Method for transforming color signal and apparatus for executing the method

An apparatus for transforming color signals having four input signals representative of colors being each divided into the lower bits and the higher bits, comprising:

• basic data color correction memory means for producing basic data, when receiving an address signal as the combination of the higher bits;
• interpolation data generating means for generating the combinations of interpolation data in accordance with the combination of the higher bits and the combination of the lower bits;
• and
• adder means for adding the output signal of said color correction memory means and the output signal of said interpolation data generating means to thereby produce an output signal,
• said interpolation data generating means including means for dividing a 16-vertex body of each object to be interpolated into twenty-four 5-vertex bodies each passing through one of sixteen lattice points constituting the 16-vertex body, and for assigning the different combinations of interpolation data to the 5-vertex bodies in one-to-one correspondence manner.

A color signal transforming apparatus comprising:

• a start address/lower bit generating memory for receiving an address signal containing first and second input signals of four input signals representative of a first calorimetric coordinate to produce a start address previously set with consideration of a color reproduction range of an output device and the modified lower bits of the two input signals;
• maximum/minimum generating means for receiving an address signal containing said first and second input signals to generate the maximum and minimum values of a third input signal of the four input signals, with consideration of the color reproduction range of the output device;
• calculating means for modifying said third input signal using the maximum and minimum values output from said maximum/minimum generating means;
• an address adder for adding the start address output from said start address/lower bit generating memory and the higher bit of a fixed number of the modified result from said calculating means;
• a basic data color correction memory for producing basic data signals representative of colors of a second calorimetric coordinate in response to an address signal as the output signal of said address adder and a fourth input signal of the four input signals;
• interpolation data generating means for generating a set of interpolation data on the basis of the combination of the higher bits output from said address adder and the combination of the modified lower bits of said input signals;
• and
• adder means for producing output signals representative of colors of the second calorimetric coordinate by adding the output signal of said basic data color correction memory and the output signal of said interpolation data generating means;
• said interpolation data generating means including means for dividing a 16-vertex body of each object to be interpolated into twenty-four 5-vertex bodies each passing through one of sixteen lattice points constituting the 16-vertex body, and for assigning the different combinations of interpolation data to the 5-vertex bodies in one-to-one correspondence manner.