Methods and apparatuses for applying different color calibrations at different locations in an imaging photometer measurement
View Patent ↗Systems and methods for applying different color calibrations at different locations in an imaging photometer measurement are disclosed herein. In one embodiment, a method for measuring a light source having a first area with a first spectral distribution and a second area having a second spectral power distribution can include selecting one or more data points in the first area for measurement. The method then includes applying a calibration to the selected data points in the first area such that a desired colorimetric result is displayed for each data point in a single colorimetric measurement of the first area. In several embodiments, the method can further include selecting one or more data points in the second area, and applying a different calibration to the selected portions of the second area such that a desired colorimetric result is also displayed for each data point in the second area.
1. A method for measuring a light source with an imaging photometer, the light source including a first area having a first spectral power distribution and a second area having a second spectral power distribution different than the first spectral power distribution, the method comprising:
determining standard chromaticity coordinates and luminance scalings for the first area and the second area of the light source;
selecting one or more data points in the first area and the second area for measurement;
calculating a first calibration for the first area and a second calibration for the second area using the standard chromaticity coordinates and luminance scalings;
applying the first calibration to the selected data points in the first area such that a desired colorimetric result is displayed for each data point in a single colorimetric measurement of the first area; and
applying the second calibration to the selected data points in the second area such that a desired colorimetric result is displayed for each data point in a single colorimetric measurement of the first area and second area.
2. The method of claim 1 wherein:
calculating a first calibration for the first area includes creating a first calibration matrix for the first area that is used to make three tristimulus values (X, Y, Z) as measured by the imaging photometer match three standard tristimulus values (X 0 , Y 0 , Z 0 ) of the first spectral power distribution of the first area; and
calculating a second calibration for the second area includes creating a second calibration matrix for the second area that is used to make three tristimulus values (X, Y, Z) as measured by the imaging photometer match three standard tristimulus values (X 0 , Y 0 , Z 0 ) of the second spectral power distribution of the second area.
3. The method of claim 1 wherein determining standard chromaticity coordinates and luminance scalings for the first area and the second area includes using a spectroradiometer to determine the chromaticity coordinates and luminance scalings.
4. The method of claim 1 wherein selecting one or more data points includes drawing a rectilinear selection area around the one or more data points in the first area and the second area.
5. The method of claim 1 wherein selecting one or more data points includes drawing a generally arcuate selection area around the one or more data points in the first area and the second area.
6. The method of claim 1 wherein selecting one or more data points includes drawing a selection area having a generally arbitrary shape around the one or more data points in the first area and the second area.
7. The method of claim 1 wherein the light source is a first light source, and wherein the method further comprises:
measuring a second light source different than the first light source, the second light source having a third area with a third spectral power distribution and a fourth area with a fourth spectal power distribution different than the third spectral power distribution, and wherein the first and second calibrations can be used to calibrate selected data points in the third and fourth areas, respectively.
8. A method for measuring a visual display, the method comprising:
providing a visual display including a first portion having a first spectral power distribution and a second portion having a second spectral power distribution different than the first spectral power distribution;
selecting a first set of data points in one of the first or second portions for measurement;
applying a first calibration to the selected first data points in one of the first or second portions such that a desired colorimetric result is displayed for each data point in a single colorimetric measurement of the selected portion, wherein applying a first calibration to the selected data points in the first portion includes creating a first calibration matrix for the first portion that is used to make three tristimulus values (X, Y, Z) as measured by the imaging photometer match three standard tristimulus values X 0 , Y 0 , Z 0 ) of the first spectral power distribution of the first portion;
selecting a second set of data points for calibration from the other one of the first or second portions; and
applying a second calibration to the selected second data points in the other one of the first or second portions such that a desired colorimetric result is displayed for each data point in a single colorimetric measurement of the first portion and the second portion of the visual display, wherein applying a second calibration to the selected data points in the second portion includes creating a second calibration matrix for the second portion that is used to make three tristimulus values (X, Y, Z) as measured by the imaging photometer match three standard tristimulus values (X 0 , Y 0 , Z 0 ) of the second spectral power distribution of the second portion.
9. The method of claim 8 wherein selecting a first or second set of data points includes drawing a rectilinear selection area around the selected data points.
10. The method of claim 8 wherein selecting a a first or second set of data points includes drawing a generally arcuate selection area around the selected data points.
11. The method of claim 8 wherein selecting a a first or second set of data points includes drawing a selection area having a generally arbitrary shape around the selected data points.
12. The method of claim 8 wherein providing a visual display includes providing at least one of an automobile instrument panel, a cockpit display, a signage display, and an organic light-emitting diode (OLED) display having at least two portions with different spectral characteristics.
13. A method for measuring a visual display with an imaging photometer, the visual display including a first area having a first spectral characteristic and a second area having a second spectral characteristic different than the first spectral characteristic, the method comprising:
determining standard chromaticity coordinates and luminance scalings for the first area and the second area;
calculating (a) a first preselected color calibration and luminance scaling for the first area using the standard chromaticity coordinates and luminance scalings, and (b) a second preselected color calibration and luminance scaling for the second area using the standard chromaticity coordinates and luminance scalings;
selecting at least a portion of the first area for measurement;
applying the first preselected color calibration and luminance scaling to the selected portion of the first area to reconfigure the selected portion of the first area in accordance with the first preselected color calibration and luminance scaling;
selecting at least a portion of the second area for measurement; and
applying the second preselected color calibration and luminance scaling to the selected portion of the second area to reconfigure the selected portion of the second area in accordance with the second preselected color calibration and luminance scaling.
14. The method of claim 13 wherein selecting a set of data points includes drawing a rectilinear selection area around the selected data points.
15. The method of claim 13 wherein selecting a set of data points includes drawing a generally arcuate selection area around the selected data points.
16. The method of claim 13 wherein selecting a set of data points includes drawing a selection area having a generally arbitrary shape around the selected data points.
17. A method for applying different color calibrations at different locations in an imaging photometer measurement, the method comprising:
measuring a source of light with an imaging photometer, the source of light having two or more portions with different spectral characteristics;
determining standard chromaticity coordinates and luminance scalings for each of the two or more portions with different spectral characteristics;
calculating a calibration matrix for each of the two or more portions using the standard chromaticity coordinates and luminance scalings; and
applying different color calibrations and luminance scalings at each of the two or more portions of the image measurement with different spectral characteristics.
18. A method for measuring a visual display, the method comprising:
measuring a light source with an imaging photometer and generating an image measurement, the light source including two or more portions having different spectral characteristics;
determining standard chromaticity coordinates and luminance scalings for each of the two or more portions of the light source;
calculating a calibration for each of the two or more portions using the standard chromaticity coordinates and luminance scalings; and
applying different color calibrations and luminance scalings at each of the two or more portions of the image measurement having different spectral characteristics.