| 摘要 |
<p>"AN ARRANGEMENT FOR TWO-DIMENSIONAL DPCM-CODING" An arrangement for the two-dimensional DPCM-coding of a television image with a quantizer which has range switching facilities and a quantizer control unit (5) which is dependent upon the image signal values, where the quantizer control unit (5) contains a pluality of series-connected registers (9,15,16,17) which store adjacent image point signal values (A,B,C,D) and a comparison device (COM) is provided in which a difference formation takes place between all the image signal values, where a control unit (32) is provided which is supplied with all the results of the difference formation and which controls a multiplexing device in such manner that only the maximum and minimum image signal values - the extreme values (E,F) - are switched through for further processing. a subtraction device (SUB) is also provided in which the differences are determined between the last image point signal value (A) and the extreme values (E,F) and between the extreme values (E,F) themselves. A difference selection control unit (43) switches through the maximum difference (MD) to a threshold value logic unit (46) which controls the quantizer (4) in accordance with the magnitude of the maximum value difference. (Fig. 3)</p> |
