| 摘要 |
<p>PURPOSE:To decide validity/invalidity corresponding to the spatial resolution of humane vision and to improve the quality of a picture by weighting the spatial frequency characteristics of an image signal and an inter-frame predictive error signal corresponding to the human vision to variably control a threshold. CONSTITUTION:An image signal processor 8 transforms orthogonally an image signal with the unit of block to transform a two dimensional spatial frequency characteristic, and executes the weighting corresponding to the characteristics of the spatial resolution of the human vision, and calculates the loading power P1 of the image signals in the block. In the meantime, an inter-frame predictive error signals obtained by a subtractor 1 are weighted similarly by an error signal processor 9 to generate a spatial frequency characteristic, and from this characteristic, the loading power P2 of the inter-frame predictive error signal in the block is calculated. A controller 10, in accordance with the values of the loading powers P1, P2, modifies a threshold T1 for the decision of a validity/invalidity decision device 3. As a result, the device 3 can executes a decision on validity/invalidity corresponding to the spatial resolution of the human vision.</p> |
