US 7,310,105 B2Granted

Image signal processing device and image signal processing method

AssigneeMatsushita Electric Industrial Co., Ltd.

InventorKazuhiro Yamada

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Abstract

A first adding circuit sums an input image signal of a target pixel and a value that is derived by multiplying respective display errors of three pixels, which are before the target pixel by one line, by weighting factors. A gradation candidate converter converts the gradation of the summed image signal to a plurality of available gradation candidates that are convertible when an error of the immediate left pixel is added. A delaying circuit delays the summed image signal. A second adding circuit sums the delayed image signal and a value that is derived by multiplying the error generated in the immediate left pixel by a weighting factor. A gradation selector selects a gradation closest to the gradation of the image signal to which the error is added from a plurality of gradation candidates, and outputs it as an image signal of the target pixel. A differencing circuit determines a display error of the target pixel.

Claims4

Dependent claims

An image signal processing device for artificially displaying M gradations by converting an input image signal of M gradations to an output image signal of N (N<M) gradations and by diffusing an error generated by the conversion to a pixel around a corresponding pixel, the image signal processing device comprising:

first adding means for diffusing, to the input image signal, an error of which calculation is in time for the timing of diffusion to the input image signal of a certain pixel, of errors to be diffused to the certain pixel;
gradation candidate converting means for converting a gradation of the image signal of which error is diffused by the first adding means to a plurality of gradation candidates as gradation candidates of the output image signal;
delaying means for delaying the image signal of which error is diffused by the first adding means;
second adding means for diffusing, to the image signal delayed by the delaying means, an error of which calculation is not in time for the timing of diffusion to the input image signal of a certain pixel, of errors to be diffused to the certain pixel;
gradation selecting means for selecting one gradation as the output image signal from the plurality of gradation candidates that are converted by the gradation candidate converting means, based on a gradation of the image signal of which error is diffused by the second adding means;
and
error calculating means for calculating, as an error generated by the conversion, a difference between the gradation of the image signal of which error is diffused by the second adding means and the gradation selected as the output image signal by the gradation selecting means.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/542,025Filed 22 Dec 2004
Priority: JP 2003-43315326 Dec 2003
Published: US 2006/0291737 A128 Dec 2006
Granted: 18 Dec 2007
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H04N 1/40087
Picture signal circuits: multi-toning, i.e. converting a continuous-tone signal for reproduction with more than two discrete brightnesses or…
G09G 3/2066
Using error diffusion in time: with error diffusion in both space and time
H04N 1/4052
Producing a dispersed dots halftone pattern, the dots having substantially the same size: by error diffusion, i.e. transferring the binarising…
G09G 3/28
Using controlled light sources: using luminous gas-discharge panels, e.g. plasma panels