An image processing system for implementing a variant of Retinex algorithm based on local illumination correction is provided to improve an intensity value of each position of an input image. The image processing system provides the ability to distinguish details when compressing dynamic range of a given image. Specifically, first the illumination of the image is estimated by performing a weighted low pass filter (WLPF) operation, and the original image is separated into the illumination and the reflectance images. Next, the estimated illumination is modified by using a non-linear mapping function based on local illumination at each pixel location. Then, the modified illumination image is combined with the reflectance image. Finally, an enhanced image is obtained after a contrast correction procedure.