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Face Detection. --- EE368 Project Presentation Ajay Gupta , Gang Xie and Jiwu Tang Stanford University 30 May, 2002. Integration of Segmentation and Template Matching Approach. Skin-Color based Segmentation. Template Matching. Refine. Skin-Color Based Segmentation.
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Face Detection --- EE368 Project Presentation Ajay Gupta, Gang Xie and Jiwu Tang Stanford University 30 May, 2002
Integration of Segmentation and Template Matching Approach Skin-Color based Segmentation Template Matching Refine
Skin-Color Based Segmentation • RGB to YCbCr conversion • Generate a binary image using the chrominace components of the skin color • Morphological Processing on the binary image to fill up the holes and remove small isolated regions • Remove some of the small regions having area less than a certain threshold value • Remove some of the non-face regions using certain feature values such as orientation and ratio of MajorAxisLength to MinorAxisLength.
Face Template Construction Step 1: Extract 169 faces from 7 training images based on the ground truth data Step 2: Decide the template size (20*20) based on statistics Step 3: Manually form a training set containing 26 faces Step 4: Manually measure the positions of the center of two eyes and the center of mouth for each face Step 5: Scale all faces to the same size Step 6: Move all faces to the same position Step 7: Apply intensity histogram equalization on each face while keep hue and saturation unchanged Step 8: Average, resize, subtract its mean, and flip
Template Matching s, t size(s) > size(t) ? no yes conv2(s, t) peak > threshold ? no yes record peak return • Inputs: • image s(x,y) • template t(-x,-y) scale s down
Template Matching Further Eliminates Skin-Colored Non-Faces After segmentation After template matching
Testing Results Image False No. Hits Positive Score ---------------------------------------------- 1 23 0 23 2 20 0 20 3 24 0 24 4 18 0 18 5 25 0 25 6 24 1 23 7 19 2 17