respect to the
first reference surface m of the board 62 according to the grating
pattern illumination generated from the first illumination source
41a is calculated, the central control unit 10 stores the relative
height phase with respect to the first reference surface m as
height phase information of the board 62. In operation S763, when
the height phase information of the board 62 is stored, the central
control unit 10 separates height phase information of the solder
62e in a corresponding inspection location by using the height
phase information of the bare board 63 in the database 80 and the
height phase information of the board 62 stored in operation S762.
When the height phase information of the solder 62e is separated in
the corresponding inspection location, the central control unit 10
calculates actual height information from the relative height phase
information of the solder 62e, and calculates a volume, a height
distribution, and an positional offset of the solder 62e by using
the calculated actual height information. Specifically, in
operation S764, when the height phase information of the solder 62e
is separated, the central control unit 10 calculates the actual
height information from the separated height phase information of
the solder 62e, and calculates the volume, the height distribution,
and the positional offset of the solder 62e.
[0078] Hereinafter, performing operation S760 when the plurality of
first illumination sources 41a is provided will be described. In
operation S761, when the relative height phase with respect to the
first reference surface m of the board 62 according to any one of
the plurality of first illumination sources 41a and the relative
height phase with respect to the first reference surface m of the
board 62 according to a remaining first illumination source 41a are
calculated, the central control unit 10 calculates a combined
height phase where noise is removed from the relative height phase
with respect to each first reference surface m. Following
operations will be identical when only the single first
illumination source 41a is provided and thus only a brief
description will be made below.
[0079] In operation S762, when the combined height phase is
calculated, the central control unit 10 stores the calculated
combined height phase as height phase information. In operation
S763, when the height phase information is stored, the central
control unit 10 separates height phase information of the solder
62e by using the height phase information of the bare board 80
stored in the database 80 and the height phase information of the
board 62 stored in operation S762. In operation S764, when the
height phase information of the solder 62e is separated, the
central control unit 10 calculates actual height information from
the separated height phase information of the solder 62e and
calculates the volume, the height distribution, and the positional
offset of the solder 62e.
[0080] In a method of measuring a 3D shape, operations 5420, S620,
and S740 of adjusting the brightness of the first illumination
source 41a, to determine goodness and badness of the board 62, will
be further described in detail with reference to FIGS. 7A through
9B.
[0081] Operations S420, S620, and S740 may be performed in a
different way with respect to when a single first illumination
source 41a is provided and when a plurality of first illumination
sources 41a is provided. Hereinafter, performing operations S420,
S620, and S740 when the single first illumination source 41a is
provided will be described with reference to FIGS. 7A, 8A, and
9A.
[0082] In operations 5422, S622, and 5742 of operations 5420, S620,
and S740, the central control unit 10 controls the illumination
controller 23 to switch on the first illumination source 41a. In
operations S423, S623, and S743, when the first illumination source
41a is switched on, the central control unit 10 selects a pre-input
adjustment command value. In operations S424, S624, and S744, when
the adjustment command value is selected, the central control unit
10 controls the illumination controller 23 to adjust the brightness
of the first illumination source 41a according to the selected
adjustment command value.
[0083] Hereinafter, operations S420, S620, and S740 when the
plurality of first illumination sources 41a is provided will be
described with reference to FIGS. 7B, 8B, and 9B.
[0084] In operations S421, S621, and 5741 of operations S420, S620,
and S740, the central control unit 10 determines whether any one of
the plurality of first illumination sources 41a is selected. In
operations S422, S622, and 5722, when the selected first
illumination source 41a is determined, the central control unit 10
controls the illumination controller 23 to switch on the selected
first illumination source 41a. In operations S423, S623, and S743,
when the selected first illumination source 41a is switched on, the
central control unit 10 selects the pre-input adjustment command
value. In operations S424, S624, and S744, when the adjustment
command value is selected, the central control unit controls the
illumination controller 23 to adjust the brightness of the first
illumination source 41a according to the selected adjustment
command value.
[0085] In operations S425, 5625, and S745, when any one of the
plurality of first illumination sources 41a is not selected, the
central control unit 10 controls the illumination controller 23 to
switch on a remaining first illumination source 41a. In operation
S426, S626, and S746, when the remaining first illumination source
41a is switched on, the central controls unit 10 selects the
pre-input adjustment command value. In operations S427, S627, and
S747, when the adjustment command value is selected, the central
control unit 10 controls the illumination controller 23 to adjust
the brightness of the remaining first illumination source 41a
according to the selected adjustment command value.
[0086] When the brightness of the first illumination source 41a is
adjusted, operations S430, S630, and S750 of calculating the
relative height phase with respect to the first reference surface m
are performed respectively. In this instance, operations S430,
S630, and S750 may be performed in a different way with respect to
when a single first illumination source 41a is provided and when a
plurality of first illumination sources 41a is provided.
Hereinafter, performing operations S430, S630, and 5750 when the
single first illumination source 41a is provided will be described
with reference to FIGS. 7A, 8A, and 9A.
[0087] In operations 5431, 5631, and S751, when the brightness of
the first illumination source 41a is adjusted, the grating
controller 22 of driving the grating moving device 42 moves the
grating device 43 the N number of times and the camera 70 takes an
image, which is reflected by emitting a grating pattern
illumination generated from the first illumination source 41a,
every movement, and the image acquisition unit 30 acquires the
taken image. In operations S432, S632, and S752, when the image
acquisition unit 30 acquires the image, an inspection area is
expanded. A concept of expanding the inspection area is applied to
calculate the height of the solder 62e based on the second
reference surface n of the board 62 that includes the conductive
pattern 62b, the solder mask 62c, the conductive pad 62d, and the
solder 62e, which are formed on the base plate 62a, as shown in
FIG. 3A. In this instance, the second reference surface n indicates
the height from a bottom surface of the board 62 to a top surface
of the solder mask 62c and the conductive pad 62d, and the height
corresponding to a centroid from the first reference surface m to
the solder mask 62c and the conductive pad 62d. Also, as shown in
FIGS. 3A and 3B, when an area A is set as the inspection area of
the board 62 or the bare board 63 and the inspection is started,
the inspection area is expanded to an area B so as to calculate a
height value of the second reference value n.
[0088] In operations S433, S633, and S753, when the image
acquisition unit 30 acquires the image in operations S431, S631,
and S751, the central control unit 10 calculates a phase map by
using an N-bucket algorithm, and stores the calculated phase map.
In operations S434, S634, and S754, when the phase map is
calculated and stored, the central control unit 10 calculates the
relative height phase with respect to the first reference surface m
in a corresponding inspection location by using a difference
between a pre-stored phase map of the first reference surface m and
the phase map stored in the central control unit 10.
[0089] Hereinafter, performing operations S430, S630, and S750 when
the plurality of first illumination sources 41a is provided will be
described with reference to FIGS. 7B, 8B, and 9B.
[0090] In operations S431, S631, and S751, when the brightness of
any one of the plurality of first illumination sources 41a is
adjusted, the grating controller 22 of driving the grating moving
device 42 moves the grating device 43 the N number of times and the
camera 70 takes an image, which is reflected by emitting a grating
pattern illumination generated from the first illumination source
41a, every movement, and the image acquisition unit 30 acquires the
taken image. In operations S432, S632, and S752, when the image
acquisition unit 30 acquires the image, an inspection area is
expanded. In operations S433, S633, and S753, when the image
acquisition unit 30 acquires the image in operations S431, S631,
and S751, the central control unit 10 calculates a phase map by
using an N-bucket algorithm and stores the calculated phase map. In
operations S434, S634, and S754, when the phase map is calculated
and stored, the central control unit 10 calculates the relative
height phase with respect to the first reference surface m in a
corresponding inspection location by using a difference between a
pre-stored phase map of the first reference surface m and the phase
map stored in the central control unit 10.
[0091] In operations S435, S635, and S755, when the brightness of a
remaining first illumination source 41a is adjusted, the grating
controller 22 of driving the grating moving device 42 moves the
grating device 43 the N number of times and the camera 70 takes an
image, which is reflected by emitting a grating pattern
illumination generated from the remaining first illumination source
41a, every movement, and the image acquisition unit 30 acquires the
taken image. When the image according to the remaining first
illumination source 41a is acquired by the image acquisition unit
30, the relative height phase according to the remaining first
illumination source 41a is calculated by performing operations
S436, S636, and S756 of expanding the inspection area, operations
S437, S637, and S757 of calculating and storing the phase map using
N-bucket algorithm, and operations S438, S638, and S758 of
calculating the relative height phase with respect to the first
reference surface m.
[0092] When the relative height phase is calculated with respect to
when the single first illumination source 41a is provided to the 3D
shape measuring system and when the plurality of first illumination
sources 41a is provided thereto, the 3D shape of target objects on
the board 62 can be measured by using the calculated relative
height phase. Also, goodness and badness of the solder 62e of the
board 62 can be determined by using the result of the
measurement.
[0093] According to the present invention, there is provided a
method of measuring a 3D shape which can measure 3D shape of target
objects on a board according to a normal inspection mode when a
measuring object is set to the normal inspection mode, and also can
measure the 3D shape of target objects on the board by searching a
database for bare board information when the measuring object is
not set to the normal inspection mode or by performing bare board
teaching when the board is supplied from a supplier having not the
bare board information, and thereby can improve a productivity of
electric circuit boards.
[0094] Also, according to the present invention, it is to improve a
measurement quality of a 3D shape by measuring the 3D shape while
maintaining a brightness of an illumination source, which is
applied to measure the 3D shape, to be regular for each
operation.
[0095] Although a few exemplary embodiments of the present
invention have been shown and described, the present invention is
not limited to the described exemplary embodiments. Instead, it
would be appreciated by those skilled in the art that changes may
be made to these exemplary embodiments without departing from the
principles and spirit of the invention, the scope of which is
defined by the claims and their equivalents.
* * * * *