| 摘要 |
A system and method for quality-based image compression utilizing adaptively sized blocks and sub-blocks of discrete cosine transform coefficient data an d a quality based quantization scale factor (100) is claimed. A block size assignment element (120) in an encoder element (104) selects the block or su b- block of an input block of pixel data to be processed. Blocks with variances larger than a threshold are subdivided, while blocks with variances smaller than a threshold are not subdivided. A transform element transforms the pixe l values of the selected blocks into the frequency domain (124). The frequency domain values are quantized (132, 134, 136, 144, 148) either on a block by block basis or a frame by frame basis utilizing a scale factor that correlat es with the quality of the image. The data is then serialized and coded (152) i n preparation for transmission. |
