| 摘要 |
<p>PURPOSE: A compression system is to operate on scrambled versus unscrambled video without any increase in the bit-rate needed to provide a given picture quality, and system performance(noise, distortion, etc.) is to be unaffected by the inclusion of the scrambling function. CONSTITUTION: A scrambling technique is based on the principle of applying local spatial distortion to the pixels in a video image to locally displace the pixels from their normal locations. A spatial image distortion (SID) scrambler has properties; displacement of each pixel of the original image by a certain amount (which may be zero) horizontally and/or vertically. maintaining a given pixel in the scrambled image with the same set of contiguous pixels that it had in the original image. pixels lying along the borders of the image preferably are not displaced to locations outside those borders, to avoid loss of portions of the image. The complementary descrambling technique restores the locally displaced pixels to their normal locations to restore the video image to its original unscrambled state.</p> |
