Optics: measuring and testing – Crystal or gem examination
Reexamination Certificate
1999-12-07
2001-05-29
Font, Frank G. (Department: 2877)
Optics: measuring and testing
Crystal or gem examination
C356S425000
Reexamination Certificate
active
06239867
ABSTRACT:
BACKGROUND OF THE INVENTION
The monetary value of diamonds, pearls, and other precious gemstones can vary considerably relative to the aesthetic features of each stone. Such features, as, color, clarity, cut, shape, brilliance, etc., are important subjective determinants of value. For example, it is not uncommon to find gemstones of identical size and weight varying significantly due to the effect of such subjective determinants. As such, consistent measurement of these characteristics is a first step towards a reliable estimate of a gemstone's monetary value.
Presently, a variety of instruments are utilized to grade gemstones, such instruments include the simple eyeglass or loupe, as well as many sophisticated imaging instruments. Imaging instruments are commonly utilized in evaluating the objective and subjective qualities of gemstones, these instruments include simple ultra-violet lamps, microscopes, chelsea filters, calcite type dichroscopes, refractometers, polariscopes, spectroscopes, etc. Imaging instruments enable operators to visually analyze gemstones through illumination and magnification, or electronically gauge the gemstones refraction and/or reflection characteristics to incident light.
However, imaging instruments and systems are presently incapable of producing a reliable and reproducible index of a gemstone's objective and subjective qualities. The choice of imaging instrument, human judgement, and visual perception are all factors which impact the consistency of gemstone appraisals. Additionally, such appraisals have been heretofore incapable of measuring several subjective determinants such as brilliance, scintillation, polish, and cut quality.
For example, traditionally, the grading of a gemstone's color fails to consider the size of the gemstone, its transparency, flaws, degree of fluorescence, a lack of standard practice in preparation of a sample, and whether or not equivalent levels of illumination were utilized. A variety of instruments and methods for color grading rely on color comparison kits for visually comparing a sample, the kits are used to subjectively assign a color based on this comparison. Since it is well known that human judgment and eyesight vary from person to person, such color grading systems are unreliable. Some sophisticated instruments assign color by measuring light frequencies transmitted through or reflected from a surface, while others use reference light to evaluate shifts in color spectra and yet others convert the light frequencies into tri-stimulus which are used to assign a color to an object. Yet, fluorescence present in more than 50% of the diamonds and many other gemstones will shift color frequencies. Magnitude of UV radiation in a light source will therefore affect color grade. As can be appreciated, these devices have yet to achieve a level of consistency acceptable to the gain trade.
Moreover, these devices do not offer a system of assigning a cut grade to an object that matches any one of the several well known round and fancy gemstone cuts. Cut analysis can be improved by direct measurements of the side, top, and bottom views of objects being analyzed. Based on these measurements, Proportions of objects can be measured and they can be assigned a shape, a cut grade, and sorted. The foregoing devices are incapable of precisely obtaining with certainty the minimum and maximum dimensions of a gemstone, such as girdle or table measurements.
Similarly, the clarity of a diamond and other transparent gemstones is based on the number, size, and distribution of flaws, inclusions, bubbles, crystals, and any other foreign matter than will distract from its internal flawless beauty. Surface defects in the form of scratches, bruting marks, naturals, and feather are also important to the quality of a gemstone. A process for automatically identifying location, size and type of internal flaws in gem stones has yet to be developed.
Additionally, such subjective determinants as brilliancy and scintillation in certain gem stones is highly prized. Naturally, inconsistent lighting conditions will produce different brilliancy readings. While a lighting standard must be developed to obtain consistent results, it should be flexible enough to allow for differences in gemstones, presently, inconsistent brilliancy and scintillation valuation of gemstones is commonplace.
Such inconsistencies in evaluating the above objective and subjective gemstone properties has encouraged the proliferation of sophisticated counterfeiting and synthetic gemstone industries which further obfuscate the gemstone appraised process. Identification or authentication of these objects is a primary component of a reliable gem appraisal practice. As sophisticated counterfeiting procedures are developed to alter appearance such as laser drilling, radiation, and the substitution of with highly reflective plastics and liquids, ever more reliable equipment and procedures are necessary to separate natural goods from those which have been altered, enhanced or those that are man made. Furthermore, there is well established need in the jewelry trade to fingerprint gemstones for future identification. Gemstones removed for cleaning or sold on consignment may be switched. Insurers and consumers are interested in reclaiming lost or stolen goods recovered by police or retailers. A method is needed that will accurately measure and automatically record many attributes of a gemstones which can be used hierarchically to match a gemstone.
In addition to the aforementioned security concerns, presently, gemstones must be shipped or sent by a courier for appraisal or for evaluation by an interested buyer. This activity is time consuming, expensive, and places inventory at risk. An electronic means of transferring text, numerical and visual data that accurately represents the various attributes of a gemstone can significantly improve transactions while reducing associated shipping, insurance and security costs. This functionality requires not only communication capability but a database capability that can automate recording of text, audio and video information from gem analysis. The database must be secure and fully integrate inventory functions with analysis, management, retailing, and marketing of gem stones and information.
The apparatus in accordance with the present invention, provides a reliable and reproducible evaluation, measurement, and recording system for quantifying heretofore objective and subjective gemstone characteristics.
SUMMARY OF THE INVENTION
A method and associated apparatus for the standardized grading of gemstones is provided in which the spectral response of a gemstone subject to a plurality of incident light sources is captured via a charge coupled device (CCD). An imaging apparatus employing a CCD camera is operably linked with an analysis station, the analysis station including a data processor and database for processing the spectral response data as captured by the CCD camera in the form of pixel data sets. The database employs a library of exemplary gemstone pixel data sets as measured by the apparatus, the library data functioning to relate, compare, and distinguish the spectral response of an individual gemstone's pixel data set to the reference pixel data sets of the database. The data processor of the analysis station provides an instruction set for facilitating communication with the imaging apparatus, analyzing communicated pixel sets, and producing reports to, identify the gemstone's shape, quantify, and reliably grade heretofore subjective qualities of gemstones. The reports are communicated from the analysis station to the imaging apparatus for reproduction by an operably linked local printer.
The data processor of the analysis station communicates with a control data processor of the imaging apparatus. The control data processor of the apparatus provides an instruction set for automating the steps necessary to precisely position and operate the imaging hardware. The control data processor has local and wide area communica
Dann Dorfman Herrell and Skillman, P.C.
Font Frank G.
Imagestatistics, Inc.
Lauchman Layla G.
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