PURPOSE: To reduce the capacity of a picture memory and to drastically shorten a processing time by adopting a system in which the preprocessing of an input picture is executed by means of inference based on a prescribed rule.

CONSTITUTION: When the input picture is generated by an image pickup means 1, an inferring means 2 executes the preprocessing for the picture by the inference based on the prescribed rule, and preprocessed data are stored into a memory means 3. By such a system, since an inference result is encoded, and the data of the input picture can be compressed, the capacity of a memory means can be reduced, and the processing time can be shortened. Further, by using a fuzzy rule for the rule in the inferring means, the inferring means can be composed with the use of a high-speed fuzzy processor, the high-speed and high-degree processing is attained, and the alteration of the contents of the preprocessing can be easily realized by replacing the fuzzy rule and altering the shape of a membership function.