Slope approximant straight line detection method

The invention provides a slope approximant straight line detection method. The method specifically includes the steps that all edge lines in an image to be processed are detected; all the edge lines are converted into a plurality of point chains which are shown by point chain first point coordinates and chain code sequences; each point chain is divided into a plurality of two-code point chains, the number of chain code values in each two-code point chain is two at most, and represented directions of the two values are adjacent; a straight line point chain is found in each two-code point chain, the slope range of the first point of each straight line point chain and the slope range of each of the rest points both have the same nonvoid subset, and the number of the points can reach a predetermined point number threshold value. According to the slope approximant straight line detection method, a straight line in the image can be detected rapidly and accurately, and the quality of the effect of application in which sampling straight line detection is needed can be better improved.