US 2007/0177230 A1 · Methods and apparatuses for determining a color calibration for different spectral light inputs in an imaging apparatus measurement

Abstract

Methods and apparatuses for determining a color calibration for different spectral light inputs in an imaging apparatus measurement are disclosed herein. In one embodiment, for example, a method for determining a color calibration for different spectral light inputs in an imaging apparatus measurement can include creating a reference color calibration and a reference luminance scaling calibration for each of a plurality of colors. The method can also include measuring a reference gray value R, G, B for each color in an image measurement of the light source. The method can further include calculating an R, G, B gray value for a first pixel in each of three filtered image measurements. The method can then include calculating pixel ratio values from each of the three first pixel gray values and comparing the reference gray values to the pixel ratio values to determine which one or more reference gray values are closest to the pixel ratio values. The method further includes calculating X, Y, Z values for the first pixel in the image measurement, and then repeating the steps of the method beginning with calculating an R, G, B gray value for each subsequent pixel in the image measurement.

Claims33

Dependent claims

A method for determining a color calibration for different spectral light inputs in an imaging apparatus measurement, the method comprising:

creating a reference color calibration and a reference luminance scaling calibration for each of a plurality of colors;
measuring a reference gray value R, G, B for each color in an image measurement of the light source;
calculating an R, G, B gray value for a first pixel in each of three filtered image measurements;
calculating pixel ratio values from each of the three first pixel gray values;
comparing the reference gray values to the pixel ratio values to determine which one or more reference gray values are most similar to the pixel ratio values;
calculating X, Y, Z values for the first pixel in the image measurement;
and
repeating the calculating an R, G, B gray value, calculating pixel ratio values, comparing the reference gray values, and calculating X, Y, Z values steps for each subsequent pixel in the image measurement.

5 more elements

A method for determining a color calibration for different spectral light inputs in an imaging photometer measurement of a light source, the method comprising:

(a) creating a reference color calibration and a reference luminance scaling calibration for each of a plurality of colors;
(b) selecting a reference color calibration and a reference luminance scaling for each particular color within an image measurement of the light source;
(c) measuring a reference gray value R, G, B for each color in the image measurement;
(d) normalizing the measured reference gray values such that each reference gray value is based on the same exposure time;
(e) capturing three filtered image measurements of the light source with the imaging photometer, the first filtered image measurement using a red color filter, the second filtered image measurement using a green color filter, and the third filtered image measurement using a blue color filter;
(e) calculating an R, G, B gray value for a first pixel in each of the three filtered image measurements;
(f) calculating pixel ratio values from each of the three first pixel gray values;
(g) determining which calculated reference gray values are most similar to the calculated pixel ratio values;
(h) calculating X, Y, Z values for the first pixel in the image measurement using one or more most similar reference color calibrations and one of more reference luminance scaling calibrations;
and
(i) repeating steps (e)-(h) for each of the remaining pixels in the image measurement.

8 more elements

A method for determining a color calibration for different spectral light inputs in an imaging photometer measurement of a light source, the method comprising:

(a) measuring brightness and color data for a plurality of different colors of the light source with a reference meter;
(b) measuring a reference gray value R, G, B for each color in the image measurement using the imaging photometer;
(c) normalizing the measured reference gray values such that each reference gray value is based on the same exposure time;
(d) calculating X, Y, Z values from the measured brightness and color date for each of the plurality of different colors of the light source;
(e) capturing three filtered image measurements of the light source with the imaging photometer, the first filtered image measurement using a red filter, the second filtered image measurement using a green filter, and the third filtered image measurement using a blue filter;
(f) calculating an R, G, B gray value for a first pixel in each of the three filtered image measurements;
(g) calculating pixel ratio values from each of the three first pixel gray values;
(h) determining which one or more calculated reference gray values are most similar to the calculated pixel ratio values;
(i) calculating a color calibration and a luminance scaling calibration for the first pixel;
(j) calculating X, Y, Z values for the first pixel in the image measurement using the color calibration and luminance scaling calibration from step (i);
and
(j) repeating steps (f)-(j) for each of the remaining pixels in the image measurement.

9 more elements

Dependencies are inferred from the claim text.

Methods and apparatuses for determining a color calibration for different spectral light inputs in an imaging apparatus measurement

Life of this patent

Methods and apparatuses for determining a color calibration for different spectral light inputs in an imaging apparatus measurement

Life of this patent

Abstract

Claims33