Chromatic coordinate converting apparatus, imaging apparatus, computer readable recording medium, and creating method of chromatic coordinate converting table

1. A chromatic coordinate converting apparatus, comprising:

a storing unit storing information representing a plurality of chromaticity values of reference lights in a chromaticity coordinate system unique to a color sensor in advance; and

a converting unit performing a chromatic coordinate conversion of a first chromaticity value being a chromaticity value generated by said color sensor into a second chromaticity value of a predetermined chromaticity coordinate system based on the information stored by said storing unit, wherein

said converting unit comprises computing weighting ratios for a weighting synthesis of reference lights so that a chromaticity of said weighting synthesis of reference lights is equal to said first chromaticity value, and

said converting unit obtains said second chromaticity value by estimating a spectroscopic characterization of incident light for said color sensor based on said information and said first chromaticity value, and thereafter, by representing the spectroscopic characterization by said predetermined chromaticity coordinate system.

2. The chromatic coordinate converting apparatus according to claim 1 , further comprising

a spectroscopic storing unit storing spectroscopic information representing a plurality of spectroscopic characterization of said reference lights; wherein

said converting unit obtains said second chromaticity value by estimating a spectroscopic characterization of incident light for said color sensor using said spectroscopic information.

3. The chromatic coordinate converting apparatus according to claim 1 , further comprising

a second storing unit storing second information representing the plurality of chromaticity values of reference lights in said predetermined chromaticity coordinate system; wherein

said converting unit obtains said second chromaticity value by using said second information.

4. The chromatic coordinate converting apparatus according to claim 3 , wherein

said plurality of reference lights are composed of a plurality of monochromatic lights different from one another within a visual light range.

5. The chromatic coordinate converting apparatus according to claim 3 , wherein

said plurality of reference lights are composed of a plurality of monochromatic lights different from one another within a visual light range and white light.

6. The chromatic coordinate converting apparatus according to claim 4 , wherein

said converting unit:

estimates a part of said spectroscopic characterization of the incident light by assuming a closed curve connecting said plurality of reference chromaticity values in said unique chromaticity coordinate system, and one straight line passing on said first chromaticity value, and by performing the weighting synthesis of the spectroscopic characterizations of the reference lights having colors corresponding to intersection points of said closed curve and said straight line among said plurality of reference lights; and

estimates a whole of said spectroscopic characterization of the incident light by repeating said estimation while changing said straight line to obtain a plurality of estimated results, and by superimposing the above-stated estimated results.

7. The chromatic coordinate converting apparatus according to claim 6 , wherein

said converting unit takes off the estimated result from an object of said superimposing when said straight line is a straight line intersecting a red-violet light of said closed curve.

8. The chromatic coordinate converting apparatus according to claim 6 , wherein

said superimposing is a weighting superimposing, and

said converting unit sets the weighting ratio of said weighting superimposing in accordance with a spectroscopic characterization of a light source illuminating an object of detection of said color sensor.

9. An imaging apparatus, comprising:

a color imaging device; and

a chromatic coordinate converting apparatus according to claim 1 performing a chromatic coordinate conversion of a chromaticity value generated by said color imaging device.

10. A non-transitory computer readable recording medium for causing a computer to execute a chromatic coordinate converting program, comprising:

a storing operation storing information representing a plurality of chromaticity values of reference lights in a chromaticity coordinate system unique to a color sensor in advance; and

a converting operation performing a chromatic coordinate conversion of a first chromaticity value being a chromaticity value generated by said color sensor into a second chromaticity value of a predetermined chromaticity coordinate system based on the information stored in said storing operation, wherein

said converting operation comprises computing weighting ratios for a weighting synthesis of reference lights so that a chromaticity of said weighting synthesis of reference lights is equal to said first chromaticity value, and

said second chromaticity value is obtained by estimating a spectroscopic characterization of incident light for said color sensor based on said information and said first chromaticity value, and thereafter, by representing the spectroscopic characterization by said predetermined chromaticity coordinate system, in said converting operation.

11. The non-transitory computer readable recording medium according to claim 10 , further comprising

storing spectroscopic information representing a plurality of spectroscopic characterization of said reference lights; wherein

said second chromaticity value is obtained by estimating a spectroscopic characterization of incident light for said color sensor using said spectroscopic information.

12. The non-transitory computer readable recording medium according to claim 10 , further comprising

storing second information representing the plurality of chromaticity values of reference lights in said predetermined chromaticity coordinate system; wherein

obtaining said second chromaticity value by using said second information, in said converting operation.

13. The non-transitory computer readable recording medium according to claim 12 , wherein

said plurality of reference lights are composed of a plurality of monochromatic lights different from one another within a visual light range.

14. The non-transitory computer readable recording medium according to claim 12 , wherein

said plurality of reference lights are composed of a plurality of monochromatic lights different from one another within a visual light range and white light.

15. The non-transitory computer readable recording medium according to claim 13 , wherein

a part of said spectroscopic characterization of the incident light is estimated by assuming a closed curve connecting said plurality of reference chromaticity values in said unique chromaticity coordinate system and one straight line passing on said first chromaticity value, and by performing a weighting synthesis of spectroscopic characterizations of reference lights having colors corresponding to intersection points of said closed curb and said straight line among said plurality of reference lights, and

a whole of said spectroscopic characterization of the incident light is estimated by repeating said estimation while changing said straight line to obtain a plurality of estimated results and by superimposing the above-stated estimated results, in said converting operation.

16. The non-transitory computer readable recording medium according to claim 15 , wherein

the estimated result when said straight line is a straight line intersecting a red-violet light of said closed curve is taken off from an object of said superimposing, in said converting operation.

17. The non-transitory computer readable recording medium according to claim 15 , wherein

said superimposing is a weighting superimposing, and

the weighting ratio of said weighting superimposing is set in accordance with a spectroscopic characterization of a light source illuminating an object of detection of said color sensor, in said converting operation.

18. The chromatic coordinate converting apparatus according to claim 1 , wherein

said storing unit stores information of a plurality of reference chromaticity values generated by said color sensor in accordance with each of a plurality of reference lights of which spectroscopic characterizations are already known, and

said converting unit estimates said spectroscopic characterization of the incident light by performing a weighting synthesis of said spectroscopic characterizations of the plurality of reference lights with a weighting ratio in accordance with a relation between said plurality of reference chromaticity values and said first chromaticity value.

19. The chromatic coordinate converting apparatus according to claim 10 , wherein

a plurality of reference chromaticity values generated by said color sensor in accordance with each of a plurality of reference lights of which spectroscopic characterizations are already known are stored, in the stored operation, and

said spectroscopic characterization of the incident light is estimated by performing a weighting synthesis of said spectroscopic characterizations of the plurality of reference lights with a weighting ratio in accordance with a relation between said plurality of reference chromaticity values and said first chromaticity value, in said converting operation.