COMPRESSED IMAGE SCRAMBLE TRANSMITTER, ITS RECEIVER, ITS TRANSMITTER-RECEIVER, ITS TRANSMISSION METHOD, ITS RECEPTION METHOD, ITS TRANSMISSION RECEPTION METHOD AND ITS RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a normal image to a rightful person and an image with image quality, which is deteriorated to such a degree that people can vaguely grasp the contents, to a non-rightful person by scrambling only a motion vector part of a compressed image at the transmission of the compressed image and descrambling the scrambled compressed image at its expansion. SOLUTION: A compressed image scrambler that applies compression to an image consisting of an input image signal and scrambling processing to the compressed image, consists of encoding means (22, 24-31) that apply encoding to the input image signal, a motion detection means 23 that calculates motion vectors from the input image signal, and a means 33 that applies scramble processing to motion vectors selected among data which have the same bit length as that of substantial motion vectors and which are taken in the bit length in the scrambling of the motion vectors.