Partial face detector red-eye filter method and apparatus

Abstract

A digital camera has an integral flash and stores and displays a digital image. Under certain conditions, a flash photograph taken with the camera may result in a red-eye phenomenon due to a reflection within an eye of a subject of the photograph. A digital apparatus has a red-eye filter which analyzes at least one partial face region identified within the digital image for the red-eye phenomenon and modifies the image to eliminate the red-eye phenomenon by changing the red area to black. The modification of the image is enabled when a photograph is taken under conditions indicative of the red-eye phenomenon. The modification is subject to anti-falsing analysis which further examines the area around the red-eye area for indicia of the eye of the subject. The detection and correction can be optimized for performance and quality by operating on subsample versions of the image when appropriate.

What is claimed is: 
     
         1 . A portable digital image capturing device having no photographic film, comprising:
 a flash for providing illumination during image acquisition;   an optical system including a lens and an image sensor for capturing a digital image;   a partial face detector for identifying one or more partial face regions within the digital image; and   a red-eye filter for modifying an area within the image indicative of a red-eye phenomenon based on an analysis of a subsample representation comprising one or more partial face regions identified within the image.   
     
     
         2 . The device of  claim 1 , wherein said red-eye filter is adapted based on a type of at least one of said one or more partial face regions identified within the digital image. 
     
     
         3 . The device of  claim 1 , wherein the analysis is performed at least in part for determining said area. 
     
     
         4 . The device of  claim 1 , wherein the analysis is performed at least in part for determining said modifying. 
     
     
         5 . The device of  claim 1 , wherein at least one partial face region within the digital image is not among said one or more partial face regions identified within the digital image that are analyzed. 
     
     
         6 . The device of  claim 1 , wherein said analysis is performed in part on a full resolution partial face region and in part on a subsample resolution of at least one different partial face region. 
     
     
         7 . The device of  claim 1 , further comprising a module for changing the degree of said subsampling. 
     
     
         8 . The device of  claim 1 , wherein said subsample representation is determined using spline interpolation. 
     
     
         9 . The device of  claim 1 , wherein said subsample representation is determined using bi-cubic interpolation. 
     
     
         10 . The device of  claim 1 , wherein said modifying the area is performed on a full resolution of at least one partial face region within the digital image. 
     
     
         11 . The device of  claim 1 , wherein said red-eye filter comprises a plurality of sub-filters. 
     
     
         12 . The device according to  claim 11 , wherein said subsampling for said sub-filters operating on selected regions of said image is determined by image size, a suspected red eye region size, filter computation complexity, empirical success rate of said sub-filter, empirical false detection rate of said sub-filter, falsing probability of said sub-filter, relations between suspected red eye regions, or results of previous analysis of one or more other sub-filters, or combinations thereof.