| 摘要 |
PURPOSE:To hold the quantity of generated information to a target value or below at a threshold value below a limit value and to prevent the degradation of restored picture quality by compressing the level of input data and after that, executing processings such as encoding when the generated information is much. CONSTITUTION:An analog signal from an input terminal 1 passes through an A/D converter 2 and is turned into a block by a block circuit 3. Maximum value/minimum value detecting circuits 4 and 5 detect the maximum value and the minimum value of every block and a subtracting circuit 7 obtaines a dynamic range (DR). Next, a frequency distribution generating circuit 8 obtains the integration-type frequency distribution of the DR, operates the information quantity through a buffering 9 and outputs the threshold value and a compressibility factor by which a transfer rate is fixed. Thus, when the information quantity is large, the data through a delay circuit 6 are compressed by a compressor 14, the threshold value does not become larger than the limit value at which the restored picture quality is degraded and they are encoded by an encoding circuit 20. Consequently, the degradation such as block distortion is not generated. |
