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Horizon Imaging, LLC offers cutting-edge image processing solutions for biometric identification using neural networks. Explore wavelet decomposition, PCA, image zones, and neural network combinations for optimal preprocessing. Enhance classification performance and convergence speed with no hand geometry or fiducial points required.
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Horizon Imaging, LLC Innovative Solutions in Image Processing IMAGE PRE-PROCESSING FOR CLASSIFICATION (BIOMETRIC IDENTIFICATION) BY A NEURAL NETWORK Anthony Vannelli, Steve Wagner, and Ken McGarvey Horizon Imaging, LLC email: info@horizonimaging.com
Raw 512x480 Image Reduced data set Classification Output Neural Network Classifier Neural Preprocessor Horizon Imaging, LLC Innovative Solutions in Image Processing Neural Network Preprocessor and Classifier • Wavelets • PCA • Image “Zones” • Combining Networks • Feed-forward Network • Back-propagation Training • Single Hidden Layer
Horizon Imaging, LLC Innovative Solutions in Image Processing Curse of dimensionality • 512x480 raw image or 245,760 inputs to network • Large neural network • Poor classification performance • Slow convergence
Region of Interest Horizon Imaging, LLC Innovative Solutions in Image Processing Biometric Identification 320x160 = 51,200 pixels
Horizon Imaging, LLC Innovative Solutions in Image Processing Preprocessing Techniques • Non-parametric • “Holistic” • Data-driven • No Hand Geometry • No Fidiucial Points
Horizon Imaging, LLC Innovative Solutions in Image Processing Preprocessing Techniques • Principal components • Large eigen-values help to classify • Reduces dimensionality • Image Processing Zones • Divide and conquer • 2x2 zones (160x80 pixels) • 4x4 zones (80x40 pixels) • Ensemble of neural networks
Horizon Imaging, LLC Innovative Solutions in Image Processing Preprocessing Techniques • Combining Neural Networks • Pick the network with the “best fit” • Average the network outputs • Voting Scheme
Neural Net #1 y1 1 Neural Net #2 Input Vector Combined Output = i y2 2 N yN > T Neural Net #N yN Horizon Imaging, LLC Innovative Solutions in Image Processing Figure 3. Voting scheme to combine Neural Networks y1 > T y2 > T 0 for yi T i = 1 for yi > T Voting Scheme to Combine Networks
Horizon Imaging, LLC Innovative Solutions in Image Processing Preprocessing Technique using Wavelets • Coiflet wavelet • Daubechies wavelet • Haar wavelet (averages adjacent pixels) Second-level wavelet approximation
Low 2 LL Low 2 High 2 LH Image f(x,y) Low 2 HL High 2 High 2 HH Horizontal filter Vertical filter Horizon Imaging, LLC Innovative Solutions in Image Processing One-Level of a Wavelet Transform
LL HL LH HH Horizon Imaging, LLC Innovative Solutions in Image Processing Third-level Wavelet Decomposition
320x160 pixels 512 x 480 Image Neural Classifier Image Preparation Wavelet Transform PCA Output Figure7. Test case with single classifier Horizon Imaging, LLC Innovative Solutions in Image Processing Test Case with Single Classifier
Image 1 Neural Classifier 512 x 480 Image Output Image Preparation Wavelet Transform Combine Networks 320 x 160 pixels Image N Neural Classifier Figure8. Test case with multiple classifiers Horizon Imaging, LLC Innovative Solutions in Image Processing Test Case with Multiple Classifiers
Horizon Imaging, LLC Innovative Solutions in Image Processing Test Cases • Coiflet 6-coefficient wavelet to 3 levels; 3rd level approximation image (40x20 pixels) and 3 sidebands form input to 4 neural networks with 800 inputs each. • Daubechies 6-coefficient wavelet to 3 levels; 3rd level approximation image (40x20) and 3 sidebands form input to 4 neural networks with 800 inputs each. • Coiflet 6-coefficient wavelet to 2 levels (80x40 pixels); 4 image zones fed to 4 separate neural networks with 800 inputs each.
Horizon Imaging, LLC Innovative Solutions in Image Processing Test Cases • Daubechies 6-coefficient wavelet to 2 levels (80x40 pixels); 4 image zones fed to 4 separate neural networks with 800 inputs each. • Harr wavelet to 2 levels (80x40 pixels); 4 image zones fed to 4 separate neural networks with 800 inputs each. • Harr wavelet to 2 levels (80x40 pixels) and then PCA transform fed to a neural network with 512 inputs.
Horizon Imaging, LLC Innovative Solutions in Image Processing Test Cases • Harr wavelet to 3 levels (40x20 pixels) fed to a neural network with 800 inputs. • Coiflet 6-coefficient wavelet to 1 level (160X80 = 12800 pixels). The first level approximation image is divided into 16 image zones (40x20 pixels per zone). The zones are fed into separate neural networks with 800 inputs each.
Summary of Performance Horizon Imaging, LLC Innovative Solutions in Image Processing