Post on 19-Jan-2018
description
Face Detection Using Color Thresholding and
Eigenimage Template Matching
Diederik MariusSumita Pennathur
Klint Rose
Approach
Input Image
YCbCrThresholding
Binary ImageProcessing
Separationof “Blobs”
SizeThreshold
Homogeneity/Aspect Ratio
ThresholdCross-covariancewith Eigenimage
DuplicateDetectionRemoval
Rejection
Match Face Location to Input Image
Indi
vidu
al b
lobs
x10
Skin Segmentation Used distribution of Cr and Cb
values for faces vs. background to thresholdSkin region: 105<Cr<135
140<Cb<165
Binary Image Processing Erosion and dilation with face-shaped
segmentation element Removes small foreground and
background objects Delineates between larger regions
Separation and Rejection Larger regions labeled and
separated Series of Rejection Thresholding:
Size of regions (>3000 total pixels) Aspect Ratio (0.5 <AR< 1.8 ) St. Dev. of image values (60<<100)
Size based thresholding
Coupled AR and St. Dev. based thresholdin
g
Eigenimages Computed from set of “good” faces Employed Sirovich-Kirby method to calculate first 10 eigenimages Eigenimage #2: most accurate location of center of face Used eigenimage #2 exclusively
1 2 3 4 5 6 7 8 9 10
Template Matching Found cross-covariance peak and
marked as potential center Removed face sized area from
image Found new highest peak - repeated
10x
False Detection Removal Thresholded detected peaks
to obtain potential faces only Determined whether
multiple peaks belong to the same person (neck, etc)
Rejection criteria: Near the same y-axis and within a predetermined vertical distance of a previous point
Rejectedpoints
Typical Detection Result Detection problems: rotated faces,
small faces, hands, faces in lower 1/3
Results Average run time: 100 seconds 95% of faces found 4.4% false positives
# Faces # Correct False Pos False Neg % Correct % FalseTraining Image 1 21 21 1 0 100 4.8Training Image 2 23 21 5 2 91 21.7Training Image 3 23 22 0 1 96 0.0Training Image 4 24 22 0 2 92 0.0Training Image 5 24 23 0 1 96 0.0Training Image 6 24 23 0 1 96 0.0Training Image 7 22 19 1 3 86 4.5Total 161 151 7 10 95 4.4
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16
5 (0)4 (19)15
5 (0)4 (19)14
5 (0)4 (19)13
5 (0)4 (19)12
5 (0)15 (08)11
2 (1)2 (20)10
2 (1)1 (22)9
1 (2)13 (14)8
5 (0)12 (16)7
5 (0)11 (17)6
5 (0)14 (13)5
5 (0)9 (18)4
5 (0)9 (18)3
5 (0)2 (20)2
2 (1)4 (19)1
Gender RecognitionFace Detection
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5 (0)4 (19)15
5 (0)4 (19)14
5 (0)4 (19)13
5 (0)4 (19)12
5 (0)15 (08)11
2 (1)2 (20)10
2 (1)1 (22)9
1 (2)13 (14)8
5 (0)12 (16)7
5 (0)11 (17)6
5 (0)14 (13)5
5 (0)9 (18)4
5 (0)9 (18)3
5 (0)2 (20)2
2 (1)4 (19)1
Gender RecognitionFace Detection