Details Keeping Histogram Equalization Approach of Low-Illumination Video Image

Traditional histogram equalization method is realized by merging of the low frequency gray level.So the gray level that denotes the image details is often emerged overly and image detail information is lost.In this paper,an improved histogram equalization algorithm was put forward.When judging whether a gray level was to be merged with another,the weight coefficients with increased step were assigned to these low frequency gray levels according to their distance to the current gray level.Thus the excessive gray level merging was avoided.At the same time a nonlinear gray level mapping method was given to enhance the contrast of the original image.Experiment results show that the algorithm has obvious improvement.