Method for enhancing a digital image based upon pixel color

A digital image processing method for enhancing a color digital image composed of a plurality of pixels having color values representative of the image, said method comprising the steps of:

• a) identifying a local neighborhood of pixels including a pixel of interest;
• b) using the color values of one or more of the pixels from the local neighborhood to calculate a color weighting factor for the pixel of interest, the color weighting factor being a near continuous function of the location of said one or more pixels in a color space;
• c) applying a spatial filter to the values of pixels from the local neighborhood to calculate a first signal value and a second signal value for the pixel of interest;
• d) using the color weighting factor to modify the first signal value;
• e) generating an enhanced pixel value for the pixel of interest from the modified first signal value and the second signal value;
• and
• f) repeating steps (a) through (e) for other pixels in the color digital image;
• wherein step b) further comprises the steps of identifying one or more color regions in the color space, calculating a pixel color coordinate in the color space for the pixel of interest, and calculating the color weighting factor as a near continuous function of the pixel color coordinate and the one or more color regions.

A digital image processing method for enhancing a color digital image composed of a plurality of pixels having color values representative of the image, said method comprising the steps of:

• a) identifying a local neighborhood of pixels including a pixel of interest;
• b) using the color values of one or more of the pixels from the local neighborhood to calculate a color weighting factor for the pixel of interest, the color weighting factor being a near continuous function of the location of said one or more pixels in a color space;
• c) applying a spatial filter to the values of pixels from the local neighborhood to calculate a first signal value and a second signal value for the pixel of interest;
• d) using the color weighting factor to modify the first signal value;
• e) generating an enhanced pixel value for the pixel of interest from the modified first signal value and the second signal value;
• and
• f) repeating steps (a) through (e) for other pixels in the color digital image;
• and further comprising the steps of using the values of pixels sampled from the local neighborhood to calculate a statistical weighting factor for the pixel of interest and using the statistical weighting factor to modify either the first signal value or second signal value.

A digital image processing method for enhancing a color digital image composed of a plurality of pixels having color values representative of the image, said method comprising the steps of:

• a) identifying a local neighborhood of pixels including a pixel of interest;
• b) using the color values of one or more of the pixels from the local neighborhood to calculate a color weighting factor for the pixel of interest, the color weighting factor being a near continuous function of the location of said one or more pixels in a color space;
• c) applying a spatial filter to the values of pixels from the local neighborhood to calculate a first signal value and a second signal value for the pixel of interest;
• d) using the color weighting factor to modify the first signal value;
• e) generating an enhanced pixel value for the pixel of interest from the modified first signal value and the second signal value;
• and
• f) repeating steps (a) through (e) for other pixels in the color digital image;
• wherein the color digital image has red, green, and blue digital image channels, and further comprising the steps of calculating color difference values as linear combinations of the red, green, and blue digital image channels, and identifying the color regions and calculating the color weighing factors in color difference space.

A digital image processing method for enhancing a color digital image composed of a plurality of pixels having color values representative of the image, said method comprising the steps of:

• a) identifying a local neighborhood of pixels including a pixel of interest;
• b) using the color values of one or more of the pixels from the local neighborhood to calculate a color weighting factor for the pixel of interest, the color weighting factor being a near continuous function of the location of said one or more pixels in a color space;
• c) applying a spatial filter to the values of pixels from the local neighborhood to calculate a first signal value and a second signal value for the pixel of interest;
• d) using the color weighting factor to modify the first signal value;
• e) generating an enhanced pixel value for the pixel of interest from the modified first signal value and the second signal value;
• and
• f) repeating steps (a) through (e) for other pixels in the color digital image;
• and further comprising the steps of calculating color difference values as CIELAB a* and b* components, and identifying the color regions and calculating the color weighing factors in color difference space.

A digital image processing method for enhancing a color digital image composed of a plurality of pixels having color values representative of the image, said method comprising the steps of:

• a) identifying a local neighborhood of pixels including a pixel of interest;
• b) using the color values of one or more of the pixels from the local neighborhood to calculate a color weighting factor for the pixel of interest, the color weighting factor being a near continuous function of the location of said one or more pixels in a color space;
• c) applying a spatial filter to the values of pixels from the local neighborhood to calculate a first signal value and a second signal value for the pixel of interest;
• d) using the color weighting factor to modify the first signal value;
• e) generating an enhanced pixel value for the pixel of interest from the modified first sigal value and the second signal value;
• and
• f) repeating steps (a) through (e) for other pixels in the color digital image;
• and further comprising the steps of calculating color difference values as C* and H* components, and identifying the color regions and calculating the color weighing factors in color difference space.

A computer program product for enhancing a color digital image composed of a plurality of pixels having color values representative of the image, said computer program product comprising:

• a computer erasable storage medium having a computer program store thereon for performing the steps of:
• a) identifying a local neighborhood of pixels including a pixel of interest;
• b) using the color values of one or more of the pixels from the local neighborhood to calculate a color weighting factor for the pixel of interest, the color weighting factor being a near continuous function of the location of said one or more pixels in a color space;
• c) applying a spatial filter to the values of pixels from the local neighborhood to calculate a first signal value and a second signal value for the pixel of interest;
• d) using the color weighting factor to modify the first signal value;
• and
• e) generating an enhanced pixel value for the pixel of interest from the modified first signal value and the second signal value;
• f) repeating steps (a) through (e) for other pixels in the color digital image.

A computer program product for enhancing a color digital image composed of a plurality of pixels having color values representative of the image, said computer program product comprising:

• a computer erasable storage medium having a computer program store thereon for performing the steps of:
• a) identifying a local neighborhood of pixels including a pixel of interest;
• b) using the color values of one or more of the pixels from the local neighborhood to calculate a color weighting factor for the pixel of interest, the color weighting factor being a near continuous function of the location of said one or more pixels in a color space;
• c) applying a spatial filter to the values of pixels from the local neighborhood to calculate a first signal value and a second signal value for the pixel of interest;
• d) using the color weighting factor to modify the first signal value;
• and
• e) generating an enhanced pixel value for the pixel of interest from the modified first signal value and the second signal value;
• f) repeating steps (a) through (e) for other pixels in the color digital image;
• wherein step b) further comprises the steps of identifying one or more color regions in the color space, calculating a pixel color coordinate in the color space for the pixel of interest, and calculating the color weighting factor as a near continuous function of the pixel color coordinate and the one or more color regions.