US 5,510,839 AGranted

Image encoding and transmitting system

AssigneeFujitsu Limited

InventorsTakashi Hamano, Kiyoshi Sakai, Kiichi Matsuda

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Abstract

An image encoding and transmitting system is an image transmission system for transmitting digital data such as TV telephones. The system for dividing input frame data into a plurality of blocks before transmitting them comprises on its sending side an intra-frame/inter-frame determiner for receiving intra-frame data and inter-frame data and selecting either of them for output, and a difference collator for having the intra-frame/inter-frame determiner compulsorily output intra-frame data at the time of data input for the next frame when one or more data in each block forming inter-frame data are larger than a predetermined threshold. The system also comprises on its receiving side an picture element domain frame data storage for storing received data in the picture element domain, and a motion vector detector for detecting according to the contents in the storage a motion vector using the data in the block surrounding the discarded block in order to guess the data in the discarded block.

Claims6

Dependent claims

An image encoding and transmitting system used in an image transmission system for dividing inputted frame image data into blocks comprising a plurality of picture elements, encoding said data in block units, and transmitting said encoded data in packet units, said system comprising:

a motion vector detector on a sending side of said image transmission system for detecting a motion vector for each of said blocks and sending said motion vector to a receiving side,
an inverse discrete cosine transform unit on said receiving side for performing an inverse discrete cosine transform on received data,
an adder for adding the present frame data as an output from said inverse discrete cosine transform unit to data obtained by multiplying the delay result obtained, by delaying data in the preceding frame according to a motion vector received from said sending side by a leak coefficient .alpha.,
a frame memory for storing an output of said adder,
a motion compensation replacement unit (MC) for replacing the data for a block whose encoded data are not received due to packet-discard using a motion vector received from said sending side and the content stored in said frame memory when a packet discard detection signal is inputted,
a variable delay unit for delaying an output from said frame memory according to a motion vector received from said sending side,
a leak coefficient unit for multiplying an output from said variable delay unit by a leak coefficient .alpha. and outputting-the product to said adder.

4 more elements

Dependencies are inferred from the claim text.