A method of printed circuit board photoelectric image enhancement based on CCD

The cause of amalgamation theory of gray level during the histogram equalization was analyzed, and the simple physical explain and analytical deduction were given, what´s more, the shortcomings of the algorithm were discussed. Histogram equalization based on reserving gray level was proposed and it´s basic principle was analyzed in order to reserve more detail information, eliminate the false outline and maintain the continuity of the image after being processed. The results of experiments verified that the printed circuit board photoelectric images acquired by CCD after being processed by the algorithm mentioned in this paper were better than that of the algorithms used by histogram equalization and [2].