Patent ID: 8131084

Claim:
An apparatus for improving sharpness of an image, the apparatus comprising: an edge detector calculating an edge value of each pixel of an input image using brightness relation with neighboring pixels; an effective edge judging unit determining, as effective edge pixels, pixels having an edge value between a first threshold value and a second threshold value set in advance among pixels of the input image; an effective edge classifying unit determining, as weak edge pixels, pixels having an edge value smaller than a third threshold value set in advance among the effective edge pixels, and determining, as strong edge pixels, pixels having an edge value greater than the third threshold value among the effective edge pixels; an isolated edge judging unit judging an isolated edge pixel included in an isolated edge among the effective edge pixels; a 2-dimensional (D) high pass filter (HPF) applying unit applying a first 2-D HPF having a first gain to the weak edge pixels excluding the isolated edge pixel, and applying a second 2-D HPF having a second gain smaller than the first gain to the strong edge pixels excluding the isolated edge pixel to generate edge strengthening values of respective pixels; and an edge strengthening value applying unit adding the edge strengthening values to brightness values of the respective pixels of the input image.