| 摘要 |
A prediction signal is substracted 14 from a video input signal to form a differential signal for transmission via a coder 46. The differential signal quantized 16 is added 20 to the prediction signal to form a predictor input signal from which the prediction signal is formed by means of pixel and line delays 24, 32, 36, 34; multipliers 26, 42, 44 which multiply by weighing coefficients C1, C2 etc. and adders 40, 38, 28 which sum the partial products. The various delays enable the prediction signal to be formed, with enhanced accuracy, from a cluster of samples (at least six and preferably more) taken from a plurality of adjacent lines and, optionally, from more than one consecutive field or picture. Limiters 22 and 30 ensure that neither the predictor input signal nor the prediction signal can go out of range. Advantageous sets of weighing coefficients are disclosed. <IMAGE> |
