| 摘要 |
<p>PURPOSE:To prevent the omission of the sematic state of a picture including a straight line character or the like important visually by providing an interpolation sub-filter and an evaluation circuit having the same characteristic as an interpolation filter in a preamplifier. CONSTITUTION:One line delay circuits 16, 17 supply data equivalent to three lines required for interpolating to the interpolation sub-filters 19, 20 or the evaluation circuit 18 or the like. The selection of the two sub-filters 19, 20 is decided according to the difference between corresponding neighboring transmission picture elements. This is carried out by the evaluation circuit 18. The preamplifier is constituted of one line delay circuits 1, 2, a delay circuit 6, the evaluation circuit 3, the interpolation sub-filters A and B. A decision circuit 11 operates the interpolation error of the interpolation filters A, B. Then, when it is decided that the interpolation error is large, the levels of the neighboring transmission points are changed by three presub-filters C-E, thereby, a large visual deterioration can be prevented.</p> |
