DIGITAL TV BROADCASTING TRANSMITTER AND ITS RECEIVER

摘要

PROBLEM TO BE SOLVED: To reduce image degradation by performing discrete cosine transformation(DCT) of an image signal and multiplexing block distortion occurrence information when a DCT coefficient is quantized and compressed to a compressed image signal to be transmitted. SOLUTION: An original image to be transmitted is supplied to an encoder 11 to be subjected to compression processing. The compressed image signal is supplied to a multiplexing circuit 12 and also supplied to a decoder 13. The decoder 13 performs expansion processing of the compressed image signal. A comparator circuit 14 compares the expanded image with the original image to detect the occurrence of block distortion. Block distortion occurrence information obtained from an output of the circuit 14 undergoes time division multiplexing with image information compressed by the circuit 12. The compressed digital image signal is modulated and amplified by a modulation/ comparator circuit 15 to be transmitted. A digital TV broadcasting receiver detects the block distortion occurrence information and reduces the effects of block distortion by smoothly connecting a block where the distortion is developed and adjacent blocks by performing smooth filter processing.