Post on 30-Dec-2015
description
ECE738 Advanced Image Processing
Face Sketch Recognition
[Tang04] IEEE Trans. CSVT, Jan 2004
(C) 2005 by Yu Hen Hu 2ECE738 Advanced Image Processing
Problem Statement
• Goal:– Match face images to
face sketches– Useful when test faces
are in sketch forms (e.g. no photo of suspect).
• Approach– Transform face images
to sketches– Match sketches of
faces using an eigen-sketch approach
(C) 2005 by Yu Hen Hu 3ECE738 Advanced Image Processing
Geometric Methods
• Fiducial grid model– Identify anchor points tip of
noise, corners of mouth– Derive other fiducial points
from the identified anchor point
• Geometric features– 35 fiducial points used– 26 distances between key
fiducial points measured.– Including sizes of nose, eyes,
eyebrows, face contours, etc.• Measure geometric features
from both face image and sketches and perform matching
(C) 2005 by Yu Hen Hu 4ECE738 Advanced Image Processing
Eigen-Sketch Method
• Convert face image into eigenface representation.• Generate eigen-sketch from each eigenface.• Project probe sketches (test sketches) onto the
subspace spanned by eigen-sketches. • Use feature vectors of eigen-face representation to
match the weight vectors • Assumption:
– Face images and sketches are normalized in size, lighting, poses, and expression neutral
– No occlusions on test images (eye glasses, beard, etc.)
(C) 2005 by Yu Hen Hu 5ECE738 Advanced Image Processing
Photo-to-sketch transformation
Photo-to-sketch transformation examples. (a) Original photo. (b) Reconstructed
photo. (c) Reconstructed sketch. (d) Original sketch.
Photo – eigen-face – eigen-sketch - sketch
(C) 2005 by Yu Hen Hu 6ECE738 Advanced Image Processing
Results
• Using Feret test set, the proposed method (sketch transform) out-performs conventional method (geometric and eigen-face) by large margin.
• Possible reason: – Geometric face: features measured on photo may be different from
sketches– Eigenface: gray scale image value differ very much between phton
and sketch.
Rank 1 2 3 4 5 6 7 8 9 10
Geometric 30 37 45 48 53 59 62 66 67 70
Eigenface 31 43 48 55 61 63 65 65 67 67
Sketch transform 71 78 81 84 88 90 94 94 95 96