Television – Image signal processing circuitry specific to television – Matrixing or mixing
Patent
1993-09-08
1999-06-01
Harvey, David E.
Television
Image signal processing circuitry specific to television
Matrixing or mixing
348720, H04N 967
Patent
active
059092548
ABSTRACT:
A method and apparatus for increasing the processing speed or decreasing circuit complexity (or both) of a digital image processor by eliminating the conventional multiplication operation from the RGB to YUV and YUV to RGB transforms having NTSC compatible equation coefficients. In particular, the change of color-basis matrix for converting RGB data to obtain YUV data is factored into a scale factor and a coefficient matrix. The coefficient matrix contains coefficients such that its product with the RGB input vector can be performed using only seven binary additions and five shift operations. This process effectively removes the conventional multiplication operations from the RGB to YUV conversion. The scale factor is conveniently absorbed into the quantization of the YUV data before transmission. The quantization process includes a multiplication already and the two multiplication steps are folded into one step. Therefore, the absorption of the scale factor into the quantization step does not increase the processing time because no multiplication steps are added. This process of factoring the transform matrix is also applied to the inverse transform process. In the inverse transform process the change of color-basis matrix for converting YUV data to RGB data is such that its implementation reduced to five addition steps and two shift steps, again effectively eliminating the conventional multiplication operations. Also, the diagonal matrix is absorbed into the descaling process so that no multiplication steps are added to the inverse transform process.
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Feig Ephraim
Linzer Elliot
Harvey David E.
International Business Machines - Corporation
Morris Daniel P.
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