1. An image correction method, comprising: identifying each pixel in an image as one of a foreground pixel and a background pixel; estimating a brightness of a background corresponding to a foreground pixel based on the brightness and a gradient of the brightness of background pixels adjacent to the foreground pixel to fill the background located in a position of the foreground pixel to obtain a background illumination map of the image according to filled backgrounds along with background pixels; and correcting the image based on the brightness of each pixel in the image and the background illumination map, wherein the estimating the brightness of the background corresponding to the foreground pixel includes, determining background pixels with an effective gradient among the background pixels adjacent to the foreground pixel; for each one of the determined background pixels with the effective gradient, calculating, based on the brightness and the gradient of the brightness of the background pixel, an estimated value of the brightness of the background corresponding to the foreground pixel; and obtaining the brightness of the background corresponding to the foreground pixel by averaging estimated values calculated for each one of the determined background pixels, wherein each one of the background pixels with the effective gradient is a pixel in a connection direction from the foreground pixel to the pixel, pixels adjacent to the pixel are background pixels.