EDGE DETECTION METHOD, EDGE DETECTION DEVICE AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To obtain an edge detection method, an edge detection device and a recording medium by which the precision of edge coordinate detection is improved and an edge in detected at a low cost without degrading the productivity. SOLUTION: The image pickup direction of a TV camera 3 is inclined at a prescribed angle to the plane of a steel plane 1 to photograph the steel plate 1. An image processor 4 preserves photographed images on the basis of program information of a recording medium 6 from the time when the luminance value in a prescribed area of a photographed images of the TV camera 3 exceeds a prescribed value, and the sum total of luminance of pixels having luminance exceeding the prescribed value is obtained for each column of pixels with respect to each photographed image, and the photographed image where the number of columns of pixels of which the sum totals of luminance exceed the threshold is maximum is selected to detect pixel coordinates of edges.