Patent ID: 7162090

Claim:
An image processing apparatus for, based on compressed image data compressed by an image compressing process for performing a discrete cosine transform process and a quantization process by a predetermined block, performing a filtering process to an expanded image on or after expanding the image by said block, wherein, in the case where a block horizontally adjacent to a subject block is a horizontal reference block, a block vertically adjacent to said subject block is a vertical reference block, and furthermore, one pixel in said subject block is a subject pixel, and one pixel in said horizontal reference block located on a boundary with said subject block and at the same vertical position as said subject pixel is a horizontal reference pixel, and one pixel in said vertical reference block located on the boundary with said subject block and at the same horizontal position as said subject pixel is a vertical reference pixel, said filtering process judges whether or not a difference value between a value of said subject pixel and a value of said vertical reference pixel is exceeding a threshold, said filtering process performs horizontal filter operation as to said subject pixel based solely on the value of said subject pixel and the value of said horizontal reference pixel, said filtering process determines whether or not to perform vertical filter operation as to said subject pixel based solely on said judgment result, and performs the vertical filter operation as to said subject pixel based solely on the value of said subject pixel and the value of said vertical reference pixel.