Generalizations of image resolution conversions using 8‐point inverse DCT
Kazuhiro Kojima, Hitoshi Kiya · Electronics and Communications in Japan (Part III Fundamental Electronic Science) · 2002
Abstract The resolution conversion method using DCT is now the mainstream of image compression techniques. This paper extends the conventional method in which the inverse DCT with the same number of points as that of DCT (3 points) in the encoding is used, and generalizes the procedure. More precisely, the resolution conversion is made executable with conversion factors of not only integers but also rational numbers. Thus, a greater degree of freedom is provided in selecting the filter for controlling the image quality. As a result, resolution conversion with any rational number factor can be performed by the 3‐point inverse DCT, and the filter characteristics can be selected according to the image properties. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 85(9): 58–68, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ecjc.1119