U.S. patent application number 13/026534 was filed with the patent office on 2011-08-25 for arrangement for and method of holding gemstones.
This patent application is currently assigned to PHOTOSCRIBE, INC.. Invention is credited to David BENDERLY, David LIATTI.
Application Number | 20110205525 13/026534 |
Document ID | / |
Family ID | 44476244 |
Filed Date | 2011-08-25 |
United States Patent
Application |
20110205525 |
Kind Code |
A1 |
BENDERLY; David ; et
al. |
August 25, 2011 |
ARRANGEMENT FOR AND METHOD OF HOLDING GEMSTONES
Abstract
A gemstone to be optically examined is held by a holder having
an internal compartment. A mounting plate supports the gemstone
table-side up in an upright position within the internal
compartment. A protective lid is mounted on the holder for movement
between a closed position in which the lid overlies the mounting
plate and the gemstone supported thereon, and an open position in
which the lid uncovers the gemstone for optical examination.
Inventors: |
BENDERLY; David; (New York,
NY) ; LIATTI; David; (Brooklyn, NY) |
Assignee: |
PHOTOSCRIBE, INC.
New York
NY
|
Family ID: |
44476244 |
Appl. No.: |
13/026534 |
Filed: |
February 14, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61308062 |
Feb 25, 2010 |
|
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Current U.S.
Class: |
356/30 |
Current CPC
Class: |
G01N 21/8806 20130101;
G01N 21/87 20130101 |
Class at
Publication: |
356/30 |
International
Class: |
G01N 21/87 20060101
G01N021/87 |
Claims
1. An arrangement for holding a gemstone to be optically examined,
comprising: a holder having an internal compartment; a mounting
plate for supporting the gemstone table-side up in an upright
position within the internal compartment; and a protective lid
mounted on the holder for movement between a closed position in
which the lid overlies the mounting plate and the gemstone
supported thereon, and an open position in which the lid uncovers
the gemstone for optical examination.
2. The arrangement of claim 1; and further comprising a support
spring for mounting the mounting plate for movement within the
internal compartment between a lowered position in which the
gemstone is mounted on the mounting plate in the open position of
the lid, and a raised position in which the gemstone is biased
against an underside of the lid in the closed position of the
lid.
3. The arrangement of claim 2, wherein the holder has a planar top
wall, and wherein the table of the gemstone in the raised position
is elevated above the top wall.
4. The arrangement of claim 3, wherein the lid has a recess formed
at the underside of the lid, and wherein the table of the gemstone
in the raised position is received in the recess.
5. The arrangement of claim 2; and further comprising a latch for
latching the mounting plate in the lowered position, and a latch
release for releasing the latch as the lid is moved from the open
position to the closed position.
6. The arrangement of claim 1; and further comprising a return
spring for constantly biasing the lid toward the open position, a
stop for stopping the lid in the open position, a lock for locking
the lid in the closed position, a lock release for releasing the
lock to enable the return spring to automatically move the lid to
the open position, and gears for slowing the movement of the lid to
the open position,
7. The arrangement of claim 1,wherein the mounting plate has a hole
in which a culet of the gemstone is received, and wherein the table
of the gemstone is directly exposed to incident light in the open
position of the lid.
8. The arrangement of claim 1, wherein the holder has a planar top
wall, and wherein the lid is mounted on the holder for pivoting
movement between the closed and open positions, and for sliding
movement on the top wall.
9. The arrangement of claim 1, wherein the holder is constituted of
a material that is magnetically attracted to a magnetic mount.
10. The arrangement of claim 1; and further comprising a drawer on
which the holder is mounted for movement along a longitudinal axis;
and a drawer spring that is tensioned when the drawer and the
holder are moved in one direction along the axis, and that
automatically returns the drawer and the holder in an opposite
direction along the axis.
11. A method of holding a gemstone to be optically examined, the
method comprising the steps of: configuring a holder with an
internal compartment; supporting the gemstone table-side up in an
upright position on a mounting plate within the internal
compartment; and mounting a protective lid on the holder for
movement between a closed position in which the lid overlies the
mounting plate and the gemstone supported thereon, and an open
position in which the lid uncovers the gemstone for optical
examination.
12. The method of claim 11; and the step of mounting the mounting
plate for movement within the internal compartment between a
lowered position in which the gemstone is mounted on the mounting
plate in the open position of the lid, and a raised position in
which the gemstone is biased against an underside of the lid in the
closed position of the lid.
13. The method of claim 12, and the steps of configuring the holder
with a planar top wall, and elevating the table of the gemstone in
the raised position above the top wall.
14. The method of claim 13, and the steps of forming the lid with a
recess at the underside of the lid, and receiving the table of the
gemstone in the raised position in the recess.
15. The method of claim 12; and further comprising the steps of
latching the mounting plate in the lowered position, and releasing
the mounting plate as the lid is moved from the open position to
the closed position.
16. The method of claim 11; and further comprising the steps of
constantly biasing the lid toward the open position, stopping the
lid in the open position, locking the lid in the closed position,
releasing the lid to automatically move the lid to the open
position, and slowing the movement of the lid to the open
position,
17. The method of claim 11; and further comprising the steps of
receiving a culet of the gemstone in a hole formed in the mounting
plate, and directly exposing the table of the gemstone to incident
light in the open position of the lid.
18. The method of claim 11, and the steps of configuring the holder
with a planar top wall, and mounting the lid on the holder for
pivoting movement between the closed and open positions, and for
sliding movement on the top wall.
19. The method of claim 11, and the step of constituting the holder
of a material that is magnetically attracted to a magnetic
mount.
20. The method of claim 11; and further comprising the steps of
mounting the holder on a drawer for movement along a longitudinal
axis, storing energy when the drawer and the holder are moved in
one direction along the axis, and releasing the stored energy to
automatically return the drawer and the holder in an opposite
direction along the axis.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 61/308,062, filed Feb. 25, 2010.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to an arrangement
for, and a method of, holding gemstones, especially cut diamonds,
to be examined by illuminating the gemstone, capturing images of
the illuminated gemstone, and analyzing the captured images with
repeatability.
[0003] The beauty and price of a gemstone, such as a cut
multi-faceted diamond, are based, for example, on its cut, carat
weight, clarity and color. Many different geometrical patterns of
cuts, such as round brilliant, oval, pear, marquise, radiant,
princess, heart, emerald, etc. are now standardized. The cut, the
carat weight, the clarity and the color of the gemstone are
typically evaluated and/or measured by a human appraiser. Such
evaluated and/or measured properties are often objectively
presented to a consumer, typically in certificate form, for price
valuation.
[0004] Optical performance of the gemstone, that is, how the
gemstone "plays with light", and optical efficiency of the
gemstone, that is, how the gemstone "reflects light", are difficult
to subjectively evaluate and measure, even for the experienced
human appraiser. Optical performance and efficiency of the gemstone
are typically characterized by such properties as its brilliance
(the amount and intensity of incident light returned from the
gemstone), scintillation (fast and local fluctuations in the
incident light returned as the gemstone moves), fire (the
dispersion of incident white light into its spectral colors),
coverage (the area of the incident light returned compared to the
total area of the gemstone table), contrast (the intensity of the
incident white light returned compared to the intensity of the
non-returned or black light), and symmetry (the balance of the
pattern of the incident light returned). A more visually active
gemstone is deemed more valuable than a less visually active
gemstone, even with the same cut, carat weight, clarity and
color.
[0005] To objectively measure such optical properties of gemstones,
the art has disclosed various computer-based systems for capturing
and analyzing images of gemstones illuminated under varying
lighting conditions. For example, U.S. Pat. No. 5,615,005 discloses
a gemstone evaluation system that captures images of a gemstone
placed table-side face-down on a glass plate in an analysis chamber
and illuminated from a plurality of different angles by a movable
light source that is moved toward the gemstone during the
evaluation. Captured images of the gemstone are analyzed by a
computer, and various optical properties of the gemstone are
measured and displayed or printed.
[0006] As another example, U.S. Pat. No. 6,813,007 discloses
another computer-based system that captures images of a gemstone
also placed table-side face-down on a glass plate, but illuminated
by light reflected off a rotary reflector that rotates during the
evaluation. Captured images of the gemstone are again analyzed by a
computer, and various optical properties of the gemstone are
measured and displayed or printed.
[0007] However, as advantageous as such computer-based systems have
been, they have not proven to be altogether satisfactory in use. A
moving system component, such as a rotating reflector or a moving
light source, causes mechanical variability and vibrations that can
interfere with the measurements, and degrade measurement accuracy
and repeatability. The light source also concomitantly generates
heat that can interfere with the measurements. Also, the glass
plate on which the gemstone is placed creates an interface at which
light interference can occur due to light refraction, thereby again
degrading measurement accuracy and repeatability. This interference
effect is aggravated by frequent contamination with dust, dirt, oil
from an operator's fingers, scratches, or like contaminants on the
glass plate. Furthermore, the placement of the gemstone on the
glass plate is variable, thereby still further worsening
measurement accuracy and repeatability. An objective, accurate and
repeatable examination of a gemstone is essential for true price
valuation of the gemstone.
SUMMARY OF THE INVENTION
[0008] One aspect of this invention is directed to an arrangement
for holding a gemstone to be optically examined. The arrangement
includes a holder having an internal compartment, a mounting plate
for supporting the gemstone table-side up in an upright position
within the internal compartment, and a protective lid mounted on
the holder for movement between a closed position in which the lid
overlies the mounting plate and the gemstone supported thereon, and
an open position in which the lid uncovers the gemstone for optical
examination. The arrangement is mounted in an apparatus for
accurately examining, with repeatability, one or more optical
properties, such as coverage and/or symmetry of the gemstone,
especially a cut, multi-faceted diamond having a table (i.e., the
uppermost, largest facet at the top of the diamond) and a culet
(i.e., the pointed or blunted bottom of the diamond). An
energizable, stationary light source is spaced away from the
gemstone and is operative for directing light rays at different
orientations to the table of the gemstone when energized.
[0009] In one embodiment, the stationary light source comprises a
plurality of light sources spaced along an axis away from, and
facing, the table of the gemstone, for directly directing the light
rays at the different orientations to the table of the gemstone.
Each light source preferably comprises a multitude of
light-emitting elements, such as light emitting diodes, arranged in
an annulus around the axis, with each annulus having a different
diameter. A support, preferably annular in shape, is advantageously
provided for supporting the light sources at different axial
distances away from the gemstone. An optional homogenizer may be
provided and supported by the support for homogenizing and making
more uniform the light from each light source directed to the
gemstone.
[0010] In another embodiment, a support is spaced from the light
source, for supporting a plurality of light reflectors of different
reflectivity, e.g., different colors of the light spectrum, and at
different angular orientations and distances along an axis away
from the table of the gemstone. Each light reflector is preferably
arranged in an annulus around the axis, each annulus having a
different diameter. The stationary light source, preferably a
plurality of light emitting diodes lying in a plane, emits uniform
light for reflection simultaneously from all the light reflectors
as the light rays at the different orientations directly to the
table of the gemstone.
[0011] An energizable stationary backlight is oppositely positioned
from either support to face the culet of the gemstone. The
backlight lies in a plane and uniformly illuminates the gemstone
when energized. The backlight could also comprise multiple light
emitting diodes arranged in a two-dimensional array, preferably
overlaid with a light homogenizer.
[0012] A controller or microprocessor, preferably a programmed
computer, is operative for energizing the light source to generate
return light from the gemstone for each light ray, as well as for
energizing the backlight to illuminate the gemstone from behind The
controller advantageously controls a power supply that supplies the
voltages for energizing the light source and the backlight. In an
advantageous embodiment, the backlight is energized first, and then
the light source is energized. When a plurality of light sources is
employed, they are individually energized, preferably, but not
necessarily, in an ordered sequence.
[0013] A solid-state imager is spaced along an axis away from the
gemstone, and preferably has a two-dimensional array of cells or
photosensors, which correspond to image elements or pixels in a
field of view of the imager. An optical focusing lens assembly is
provided for capturing the return light from the gemstone and the
light in the field of view of the backlit gemstone, and for
projecting the captured light onto the imager during an exposure
time period. The imager may be a charge coupled device (CCD) or a
complementary metal oxide semiconductor (CMOS) device, together
with associated integrated bandpass spectral filters and electronic
circuits for producing electrical signals corresponding to a
two-dimensional array of pixel information over the field of view,
and is similar to that used in a digital camera. The imager is
operative for imaging the return light from the light rays as a
plurality of frontlit images, and for imaging the light in the
field of view of the backlit gemstone as a backlit image.
[0014] The controller is further operative, as described in detail
below, for processing at least one of the frontlit images and the
backlit image, to determine the coverage and/or symmetry properties
of the gemstone. Other optical properties that can be determined
are the aforementioned contrast, fire, brilliance and
scintillation.
[0015] The apparatus advantageously also comprises one or two
position adjusters for axially adjusting a position of the imager
and/or the light source relative to each other and the gemstone. A
gemstone holder or fixture is operative for holding and
automatically positioning the gemstone in a predetermined upright
position in which the table of the gemstone is uncovered and
directly exposed to each light ray. A support plate, preferably of
rigid material, commonly mounts the light source, the backlight,
the imager and the gemstone holder. Shock-absorbers on the support
plate are employed for resisting shock forces from reaching the
light source, the backlight, the imager and the gemstone holder.
Such forces can originate from the environment exterior to the
apparatus, or from the interior, for example, from cooling fans
within the power supply, also mounted on the support plate.
[0016] Still another aspect of this invention is directed to a
method of examining at least one optical property, such as coverage
and/or symmetry, of the gemstone. The method is performed by
directing light rays at different angular orientations to the
gemstone by energizing a stationary light source to generate return
light from the gemstone for each light ray, imaging the return
light as a plurality of frontlit images, and processing at least
one of the frontlit images.
[0017] The method is further performed by directing the light rays
to an uncovered table of the gemstone, and by positioning an
energizable stationary backlight to face a culet of the gemstone.
The backlight is energized to illuminate the gemstone from behind
The light in the field of view of the backlit gemstone is imaged as
a backlit image. The backlit image is processed, preferably
together with the at least one frontlit image, to determine the
optical property of the gemstone.
[0018] As a preferred initial step, the backlit image is processed
to determine a silhouette or outline of the backlit gemstone, and a
number of total pixels is counted within an area or region of
interest of the gemstone. Symmetry is advantageously determined by
processing each frontlit image of the return light, generating
virtual images mirror symmetrical to the frontlit images, counting
a number of symmetrical pixels common to each frontlit image and
its respective virtual image within the area of the gemstone, and
analyzing the counted number of symmetrical pixels compared to the
number of total pixels. Coverage is advantageously determined by
counting a number of coverage pixels having an intensity above a
predetermined value in coverage regions of the backlit image within
the area of the gemstone, and analyzing the number of coverage
pixels compared to the number of total pixels.
[0019] Thus, the apparatus of this invention has no rotating light
reflectors or moving light sources, as in the prior art, that could
cause mechanical variability and vibrations to interfere with the
measurements, and thereby degrade measurement accuracy and
repeatability. The light emitting diodes of this invention are
stationary and are relatively cool-running devices that do not
generate heat, as in the prior art, to interfere with the
measurements. Rather than moving the light incident on the
gemstone, the spaced-apart light sources in one embodiment are
energized, one at a time, or the light reflectors in another
embodiment simultaneously reflect light incident thereon, thereby
obtaining multiple frontlit images to be processed. The arrangement
of this invention does not place the gemstone table-side face-down
on a glass plate and thus avoids light interference effects, as in
the prior art, due to light refraction from a covered table. The
arrangement of this invention holds the gemstone in a
predetermined, upright position in which the table is uncovered and
directly exposed to the light rays. The lack of a glass plate means
that no contamination can occur due to dust, dirt, oil from an
operator's fingers, scratches, or like contaminants. The
arrangement of this invention provides an objective, accurate and
repeatable examination of the coverage and/or symmetry, as well as
other optical properties, of a gemstone essential for true price
valuation of the gemstone.
[0020] The novel features which are considered as characteristic of
the invention are set forth in particular in the appended claims.
The invention itself, however, both as to its construction and its
method of operation, together with additional objects and
advantages thereof, will be best understood from the following
description of specific embodiments when read in connection with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is an exploded, front elevational view of an
apparatus for accurately determining at least one optical property,
such as symmetry and/or coverage, of gemstones in accordance with
the method of this invention;
[0022] FIG. 2 is a side elevational view of part of the apparatus
of FIG. 1, with a cover removed;
[0023] FIG. 3 is an enlarged, sectional view of one embodiment of
an annular support for supporting a plurality of light sources
facing a table of a gemstone, as employed in the apparatus of FIG.
1;
[0024] FIG. 4 is a perspective view of a gemstone holder being
prepared to receive a gemstone, prior to being placed in the
apparatus of FIG. 1;
[0025] FIG. 5 is a perspective view of the gemstone holder of FIG.
4 during loading of the gemstone;
[0026] FIG. 6 is a perspective view of the gemstone holder of FIG.
5 after loading of the gemstone;
[0027] FIG. 7 is a perspective view of the gemstone holder of FIG.
6 ready to be placed in the apparatus of FIG. 1;
[0028] FIG. 8 is a broken-away, perspective view of the gemstone
holder of FIG. 7 placed in an open drawer of the apparatus of FIG.
1;
[0029] FIG. 9 is a broken-away, perspective view of the gemstone
holder of FIG. 7 during closure of the drawer of the apparatus of
FIG. 1;
[0030] FIG. 10 is an exploded, perspective view of parts of the
gemstone holder of FIG. 4;
[0031] FIG. 11 is an exploded, perspective view of parts of the
drawer of FIG. 8;
[0032] FIG. 12 is a backlit image of the gemstone taken in
accordance with this invention;
[0033] FIG. 13 is a display setting forth the coverage and symmetry
properties of the gemstone examined in accordance with this
invention; and
[0034] FIG. 14 is an enlarged, sectional view of another embodiment
of an annular support analogous to that shown in FIG. 3, but
operative for supporting a plurality of light reflectors facing a
table of a gemstone, for use in the apparatus of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] Referring now to FIG. 1 of the drawings, reference numeral
10 generally identifies an apparatus for accurately determining,
with repeatability, one or more optical properties such as coverage
and/or symmetry of a gemstone 12, especially a cut, multi-faceted
diamond having, as best shown in FIG. 3, a table 14 (i.e., the
uppermost, largest facet at the top of the diamond) and a culet 16
(i.e., the pointed or blunted bottom of the diamond). Although FIG.
3 depicts that the gemstone 12 has a round cut, the apparatus 10 is
equally applicable for determining the coverage and symmetry of
gemstones having other cuts, such as oval, pear, marquise, radiant,
princess, heart, emerald, etc.
[0036] As shown in FIGS. 1-2, the apparatus 10 includes a
horizontal support plate 18, preferably of rigid material, on which
an upright, vertical standard 20 is mounted. A gemstone holder 22
or fixture, as best shown in FIGS. 4-11, is mounted on the support
plate 18 behind a drawer front panel 126 and is operative, as
described below, for holding and automatically positioning the
gemstone 12 in a predetermined upright position. An annular support
24, as best shown in FIG. 3, is mounted on the standard 20 above
the gemstone holder 22. In the embodiment of FIG. 3, the annular
support 24 is operative, as described below, for supporting a
plurality of light sources that face the table 14 of the gemstone
12 in the holder 22. In an alternate embodiment, as described below
in connection with FIG. 14, a different annular support is
operative for supporting a plurality of light reflectors that face
the table 14 of the gemstone 12 in the holder 22. A backlight 30 is
mounted on the support plate 18 and faces the culet 16 of the
gemstone 12 in the holder 22.
[0037] A solid-state imager 26 is also mounted on the standard 20
above the annular support 24 and is operative, as described below,
for imaging light returning from the gemstone 12. An optical
focusing lens assembly 28 is also mounted on the standard 20
between the annular support 24 and the imager 26, and is operative
for capturing the light returning from the gemstone, and for
projecting the captured light onto the imager 26 during an exposure
time period. The imager 26, the lens assembly 28, the annular
support 24, the gemstone 12 and the backlight 30 are all aligned
along an optical path or axis 32 that is parallel to the elongation
of the vertical standard 20.
[0038] A first position adjuster 34 is operative for axially
adjusting a position of the imager 26 and the lens assembly 28
along the optical path 32 relative to the gemstone 12. A second
position adjuster 36 is operative for axially adjusting a position
of the annular support 24 along the optical path 32 relative to the
gemstone 12. A power supply 38 is mounted on the support plate 18
and is operative, as described below, for supplying power to the
light sources in the annular support 24 and to the backlight 30.
Shock absorbers 40 between the power supply 38 and the support
plate 18, as well as shock absorbers or feet 42 on the bottom of
the support plate 18, are employed for resisting shock forces from
reaching the light sources, the backlight 30, the imager 26, the
lens assembly 28 and the gemstone holder 22. Such forces can
originate from the environment exterior to the apparatus 10, or
from the interior, for example, from cooling fans within the power
supply 38. A cover 44 is removably mounted over the components
mounted on the support plate 18 and on the standard 20. The cover
44 has a cutout 46 to provide access to a handle 48 on the drawer
front panel 126, and clearance for the latter.
[0039] As shown in FIG. 3, the annular support 24 has a cylindrical
lower housing portion 50 and a frustoconical upper housing portion
52, together resembling a domed structure symmetrical about the
axis 32. The upper housing portion 52 has an axial passage 56
through which light passes en route to the imager 26. An optional
dome-like homogenizer 54 of light-homogeneous material may be
provided within the annular support 24 and has opposite openings
58, 60 through which light passes.
[0040] A plurality of energizable, stationary light sources 62, 64,
66, 68, 70, 72, 74 is supported by the annular support 24 and
spaced along the axis 32 at different axial distances away from,
and facing, the table 14 of the gemstone 12. Each light source 62,
64, 66, 68, 70, 72, 74 comprises a multitude of light-emitting
elements, such as light emitting diodes (LEDs), arranged in an
annulus around the axis 32, with each annulus having a different
diameter. In a preferred embodiment, there are seven annular light
sources, and each annular light source comprises about fifty to
seventy LEDs mounted on respective annular flexible circuit boards
76. Each LED is operative for emitting light rays to the gemstone
when energized. More or fewer than seven annular light sources
could be employed. More or fewer than fifty to seventy LEDs may
comprise each annular light source. Advantageously, the LEDs are
preselected such that their individual output powers are
substantially the same. When energized, each annular light source
generates a light ray in an annular zone of generally uniform
illumination, but at a different angular orientation relative to,
as well as a different axial distance from, the gemstone 12.
[0041] As noted above, the energizable stationary backlight 30
faces the culet 16 of the gemstone 12, lies in a plane and
uniformly illuminates the gemstone from behind when energized. The
backlight 30 also comprise multiple LEDs arranged in a
two-dimensional array, preferably overlaid with a planar light
homogenizer of light-homogeneous material. When energized, the
backlight 30 generates a planar zone of homogenized light of
generally uniform illumination behind the gemstone 12.
[0042] A controller 80 (see FIG. 1) or microprocessor, preferably a
programmed computer, is operatively connected to the power supply
38, and is operative for individually energizing the light sources
62, 64, 66, 68, 70, 72, 74 to generate return light from the
gemstone 12 for each light source in the annular support, as well
as for energizing the backlight 30 to illuminate the gemstone 12
from behind The power supply 38 has an output 82 that supplies the
voltages for energizing the light sources, and an output 84 that
supplies the voltage for energizing the backlight 30. The
electrical wiring between the power supply 38 the light sources and
the backlight 30 are not shown for clarity. In an advantageous
embodiment, the backlight 30 is energized first, and then the
plurality of light sources 62, 64, 66, 68, 70, 72, 74 is energized,
preferably, but not necessarily, in an ordered sequence, e.g., from
the closest to the furthest annular light source.
[0043] As noted above, the solid-state imager 26 is spaced along
the axis 32 away from the gemstone 12, and preferably has a
two-dimensional array of cells or photosensors, which correspond to
image elements or pixels in a field of view of the imager. The
optical focusing lens assembly 28 is operative for capturing the
return light from the gemstone 12 and the light in the field of
view of the backlit gemstone 12, and for projecting the captured
light onto the imager 26 during an exposure time period. The imager
26 may be a charge coupled device (CCD) or a complementary metal
oxide semiconductor (CMOS) device, together with associated
integrated spectral filters and electronic circuits for producing
electrical signals corresponding to a two-dimensional array of
pixel information over the field of view, and is similar to that
used in a digital camera. The imager 26 is operative for imaging
the return light from the gemstone 12 from each light source
through the passage 56 as a plurality of frontlit images, and for
imaging the light in the field of view of the backlit gemstone 12
through the passage 56 as a backlit image. The frontlit images
represent different images of the gemstone taken at different
relative orientations and/or distances between the gemstone and the
light source and simulate the effect of a moving light source, but
without the above-described drawbacks thereof.
[0044] The controller 80 is further operative, as described in
detail below, for processing the backlit and the frontlit images,
to determine the symmetry and/or coverage of the gemstone 12. The
controller 80 is located exteriorly of the apparatus outside the
cover 44, but could be incorporated within the cover. Input data
can be input to the controller 80 via an input device 86, e.g., a
mouse, keyboard, joystick, etc. Measurement data can be output from
the controller 80 via an output device, e.g., a monitor 88, a
printer 92, an internet connection 90, etc.
[0045] As noted above, the gemstone holder 22 or fixture is
operative for holding and automatically positioning the gemstone 12
in a predetermined upright position in which the table 14 of the
gemstone 12 is uncovered (see FIG. 3) and directly exposed to the
light from each annular light source 62, 64, 66, 68, 70, 72, 74. In
the predetermined upright position, the light from each LED enters
the gemstone 12 slightly below the table 14 to minimize any
specular reflections off the table 12. In the predetermined upright
position, the table 14 of the gemstone 12 is preferably slightly
above a top surface 128 of the holder 22.
[0046] As depicted in FIGS. 4-7, the gemstone holder 22 includes a
protective lid 96 pivotably mounted on the gemstone holder 22 for
movement between an open position (FIG. 5) and a closed position
(FIG. 7). A stop 130 is mounted on the holder 22 and extends above
the top surface 128 to abut against an extension 132 of the lid 96
to define the open position. A shoulder 138 (see FIG. 10) formed in
a curved recess 140 on the underside of the lid 96 abuts against a
lock 142 that extends above the top surface 128 to define the
closed position. A release 122 releases the lock 142 when
depressed. FIG. 10 depicts a stationary gear 100 fixed to the
holder 22. Gear 100 meshes with sector gear 102 that is mounted on
a spindle 104 that is jointly movable with the lid 96. A
tensionable spring 106 is connected to the lid 96 via the spindle
104. The spindle 104 has a curved surface 134 and a flat surface
136. The spring 106 acts to constantly bias the lid 96 to the open
position. The gears 100, 102 act to slow the rate at which the lid
96 is moved to the open position by the spring 106.
[0047] In FIG. 4, an operator has already manually depressed the
release 122 and released the lock 142 from the shoulder 138,
thereby enabling the tensioned spring 106 to pivot the lid 96 until
it is held in the illustrated open position by mutual engagement
between the stop 130 and the extension 132. During this pivoting
movement, the lock 142 passes with clearance along the curved
recess 140 in the lid 96. A mounting plate 94 having a hole 98
therein (see FIG. 5) is exposed in the open position. FIG. 10
depicts a flanged sleeve 108 that holds the mounting plate 94
against the restoring force of a return spring 110. The mounting
plate 94 and the sleeve 108 are jointly movable up-and-down. In
FIG. 4, the operator pushes the mounting plate 94 down, where it is
latched in the down position by mutual frictional engagement
between the sleeve 108 and the curved surface 134 of the spindle
104.
[0048] In FIG. 5, the operator loads the gemstone 12 into the hole
98 of the mounting plate 94. Holes 98 of different sizes and
mounting plates 94 of different heights can be used to accommodate
differently sized gemstones. Tweezers 112 or gloves are recommended
to avoid contamination. In FIG. 6, the operator pivots the lid 96
against the force of the spring 106 to the closed position until
the lock 142 lockingly engages the shoulder 138. This action turns
the spindle 104 until the flat surface 136 faces the sleeve 108,
thereby unlatching the sleeve 108 and the mounting plate 94, both
of which are released and move up under the force of the spring
110. In FIG. 7, the table 14 of the gemstone 12 is pressed against
the underside of the closed lid 96 inside and against an inner wall
of another curved recess 144 (see FIG. 10) due to the force of the
spring 110. This is the aforementioned predetermined upright
position of the gemstone 12, which is repeatable for the same
gemstone, as well as from one gemstone to the next. The table 14 is
positioned in a plane slightly above the top surface 128 of the
holder 22. The gemstone holder 22 with its pre-positioned gemstone
12 is now ready to be placed in the apparatus 12.
[0049] In FIG. 8, a drawer 114 is pulled out in the direction of
the arrow A by the handle 48, and the gemstone holder 22 with its
pre-positioned gemstone 12 is placed in the drawer 114 and held in
a predetermined position by a magnetic mount 116. FIG. 11 depicts
that the drawer 114 includes a linear toothed track 118 that meshes
with a spring-biased, viscous oil-dampened gear 120. When the
drawer 114 is pulled out, the track 118 rotates the gear 120 and
tensions the spring therein. The drawer 114 is then released and
moves in the opposite direction of the arrow A due to the restoring
force of the spring. This return released movement of the drawer
114 is slowed due to the viscous oil and prevents the gemstone from
being jarred from its predetermined upright position.
[0050] During the return movement of the drawer 114, the gem holder
22 approaches the overhead annular support 24 and eventually is
positioned in a loaded position directly thereunder, as shown in
FIG. 3. Just prior to being positioned in the loaded position, the
lid 96 is unlatched and released to its open position, as depicted
in FIG. 9. This is accomplished by mutual abutment between a
release member 146 mounted on a side block 124 and the release 122
on the holder 22. When the release member 146 abuts the release 122
during the return movement of the drawer 114, the lock 142 is
disengaged from the shoulder 138, and the lid 96 is automatically
opened under the force of the spring 106. The gemstone 12 is not
disturbed from its predetermined upright position during the
opening of the lid 96, since the gemstone passes with clearance
along the curved recess 144.
[0051] As previously mentioned, the controller 80 processes the
backlit and the frontlit images, to determine the aforementioned
symmetry and/or coverage, as well as other optical properties, of
the gemstone 12. As an initial step, the controller 80 energizes
the backlight 30 and processes the backlit image, which resembles a
circular dark region of interest for a round cut gemstone, analyzes
the silhouette or shape, fills in any bright areas within the dark
region of interest, rotates the dark region of interest (only if it
is non-circular), determines the perimeter and the area of the dark
region of interest, and counts the number of total pixels within
the area of the gemstone.
[0052] Coverage is advantageously determined by processing the
backlit image, as depicted in FIG. 12, and counting the number of
total pixels within an area of the gemstone as described above,
counting a number of coverage pixels having an intensity above a
predetermined value in coverage regions of the backlit image within
the area of the gemstone, and analyzing the number of coverage
pixels compared to the number of total pixels to obtain a coverage
ratio indicative of the percentage of light that is reflected. The
higher the coverage ratio, the greater the coverage.
[0053] Optical symmetry, as distinguished from geometrical
symmetry, is advantageously determined by processing each frontlit
image of the return light, generating virtual images mirror
symmetrical to the respective frontlit images, counting a number of
symmetrical pixels common to each frontlit image and its respective
virtual image within the area of the gemstone, and analyzing the
counted number of symmetrical pixels compared to the number of
total pixels as previously counted. More specifically, each
frontlit image and its respective virtual image are juxtaposed, and
the pixels of the juxtaposed images are compared. Intensity values
are determined for the compared pixels, and their difference is
determined. If each difference lies within a certain range, e.g.,
between zero and 10, then the compared pixels are deemed
symmetrical. The number of the symmetrical pixels is then compared
to the number of total pixels to obtain a symmetrical ratio for
each set of frontlit and virtual images. All the symmetrical ratios
are averaged to obtain a final symmetrical ratio. The higher the
final symmetrical ratio, the greater the optical symmetry.
[0054] Thus, the apparatus of this invention provides an objective,
accurate and repeatable measure of symmetry and/or coverage
properties of a gemstone essential for true price valuation of the
gemstone. Other optical properties, such as contrast, fire,
brilliance and scintillation can also be determined. FIG. 13
depicts an exemplary printout or certificate printed by the local
printer 92 and depicting the symmetry and coverage properties in a
line graph format, in which such designations as "fair, good, very
good and excellent" are employed, rather than numerical
percentages, for convenience. Other display formats could be
employed. This measurement data can also be printed on a remote
printer via the internet 90, or locally displayed on the monitor
88, or remotely displayed.
[0055] As previously mentioned, FIG. 14 depicts an alternate
embodiment, analogous to that shown in FIG. 3, for illuminating the
uncovered table 14 of the gemstone 12. An annular hemispherical
support 150 is spaced from a light source 152, for supporting a
plurality of light reflectors 154, 156, 158, 160, 162, 164, and 166
of different reflectivity, e.g., different colors of the light
spectrum, i.e., red, orange, yellow, green, blue, indigo and
violet, and at different orientations and/or distances along the
axis 32 away from the uncovered table 14 of the gemstone 12. Each
light reflector is preferably arranged in an annulus around the
axis 32, each annulus having a different diameter. More or fewer
than the seven illustrated reflectors could be employed. The
stationary light source 152, preferably a plurality of light
emitting diodes lying in a plane, emits uniform light for
reflection simultaneously from all the light reflectors as the
light rays at the different orientations directly to the table 14
of the gemstone 12. A light baffle 168 blocks any light from the
light source 152 from entering the gemstone from behind
[0056] When the stationary light source 152 is energized, each
annular light reflector reflects a light ray in an annular zone of
generally uniform illumination and at a different wavelength, but
at a different angular orientation relative to, as well as a
different axial distance from, the gemstone 12. The support 150 has
opposite openings 170, 172 through which light reflected off the
gemstone passes en route to the imager, as described above. In a
variant of the embodiment of FIG. 14, rather than reflectors,
light-transmissive windows of different wavelengths can be
employed.
[0057] It will be understood that each of the elements described
above, or two or more together, also may find a useful application
in other types of constructions differing from the types described
above.
[0058] While the invention has been illustrated and described as
embodied in an arrangement for, and a method of, holding a
gemstone, it is not intended to be limited to the details shown,
since various modifications and structural changes may be made
without departing in any way from the spirit of the present
invention.
[0059] Without further analysis, the foregoing will so fully reveal
the gist of the present invention that others can, by applying
current knowledge, readily adapt it for various applications
without omitting features that, from the standpoint of prior art,
fairly constitute essential characteristics of the generic or
specific aspects of this invention and, therefore, such adaptations
should and are intended to be comprehended within the meaning and
range of equivalence of the following claims.
[0060] What is claimed as new and desired to be protected by
Letters Patent is set forth in the appended claims.
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