Image data transmission using sub-band coding and intermediate recording

摘要

An image data recording and transmission system is described in which a data compressor 76 decorrelates input image data into sub band component data, a data recorder 78 stores the sub band data, a data decompressor 80 decompresses data read from the data recorder and a transmission signal generator 82 produces a bandwidth limited transmission signal from the decompressed data. The combined action of a data sequencer (18 Fig. 1), a quantiser (14) and an entropy encoder (20) within the data compressor act to remove from the data stream that information corresponding to frequencies not transmittable with the bandwidth limited transmission signal (e.g. PAL or NTSC) subsequently produced by a transmission signal generator 82. Accordingly. the data recorder need not use storage capacity recording data which cannot be used by the transmission signal generator.