Determining the age of a human subject in a digital image

1. A method for ascertaining the age class of a human subject in a digital image, the human subject having a redeye defect pair, each defect of the redeye defect pair having one or more redeye defect pixels, the method comprising using a processor to perform the steps of:

identifying two regions of redeye defect pixels corresponding to the redeye defect pair;

measuring a distance between said regions;

determining a region size based upon a size of at least one of said regions;

determining a normalized region size by forming a ratio involving said region size and said distance; and

determining an age class responsive to the normalized region size.

2. The method of claim 1 wherein said distance is calculated from corresponding points in each of said regions.

3. The method of claim 1 wherein said measuring of said distance further comprises determining a centroid of each said region and determining a separation of said centroids.

4. The method of claim 1 wherein said measuring of said distance further comprises measuring a separation of said eyes, determining an out-of-plane rotation of the head of the human subject relative to a subject plane defined by said digital image, and correcting said separation for said rotation.

5. The method of claim 1 wherein said region size is a count of the number of redeye defect pixels in one or both of the redeye defects.

6. The method of claim 1 wherein said determining said region size further comprises measuring a size of each of said regions and determining an average of said sizes of each of said regions.

7. The method of claim 6 wherein the size of each of said regions is the square root of the product of a count of the number of redeye defect pixels in a respective redeye defect times the inverse of the mathematical constant π.

8. The method of claim 6 wherein the size of each of said regions is the radius of the smallest circle that inscribes the respective redeye defect.

9. The method of claim 6 wherein said measuring of said distance further comprises determining a centroid of each of said regions; and the size of each of said regions is the radius of the smallest circle that inscribes the respective redeye defect.

10. The method of claim 6 wherein said measuring of said distance further comprises determining a centroid of each of said regions; and the size S C of each of said regions is given by:

S

C

=

max

i

⁢

[

(

x

i

-

x

C

)

2

+

(

y

i

-

y

C

)

2

]

wherein:

(x i , y i ) are the coordinate locations of the i th redeye defect pixel of the respective redeye defect; and

(x C , y C ) is the centroid of the respective defect.

11. The method of claim 6 wherein said measuring of said distance further comprises determining a centroid of each of said regions; and the size of each of said regions is the largest circle centered at the centroid of the respective redeye defect that inscribes only redeye defect pixels.

12. The method of claim 1 further comprising inducing pupil dilation in the human subject; capturing the digital image with a camera during said pupil dilation.

13. The method of claim 1 wherein said camera defines an optical axis and said method further comprises illuminating said human subject, during said capturing, with a light source positioned close to said optical axis of said camera.

14. The method of claim 1 wherein determining said age class further comprises accessing a look-up table value corresponding to said distance and said region size.

15. The method of claim 1 wherein said determining said age class further comprises computing said age class with an age classifier.

16. The method of claim 15 wherein said computing utilizes said size, said distance, and one or more additional features.

17. The method of claim 16 wherein said additional features include at least one of : wrinkle analysis and hair color analysis.

18. The method of claim 15 wherein said determining said age class further comprises selecting said age class and assigning a probability.

19. The method of claim 18 wherein said age range is selected from the categories: baby, child, adult, and older adult.

20. The method of claim 15 wherein said age classifier is a Bayesian classifier.

21. A method for ascertaining the age class of a human subject in a digital image, the human subject having a redeye defect pair, each redeye defect of the redeye defect pair having one or more redeye defect pixels, the method comprising using a processor to perform the steps of:

identifying two regions of redeye defect pixels corresponding to the redeye defect pair;

measuring a distance between said regions;

determining a region size based upon a size of at least one of said regions; and

determining an age class from said distance and said region size;

wherein said determining said age class further comprises computing said age class with an age classifier; and

wherein said determining of said region size further comprises computing a redeye feature F and using said redeye feature F in said age classifier, said redeye feature F being given by:

F

=

int

⁡

(

S

-

B

R

D

-

B

⁢

K

)

+

1

wherein:

S is said region size;

B is a function of pixels of blur in the image;

K is a constant multiplier; and

R D is said distance.

22. The method of claim 21 wherein R D is in units of pixels and is given by:

R D =√{square root over (( x 1 − x 2 ) 2 +( y 1 − y 2 ) 2 )}{square root over (( x 1 − x 2 ) 2 +( y 1 − y 2 ) 2 )}

wherein (x 1 , y 1 ) and (x 2 , y 2 ) are the coordinate locations of corresponding said redeye defect pixels of each redeye defect of the redeye defect pair.

23. The method of claim 21 wherein said determining further comprises measuring a size of each of said regions and determining an average of said sizes of each of said regions.

24. A method for ascertaining the age class of a human subject in a digital image, the human subject having a redeye defect pair, each redeye defect of the redeye defect pair having one or more redeye defect pixels, the method comprising using a processor to perform the steps of:

identifying two regions of redeye defect pixels corresponding to the redeye defect pair;

measuring a distance between said regions;

determining a region size based upon a size of at least one of said regions; and

determining an age class from said distance and said region size;

wherein said determining said age class further comprises computing said age class with an age classifier; and

wherein said measuring of said distance further comprises determining an angle of out-of-plane rotation of the head of the human subject relative to a subject plane defined by said digital image; and said determining of said region size further comprises computing a redeye feature F and using said redeye feature Fin said age classifier, said redeye feature F being given by:

F

=

int

⁡

(

cos

⁢

⁢

A

⁢

⁢

(

S

-

B

)

R

D

-

B

⁢

K

)

+

1

wherein:

B is a function of pixels of blur in the image;

K is a constant multiplier;

A is said angle of out-of-plane rotation;

S is said region size; and

R D is said distance.

25. The method of claim 24 wherein B=2 and K=240 −1 .

26. The method of claim 24 wherein R D is in units of pixels and is given by:

R D =√{square root over (( x 1 − x 2 ) 2 +( y 1 − y 2 ) 2 )}{square root over (( x 1 − x 2 ) 2 +( y 1 − y 2 ) 2 )}

wherein (x 1 , y 1 ) and (x 2 , y 2 ) are the coordinate locations of corresponding said redeye defect pixels of each redeye defect of the redeye defect pair.

27. The method of claim 24 wherein said determining further comprises measuring a size of each of said regions and determining an average of said sizes of each of said regions.

28. A system for ascertaining the age class of a human subject in a digital image, the human subject having a redeye defect pair, each redeye defect of the redeye defect pair having one or more redeye defect pixels, the apparatus comprising:

means for identifying two regions of redeye defect pixels corresponding to the redeye defect pair;

means for measuring a distance between said regions;

means for determining a region size based upon a size of at least one of said regions;

means for determining a normalized region size by forming a ratio involving said region size and said distance; and

means for determining an age class responsive to the normalized region size.

29. A non-transitory computer readable storage medium having a computer program stored thereon for ascertaining the age class of a human subject in a digital image, the human subject having a redeye defect pair and each redeye defect of the redeye defect pair having one or more redeye defect pixels, wherein said computer program:

identifies two regions of redeye defect pixels corresponding to the redeye defect pair;

measures a distance between said regions;

determines a region size based upon a size of at least one of said regions; and

determines a normalized region size by forming a ratio involving said region size and said distance; and

determines an age class responsive to the normalized region size.

30. A photofinishing method comprising:

inputting a photofinishing order having one or more digital images;

ascertaining an age class of a human subject in at least one of said digital images, the human subject having a redeye defect pair, each redeye defect of the redeye defect pair having one or more redeye defect pixels, said ascertaining including using a processor to perform the steps of:

identifying two regions of redeye defect pixels corresponding to the redeye defect pair,

measuring a distance between said regions,

determining a region size based upon a size of at least one of said regions,

determining a normalized region size by forming a ratio involving said region size and said distance;

determining an age class responsive to the normalized region size; and

modifying fulfillment of said photofinishing order responsive to said ascertained age class.

31. The method of claim 30 wherein said modifying further comprises selecting one of a plurality of advertisements responsive to said ascertaining, and providing said advertisement in said fulfillment.

32. A system for ascertaining the age class of a human subject in a digital image, the human subject having a redeye defect pair, each redeye defect of the redeye defect pair having one or more redeye defect pixels, the apparatus comprising the following components:

a redeye defect detector that identifies two regions of redeye defect pixels corresponding to the redeye defect pair;

a feature extractor that measures a distance between said regions identified by the redeye defect detector and determines a region size based upon a size of at least one of said regions; and

an age classifier that determines an age class from said distance and said region size measured and determined by said feature extractor;

wherein said feature extractor computes a redeye feature F and the age classifier uses said redeye feature F to determine said age class, wherein said redeye feature F being given by:

F

=

int

⁡

(

S

-

B

R

D

-

B

⁢

K

)

+

1

wherein:

S is said region size;

B is a function of pixels of blur in the image;

K is a constant multiplier; and

R D is said distance

wherein one or more of the components are implemented using a data processor.

33. A system as claimed in claim 32 , wherein R D is in units of pixels and is given by:

R D =√{square root over (( x 1 − x 2 ) 2 +( y 1 − y 2 ) 2 )}{square root over (( x 1 − x 2 ) 2 +( y 1 − y 2 ) 2 )}

wherein (x 1 , y 1 ) and (x 2 , y 2 ) are the coordinate locations of corresponding said redeye defect pixels of each redeye defect of the redeye defect pair.

34. A system as claimed in claim 32 wherein said feature extractor measures a size of each of said regions and determines an average of said sizes of each of said regions.

35. A system for ascertaining the age class of a human subject in a digital image, the human subject having a redeye defect pair, each redeye defect of the redeye defect pair having one or more redeye defect pixels, the apparatus comprising the following components:

a redeye defect detector that identifies two regions of redeye defect pixels corresponding to the redeye defect pair;

a feature extractor that measures a distance between said regions identified by the redeye defect detector and determines a region size based upon a size of at least one of said regions; and

an age classifier that determines an age class from said distance and said region size measured and determined by said feature extractor;

wherein said feature extractor determines an angle of out-of-plane rotation of the head of the human subject relative to a subject plane defined by said digital image, and computes a redeye feature F that is used by said age classifier to determine said age class, wherein said redeye feature F is given by:

F

=

int

⁡

(

cos

⁢

⁢

A

⁡

(

S

-

B

)

R

D

-

B

⁢

K

)

+

1

wherein:

B is a function of pixels of blur in the image;

K is a constant multiplier;

A is said angle of out-of-plane rotation;

S is said region size; and

R D is said distance

wherein one or more of the components are implemented using a data processor.

36. A system for ascertaining the age class of a human in a digital image as claimed in claim 35 , wherein B=2 and K=240 −1 .

37. A system for ascertaining the age class of a human in a digital image as claimed in claim 35 , wherein R D is in units of pixels and is given by:

R D =√{square root over (( x 1 − x 2 ) 2 +( y 1 − y 2 ) 2 )}{square root over (( x 1 − x 2 ) 2 +( y 1 − y 2 ) 2 )}

wherein (x 1 , y 1 ) and (x 2 , y 2 ) are the coordinate locations of corresponding said pixels of each redeye defect of the redeye defect pair.

38. A system for ascertaining the age class of a human in a digital image as claimed in claim 35 , wherein said feature extractor determines a region size measures a size of each of said regions and determines an average of said sizes of each of said regions.

39. A system for ascertaining the age class of a human subject in a digital image, the human subject having a redeye defect pair, each redeye defect of the redeye defect pair having one or more redeye defect pixels, the apparatus comprising the following components:

a redeye defect detector that identifies two regions of redeye defect pixels corresponding to the redeye defect pair;

a feature extractor that measures a distance between said regions identified by the redeye defect detector and determines a region size based upon a size of at least one of said regions;

a normalizer that determines a normalized region size by forming a ratio involving said region size and said distance;

an age classifier that determines an age class responsive to said normalized region size determined by said normalizer; and

wherein one or more of the components are implemented using a data processor.