| 摘要 |
PURPOSE:To improve the conpressibility of picture data without losing the reproducibility of the picture by discriminating a section with a constant density level in the said picture data from the section whose density level is continuously changed, and encoding at every section. CONSTITUTION:An analog picture obtained from a original 1 is converted into a digital value by an A/D converter 2 and the converted output is supplied to a subtractor 1 and a delay circuit 4. The subtractor 3 calculates the absolute value and code of the density level difference between adjacent picture elements and the found absolute value and code are inputted a zero detector 5 and a density changing band encoder 6, respectively. When detecting the density difference ''0'' inputted from the subtractor 3, the detector 5 sends the detected signal to a run length encoder 8 and the encoder 6. The encoder 8 counts up the number of picture elements of a picture data during the detected signal is applied, and outputs a run length code at the time when the detected signal is reduced. The encoder 6 recognizes a division whose density level is continuously changed and generates a density changing band code and a discrimination code. Outputs from the encoders 6 and 8 are sent to a transmission line alternately through a switching circuit 10. |
