A new algorithm of image edge detection and its application

On the basis of grey level nonlinear transformation and stepwise ratio, a new method of image edge detection is put forward. First, in order to avoid insignificance of stepwise ratio when the value of grey level is zero, the grey level nonlinear transformation is done against the grey level of original image. Moreover, the stepwise ratios are solved between the middle pix and others in 3times3 plate and the two thresholds are given. The edges of image can be detected by means of the comparative results between the stepwise ratios and the thresholds, and the image edges can be detected from eight directions by means of this method. At last, the corresponding simulation experiment is implemented and its ability of edge detection is tested. Compared with other methods, the result shows that this algorithm can make the character segmented from the background distinctly, effectively approve the speed and accuracy of vehicle license plate recognition.