Possibilities of Quality Evaluation of Hulled Nonglutinous Rice Using Light Transmittance and Video Image Data Processing System

Abstract

Present methods to evaluate rice quality in Japan rely upon a visual rating of the appearance of hulled nonglutinous rice grain. A new objective and uniform test for quality evaluation of rice is needed.
A video image data processing apparatus which variegates the lights and shades of images with twelve colors was employed to the quality evaluation of rice.
Results obtained were as follows:
1) The image made by ray passed through normal rice grain was indicated on the TV monitor with light and dark blue, whereas the images of milky-white grain, green grain, basal-white grain, white-belly grain, germinated grain, rusty grain, opaque grain and brown-discolored grain (insect-injured grain) were indicated with light green, orange, yellow, brown, olive, red, violet and magenta according to the degree of injury.
2) The color pattern varied with samples of the official standard grade of rice.
3) The digital readout of the ratio of the identical color area to the total projected area of rice samples had potential for the determination of the percentage of inferior grains in rice samples.
4) It was also shown that normal grain was well contrasted with inferior grains when the rice grains were put between two polarizing plates and were seen through.