Malaysia is one of the countries that imports rubies from Myanmar for various uses in the manufacturing industries, precious stone industries, dentistry, and medical applications. Previous tools for determining the gradation of ruby stones are based on the assessment by human eyes and require a lot of experience. In this study, the research presented a conceptual model of optical properties of ruby stones using the CCD Tomography technique. The transparency and clarity of the ruby stones are some of the important attributes that are evaluated in the study. The first objective of this present study was to examine the optical properties of ruby stones using charge-coupled device (CCD) tomography. The second objective was to investigate and identify the light intensities of various grades of ruby stones using CCD tomography and Laboratory Virtual Instrument Engineering Workbench (LabVIEW) programming software as classified commercially by the Gemmological Institute of America (GIA) database. The third objective was to validate the optical properties of the ruby stones by comparing the simulation output images to that of the experimental output images. Here, the research presented a standardized conceptual model for the optical properties of the ruby stones using the CCD Tomography technique. A Linear Back Projection (LBP) algorithm was used for reconstructing the 3D images of the ruby stones based on the Refractive Index (RI) values of 1.762 and 1.770. The algorithm was programmed using the LabVIEW programming software tools. These image reconstructions assisted in analysing the transparency of the ruby stones after the 2-sample t-test, which were necessary for evaluating and grading the stone quality. Apart from that, two types of CCD tomography image reconstruction systems, with and without the use of a laser as the light source, were analysed to investigate the best conceptual modeling with which to evaluate the optical properties of ruby stones. The study suggested that the image reconstruction system with laser as the light source or transmitter was efficient in differentiating between the 2 different RI values of the ruby stones. The result also concluded that the relative error value between the theoretical and experimental value of this system is 10.15% which has successfully proved the capability of CCD tomography system in evaluating the optical properties of ruby stone based on its clarity.

Rubies are the most sought-after gems owing to their brilliance, hardness, and high-value. They require a complicated technique for determining their originality due to the lack of quantitative analysis. One of the important criteria in analyzing the rubies is the clarity. This research aims to develop an inspection system using a CCD (Charge-Coupled Device) linear sensor for determining the clarity of ruby stones. A CCD linear sensor system is developed to inspect the clarity of rubies. Several experiments are conducted using the CCD linear system to validate the capability of the CCD linear sensor in inspecting the clarity of rubies. The mean CCD voltage output in the laser ON condition when synthetic ruby is in the system shows a higher value compared to when there is no ruby in the system with 1.7918 V and 1.5835 V respectively. When natural ruby is placed in the CCD linear system in the laser ON condition, the CCD voltage output is 1.9771 V. The CCD voltage output data is validated using the statistical analysis and the reverse mathematical modelling. The reverse mathematical modelling proves that the CCD linear sensor system is an effective and reliable system in inspecting the clarity of rubies. The result shows almost similar refractive index values of natural and synthetic rubies to their actual refractive index with 98.87% and 94.33% accuracy respectively. Overall, it can be concluded that this CCD linear system provides a quantitative, accurate and reliable technique with average accuracy of 96.90%.