DIGITAL DATA COMPRESSING METHOD AND DEVICE

摘要

PROBLEM TO BE SOLVED: To maintain the quality of picture by detecting the local maximum value of histogram and calculating, based on a different measured between these maximum value and the average delta of these distances at a quantizing step so as to reduce the loss of a signal to noise ratio. SOLUTION: An original picture or a source picture coded in advance and then decoded is transferred to a decomposing circuit 10 executing discrete cosine transformation. Thus a histogram calculation circuit 11 sends a quantization step value to a quantization device 12 through a control circuit 13. The quantization device 12 sends a coefficient quantized to an entropy coder 14 supplying a coded binary stream. When the flow of sent data generating the supposition of incorrect calculation at the quantization step is very much larger than a net value, this entropy coder 14 is connected to the controller 13 for correcting the quantization step sent from the circuit 11.