| 摘要 |
<p>PURPOSE: To provide a picture data encoder capable of improving the picture quality of blocks provided with edges and improving the quality of the entire pictures. CONSTITUTION: In this picture data encoder provided with a block division means 1 for dividing a screen into the blocks composed of plural picture elements, a DCT processing means 2 for transforming pixel data for the respective blocks to a DCT (discrete cosine transformation) coefficient by discrete cosine transformation, a quantization means 3 for linearly quantizing the DCT coefficient by using a quantization table and an encoding means 4 for variable length encoding the quantized data, an edge detection means 5 for detecting whether or not the edge is present in the divided blocks and a quantization control means 6 for selecting a table whose step size is small as the quantization table to be used by the quantization means when the edge is present in the block are provided. A large information amount is allocated when the edge is provided inside the block and a small information amount is allocated when the edge is not allocated inversely.</p> |
