Apparatus for binary-coding image and method using the same

摘要

Provided are an apparatus and method for binary-coding images considering the brightness of a current pixel and a difference in brightness between pixels. The apparatus includes a detector for detecting a local adaptive critical value for a pixel according to a regional characteristic of the pixel in the image, and a comparator for comparing the local adaptive critical value with the value of the pixel and outputting a binary-coded pixel value corresponding to the pixel. In detecting the local adaptive critical value, a local average parameter F_Loc related to high frequency elements is supplied after being controlled according to a locally windowed region. Frequencies for converting from black pixels to white pixels or from white pixels to black pixels are reduced in a binary-coded output image so that an image with a reduced number of high frequency elements can be obtained to improve the compressibility of the binary-coded output image.