| 摘要 |
PURPOSE:To improve the precision of conversion and the conversion speed by providing three frame memories, a lookup table means, three latch means where picture data is latched, and an adder and operating multiplication with the look-up table means and operating addition with the adder. CONSTITUTION:A look-up table in a ROM 24 uses picture data from a latch circuit 20 as an argument to generate picture data whose value is obtained by multiplying the argument by a prescribed coefficient. For example, conversion formulas of YUV RGB are R=Y+1.403V, B=Y+1.773U, and G=1.704Y+(-0.509)R+(-0.194)B. Consequently, a relatively small-capacity memory having 5k-Ward storage capacity is sufficient as the ROM 24. An adder 26 adds picture data from the ROM 24 and the picture data from a latch circuit 22. The multiplication and addition of digital picture data are quickly processed with hardware in this manner to improve the conversion precision as well as the conversion speed.
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