| 摘要 |
PURPOSE:To obtain a large compression rate in a natural image from a small- sized circuit scale by comparing a change in an image signal with an evaluation function decreased monotonously and outputting a distance between samples and a code in the changing direction as transmission values when a large change exists. CONSTITUTION:An input signal is A/D-converted by an A/D converter. A subtractor 6 calculates a difference between an initial value of an input signal and each sample. An output of a counter 4 is given to a ROM 8 as an address. An evaluation function decreased monotonously defined in a range in the unit of sample value is recorded in the ROM 8, a comparator 8 compares the said difference and the evaluation function and generates an output when the difference exceeds the evaluation function. A register 5 rewrites the initial value of the image signal by the output. The counter 4 counts the number of samples and is reset by the output of the comparator 9 and outputs the code of the result of the difference with the count value just before resetting as a transmission value. Thus, the part having a rapid change is finely sampled and the part of slow change is coarsely sampled. |
