Ruby Stone Clarity Inspection System Using Charge-Coupled Device (CCD) Linear Sensor

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%.