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Automatic measuring method for color grading of diamonds

A technology of color grading and automatic measurement, which is applied in the direction of color measurement devices and electric radiation detectors for color measurement. present effect

Inactive Publication Date: 2017-06-13
SHANDONG MEASUREMENT SCI RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the integral measurement method cannot distinguish and solve such problems, resulting in grading differences in measurement.

Method used

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  • Automatic measuring method for color grading of diamonds
  • Automatic measuring method for color grading of diamonds
  • Automatic measuring method for color grading of diamonds

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0039] The invention is mainly composed of a sample collection system, a microscopic area positioning and display system, and a spectrum collection and calculation system.

[0040] (1) The sample collection system includes:

[0041] Light source conforming to CIE standard illuminant D65, adjustable two-dimensional platform and V-groove.

[0042] Put the tested diamond sample in the V-shaped groove, and the light source illuminates the surface of the V-shaped groove. The surface is a white diffuse surface with an average spectral reflectance of 95% and no spectral selectivity. The V-shaped groove ensures that the tested diamond The sides of the sample are kept perpendicular to the measuring head. At the same time, the V-shaped groove is in an adjustable state, and the purpose of the adjustment is to make each measuring surface of the diamond sample in the groove conveniently rotate for convenient measurement. The light enters the sample under test after being diffused. The c...

Embodiment 2

[0051] Embodiment 2: experimental process

[0052] (1) Uniformity test of samples

[0053] After many comparisons, the 2013 standard object developed by NGTC was selected, and the measured results were calculated by the color calculation system to obtain the chromaticity coordinates (x, y) of the diamond color, projected on the coordinate axis as figure 1 As shown, it can be seen that all projection points are basically distributed linearly, except for G, H, and I, the overall uniformity is good.

[0054] The differences between x, y, and indices between adjacent color levels are shown in the table below.

[0055]

[0056] (2) Stability and error testing of results

[0057] Taking the D color diamond as an example, fix the same test surface and test it ten times in a row. The results are shown in the table below.

[0058]

[0059] From the data in the table, it can be seen that the stability and reproducibility of the test results are good. Due to the rigor of the test ...

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Abstract

The invention relates to a measuring technique for gemstone colors, particularly discloses an automatic measuring method for color grading of diamonds. The method is characterized in that a pavilion area of an under-tested diamond sample is perpendicular to an microscope zoom lens, a light is diffused and enters the under-tested diamond sample; after an amplified signal is amplified by the zoom lens, a beam of light enters an image CCD to form an imaging and displayed in the positioning display. Another beam of light into a spectrometer, an optical signal spectral acquisition is collected and a color coordinates x, y of the under-tested sample is measured. A system program converts the x, y values of the color coordinates into color gradation values which conform to the human eye's grading system automatically. An essential difference between the method of present invention and a currently used color measuring system are as follow: the automatic measuring method for color grading of diamonds can realize the automatic grading of diamonds according to the human eye observation condition and solve problems about a measuring discrepancy and a color grading error which cannot be solved by the conventional diamond color measuring system.

Description

[0001] (1) Technical field [0002] The invention relates to gemstone color measurement technology, in particular to an automatic measurement method for diamond color grading. [0003] (2) Background technology [0004] Diamond color is a very important indicator in diamond evaluation. The national standard is divided into 12 continuous color grades according to the color change of diamonds, which are represented by letters and numbers: [0005] [0006] The above-mentioned color grades are all calibrated by master stones. A set of standard color stones is essential in color grading. Our country uses a set of 11 standard color stones. Diamond color grading has always been carried out mainly by human eye observation. This human eye observation method is very strict: [0007] (1) Relevant personnel are required to have normal color vision and professionals who have received specialized skills training. When assessing, two or more technicians are required to complete the co...

Claims

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Application Information

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IPC IPC(8): G01J3/50
CPCG01J3/50
Inventor 程佑法范春丽李建军刘海彬朱红伟张丛森
Owner SHANDONG MEASUREMENT SCI RES INST
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