LINE DETECTION METHOD.

摘要

The most appropriate lines are recognized as lines from all of the conceivable ones of two rectangular windows (12, 14) by assuming dust and scratches as part of the lines at a preparatory stage. The gradient and characterizing value of each line are determined and each rectangular window is converted to a parallelogram along this gradient. The gradient and characteristic value of the line are determined at the detection stage by utilizing this parallelogramic window. In this manner, even when image data are worse, the line can be detected and a weld line, an edge of an object of detection, etc., can be detected accurately.