Patent ID: 8331718

Claim:
A method of revising edges of an image, comprising: sampling a window of a square shape from an input image; classifying the input image into a homogeneous area and a heterogeneous area; determining a maximum window for the homogeneous area and a minimum window for the heterogeneous area; performing a first noise filtering process for the homogeneous area; determining an area estimated to have a minimum variance among a plurality of areas of the heterogeneous area corresponding to the minimum window; and performing a second noise filtering process for the area estimated to have the minimum variance, wherein the second noise filtering is not performed for the other areas among the plurality of areas of the heterogeneous area corresponding to the minimum window, wherein the step of determining the area estimated to have the minimum variance includes: determining first to fourth areas from the minimum window, the first to fourth areas corresponding to an upper side area, a lower side area, a left side area and a right side area with respect to a center pixel of the minimum window, respectively; calculating first to fourth variances of the first to fourth areas; and calculating an intersection of a comparison between the first variance and the second variance and a comparison between the third variance and the fourth variance to determine a minimum variance area, wherein the first to fourth variances correspond to (σ A ) 2 , (σ B ) 2 , (σ C ) 2 , and (σ D ) 2 respectively.