PICTURE DATA COMPRESSION MEANS

PURPOSE:To obtain a real reproduced picture with ease of data compression even when the brightness or color of the entire pattern are changed by using an addition means to a means value before or after compression of data operated by an arithmetic means. CONSTITUTION:The picture data picked up by a TV camera 12 is subjected to operation of a different Di of each picture element (i) corresponding to the preceding picture plane stored in the preceding picture plane memory 15 by a differential arithmetic section 14 and the result is fed to a normalized arithmetic section 3. The arithmetic section 3 calculates a means value X of the difference Di, the mean values X is subtracted from the difference Di, the result is coded and compressed by a compressing section 16, fed to a differential mean addition section 4, the mean value X calculated by the arithmetic section 3 and sent from a line control section 19. When the transmitted data is received by a line control section 22, the compressed data except the added mean value X is expanded by an expanding section 23 and the normalized data (Di-X) is sent to a restoration arithmetic section 24a. The arithmetic section 24a adds the mean value X, applies differentiation Di and the difference Di is added to the picture element (i) corresponding to the preceding pattern stored in the preceding picture plane memory 25 and recovered.