Improvement of Method to Estimate Colors of Amber

Abstract

In a previous study, we demonstrated the color features of ambers and a method to estimate amber colors. We specifically focused on the red, green, blue (RGB) color space and the hue, saturation, value (HSV) color space. We proposed a method to estimate amber in four colors (yellow, brown, black, and ambers with an outer cover (AOCs) created with solid resin or amber dirt). However, due to the presence of ambers with partially exposed outer covers (APEOCs), the estimation accuracy of AOCs was 57.1%. In this paper, we therefore demonstrate the color features of ambers and a method aimed at improving the estimation accuracy of AOCs. Specifically, we focus on five kinds of ambers: three colors (yellow, brown, and black), AOCs and APEOCs are examined. The proposed method consists of masking, detection of AOC, estimation of amber color, and detection of APEOC. Experimental results for 185 ambers show that the proposed method can estimate amber color with an accuracy of 96.7%. It is also shown that an estimation accuracy of 91.4% for AOC color estimations is achieved.