| 摘要 |
<p>The amount of high frequency variation, horizontally and/or vertically, which is in a video image is evaluated by processing a video signal representing the image so as to produce a lower definition version thereof, reconstructing the video signal from the lower definition version, subtracting the reconstructed signal from the original signal to produce an error signal and low pass filtering the modulus of the error signal. The resultant signal is indicative of the amount of detail in the video image and, for example, may be used, in a system where a high definition image signal is conveyed by the combination of a low definition signal (compatible with conventional receivers) and an error signal, to decide whether or not to transmit the error signal in respect of a particular part of the video image.</p> |
