Method and Apparatus for Determining Sensor Format Factors from Image Metadata

• US 20130121525A1
• Filed: 10/14/2008
• Published: 05/16/2013
• Est. Priority Date: 08/29/2008
• Status: Active Grant

• Current Assignee: Adobe Inc.
• Original Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Inventors: Chen, Simon, Chien, Jen-Chan, Jin, Hailin
• Granted Patent: US 8,842,190 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06T 3/12 Panospheric to cylindrical image transformations
• CPC Class Codes: G06T 3/4038 Image mosaicing, e.g. composing plane images from plane sub-images
• CPC Class Codes: H04N 23/698 for achieving an enlarged field of view, e.g. panoramic image capture

Abstract

Method and apparatus for determining sensor format factors from image metadata in which one of multiple techniques is applied to determine a sensor format factor for a camera from information in the metadata. Information from the metadata may be used to identify which of the multiple techniques to use. For example, the camera make and model may be used to determine a particular technique to use. As another example, the presence or absence of particular attributes or values for particular attributes may be used in determining a particular technique. In one embodiment, a profile database may be searched according to information in the metadata to determine if a sensor format factor for the camera is in the database. If the sensor format factor for the camera is not in the database, other information in the metadata may be examined to determine a particular technique from among the plurality of techniques.

Claims

1. A computer-implemented method, comprising:

performing, by one or more computing devices;

examining metadata corresponding to an input image to determine a particular one of a plurality of techniques for determining a sensor format factor for a camera from information in the metadata, wherein the sensor format factor indicates a ratio of the diagonal of 35 mm film to the diagonal of a camera sensor; and

applying the particular technique to information obtained from the metadata corresponding to the input image to determine the sensor format factor for a particular camera used to capture the input image.

2. The computer-implemented method as recited in claim 1, wherein said examining metadata corresponding to an input image to determine a particular one of a plurality of techniques for determining a sensor format factor for a camera from information in the metadata comprises:

searching a profile database according to camera make and camera model information in the metadata to determine if a sensor format factor for the camera is stored in the profile database;

if the sensor format factor for the camera is not stored in the profile database, examining other information in the metadata to determine the particular technique for determining the sensor format factor for the camera from the information in the metadata.

3. The computer-implemented method as recited in claim 1, wherein the plurality of techniques includes:

a first technique comprising determining the sensor format factor from dimensions of 35 mm film and dimensions of a sensor region used to capture the image;

a second technique comprising determining the sensor format factor from focal length of the lens used to capture the image and focal length in 35 mm film of the lens used to capture the image; and

a third technique comprising assigning a default value to the sensor format factor based on camera make as determined from the metadata.

4. The computer-implemented method as recited in claim 3, wherein said determining the sensor format factor from the dimensions of 35 mm film and the dimensions of the sensor region used to capture the image comprises:

obtaining values for image width, image length, focal plane X resolution, and focal plane Y resolution from the metadata;

calculating focal plane image width from the image width and the focal plane X resolution;

calculating focal plane image height from the image height and the focal plane Y resolution;

dividing the sum of the squares of 35 mm film width and height by the sum of the squares of the focal plane image width and the focal plane image height; and

taking the square root of the results of said dividing to generate the sensor format factor.

5. The computer-implemented method as recited in claim 3, wherein said determining the sensor format factor from the focal length used to capture the image and the focal length in 35 mm film comprises:

obtaining values for the focal length and the focal length in 35 mm film from the metadata; and

dividing the focal length in 35 mm film by the focal length to generate an estimated sensor format factor; and

clipping the estimated sensor format factor to generate the sensor format factor.

6. The computer-implemented method as recited in claim 5, wherein said clipping the estimated sensor format factor to generate the sensor format factor comprises:

if the absolute value of the estimated sensor format factor −

1.0 is less than or equal to 0.25 or if the absolute value of the estimated sensor format factor −

1.5 is less than or equal to 0.25, and if the absolute value of the estimated sensor format factor −

1.0 is less than the absolute value of the estimated sensor format factor −

1.5, setting the sensor format factor to 1.0;

if the absolute value of the estimated sensor format factor −

1.0 is less than or equal to 0.25 or if the absolute value of the estimated sensor format factor −

1.5 is less than or equal to 0.25, and if the absolute value of the estimated sensor format factor −

1.0 is greater than or equal to the absolute value of the estimated sensor format factor −

1.5, setting the sensor format factor to 1.5.

7. The computer-implemented method as recited in claim 3, wherein said examining metadata corresponding to an input image to determine a particular one of a plurality of techniques for calculating a sensor format factor for a camera from information in the metadata comprises:

examining the metadata to determine if the first technique is applicable;

if the first technique is applicable, applying the first technique to determine the sensor format factor;

if the first technique is not applicable, examining the metadata to determine if the second technique is applicable;

if the second technique is applicable, applying the second technique to determine the sensor format factor;

if the second technique is not applicable, defaulting to the third technique to determine the sensor format factor.

8. The computer-implemented method as recited in claim 3, wherein the plurality of techniques further includes a fourth technique comprising searching a profile database according to the metadata to determine if a sensor format factor for the camera is stored in the profile database.

9. The computer-implemented method as recited in claim 8, wherein said searching a profile database according to the metadata to determine if a sensor format factor for the camera is stored in the profile database comprises:

determining camera make and camera model of the particular camera from the metadata;

attempting to match the camera make and the camera model from the metadata to information stored in a profile in the profile database; and

if a match is found and if the profile includes a sensor format factor for the camera make and the camera model, assigning the sensor format factor from the matched profile to the sensor format factor for the particular camera used to capture the input image.

10. The computer-implemented method as recited in claim 8, wherein said examining metadata corresponding to an input image to determine a particular one of a plurality of techniques for calculating a sensor format factor for a camera from information in the metadata comprises:

examining the metadata to determine if the fourth technique is applicable;

if the fourth technique is applicable, applying the fourth technique to determine the sensor format factor;

if the fourth technique is not applicable, examining the metadata to determine if the first technique is applicable;

if the first technique is applicable, applying the first technique to determine the sensor format factor;

if the first technique is not applicable, examining the metadata to determine if the second technique is applicable;

if the second technique is applicable, applying the second technique to determine the sensor format factor;

if the second technique is not applicable, defaulting to the third technique to determine the sensor format factor.

11. The computer-implemented method as recited in claim 1, further comprising:

locating, in a profile database, a particular profile that best matches the metadata corresponding to the image;

retrieving, from the particular profile, data specific to a particular camera/lens combination indicated by the particular profile; and

adjusting the data according to the determined sensor format factor.

12. A system, comprising:

at least one processor; and

a memory comprising program instructions, wherein the program instructions are executable by the at least one processor to;

examine metadata corresponding to an input image to determine a particular one of a plurality of techniques for determining a sensor format factor for a camera from information in the metadata, wherein the sensor format factor indicates a ratio of the diagonal of 35 mm film to the diagonal of a camera sensor; and

apply the particular technique to information obtained from the metadata corresponding to the input image to determine the sensor format factor for a particular camera used to capture the input image.

13. The system as recited in claim 12, wherein, to examine metadata corresponding to an input image to determine a particular one of a plurality of techniques for determining a sensor format factor for a camera from information in the metadata, the program instructions are executable by the at least one processor to:

search a profile database according to camera make and camera model information in the metadata to determine if a sensor format factor for the camera is stored in the profile database;

if the sensor format factor for the camera is not stored in the profile database, examine other information in the metadata to determine the particular technique for determining the sensor format factor for the camera from the information in the metadata.

14. The system as recited in claim 12, wherein the plurality of techniques includes:

a first technique configured to determine the sensor format factor from dimensions of 35 mm film and dimensions of a sensor region used to capture the image;

a second technique configured to determine the sensor format factor from focal length of the lens used to capture the image and focal length in 35 mm film of the lens used to capture the image; and

a third technique configured to assign a default value to the sensor format factor based on camera make as determined from the metadata.

15. The system as recited in claim 14, wherein, to determine the sensor format factor from the dimensions of 35 mm film and the dimensions of the sensor region used to capture the image, the program instructions are executable by the at least one processor to:

obtain values for image width, image length, focal plane X resolution, and focal plane Y resolution from the metadata;

calculate focal plane image width from the image width and the focal plane X resolution;

calculate focal plane image height from the image height and the focal plane Y resolution;

divide the sum of the squares of 35 mm film width and height by the sum of the squares of the focal plane image width and the focal plane image height; and

take the square root of the results of said dividing to generate the sensor format factor.

16. The system as recited in claim 14, wherein, to determine the sensor format factor from the focal length used to capture the image and the focal length in 35 mm film, the program instructions are executable by the at least one processor to:

obtain values for the focal length and the focal length in 35 mm film from the metadata; and

divide the focal length in 35 mm film by the focal length to generate an estimated sensor format factor; and

clip the estimated sensor format factor to generate the sensor format factor.

17. The system as recited in claim 14, wherein, to examine metadata corresponding to an input image to determine a particular one of a plurality of techniques for calculating a sensor format factor for a camera from information in the metadata, the program instructions are executable by the at least one processor to:

examine the metadata to determine if the first technique is applicable;

if the first technique is applicable, apply the first technique to determine the sensor format factor;

if the first technique is not applicable, examine the metadata to determine if the second technique is applicable;

if the second technique is applicable, apply the second technique to determine the sensor format factor;

if the second technique is not applicable, default to the third technique to determine the sensor format factor.

18. The system as recited in claim 14, wherein the plurality of techniques further includes a fourth technique configured to search a profile database according to the metadata to determine if a sensor format factor for the camera is stored in the profile database.

19. The system as recited in claim 18, wherein, to search a profile database according to the metadata to determine if a sensor format factor for the camera is stored in the profile database, the program instructions are executable by the at least one processor to:

determine camera make and camera model of the particular camera from the metadata;

attempt to match the camera make and the camera model from the metadata to information stored in a profile in the profile database; and

if a match is found and if the profile includes a sensor format factor for the camera make and the camera model, assign the sensor format factor from the matched profile to the sensor format factor for the particular camera used to capture the input image.

20. The system as recited in claim 18, wherein, to examine metadata corresponding to an input image to determine a particular one of a plurality of techniques for calculating a sensor format factor for a camera from information in the metadata, the program instructions are executable by the at least one processor to:

examine the metadata to determine if the fourth technique is applicable;

if the fourth technique is applicable, apply the fourth technique to determine the sensor format factor;

if the fourth technique is not applicable, examine the metadata to determine if the first technique is applicable;

if the first technique is applicable, apply the first technique to determine the sensor format factor;

if the first technique is not applicable, examine the metadata to determine if the second technique is applicable;

if the second technique is applicable, apply the second technique to determine the sensor format factor;

if the second technique is not applicable, default to the third technique to determine the sensor format factor.

21. The system as recited in claim 12, wherein the program instructions are executable by the at least one processor to:

locate, in a profile database, a particular profile that best matches the metadata corresponding to the image;

retrieve, from the particular profile, data specific to a particular camera/lens combination indicated by the particular profile; and

adjust the data according to the determined sensor format factor.

22. A non-transitory computer-readable storage medium storing program instructions, wherein the program instructions are computer-executable to implement:

examining metadata corresponding to an input image to determine a particular one of a plurality of techniques for determining a sensor format factor for a camera from information in the metadata, wherein the sensor format factor indicates a ratio of the diagonal of 35 mm film to the diagonal of a camera sensor; and

applying the particular technique to information obtained from the metadata corresponding to the input image to determine the sensor format factor for a particular camera used to capture the input image.

23. The non-transitory computer-readable storage medium as recited in claim 22, wherein, in said examining metadata corresponding to an input image to determine a particular one of a plurality of techniques for determining a sensor format factor for a camera from information in the metadata, the program instructions are computer-executable to implement:

searching a profile database according to camera make and camera model information in the metadata to determine if a sensor format factor for the camera is stored in the profile database;

if the sensor format factor for the camera is not stored in the profile database, examining other information in the metadata to determine the particular technique for determining the sensor format factor for the camera from the information in the metadata.

24. The non-transitory computer-readable storage medium as recited in claim 22, wherein the plurality of techniques includes:

a first technique comprising determining the sensor format factor from dimensions of 35 mm film and dimensions of a sensor region used to capture the image;

a second technique comprising determining the sensor format factor from f focal length of the lens used to capture the image and focal length in 35 mm film of the lens used to capture the image; and

a third technique comprising assigning a default value to the sensor format factor based on camera make as determined from the metadata.

25. The non-transitory computer-readable storage medium as recited in claim 24, wherein, in said determining the sensor format factor from the dimensions of 35 mm film and the dimensions of the sensor region used to capture the image, the program instructions are computer-executable to implement:

obtaining values for image width, image length, focal plane X resolution, and focal plane Y resolution from the metadata;

calculating focal plane image width from the image width and the focal plane X resolution;

calculating focal plane image height from the image height and the focal plane Y resolution;

dividing the sum of the squares of 35 mm film width and height by the sum of the squares of the focal plane image width and the focal plane image height;

and taking the square root of the results of said dividing to generate the sensor format factor.

26. The non-transitory computer-readable storage medium as recited in claim 24, wherein, in said determining the sensor format factor from the focal length used to capture the image and the focal length in 35 mm film, the program instructions are computer-executable to implement:

obtaining values for the focal length and the focal length in 35 mm film from the metadata; and

dividing the focal length in 35 mm film by the focal length to generate an estimated sensor format factor; and

clipping the estimated sensor format factor to generate the sensor format factor.

27. The non-transitory computer-readable storage medium as recited in claim 24, wherein, in said examining metadata corresponding to an input image to determine a particular one of a plurality of techniques for calculating a sensor format factor for a camera from information in the metadata, the program instructions are computer-executable to implement:

examining the metadata to determine if the first technique is applicable;

if the first technique is applicable, applying the first technique to determine the sensor format factor;

if the first technique is not applicable, examining the metadata to determine if the second technique is applicable;

if the second technique is applicable, applying the second technique to determine the sensor format factor;

if the second technique is not applicable, defaulting to the third technique to determine the sensor format factor.

28. The non-transitory computer-readable storage medium as recited in claim 24, wherein the plurality of techniques further includes a fourth technique comprising searching a profile database according to the metadata to determine if a sensor format factor for the camera is stored in the profile database.

29. The non-transitory computer-readable storage medium as recited in claim 28, wherein, in said searching a profile database according to the metadata to determine if a sensor format factor for the camera is stored in the profile database, the program instructions are computer-executable to implement:

determining camera make and camera model of the particular camera from the metadata;

attempting to match the camera make and the camera model from the metadata to information stored in a profile in the profile database; and

if a match is found and if the profile includes a sensor format factor for the camera make and the camera model, assigning the sensor format factor from the matched profile to the sensor format factor for the particular camera used to capture the input image.

30. The non-transitory computer-readable storage medium as recited in claim 28, wherein, in said examining metadata corresponding to an input image to determine a particular one of a plurality of techniques for calculating a sensor format factor for a camera from information in the metadata, the program instructions are computer-executable to implement:

examining the metadata to determine if the fourth technique is applicable;

if the fourth technique is applicable, applying the fourth technique to determine the sensor format factor;

if the fourth technique is not applicable, examining the metadata to determine if the first technique is applicable;

if the first technique is applicable, applying the first technique to determine the sensor format factor;

if the first technique is not applicable, examining the metadata to determine if the second technique is applicable;

if the second technique is applicable, applying the second technique to determine the sensor format factor;

if the second technique is not applicable, defaulting to the third technique to determine the sensor format factor.

31. The non-transitory computer-readable storage medium as recited in claim 22, wherein the program instructions are computer-executable to implement:

locating, in a profile database, a particular profile that best matches the metadata corresponding to the image;

retrieving, from the particular profile, data specific to a particular camera/lens combination indicated by the particular profile; and

adjusting the data according to the determined sensor format factor.