Rapid detection of color-treated pearls and separation of pearl types
				using fluorescence analysis

Tsai, Tsung Han; Zhou, Chunhui

doi:10.1364/ao.427203

Cited by 7 publications

(3 citation statements)

References 31 publications

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“…In particular, birefringence at IR wavelengths is important for defining polarization optical elements within those wavelengths, which have lower optical losses. The presented numerical RGB analysis can also be used for photoluminescence spectra to detect slight color changes in natural and colored pearls, [ 31 ] suggesting its potential application in authentication and quality assurance of gemstones.…”

Section: Discussionmentioning

confidence: 99%

RGB‐Color Image Analysis for Determination of Birefringence of Micro‐Films and Columnar Coatings

Ryu

Han

Grinevičiūtė

et al. 2022

Laser & Photonics Reviews

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The birefringence analysis of thin ≈13.33333ptμ$\approx 1\hspace*{3.33333pt}\umu $m SiO2 films deposited via evaporation at a glancing angle of 3.33333pt70∘$\hspace*{3.33333pt}{70}^{\circ}$ to the normal on resist pillar arrays on Si and nanopatterned SiO2 substrates is carried out by spectral and color (red–green–blue [RGB]) imaging modes. Retardance and birefringence of the films deposited over flat and structured regions can be distinguished with only ≈1% difference between neighboring regions for the visible spectral range using RGB numerical analysis of images. The Michel‐Lévy color map is used for color rendering of birefringence to make quantitative measurements by numerical RGB color filtering. It is shown that by using λ/2$\lambda /2$ at 530 nm waveplate inserted at π/4$\pi /4$ angle to the cross polarizer‐analyzer setup, the range of changes in chromaticity xy‐coordinates expands approximately twice upon angular rotation of a birefringent sample. This facilitates a better signal‐to‐noise determination of birefringence. The proposed method with λ/2$\lambda /2$‐plate color shifting can be directly used to determine birefringence from step‐like spectral features in reflection and transmission polariscopy. Direct measurement of birefringence (normalΔn=0.023${\Delta}n=0.023$) and retardance of SiO2 chevron film is carried out using Berek compensator as a benchmark.

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Section: Discussionmentioning

confidence: 99%

RGB‐Color Image Analysis for Determination of Birefringence of Micro‐Films and Columnar Coatings

Ryu

Han

Grinevičiūtė

et al. 2022

Laser & Photonics Reviews

View full text Add to dashboard Cite

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“…In recent years, advanced testing instruments such as X-ray crystallography, ultraviolet-visible spectroscopy, infrared absorption, photoluminescence, fluorescence spectroscopy, and laser ablation-inductively coupled plasma-mass spectroscopy have also been used to reveal the mineral type and detect lab-grown or treated gemstone materials. [4][5][6][7][8][9][10] Unfortunately, most of these advanced instruments are expensive, which limits the possibility of confidently identifying colored gemstones without submitting the samples to well-equipped gemological laboratories.…”

Section: Introductionmentioning

confidence: 99%

Rapid gemstone mineral identification using portable Raman spectroscopy

Tsai

Wen-xing

2023

J Raman Spectroscopy

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Mineral identification is the first step in gemstone characterization, which is the foundation for maintaining transparency in gemstone trading. Current techniques have complex protocols and require expensive instrumentation, severely restricting their use to trained experts or large gemological laboratories and limiting the processing speed. A simple and inexpensive automatic identification instrument can fulfill the needs of the Gemology Society. Hence, we propose a portable setup for the automatic mineral identification of gemstones based on a custom-built 405 nm Raman spectroscopy probe system. This device enables the noninvasive mineral identification of commonly encountered loose or mounted gemstone materials in the market and generates the results in seconds. It is mechanically designed to allow safe operation under normal office conditions, and the pre-aligned sample stage significantly simplifies the sample alignment process. Fifty-seven types of gemstone materials in the trading market were tested with the device to prove the usability of the system. The primary purpose of this device is to automatically identify the types of minerals in the gemstones. It can also be extended to identify labgrown gemstones in the selected mineral species.

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“…This damage also affects the colour of the Pearl itself, and this is because the colour of the Pearl is the most crucial feature of a pearl. The value of the Pearl depends on its quality and rarity (Tsai & Zhou, 2021). One method that can be used to process Pearl's image is Computer Vision (Tian, 2009).…”

Section: Introductionmentioning

confidence: 99%

Lombok Pearl Quality Classification Using a Combination of Feature Extraction and Artificial Neural Networks Based on Shape

Imran

Yani

Muslim

et al. 2022

pilar

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Lombok is attracted to the Moto GP event, which is held annually. Various tourism brands are owned by the island of Lombok, one of which is Mutiara. The ideal Pearl is perfectly round and smooth, but there are a variety of other shapes as well. One method that can be used to process Pearl's image is Computer Vision. For that, it is necessary to have a way to classify the quality of a Pearl based on its shape. The purpose of this study is to propose a system for pearl image classification by combining feature extraction with artificial neural networks. The method used in this study is GLCM feature extraction and Neural Networks. The proposed system can provide good classification results by combining the GLCM method and the Neural Network. This study uses Epochs 5, 10, 15, 30, 50, 100, 200, 300, and 500 with a learning rate of 0.5. The results of this study indicate that Epoch 100 gives the highest accuracy, 91.66%.

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Rapid detection of color-treated pearls and separation of pearl types using fluorescence analysis

Cited by 7 publications

References 31 publications

RGB‐Color Image Analysis for Determination of Birefringence of Micro‐Films and Columnar Coatings

RGB‐Color Image Analysis for Determination of Birefringence of Micro‐Films and Columnar Coatings

Rapid gemstone mineral identification using portable Raman spectroscopy

Lombok Pearl Quality Classification Using a Combination of Feature Extraction and Artificial Neural Networks Based on Shape

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