RED-EYE FILTER METHOD AND APPARATUS

• US 20090027520A1
• Filed: 08/19/2008
• Published: 01/29/2009
• Est. Priority Date: 10/09/1997
• Status: Active Grant

• Current Assignee: FotoNation Limited (Adeia Inc.)
• Original Assignee: FotoNation Vision Limited (Adeia Inc.)
• Inventors: Steinberg, Eran, Prilutsky, Yury, Bigioi, Petronel, Corcoran, Peter, DeLuca, Michael J.
• Granted Patent: US 7,746,385 B2
• Time in Patent Office: Days
• US Class Current: 348/241
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/30201 Face
• CPC Class Codes: G06T 2207/30216 Redeye defect
• CPC Class Codes: G06T 5/94 based on local image properties, e.g. for local contrast enhancement
• CPC Class Codes: G06T 7/90 Determination of colour characteristics
• CPC Class Codes: G06V 40/162 using pixel segmentation or colour matching
• CPC Class Codes: G06V 40/165 using facial parts and geometric relationships
• CPC Class Codes: G06V 40/193 Preprocessing; Feature extraction
• CPC Class Codes: H04N 1/6086 by scene illuminant, i.e. conditions at the time of picture capture, e.g. flash, optical filter used, evening, cloud, daylight, artificial lighting, white point measurement, colour temperature
• CPC Class Codes: H04N 1/62 Retouching, i.e. modification of isolated colours only or in isolated picture areas only
• CPC Class Codes: H04N 1/624 Red-eye correction control of camera based on recognised facial parts H04N23/611
• CPC Class Codes: H04N 23/63 by using electronic viewfinders
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 23/80 Camera processing pipelines; Components thereof
• CPC Class Codes: H04N 9/70 for colour killing

Abstract

A digital image acquisition system having no photographic film, such as a digital camera, has a flash unit for providing illumination during image capture and a red-eye filter for detecting a region within a captured image indicative of a red-eye phenomenon, the detection being based upon a comparison of the captured image and a reference image of nominally the same scene taken without flash. In the embodiment the reference image is a preview image of lower pixel resolution than the captured image, the filter matching the pixel resolutions of the captured and reference images by up-sampling the preview image and/or sub-sampling the captured image. The filter also aligns at least portions of the captured image and reference image prior to comparison to allow for, e.g. movement in the subject.

Claims

1. A digital image acquisition system having no photographic film, comprising a portable apparatus for capturing digital images, a flash unit for providing illumination during image capture, and a red-eye filter for detecting red-eye phenomenon in a captured image based upon a comparison of said captured image and a reference image of nominally the same scene taken without flash, wherein the red eye filter further includes an alignment filter for aligning at least portions of the captured image and reference image prior to said comparison.

2. A system according to claim 1, wherein the red eye filter detects said red-eye phenomenon by identifying a region in the captured image having a color indicative of a red-eye phenomenon and comparing said identified region with the corresponding region in the reference image, wherein the red eye filter further designates said region as indicative of a red-eye phenomenon if said corresponding region does not have a color indicative of a red-eye phenomenon.

3. A system according to claim 2, wherein the decision as to whether a region has a color indicative of a red-eye phenomenon is determined on a statistical basis as a global operation on the entire region.

4. A digital image acquisition system having no photographic film, comprising a portable apparatus for capturing digital images, a flash unit for providing illumination during image capture, and a red-eye filter for detecting red-eye phenomenon in a captured image based upon a comparison of said captured image and a reference image of nominally the same scene taken without flash, wherein the red eye filter is configured to detect said red-eye phenomenon by identifying a region in the captured image having a color indicative of a red-eye phenomenon and comparing said identified region with the corresponding region in the reference image, wherein the red eye filter further designates said region as indicative of a red-eye phenomenon if said corresponding region does not have a color indicative of a red-eye phenomenon.

5. A system according to claim 4, wherein the decision as to whether a region has a color indicative of a red-eye phenomenon is determined on a statistical basis as a global operation on the entire region.

6. A portable apparatus for capturing digital images, comprising optics and a sensor, a flash unit, a processor and a red eye filter, wherein the apparatus comprises processor-readable code embedded in or more media for programming the processor to perform a method of detecting a red-eye phenomenon within a digital image captured by the apparatus, wherein the method comprising identifying a region within a captured image indicative of a red-eye phenomenon including comparing said captured image and at least one reference eye color characteristic.

7. The apparatus of claim 6, wherein said at least one reference eye color characteristic comprises an eye color characteristic of a reference image of nominally the same scene taken without flash, and wherein the reference image is a preview image of lower pixel resolution than the captured image, the method further comprising matching the pixel resolutions of the captured and reference images including up-sampling the preview image or sub-sampling the captured image, or a combination thereof.

8. The apparatus of claim 7, wherein the method further comprises aligning at least portions of the captured image and reference image prior to said comparison.

9. The apparatus of claim 8, wherein the method further comprises analysing a shape so that the identifying comprises identifying a region in the captured image having both a shape and color indicative of a red-eye phenomenon for subsequent comparison with the corresponding region in the reference image.

10. The apparatus of claim 8, wherein the method further comprises analysing a shape to determine subsequent to said comparison whether a region designated as indicative of a red-eye phenomenon has a shape indicative of a red-eye phenomenon.

11. The apparatus of claim 7, wherein said digital image acquisition system is a camera is a combination of a digital camera and an external processing device.

12. The apparatus of claim 11, wherein said red-eye filter is located in said external processing device.

13. The apparatus of claim 7, wherein the method further comprises modifying the color of the pixels within a region indicative of a red-eye phenomenon.

14. The apparatus of claim 6, wherein said at least one reference eye color characteristic comprises an eye color characteristic of a reference image of nominally the same scene taken without flash, and the method further comprising aligning at least portions of the captured image and reference image prior to said comparison.

15. The apparatus of claim 14, wherein the method further comprises analysing a shape so that the identifying comprises identifying a region in the captured image having both a shape and color indicative of a red-eye phenomenon for subsequent comparison with the corresponding region in the reference image.

16. The apparatus of claim 15, wherein the method further comprises analysing a shape to determine subsequent to said comparison whether a region designated as indicative of a red-eye phenomenon has a shape indicative of a red-eye phenomenon.

17. The apparatus of claim 6, wherein the method further comprises detecting said region indicative of a red-eye phenomenon by identifying a region in the captured image at least having a color indicative of a red-eye phenomenon and comparing said identified region with the corresponding region in the reference image, and designating said region as indicative of a red-eye phenomenon if said corresponding region does not have a color indicative of a red-eye phenomenon.

18. The apparatus of claim 17, wherein the method further comprises deciding whether a region has a color indicative of a red-eye phenomenon by determining on a statistical basis as a global operation on the entire region.

19. The apparatus of claim 6, wherein the method further comprises analysing a shape so that the identifying comprises identifying a region in the captured image having both a shape and color indicative of a red-eye phenomenon for subsequent comparison with the corresponding region in the reference image.

20. The apparatus of claim 6, wherein the method further comprises analysing a shape to determine subsequent to said comparison whether a region designated as indicative of a red-eye phenomenon has a shape indicative of a red-eye phenomenon.

21. The apparatus of claim 6, wherein said digital image acquisition system is a digital camera.

22. The apparatus of claim 6, wherein the method further comprises analysing a shape, so that the identifying comprises identifying a region in the captured image having both a shape and color indicative of a red-eye phenomenon for subsequent comparison with a reference eye shape characteristic and the reference eye color characteristic, respectively.

23. The apparatus of claim 22, wherein the method further comprises modifying the color of the pixels within a region indicative of a red-eye phenomenon.

24. The apparatus of claim 6, wherein the method further comprises modifying the color of the pixels within a region indicative of a red-eye phenomenon.