METHOD AND APPARATUS FOR SHUFFLING IMAGE DATA INTO STATISTICALLY AVERAGED DATA GROUPS AND FOR DESHUFFLING THE DATA

In a data compression process such as employed to compress video or other data, it is preferable not to compress the image data representative of the video image in a sequential format, or to take the data from the same area of the image. To equalize the information content of the data prior to compression, the present shuffling/deshuffling technique divides the video image into a multitude of image representing blocks, and selects a predetermined number of the image blocks from different spatial locations in the image, to form a succession of data sets representative of the video image information. That is, the selection of the image representing blocks is such that the information content (complexity) in each data set is similar to the information content in each other data set and further similar to the average information content of the entire video image. Thus, the subsequent quantizing factor used in the compression process will tend to be similar for successive data sets, thereby reducing any distortion introduced by the compression process. The image representing blocks may be formed of sequentially scanned blocks of the video image, or of transform coefficients representing similar blocks of the video image. The shuffled data is deshuffled by the inverse process.