Automatic red-eye object classification in digital photographic images
View Patent ↗Automatic red-eye object classification in digital photographic images. A method for classifying a candidate red-eye object in a digital photographic image includes several acts. First, a candidate red-eye object in a digital photographic image is selected. Next, RGB pixels of the candidate red-eye object are converted into YUV pixels. Then, the YUV pixels satisfying a constraint that is a function of the YUV pixels are summed. Next, the sum is determined to be greater than or equal to a scaled version of the total number of YUV pixels in the candidate red-eye object. Finally, the candidate red-eye object is transformed into a true red-eye object.
1. A method for classifying a candidate red-eye object in a digital image, the method comprising the acts of:
i) selecting a candidate red-eye object in a digital image;
ii) converting RGB pixels of the candidate red-eye object into YUV pixels;
iii.a) summing the YUV pixels satisfying a first constraint that is a function of the YUV pixels, and iii.b) summing the number of pixels satisfying a second constraint:
x′ (r,s)3 −x′ (r,s)2 >δ′min( x (r,s)2 , x (r,s)3 )
where:
x is the digital image with RGB pixels x (r,s) =[ x (r,s)1 , x (r,s)2 , x (r,s)3 ];
x′ is a YUV version of x with YUV pixels x′ (r,s) ,=[x′ (r,s)1 , x′ (r,s)2 , x′ (r,s)3 ];
(r,s) are pixel locations; and
δ′ is a tunable parameter;
iv) determining that the sum of iii.a) is greater than or equal to a first scaled version of the total number of YUV pixels in the candidate red-eye object, and determining that the sum of iii.b) is less than or equal to a second scaled version of the total number of YUV pixels in the candidate red-eye object; and
v) transforming the candidate red-eye object into a true red-eye object.
2. The method as recited in claim 1 , wherein the first constraint is:
x′ (r,s)3 −x′ (r,s)2 >δx′ (r,s)1
where:
δ is a tunable parameter.
3. The method as recited in claim 2 , wherein the acts iii.a), iii.b), iv), and v) are accomplished according to the following equation:
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where:
O i is the candidate red-eye object;
{d (r,s) i =0; (r,s) εΦ i } denotes transforming the candidate red-eye object into a false red-eye object;
|Φ i | denotes the total number of pixels of O i ;
i is a positive whole number; and
A and A′ are tunable parameters.
4. One or more computer-readable non-transitory media storing computer-readable instructions thereon which, when executed by a processor, implement a method for classifying a candidate red-eye object in a digital image, the method comprising the acts of:
i) selecting a candidate red-eye object in a digital image;
ii) converting RGB pixels of the candidate red-eye object into YUV pixels;
iii.a) summing the YUV pixels satisfying a first constraint that is a function of the YUV pixels, and iii.b) summing the number of pixels satisfying a second constraint:
x′ (r,s)3 −x′ (r,s)2 >δ′min( x (r,s)2 , x (r,s)3 )
where:
x is the digital image with RGB pixels x (r,s) =[x (r,s)1 , x (r,s)2 , x (r,s)3 ];
x′ is a YUV version of X with YUV pixels x′ (r,s) =[x′ (r,s)1 , x′ (r,s)2 , x′ (r,s)3 ];
(r,s) are pixel locations; and
δ′ is a tunable parameter;
iv) determining that the sum of iii.a) is greater than or equal to a first scaled version of the total number of YUV pixels in the candidate red-eye object, and determining that the sum of iii.b) is less than or equal to a second scaled version of the total number of YUV pixels in the candidate red-eye object; and
v) transforming the candidate red-eye object into a true red-eye object.
5. An image processing apparatus comprising:
an electronic display; and
a processor in electronic communication with the electronic display; and
the one or more computer-readable media as recited in claim 4 .
6. The image processing apparatus as recited in claim 5 , wherein:
the image processing apparatus further comprises a printer;
the one or more computer-readable media comprises one or more of a RAM, a ROM, and a flash EEPROM; and
the electronic display comprises a liquid crystal display.