CCD Rice Grain Positioning Algorithm for Color Sorter with Line CCD Camera

Positioning is one of the most important operations in color sorting systems for falling grain which directly affects the performance of these systems. Linescan Charge Coupled Device (CCD) image sensor is widely used in the color sorting systems, however, the processing algorithms are much complex. In this paper, a complete set of algorithms is presented for the above systems. First, the Line-Scan Merging (LSM) algorithm, a novel connected component labeling algorithm that can be applied on line scan CCD imaging system, is proposed. The end points of objects will be given by LSM. Second, the direct least squares ellipse-fitting (direct ellipse-fitting for short) algorithm is applied to position the single grain with the end points of it from the result of LSM. Finally, the direct ellipse-fitting algorithm is modified to position the connected grains to solve the problem of difficulty in segmenting the connected objects and accurately positioning them. The experimental results show that the proposed algorithms can be successful in positioning the falling grain. KeywordsColor Sorter, Line Scan Camera, Mechatronics, Image Processing.