Method and system for separating illumination and reflectance using a log color space
First Claim
1. An automated computerized method for generating an illumination invariant, chromaticity representation of an image, comprising the steps of:
- providing an image comprising an array of pixels, each pixel having N band color values;
transforming the N bands to log color space values in a log color space;
generating a bi-illuminant chromaticity plane in the log color space; and
projecting the log color space values to the chromaticity plane to provide chromaticity representation values corresponding to the pixels of the image.
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Abstract
In a first exemplary embodiment of the present invention, an automated, computerized method for generating an illumination invariant, chromaticity representation of an image is provided. The method of the present invention comprises the steps of providing an image comprising an array of pixels, each pixel having N band color values, transforming the N bands to log color space values in a log color space, generating a bi-illuminant chromaticity plane in the log color space and projecting the log color space values to the chromaticity the plane to provide chromaticity representation values corresponding to the pixels of the image.
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Citations
27 Claims
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1. An automated computerized method for generating an illumination invariant, chromaticity representation of an image, comprising the steps of:
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providing an image comprising an array of pixels, each pixel having N band color values;
transforming the N bands to log color space values in a log color space;
generating a bi-illuminant chromaticity plane in the log color space; and
projecting the log color space values to the chromaticity plane to provide chromaticity representation values corresponding to the pixels of the image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 24, 25, 26, 27)
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13. An automated computerized method for generating an illumination invariant, material image, comprising the steps of:
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providing an original image comprising an array of pixels, each pixel having N band color values;
generating a histogram on a bi-illuminant chromaticity plane, the histogram being divided into bins;
calculating an envelope value for each bin of the histogram;
co-relating each of the pixels of the original image to a corresponding bin of the histogram; and
mapping the N band color values of each pixel to the envelope value of the co-related bin to provide the material image. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A computer system which comprises:
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a CPU; and
a memory storing an image file defining an image comprising an array of pixels, each pixel having N band color values;
the CPU being arranged and configured to execute a routine;
to transform the N bands to log color space values in a log color space;
to generate a bi-illuminant chromaticity plane in the log color space; and
to project the log color space values to the chromaticity plane to provide chromaticity representation values corresponding to the pixels of the image.
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23. A computer system which comprises:
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a CPU; and
a memory storing an image file defining an image comprising an array of pixels, each pixel having N band color values;
the CPU being arranged and configured to execute a routine;
to generate a histogram on a bi-illuminant chromaticity plane, the histogram being divided into bins;
to calculate an envelope value for each bin of the histogram;
to co-relate each of the pixels of the original image to a corresponding bin of the histogram; and
to map the N band color values of each pixel to the envelope value of the co-related bin to provide the material image.
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Specification