| 摘要 |
PURPOSE:To obtain a masking arithmetic unit that can save the desired capacity of a table memory by using the output of a computing element as the read address of the table memory and calculating the secondary member of an arithmetic formula with reference to the table memory. CONSTITUTION:The table memories 1-3 obtain Y1=a1R+alpha4R<2>, Y2=a2G+alpha5G<2> and Y3=a3B+alpha6B<2> at every color. The subtractors 4-6 obtain the subtraction values R-G, G-B and B-R between two colors. Then the absolute value circuits 7-9 obtain the absolute values ¦R-G¦, ¦G-B¦ and ¦B-R¦ for each subtraction value. These subtraction outputs are used as the read addresses to obtain Y4=alpha7¦R-G¦<2>, Y5=alpha8¦G-B¦<2> and Y6=alpha9¦B-R¦<2> from table memories 10-12 respectively. Then the outputs Y1-Y3 obtained from memories 1-3 are added with the outputs Y4-Y6 obtained from memories 10-12 by an adder 10 to obtain an output Y=Y1+Y2+Y3+Y4+Y5+Y6. Thus it is possible to save the capacity of those table memories and to attain the accurate color reproducibility via an inexpensive arithmetic unit. |
