Digital video color processor with anti-aliasing filter

Claim 1

A system for digitally processing a digital signal representing digitized color images, by generating from the digital signal a set of transformed component signals corresponding to different polynomial terms of a color transformation, including: a first low-pass filter for receiving the digital signal and generating a first filtered signal therefrom; a second low-pass filter, connected in parallel with the first low-pass filter, for receiving the digital signal and generating a second filtered signal therefrom; a first color correction circuit for receiving the first filtered signal and applying thereto a first order polynomial term of the color transformation to generate a first transformed component signal, wherein the first color correction circuit has a first clock frequency; and a second color correction circuit for receiving the second filtered signal and applying thereto a second order polynomial term of the color transformation to generate a second transformed component signal, wherein the second color correction circuit has a second clock frequency, wherein the first filtered signal has no significant frequency components with frequency greater than half the first clock frequency, and the second filtered signal has no significant frequency components with frequency greater than one fourth of the second clock frequency.

Claim 2

A system for digitally processing a digital signal representing digitized color images, by generating from the digital signal a set of transformed component signals corresponding to different polynomial terms of a color transformation, including: a first low-pass filter for receiving the digital signal and generating a first filtered signal therefrom; a second low-pass filter, connected in parallel with the first low-pass filter, for receiving the digital signal and generating a second filtered signal therefrom; a first color correction circuit for receiving the first filtered signal and applying thereto a first order polynomial term of the color transformation to generate a first transformed component signal, wherein the first color correction circuit has a first clock frequency; and a second color correction circuit for receiving the second filtered signal and applying thereto a second order polynomial term of the color transformation to generate a second transformed component signal, wherein the second color correction circuit has a second clock frequency, wherein the first filtered signal has no significant frequency components with frequency greater than half the first clock frequency, and the second filtered signal has no significant frequency components with frequency greater than one fourth of the second clock frequency.

Claim 6

A system for digitally performing a color transformation on a digital signal representing digitized color images, including: a set of parallel low-pass filters, each for receiving the digital signal and removing frequency components of the digital signal above a selected cutoff frequency, to reduce aliasing during subsequent color correction; a set of color correction circuits, each for receiving a filtered output signal from a different one of the set of the low-pass filters and applying thereto a polynomial term of a color transformation to generate a transformed component signal; and means for combining the transformed component signals to produce a transformed digital signal.

Claim 7

A system for digitally performing a color transformation on a digital signal representing digitized color images, including: a set of parallel low-pass filters, each for receiving the digital signal and removing frequency components of the digital signal above a selected cutoff frequency, to reduce aliasing during subsequent color correction; a set of color correction circuits, each for receiving a filtered output signal from a different one of the set of the low-pass filters and applying thereto a polynomial term of a color transformation to generate a transformed component signal; and means for combining the transformed component signals to produce a transformed digital signal.

Claim 8

A system for digitally processing a digital signal comprising a red data stream, a blue data stream, and a green data stream, by generating from each of the red data stream, the blue data stream, and the green data stream a set of transformed component signals corresponding to different color transformation polynomial terms, including: a first set of low-pass filters for receiving the red data stream and generating therefrom a first set of filtered signals; a second set of low-pass filters for receiving the green data stream and generating therefrom a second set of filtered signals; a third set of low-pass filters for receiving the blue data stream and generating therefrom a third set of filtered signals; a first group of color correction circuits for receiving the first set of filtered signals and applying to each filtered signal in the first set a different polynomial term of a first color transformation, wherein the first set of low-pass filters ensures that application of each said polynomial term to each filtered signal in the first set does not result in an attempt to introduce frequency components having greater than half the clock frequency of each color correction circuit of the first group of color correction circuits receiving said filtered signal in the first set, which attempt would otherwise introduce aliasing; a second group of color correction circuits for receiving the second set of filtered signals and applying to each filtered signal in the second set a different polynomial term of a second color transformation, wherein the second set of low-pass filters ensures that application of each said polynomial term to each filtered signal in the second set does not result in an attempt to introduce frequency components having greater than half the clock frequency of each color correction circuit of the second group of color correction circuits receiving said filtered signal in the second set, which attempt would otherwise introduce aliasing; and a third group of color correction circuits for receiving the third set of filtered signals and applying to each filtered signal in the third set a different polynomial term of a third color transformation, wherein the third set of low-pass filters ensures that application of each said polynomial term to each filtered signal in the third set does not result in an attempt to introduce frequency components having greater than half the clock frequency of each color correction circuit of the third group of color correction circuits receiving said filtered signal in the third set, which attempt would otherwise introduce aliasing.

Claim 9

A system for digitally processing a digital signal comprising a red data stream, a blue data stream, and a green data stream, by generating from each of the red data stream, the blue data stream, and the green data stream a set of transformed component signals corresponding to different color transformation polynomial terms, including: a first set of low-pass filters for receiving the red data stream and generating therefrom a first set of filtered signals; a second set of low-pass filters for receiving the green data stream and generating therefrom a second set of filtered signals; a third set of low-pass filters for receiving the blue data stream and generating therefrom a third set of filtered signals; a first group of color correction circuits for receiving the first set of filtered signals and applying to each filtered signal in the first set a different polynomial term of a first color transformation, wherein the first set of low-pass filters ensures that application of each said polynomial term to each filtered signal in the first set does not result in an attempt to introduce frequency components having greater than half the clock frequency of each color correction circuit of the first group of color correction circuits receiving said filtered signal in the first set, which attempt would otherwise introduce aliasing; a second group of color correction circuits for receiving the second set of filtered signals and applying to each filtered signal in the second set a different polynomial term of a second color transformation, wherein the second set of low-pass filters ensures that application of each said polynomial term to each filtered signal in the second set does not result in an attempt to introduce frequency components having greater than half the clock frequency of each color correction circuit of the second group of color correction circuits receiving said filtered signal in the second set, which attempt would otherwise introduce aliasing; and a third group of color correction circuits for receiving the third set of filtered signals and applying to each filtered signal in the third set a different polynomial term of a third color transformation, wherein the third set of low-pass filters ensures that application of each said polynomial term to each filtered signal in the third set does not result in an attempt to introduce frequency components having greater than half the clock frequency of each color correction circuit of the third group of color correction circuits receiving said filtered signal in the third set, which attempt would otherwise introduce aliasing.

Claim 13

A method for digitally performing a color transformation on a digital signal representing digitized color images, including the steps of: generating a first low-pass filtered signal from the digital signal; generating a second low-pass filtered signal from the digital signal; applying a first order polynomial term of a color transformation to the first low-pass filtered signal to generate a first transformed component signal; and applying a second order polynomial term of a color transformation to the second low-pass filtered signal to generate a second transformed component signal.

Claim 14

A method for digitally performing a color transformation on a digital signal representing digitized color images, including the steps of: generating a first low-pass filtered signal from the digital signal; generating a second low-pass filtered signal from the digital signal; applying a first order polynomial term of a color transformation to the first low-pass filtered signal to generate a first transformed component signal; and applying a second order polynomial term of a color transformation to the second low-pass filtered signal to generate a second transformed component signal.

Claim 17

A method for digitally performing a color transformation on a digital signal representing digitized color images, including the steps of: generating a set of low-pass filtered signals, wherein each of the low-pass filtered signals is generated by removing frequency components of the digital signal above a selected cutoff frequency to reduce aliasing during subsequent color transformation; and applying a different polynomial term of a color transformation to each of the low-pass filtered signals, to generate a set of transformed component signals.

Claim 18

A method for digitally performing a color transformation on a digital signal representing digitized color images, including the steps of: generating a set of low-pass filtered signals, wherein each of the low-pass filtered signals is generated by removing frequency components of the digital signal above a selected cutoff frequency to reduce aliasing during subsequent color transformation; and applying a different polynomial term of a color transformation to each of the low-pass filtered signals, to generate a set of transformed component signals.