Image encoding apparatus and image decoding apparatus

摘要

An input image is subjected to transform by a DCT transforming unit 20. A coefficient analyzing unit 30 compares a predetermined coefficient and coefficient data 120, and obtains low-frequency image data 150 of the input image by a high-frequency coefficient masking unit 50 and an inverse DCT unit 60 on the basis of a result of that comparison. A pixel subsampling unit 70 receives this low-frequency image data 150, and generates a subsampled image on the basis of the aforementioned result of comparison. The subsampled image and coefficient information are transmitted to a decoding side. A decoding apparatus decodes an image on the basis of the subsampled image and the coefficient information.