Optics: measuring and testing – Crystal or gem examination
Reexamination Certificate
2002-03-25
2004-11-02
Stafira, Michael P. (Department: 2877)
Optics: measuring and testing
Crystal or gem examination
Reexamination Certificate
active
06813007
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to electronic apparatus for generating data for determining properties of gemstones, such as cut diamonds, as well as methods of and computer programs for determining properties of gemstones using the generated data. In particular, but not exclusively, it relates to electronic apparatus for generating data for determining properties as well as methods of and computer programs for determining properties of gemstones in which a plurality of images of the gemstone are captured for analysis under different lighting conditions.
BACKGROUND OF THE INVENTION
The beauty of a gemstone, such as a cut diamond, derives from its light handling ability. What attracts the eye is the “game of light” played by a well-cut diamond as incident light is reflected and refracted off its many facets. Diamonds and other gemstones may be cut according to many different standardised cut patterns such as the standard round brilliant cut, oval, pear, marquise, radiant, princess, heart, emerald cut etc. The most popular cut is the standard round brilliant (SRB) cut as shown in FIG.
1
. Diamond cutting and polishing is a highly skilled art and a well-cut diamond, having superior optical performance, will command a significant price premium over a poorly cut diamond having inferior optical performance.
When showing a cut diamond to an untrained observer, one frequently refers to the four C's of a gemstone, being its carat weight, its clarity, its cut and its colour. Carat weight, clarity and colour can be relatively easily measured objectively and are therefore generally useful. Cut may also be specified or measured in terms of the geometry of the various facets. However, what really matters is the light handling ability of the gemstone and reference is often made to more subjective parameters of a cut diamond, such as its brilliance (the intensity of light returned), scintillation (fast and local fluctuations in the light returned as the diamond moves relative to the lighting conditions), fire (the dispersion of white light into spectral colours) and symmetry (the symmetry of light patterns such as the so-called “hearts and arrows”). It can be difficult, particularly for an untrained observer, to make a personal appraisal of these subjective parameters. It can also be difficult to compare the light handling abilities of two diamonds with the same carat weight, clarity and colour, and therefore to appreciate why one is more valuable than the other.
It is recognised that properties such as brilliance, fire and symmetry should be derived, whether by experimental observation or theoretical computer modelling, under a variety of lighting conditions. Moreover, with the property of scintillation it is clearly essential to observe or model the diamond under a variety of lighting conditions. Electronic apparatus for capturing images of gemstones under varying lighting conditions for analysis are known.
DESCRIPTION OF THE RELATED TECHNOLOGY
International Patent Publication number WO 96/23207 describes a device which captures colour images of a gemstone placed in an analysis chamber and illuminated by a uniform annular light which may be moved along an axis such that the gemstone may be illuminated from a plurality of different angles. The device performs a spectral analysis of the captured images using a tuneable optical band pass filter to determine the colour of the gemstone. Digital images of the gemstone may also be stored, displayed or transmitted over a data network.
The website (www.gemex.com) of GemEx Systems, Inc, a US company, describes a device called the BrillianceScope Analyser which is described as an imaging spectrophotometer. Colour images of a diamond are captured in a controlled lighting environment consisting of six lighting angles, five of which provide reflected light and one of which provides diffuse lighting. These images may then be analysed to generate a report on the diamond. The BrillianceScope Analyser device operates on the same principle as the device described in International Patent Publication number WO 96/23207 referred to above, in that the gemstone is placed in an analysis chamber and illuminated by a uniform annular light which may be moved along an axis such that the gemstone is illuminated from different angles. The images may be analysed by a computer, and the properties of “white light”, “coloured light” and “scintillation” for a diamond are determined and displayed on three line chart scales from ‘low’, to ‘medium’ to ‘high’. Captured images may also be shown in a repeating sequence in one display area, giving the effect of light movement.
International Patent Publication number WO 99/61890 describes a system for the standardised grading of gemstones. A gemstone is subject to a plurality of incident light sources and images are captured for analysis. Images of the gemstone, such as a SRB cut diamond, may be captured from various viewpoints such as from the pavilion, from the crown and side-on. The gemstone is supported by a rotatable platform which is rotated when images are being captured from a side-on viewpoint to obtain profile and colour images from a variety of rotational positions and to detect internal flaws and inclusions. When capturing images from above and below the gemstone, the platform is moved along an axis from a level position to a down and an up position respectively. The fixed focal length camera is also moved along an axis to focus on the gemstone when the platform is moved between the up, down and level positions. A captured image may be analysed by a processor to obtain colour measurements and measures of the brilliance and scintillation of the gemstone.
One object of the present invention is to provide an electronic apparatus, method and computer program for generating data for improved determination of properties of a gemstone, such as brilliance, scintillation, fire and symmetry.
Another object of the present invention is to provide an electronic apparatus for generating data for determining properties of gemstones which is more compact, lightweight, mechanically simpler, and therefore less expensive to manufacture, than conventional apparatus, making it more suitable for use in retail premises, such as jewellers shops.
Another object of the present invention is to provide an electronic apparatus, method and computer program enabling a observer to more easily compare two diamonds and their properties, in particular the properties of brilliance, scintillation, fire and symmetry.
Another object of the present invention is to provide an electronic apparatus, method and computer program for generating data for determining properties of a cut gemstone which is adapted to and takes into account attributes of the shape and/or symmetry of the cut pattern of a particular gemstone.
Another object of the present invention is to provide an electronic apparatus, method and computer program for generating data for determining properties of a gemstone in which the gemstone is illuminated under more realistic lighting conditions.
Another object of the present invention is to provide an electronic apparatus, method and computer program for measuring the symmetry of a gemstone in terms of the light returned.
SUMMARY OF CERTAIN INVENTIVE ASPECTS
According to a first aspect of the present invention there is provided an apparatus for generating data for use in determining a property of a gemstone, such as a cut diamond, the apparatus comprising:
a support structure for supporting a gemstone placed at an observation position, the support structure being arranged such that, if the gemstone has an axis of symmetry, the gemstone is supportable such that the axis of symmetry is parallel to an axis X passing through the observation position;
illumination means arranged to illuminate a gemstone so placed with a spatially varied light pattern;
rotation means arranged to cause relative rotation between the light pattern and the support structure generally about the axis X; and
a camera arranged to capture, at each of a pl
Keersmaekers Christiaan Louis Cecile
Lapa Dave
Van de Velde Marc Frans Alida
Knobbe Martens Olson & Bear LLP
Overseas Diamonds Technologies
Stafira Michael P.
LandOfFree
Apparatus for generating data for determining a property of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for generating data for determining a property of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for generating data for determining a property of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3302611