| 摘要 |
PURPOSE:To output an edge of a character, a font and a line drawing generated artificially in an excellent way and to realize proper quantization for a picture from any input source with ease of configuration. CONSTITUTION:After multi-value picture information is transformed by orthogonal transformation, the result is compressed through quantization. Whether or not an edge is an edge generated artificially on an orthogonal transformation coordinate by a DCT circuit 101 is identified and the quantization condition is revised based on quantization tables 109, 110. The identification is implemented depending whether or not there is any component having a threshold level or over of an AC power of a high frequency or an AC absolute value. Moreover, the quantization condition is revised according to a relation of S1/S2<S1'/S2'<=1, where S1 is a quantization step at a low frequency and S2' is a quantization step of a high frequency. |
