I have picture with high resolution with 20M memory space and this image has been taken from the standing away from the window in room which has significantly less light as compared to outside. Image has less contrast due to large number of bright pixels in it and also large number of near to dark pixels from room objects. I want to enhance the image contrast having pixels with high intensity values and also with having low intensity values without changing the remaining pixels which are in between these range. Image has been taken with almost half of the areas with having high intensity values and half of area having low intensity values. I have read the quantization techniques with uniform quantization and non-uniform quantization Wiki but i am unable to understand the the concept I mean in what direction i need to understand the concept behind this to improve the contrast and what techniques are available to apply these kind of problems.