Non-Contact Measurement of Soil Clod Fineness by Image Analysis
——Effect of Illuminance Level on Classification of Soil Clod Fineness——

Abstract

The purpose of this study is to develop an algorithm for real-time measurement of soil clod fineness by image processing. Five sizes of soil clod were prepared by sieving. Surface images of the soil fragments after rotary tillage were captured using a digital video camera under 22 different lighting conditions. Thirty-four image features were measured. The effect of lighting conditions on the variation of image features was clarified by non-parametric analysis of variance. The relation between the clod size and texture features could be expressed in terms of multiple regression equations with coefficients of determination greater than 0.9100. The obtained equations showed high accuracy in distinguishing soil clod sizes under various illuminance conditions.