| 摘要 |
PURPOSE:To make it possible to expand and contract easily a picture with small memory capacity by performing interpolaring arithmetic extraction of a sample TV signal by varying and setting independently to a period differing from a sampling period corresponding to the number of frames and respective horizontal and vertical scanning positions. CONSTITUTION:Picture elements of a TV signal with picture-element interval (h) and sampling frequency M are converted into those with picture-element interval (g) and sampling frequency N, which are outputted and displayed at intervals (h). At this time, the picture is contracted or expanded according to whether sampling-frequency ratio M/N=K is greater or less than one. Adder 11 adds together contraction-expansion ratio K and fine contraction-expansion ratio DELTAk and the sum is inputted to switch circuit 12. Circuit 12 extracts selectively and inputs set value ''0'' and K+DELTAk to adder 13, which performs addition to a picture-element ccoordinate position one sample before to outputs the sum. The output of adder 13 is delayed by one sampling period through delay circuit 14 and fed back to adder 13 for the calculation of the next coordinate position. Fine contraction-expansion ratio DELTAk operates on the basis of vertical synchronizing signal V, horizontal synchronizing signal H, frame signal F and a clock signal and is set freely, so that the contraction-expansion ratio can easily be caried. |
