Cotton Color Measurement Problems: Part Ii. Instrument Test and Evaluation

An experimental cotton color/trash meter was developed previously for the purpose of improving cotton color measurement by removing trash-particle effects on color measurement with image processing. In this work, the experimental meter was tested extensively on a large number of cotton samples varying widely in color and trash content. Testing involved: (1) comparing the measurement accuracy of the experimental meter to that of conventional meters that use diffuse reflectance for color measurement, and (2) comparing the experimental and conventional meters’ ability to predict clean lint color from that of uncleaned lint. Results indicated that basic cotton color measurement was as accurate with the experimental meter as it was with conventional meters. Additionally, the experimental meter’s color measurements on uncleaned lint correlated better with cleaned lint color than did those of the conventional meters in every case. With the Z (blue-band reflectance) color measurement, the superiority of the experimental meter’s correlation between uncleaned and cleaned lint color was statistically significant. The reduction in root-mean-square error with the experimental meter was about 14% for the Y (broad-band green reflectance) measurement and about 22% for Z. These reductions in prediction error had statistical as well as practical significance.