Provided are an apparatus and method for improving image quality, by generating a first image and a second image, detecting pixels from the second image based on a difference between a value of the at least one second pixel and a value of at least one input pixel from the input image, by comparing the second image to the input image, and changing the value of the at least one input pixel in the input image by using a value of the at least one first pixel in the first image, which is located in a location that corresponds to a location of the detected at least one second pixel in the second image.