Imaging device analysis methods, imaging device analysis systems, and articles of manufacture

• US 20060175531A1
• Filed: 02/08/2005
• Published: 08/10/2006
• Est. Priority Date: 02/08/2005
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: DiCarlo, Jeffrey M.
• Granted Patent: US 7,760,253 B2
• Time in Patent Office: Days
• US Class Current: 250/208.100
• CPC Class Codes: H04N 17/002 for television cameras

Abstract

Imaging device analysis methods, imaging device analysis systems, and articles of manufacture are described. According to one embodiment, an imaging device analysis method includes providing a plurality of first responsivity values corresponding to a first responsivity function of an imaging device, first determining that error associated with the first responsivity values is unacceptable, providing a plurality of second responsivity values corresponding to a second responsivity function of the imaging device responsive to the first determining, wherein the providing the second responsivity values comprises constraining the second responsivity values to comprise values of the same sign, second determining error associated with the second responsivity values, and selecting the second responsivity values responsive to the second determining yielding acceptable error.

Claims

1. An imaging device analysis method comprising:

providing a plurality of first responsivity values corresponding to a first responsivity function of an imaging device;

first determining that error associated with the first responsivity values is unacceptable;

providing a plurality of second responsivity values corresponding to a second responsivity function of the imaging device responsive to the first determining, wherein the providing the second responsivity values comprises constraining the second responsivity values to comprise values of the same sign;

second determining error associated with the second responsivity values; and

selecting the second responsivity values responsive to the second determining yielding acceptable error.

2. The method of claim 1 wherein the providing the first responsivity values comprises constraining all of the first responsivity values to comprise values of the same sign.

3. The method of claim 1 wherein the providing the second responsivity values comprises constraining all of the second responsivity values to comprise values of the same sign.

4. The method of claim 1 wherein the first and the second determinings individually comprise:

estimating a response of the imaging device using the respective ones of the first and the second responsivity values; and

comparing the response with a measured response of the imaging device to provide the error.

5. The method of claim 1 wherein the selecting comprises selecting the second responsivity values as the responsivity function of the imaging device.

6. The method of claim 1 wherein the selecting comprises selecting the second responsivity values corresponding to a plurality of second responsivity functions for respective channels of the imaging device.

7. The method of claim 1 wherein the providing the second responsivity values comprises executing an optimization routine to provide the second responsivity values.

8. The method of claim 7 wherein the second responsivity values comprise the output of the optimization routine without modification.

9. The method of claim 1 wherein the second determining comprises determining the error comprising a minimal value with the second responsivity values comprising values of the same sign.

10. An imaging device analysis method comprising:

accessing light source data comprising spectral power distribution information regarding light provided by a light source;

accessing response data comprising information generated by an imaging device responsive to reception of the light provided by the light source; and

processing the light source data and the response data to generate a plurality of responsivity values of a responsivity function of the imaging device, wherein all of the responsivity values are generated using the light source data and the response data and comprise values of the same sign.

11. The method of claim 10 wherein the responsivity values comprise values for a plurality of responsivity functions for respective channels of the imaging device.

12. The method of claim 10 wherein the processing comprises processing to generate the responsivity values without clipping.

13. The method of claim 10 wherein the processing comprises processing using an optimization routine and the responsivity values comprise the output of the optimization routine without modification.

14. The method of claim 10 further comprising:

estimating a response of the imaging device using the responsivity values; and

determining error associated with the responsivity function using the response.

15. The method of claim 14 wherein the determining the error comprises comparing the response with the response data.

16. The method of claim 10 wherein the responsivity function provides minimal error for the responsivity values having the same sign.

17. An imaging device analysis system comprising:

processing circuitry configured to generate a plurality of first responsivity values of the same sign corresponding to a first predictive responsivity function of an imaging device, to calculate a first error value using the first responsivity values and image data generated by the imaging device responsive to received light, to identify a plurality of second responsivity values of the same sign corresponding to a second predictive responsivity function of the imaging device responsive to the first error value being unacceptable, to calculate a second error value using the second responsivity values and the image data, and to select the second responsivity values and the second predictive responsivity function as the responsivity function for the imaging device responsive to the second error value being acceptable.

18. The system of claim 17 wherein all responsivity values of the first predictive responsivity function comprise values of the same sign.

19. The system of claim 17 wherein all responsivity values of the second predictive responsivity function comprise values of the same sign.

20. The system of claim 17 wherein the second responsivity values comprise values for a plurality of second predictive responsivity functions for respective channels of the imaging device, and wherein the selection comprises selection of the plural second predictive responsivity functions for the respective channels of the imaging device.

21. The system of claim 17 wherein the processing circuitry is configured to access the image data comprising a measured response, to generate plural respective estimated responses using respective ones of the first predictive responsivity function and the second predictive responsivity function, and to compare the measured response with individual ones of the plural estimated responses to calculate respective ones of the first error value and the second error value.

22. The system of claim 17 wherein the processing circuitry is configured to identify the second responsivity values without clipping.

23. The system of claim 17 wherein the processing circuitry is constrained to identify only values of the same sign as responsivity values for all predictive responsivity functions.

24. The system of claim 17 wherein the processing circuitry is configured to execute an optimization routine to identify the second responsivity values.

25. The system of claim 24 wherein the output of the optimization routine comprises the second responsivity values without modification.

26. The system of claim 17 wherein the processing circuitry is configured to select the second predictive responsivity function responsive to the second error value comprising a minimal error value for the predictive responsivity functions comprising the responsivity values of the same sign.

27. The system of claim 17 wherein the processing circuitry comprises processing circuitry of the imaging device.

28. An imaging device analysis system comprising:

processing circuitry configured to identify a plurality of predictive responsivity functions individually indicative of responsivity of an imaging device to received light, wherein individual ones of the predictive responsivity functions comprise a plurality of responsivity values, wherein the processing circuitry is constrained to identify the predictive responsivity functions individually comprising all respective responsivity values of the same sign, and wherein the processing circuitry is configured to select one of the predictive responsivity functions as a responsivity function to be used by the imaging device.

29. The system of claim 28 wherein the processing circuitry is configured to determine associated error for respective ones of the predictive responsivity functions and to select the one of the predictive responsivity functions having minimal associated error of the plural predictive responsivity functions comprising the responsivity values of the same sign.

30. An imaging device analysis system comprising:

means for accessing a plurality of initial responsivity values predictive of responsivity of an imaging device;

means for identifying other responsivity values predictive of the responsivity of the imaging device;

means for constraining the other responsivity values to comprise values of the same sign before the identification of the other responsivity values; and

means for selecting the other responsivity values to comprise a responsivity function of the imaging device.

31. The system of claim 30 further comprising means for constraining the initial responsivity values to comprise values of the same sign.

32. The system of claim 30 wherein the means for identifying comprises means for executing an optimization routine, and the other responsivity values comprise values outputted from the optimization routine without modification.

33. The system of claim 30 wherein the means for identifying and the means for constraining comprise means for executing an optimization routine constrained to only identify non-negative responsivity values.

34. The system of claim 30 wherein the means for constraining comprises means for constraining without clipping.

35. The system of claim 30 further comprising:

means for estimating an estimated response of the imaging device using the other responsivity values;

means for comparing the estimated response with a measured response of the imaging device for determining error; and

wherein the means for selecting comprises means for selecting the other responsivity values responsive to the determination of the error.

36. The system of claim 35 wherein the means for selecting comprises means for selecting responsive to the error comprising minimal error for all responsivity values comprising values of the same sign.

37. An article of manufacture comprising:

media comprising programming configured to cause processing circuitry to perform processing comprising;

providing an initial predictive responsivity function of an imaging device;

first determining an estimated response of the imaging device using the initial predictive responsivity function;

second determining an accuracy of the estimated response of the imaging device;

responsive to the second determining, searching to identify another predictive responsivity function; and

constraining the searching to other predictive responsivity functions individually comprising all responsivity values of the same sign.

38. The article of claim 37 wherein the programming is configured to cause processing circuitry to perform processing comprising constraining the initial predictive responsivity function to only comprise responsivity values of the same sign.

39. The article of claim 37 wherein the second determining comprises comparing the estimated response with a measured response of the imaging device to determine error.

40. The article of claim 37 wherein the programming is configured to cause processing circuitry to perform processing comprising determining error associated with the other predictive responsivity functions and selecting the another predictive responsivity function responsive to the another predictive responsivity function having minimal error of the other predictive responsibility functions individually comprising all responsivity values of the same sign.