Graphic information compression method and system
AssigneeRicoh Company, Ltd.
InventorYasuyuki Komura
Life of this patent
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Abstract
Graphic information is encoded in the form of an electrical pulse train, which is divided into a number of blocks of equal length. Only those blocks containing pulses are retained, and are combined for transmission with a decoding signal for subsequent synthesis of the original pulse train. The compression efficiency may be further increased by converting the pulse train into delta graphic form, or a modified delta graphic form in which extremely short pulses are suppressed prior to compression.
Claims11
A method of compressing graphic information for transmission which is encoded in the form of an electrical pulse train in which an original graphic document is scanned in a regular orthogonal pattern having a predetermined number of blocks of equal length and a predetermined number of lines of equal length to produce the electrical pulse train, the number of blocks per line thus being equal to the predetermined number of blocks divided by the predetermined number of lines, comprising the steps of:
- a. determining which of the blocks contain pulses and producing electrical block signals indicative thereof;
- b. combining in a predetermined arrangement the block signals and only those blocks containing pulses for transmission;
- c. determining which of the lines include blocks which contain pulses and producing electrical line signals indicative thereof;
- and
- d. combining the line signals with the block signals and only those blocks containing pulses in a second predetermined arrangement for transmission, the second predetermined arrangement being such that for each line, a line signal is followed by a block signal followed by only those blocks of the line containing pulses when the line contains at least one pulse, and only the line signal is provided when the line is devoid of pulses.
A system for compressing graphic information for transmission which is encoded in the form of an electrical pulse train in which an original graphic document is scanned in a regular orthogonal pattern having a predetermined number of blocks of equal length and a predetermined number of lines of equal length to produce the electrical pulse train, the number of blocks per line thus being equal to the predetermined number of blocks divided by the predetermined number of lines, comprising:
- first means into which the pulse train is fed and which is operative to determine which of the blocks contain pulses and produce electrical block signals indicative thereof;
- second means into which the pulse train is also fed, which is responsive to the output of the first means, and is operative to combine in a predetermined arrangement the block signals and only those blocks containing pulses for transmission;
- and
- third means communicating with at least one of the first and second means and being operative to determine which of the lines include blocks which contain pulses and produce electrical line signals indicative thereof, the second means being further operative to combine the line signals with the block signals and only those blocks containing pulses in a second predetermined arrangement for transmission, the second predetermined arrangement being such that for each line, a line signal is followed by a block signal followed by only those blocks of the line containing pulses when the line contains at least one pulse, and only the line signal is provided when the line is devoid of pulses.
A system for transmission and reception of graphic information which is encoded in the form of an electrical pulse train divided into a predetermined number of blocks of equal length, comprising, in combination, a transmission unit, a communication link and a receiving unit, the transmission unit comprising;
- first means into which the pulse train is fed and which is operative to determine which of the blocks contain pulses and produce an electrical block signal indicative thereof;
- and
- second means into which the pulse train is also fed, which is responsive to the output of the first means, and is operative to combine in a predetermined arrangement the block signal and only those blocks containing pulses for transmission;
- the communications link being arranged to convey the output of the second means to the receiving unit, the receiving unit comprising;
- first storage means responsive to the output of the second means and operative to store only the transmitted blocks;
- second storage means responsive to the output of the second means and operative to store only the block signal;
- and
- gate means having access to the contents of the first and second storage means and being operative to, according to the predetermined arrangement, generate blocks devoid of pulses where indicated by the block signal and gate therethrough blocks containing pulses where indicated by the block signal to thereby synthesize the original electrical pulse train.
Dependencies are inferred from the claim text.