| 摘要 |
When television signals are transmitted digitally over PCM networks, it is sometimes necessary to reduce the bit rate of video signals, such as chrominance signals, on the transmission path from the rate given by the sampling frequency without significantly impairing the picture quality. To accomplish this, the transmitting portion of the novel transmission system includes a transmit filter (FIG. 2) which, at every other sample value in the horizontal and vertical directions of the picture, transmits a numerical value (C) which has the same number of bits as the sample values and depends on this sample value and the sample values of surrounding picture elements, and the receiving portion includes a receive filter (FIG. 3) in which the values of the picture elements to be inserted between the transmitted picture-element values are calculated from the values received for the surrounding picture elements. The digital filtering is performed jointly by the transmit filter and the receive filter in such a way that the horizontal and vertical resolutions are substantially preserved, and that only the diagonal resolution is reduced. An inexpensive realization is given for the two filters. |
