Digital color correction system having gross and fine adjustment modes

A method for correcting a color video signal including a first color component signal, a second color component signal, and a third color component signal, by converting pixels, of the color video signal, whose color component signal values determine a first color, to corrected pixels whose color component signal values determine a second color, said method including the steps of:

• (a) processing the first color component signal in correction circuitry in accordance with a first transfer function to generate a first corrected color component signal, processing the second color component signal in the correction circuitry in accordance with a second transfer function to generate a second corrected color component signal, and processing the third color component signal in the correction circuitry in accordance with a third transfer function to generate a third corrected color component signal;
• (b) before performing step (a), controlling the correction circuitry in response to a control signal by automatically modifying all of the first transfer function, the second transfer function, and the third transfer function to cause the correction circuitry to operate in a mode converting each pixel of the color video signal whose color component signal values determine the first color into a corrected pixel of the corrected output video signal whose color component signal values determine the second color, wherein the first color is determined by a first value of the first color component signal, a second value of the second color component signal, and a third value of the third color component signal, and wherein said automatic modification of the first transfer function includes interpolation of values of the first transfer function in a limited selected range including said first value, in response to said control signal;
• and
• (c) before step (b), generating the control signal in a manner so that said control signal is indicative of data determining the first color and the second color.

A method for correcting a color video signal, said color video signal representing pixels of a color image and comprising a first color component signal, a second color component signal, and a third color component signal, by converting those of the pixels, whose color component signal values determine a first color, to corrected pixels, whose color component signal values determine a second color, said method including the steps of:

• (a) generating a control signal specifying the first color and the second color, said first color determined by a first value of the first color component signal, a second value of the second color component signal, and a third value of the third color component signal, and said second color determined by a fourth value of the first color component signal, a fifth value of the second color component signal, and a sixth value of the third color component signal;
• (b) in response to the control signal, supplying first transfer function data to a first color component correction circuit, second transfer function data to a second color component correction circuit, and third transfer function data to a third color component correction circuit, to cause said first, second, and third color component correction circuit, respectively, to implement a first transfer function, a second transfer function, and a third transfer function, wherein the first transfer function data include:
• data specifying replacement of said first value with said fourth value;
• and
• data specifying replacement of values of the first color component signal other than said first value, but in a selected range including said first value, with interpolated values;
• and
• (c) processing the first color component signal in the first color component correction circuit to generate a first corrected color component signal, processing the second color component signal in the second color component correction circuit to generate a second corrected color component signal, and processing the third color component signal in the third color correction circuit to generate a third corrected color component signal,
• wherein the first corrected color component signal, the second corrected color component signal, and the third corrected color component signal, determine said corrected pixels.

A system for correcting a color video signal, said color video signal representing pixels of a color image and comprising a first color component signal, a second color component signal, and a third color component signal, by converting those of the pixels, whose color component signal values determine a first color to corrected pixels, whose color component signal values determine a second color, said system including:

• means for generating a control signal specifying the first color and the second color, said first color determined by a first value of the first color component signal, a second value of the second color component signal, and a third value of the third color component signal, and said second color determined by a fourth value of the first color component signal, a fifth value of the second color component signal, and a sixth value of the third color component signal;
• a first color component correction circuit, including means for processing the first color component signal to generate a first corrected color component signal;
• a second color component correction circuit, including means for processing the second color component signal to generate a second corrected color component signal;
• a third color component correction circuit, including means for processing the third color component signal to generate a third corrected color component signal, wherein the first corrected color component signal, the second corrected color component signal, and the third corrected color component signal determine said corrected pixels;
• means for supplying first transfer function data to the first color component correction circuit, second transfer function data to the second color component correction circuit, and third transfer function data to the third color component correction circuit in response to the control signal, to cause said first, second, and third color component correction circuit, respectively, to process the first color component signal in accordance with a first transfer function, to process the second color component signal in accordance with a second transfer function, and to process the third color component signal in accordance with a third transfer function, wherein the first transfer function data include:
• data specifying replacement of said first value with said fourth value;
• and
• data specifying replacement of values of the first color component signal other than said first value, but in a selected range including said first value, with interpolated values.