Detection of fissures in rice grains using imaging enhancement

Rapid moisture adsorption by low-moisture rice grains may cause the grains to fissure. The combination of physical properties such as stress and strain has a continuous influence on the rice grain. Rice grains with stress fissures break more readily than sound kernels during harvesting, handling, milling, and transporting, and thereby reduce the quality and market value of the rice grain. Stress fissure detection remains one of the most important tasks in rice grain quality inspection. A machine vision system was used to obtain images of fissured rice grains. The system consisted of a CCD (Charge Coupled Device) black/white camera, an image frame grabber, and a computer. An image processing program (Image-Pro Plus) was used to study and evaluate the images. The procedures to detect fissures in rice grain using Image-Pro Plus were developed. The fissure pattern difference between long and medium grain rice was recognized after analyzing the processed images of the fissured grains. The computer vision system with Image-Pro Plus used in our study was able to reveal 94% of all the fissure lines detected in medium rice samples by a human expert and 100% in long rice samples.