| 摘要 |
PURPOSE:To improve the reproduction picture quality by performing the adaptive coefficient selection to the coefficient distribution different for each picture element block in the transformed coding system to perform the adaptation processing. CONSTITUTION:By a blocking device 101, a rectangular region in an image is segmented as a picture element block from a digital image signal, an orthogonal transformation is performed by a transformation unit 103 and the transformation coefficients are obtained. An activity calculator 211 calculates the precision of an image in the block and a waveform analyzer 205 analyzes the waveform of the image. From the obtained precision and waveform information, an optimum mask is selected from a mask dictionary 209 by a mask selector 208. Based on the mask, the transformation coefficients are selected by a coefficient selector 105. The transformation coefficients after selection are quantized by a quantizer 107, coded by an encoder 109 and subsequently, outputted to a transmission line 111. |
