# US 8,542,915 B1 · Systems and methods for color conversion using intelligent boundary point perturbation

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- Number: US 8,542,915 B1
- Document ID: US8542915B1
- Status: Granted
- Kind: B1
- Application number: 13/163,282
- Filed: 2011-06-17
- Granted: 2013-09-24
- Earliest claimed: 2010-06-18
- Assignees: CSR Imaging US, LP
- Applicants: Fred Andree; Thomas A. Schuneman
- Inventors: Fred Andree; Thomas A. Schuneman
- Web page: https://patentgrep.com/patent/US8542915B1

## CPC

- H04N 1/6019: {using look-up tables (H04N1/6025 takes precedence)}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Systems and methods which provide color conversion using intelligent boundary point perturbation techniques are shown. Embodiments operate to initially select only boundary point indices for indexing data of an input color space to a color space transformation matrix representing the transformation between the input color space and an output color space. A boundary point perturbation process is applied to the initially selected boundary point indices to intelligently alter the boundary point index selections and thereby provide selection of boundary point indices having intelligent boundary point perturbation. Embodiments of the invention utilize an intelligent address generator to selectively apply constraints when indexing the input color space values to boundary points within a color look up table for transforming the input color space values to appropriate output color space values using the boundary point indices provided by the boundary point perturbation process.

## Claims

### Claim 1

A method comprising:
receiving, at one or more processors, N-dimensional input color space pixel information;
selecting, at one of said one or more processors, a boundary point index individually for each input color space dimension of the N-dimensional input color space pixel information;
determining, at one of said one or more processors, using information based decision metrics, if one or more of the selected boundary point indices is to be adjusted; and
adjusting, at one of said one or more processors, the one or more of the selected boundary point indices according to the information based decision metrics to thereby implement an intelligent boundary point perturbation process.

### Claim 2 (depends on 1)

The method of claim 1, wherein the boundary point indices correspond to sub-unit nodes of a color look up table used in transforming the input color space pixel information into output color space pixel information.

### Claim 3 (depends on 2)

The method of claim 2, wherein the selecting the boundary point index individually for each input color space dimension comprises:
selecting the boundary point index for each input color space dimension without interpolation.

### Claim 4 (depends on 2)

The method of claim 2, wherein the selecting the boundary point index individually for each input color space dimension comprises:
using a one-dimensional look up table to map an input color space dimension value of the N-dimensional input color space pixel information to a respective boundary point index.

### Claim 5 (depends on 2)

The method of claim 2, wherein the selecting the boundary point index individually for each input color space dimension comprises:
selecting a lower boundary point index for any input color space pixel dimension value that falls between two boundary point indices.

### Claim 6 (depends on 1)

The method of claim 1, wherein the determining if one or more of the selected boundary point indices is to be adjusted comprises:
determining a perturbation threshold value for each input color space dimension independent of an input color space dimension value; and
using the perturbation threshold value in association with a boundary point perturbation index to determine if boundary point perturbation is to be applied.

### Claim 7 (depends on 6)

The method of claim 6, wherein the determining a perturbation threshold value for each input color space dimension independent of an input color space dimension value comprises:
using a pixel location of the N-dimensional input color space pixel information to determine the perturbation threshold value.

### Claim 8 (depends on 6)

The method of claim 6, wherein the using the perturbation threshold value in association with a boundary pint perturbation index comprises:
comparing the perturbation threshold value for an input color space dimension to boundary point offset information provided by the boundary point perturbation index.

### Claim 9 (depends on 1)

The method of claim 1, wherein information based decision metrics comprise a statistically derived noise matrix to control the boundary point index perturbation adjustment determination.

### Claim 10 (depends on 9)

The method of claim 9, wherein the noise matrix comprises a multi-dimensional matrix mapping pixel locations to information for control the boundary point index perturbation alteration determination.

### Claim 11 (depends on 1)

The method of claim 1, further comprising:
generating a color look up table address from the boundary point indices provided by the intelligent boundary point perturbation process, wherein the generated color look up table address maps to a particular boundary point in the color look up table providing output color space pixel information corresponding to the input color space pixel information.

### Claim 12 (depends on 11)

The method of claim 11, wherein the generating a color look up table address comprises:
determining if a boundary point constraint is to be implemented with respect to the boundary point indices; and
limiting the particular boundary points in the color look up table for which the color look up table address may be generated.

### Claim 13

A system comprising:
one or more computers comprising:
a boundary point mapper operable to individually index each input color space dimension value of a pixel of an input color space to a corresponding boundary point index, wherein the boundary point indices are associated with sub-unit nodes of a color space transformation matrix representing transformation between the input color space and an output color space; and
a boundary point perturbation system operable to determine, using information based decision metrics, if one or more boundary point indices, provided by the boundary point mapper, is to be altered and to alter the one or more boundary point indices according to the determinations.

### Claim 14 (depends on 13)

The system of claim 13, wherein the boundary point mapper comprises an index mapper for each dimension of the input color space.

### Claim 15 (depends on 14)

The system of claim 14, wherein the index mapper for each dimension of the input color space comprises a one-dimensional look up table mapping an associated input color space dimension value to at least one index, wherein the at least one index comprises a corresponding one of the boundary point indices.

### Claim 16 (depends on 15)

The system of claim 15, wherein the at least one index further comprises a boundary point perturbation index for use by the boundary point perturbation system in determining if the corresponding boundary point index is to be altered.

### Claim 17 (depends on 16)

The system of claim 16, wherein the boundary point perturbation index comprises a value derived from a distance the boundary point index is from the input color space dimension value.

### Claim 18 (depends on 13)

The system of claim 13, wherein the boundary point perturbation system comprises an additive boundary point index perturbation system.

### Claim 19 (depends on 18)

The system of claim 18, wherein the boundary point index for each input color space dimension comprises a lower boundary point index where any input color space pixel dimension value that falls between two boundary point indices.

### Claim 20 (depends on 13)

The system of claim 13, wherein the information based decision metrics comprise:
a statistically derived noise matrix for each dimension of the input color space.

### Claim 21 (depends on 20)

The system of claim 20, wherein the noise matrix for each dimension of the input color space provides a threshold value for an associated input color space dimension value for use in determining when to alter initially selected boundary point indices.

### Claim 22 (depends on 20)

The system of claim 20, wherein the boundary point perturbation system further comprises:
a comparator for each dimension of the input color space.

### Claim 23 (depends on 22)

The system of claim 22, wherein the comparator for each dimension of the input color space provides a comparison of a boundary point perturbation index provided by the boundary point mapper and a threshold provided by a corresponding one of the statistically derived noise matrices for determining when to alter initially selected boundary pint indices.

### Claim 24 (depends on 22)

The system of claim 22, wherein the boundary point perturbation system further comprises:
an adder for each dimension of the input color space.

### Claim 25 (depends on 24)

The system of claim 24, wherein the adder for each dimension of the input color space provides a sum of a boundary point index provided by the boundary point mapper and an output of an associated one of the comparators.

### Claim 26 (depends on 13)

The system of claim 13, further comprising:
an intelligent address generator operable to map boundary point indices provided by the boundary point mapper, as altered by the boundary point perturbation system, to appropriate addresses of the color space transformation matrix representing transformation between the input color space and the output color space.

### Claim 27 (depends on 26)

The system of claim 26, wherein the intelligent address generator is operable to apply boundary point mapping constraints with respect to particular input color space input values.

### Claim 28 (depends on 26)

The system of claim 26, wherein the color space transformation matrix comprises N-dimensional color look up table, wherein N is equal to the dimensions of the input color space.

### Claim 29

A computer program product for wireless communications in a wireless network, comprising:
a non-transitory computer-readable medium having program code recorded thereon, said program code comprising:
program code to select a boundary point index individually for each input color space dimension of N-dimensional input color space pixel information;
program code to determine, using information based decision metrics, if one or more of the selected boundary point indices are to be adjusted; and
program code to adjust the one or more of the selected boundary point indices according to the determination to thereby provide an intelligent boundary point perturbation process.

### Claim 30 (depends on 29)

The computer program product of claim 29, wherein the boundary point indices correspond to sub-unit nodes of a color look up table used in transforming the input color space pixel information into output color space pixel information.

### Claim 31 (depends on 30)

The computer program product of claim 30, wherein the program code to select the boundary point index for each input color space dimension uses a one-dimensional look up table to map an input color space dimension value of the N-dimensional input color space pixel information to a respective boundary point index.

### Claim 32 (depends on 30)

The computer program product of claim 30, wherein the program code to select the boundary point index for each input color space dimension comprises:
program code to select a lower boundary point index for any input color space pixel dimension value that falls between two boundary point indices.

### Claim 33 (depends on 29)

The computer program product of claim 29, wherein the program code to determine if one or more of the selected boundary point indices is to be adjusted comprises:
program code to determine a perturbation threshold value for each input color space dimension independent of an input color space dimension value; and
program code to determine if boundary point perturbation is to be applied using the perturbation threshold value in association with a boundary point perturbation index.

### Claim 34 (depends on 33)

The computer program product of claim 33, wherein the program code to determine a perturbation threshold value for each input color space dimension independent of an input color space dimension value uses a pixel location of the N-dimensional input color space pixel information to determine the perturbation threshold value.

### Claim 35 (depends on 33)

The computer program product of claim 33, wherein the program code to determine if boundary point perturbation is to be applied using the perturbation threshold value in association with a boundary pint perturbation index comprises:
program code to compare the perturbation threshold value for an input color space dimension to boundary point offset information provided by the boundary point perturbation index.

### Claim 36 (depends on 29)

The computer program product of claim 29, wherein the information based decision metrics comprise a statistically derived noise matrix to control a boundary point index perturbation alteration determination.

### Claim 37 (depends on 36)

The computer program product of claim 36, wherein the noise matrix comprises a multi-dimensional matrix mapping pixel locations to information for control the boundary point index perturbation alteration determination.

### Claim 38 (depends on 29)

The computer program product of claim 29, further comprising:
program code to generate a color look up table address from the boundary point indices, wherein the generated color look up table address maps to a particular boundary point in the color look up table providing output color space pixel information corresponding to the input color space pixel information.

### Claim 39 (depends on 38)

The computer program product of claim 38, wherein the code to generate a color look up table address comprises:
code to determine if a boundary point constraint is to be implemented with respect to the boundary point indices; and
code to limit the particular boundary points in the color look up table for which the color look up table address may be generated.