Enhancement method of low-illumination image

An enhancement method for low-illumination image comprises the following steps: (1) inputting images; dividing the images f(x, y) with the sizes of M*N into rectangular areas which are not mutually overlapped in different sizes of m*n; (2) setting the size of a Wallis filter sliding template B; and selecting the points at the lower right corners of the rectangular areas as the central points of the template to be served as the central points; and expanding the points to the periphery of the image so as to obtain the pixels in the template; (3) solving the mean and variance of a filter template covering the image area for each rectangular area; (4) solving the multiplicative coefficient and the additive coefficient of each rectangular area filter by using the expected mean and variance; (5) solving the multiplicative coefficient and the additive coefficient of different pixel points in the images by using the double-linear interpolation; (6) calculating the pixel gray value of the points after being enhanced by using a Wallis filter based on the above coefficients; (7) linearly stretching the images after being filtered and improving the contrast when the multiplicative coefficient of the filter is less than 1. The method has strong universality, high robustness and high enhancement effect.