1. An apparatus, comprising: a camera that captures an image; a smoothing unit that is configured to generate, using a processor, 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 is configured to identify, using the processor, 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 is configured to estimate, using the processor, 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, wherein a number of pixels in the first window is smaller than a number of pixels in the at least one smoothed image, and a number of pixels in the second window is smaller than a number of pixels in the captured image, and wherein the estimating unit is configured to estimate a number of sharp pixels from the differences in grayscale value and generate an edge sharpness score based on a ratio of a number of sharp pixels in a region of the captured image comprising the second window, and a number of pixels in the region belonging to an edge of the captured image.