1. An apparatus, comprising: a camera that captures an image; a smoothing unit that generates at least one smoothed image based on the captured image, over at least one of an x-axis direction and a y-axis direction; an identifying unit that identifies a first window comprising a first plurality of pixels around an edge pixel of the at least one smoothed image, and a second window in the captured image comprising a second plurality of pixels around an edge pixel of the captured image, and corresponding to the first plurality of pixels in the first window; and an estimating unit that estimates edge sharpness by determining differences in grayscale value between first pairs of pixels from the first window and second pairs of pixels from the second window over at least one of an x-axis direction and a y-axis direction of each of the first window and the second window.