| 摘要 |
An FFT analysis is performed on the decoded image data of one frame, and a cutoff frequency based on the assumption that the original signal has first-order attenuation characteristics is obtained in both the horizontal and vertical directions. A sampled-data H∞ filter (digital filter), previously designed to have different parameters corresponding to different cutoff frequencies is selected. By using this filter, a filtering process is performed on the image data decoded both in the horizontal and vertical directions. Since the variety of the analog frequency characteristics of the original image is taken into account for every frame of the image, the information that seems to be noise in the original image is less likely to be removed, and mosquito noise and block noise associated with a coding/decoding process can be efficiently removed. |
