1. A method of processing an input image, the method comprising: obtaining a first blurred image and a second blurred image from the input image; estimating illuminance of the input image by combining the first blurred image and the second blurred image; generating a dark region amplified image from the input image; generating a bright region conserved image from the input image; applying weights to the dark region amplified image and the bright region conserved image, respectively, according to the estimated illuminance; and combining the weighted dark region amplified image and the weighted bright region conserved image to generate a final image.