| 摘要 |
1. A method of detecting the edge structures in a video signal, with a decision criterion being derived from the environment of a pixel so as to effect coding with the least number of bits, with windows each composed of one image pixel and its immediately adjacent environment pixels being stored in a given sequence in a shift register and only the immediately adjacent environment pixels of an image pixel are read out of the shift register in parallel and are fed to a computer for the formation of an average and image pixels (1) identified as an edge as well as image pixels (0) identified as not being an edge are binarily marked, characterized in that - the entire image is subdivided into partial image regions which are each coded as a whole ; - the respectively determined average is fed to a comparator and the comparator individually compares this average with the associated adjacent environment pixels taken from the shift register for each image pixel and derives a three-value signal therefrom (1, 0, -1) depending on whether the brightness of an environment pixel lies a given amount above (1), within (0), or below (-1) a tolerance range ; - these individual three-value comparison results are intermediately stored and utilized to detect edges and their orientation in such a manner that the number of the values (1, 0, -1) and their sequence in a fixed direction around the image pixel define the edge orientation ; - it is determined, by way of a freely selectable number of determined edge pixels and their local association in said partial image region, whether this partial image region as a whole is to be considered an edge block and thus to be marked by a binary value ; - this binary value for the entire partial image region that is to be considered an edge block is utilized to control an image coding algorithm. |
