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Emerging biometrics Presenter : Shao-Chieh Lien Adviser : Wei-Yang Lin
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Contents Introduction Iris recognition Image Acquisition Iris localization 2-D Wavelet demodulation Recognition Comparison Reference
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Introduction John Daugman’s algorithm The basis of almost all currently (as of 2006) commercially deployed iris-recognition systems
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Introduction (cont.) Aged 12 in a refugee camp in Pakistan 18 years later to a remote part of Afghanistan
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Iris recognition (infrared light)
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Image Acquisition Iris radius: 80-130 pixels
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Iris localization A smoothing function such as a Gaussian of scale σ Searching iteratively for the maximal contour integral Three parameter space of center coordinates and radius defining a path of contour integration
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Iris localization (cont.) The path of contour integration in the equation is changed from circular to arcuate. It is used to localize both the upper and lower eyelid boundaries. Images with less than 50% of the iris visible between the fitted eyelid splines are deemed inadequate.
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Regardless of Size, Position, and Orientation
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Regardless of Size, Position, and Orientation (cont.) r: [0, 1] θ: [0, 2π] (x p (θ), y p (θ)): pupillary boundary points (x s (θ), y s (θ)): limbus boundary points
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2-D Wavelet demodulation A given area of the iris is projected onto complex-valued 2-D Gabor wavelets: α, β are the multiscale 2-D wavelet size parameters
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2-D Wavelet demodulation (cont.) ω is wavelet frequency (r 0, θ 0 ) represent the polar coordinates of each region of iris
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2-D Wavelet demodulation (cont.) 2048 such phase bits (256 bytes) are computed for each iris
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2-D Wavelet demodulation (cont.) Advantage: phase angles remain defined regardless of how poor the image contrast may be
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Test of statistical independence HD: Hamming Distance ∥ maskA ∩ maskB ∥ : total number of phase bits that mattered in iris comparisons after artifacts such as eyelashes and specular reflections were discounted HD = 0: perfect match
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Experiment result 4258 different iris images Bernoulli trial: successive “coin tosses.”
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Binomial Distribution N = 249, p = 0.5, x = m/N, x is the Hamming Distance (HD)
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Experiment result
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Genetically Identical Eyes
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Best match F 0 (x): the probability of getting a false match 1-F 0 (x): the probability of not making a false match (single test) [1-F 0 (x)] n : best of n
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Best match (cont.) F n (x) = 1-[1-F 0 (x)] n f n (x): density function
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Best match (cont.)
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False match probability
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Decision Environment Less favorable conditions: images acquired by different camera platforms
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Decision Environment (cont.) Ideal conditions: almost artificial
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“decidability” index d’ μ1, μ2: mean σ1, σ2: standard deviation
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Probabilities Table Not stable “authentics” distributions depend strongly on the quality of imaging (e.g., motion blur, focus, noise, etc.) Different for different optical platforms
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Comparison Fujitsu PalmSecure (palm vein recognition) IrisGuard H100 (iris recognition) Hitachi UB READER (finger vein recognition) [7] International Biometric Group, “Comparative Biometric Testing, Round 6 Public Report”, 2006.
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Acquisition Devices Fujitsu PalmSecure IrisGuard H100 Hitachi UB READER
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Test Environment
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Comparison Processes ∼ 90,000 genuine comparisons and ∼ 116m impostor comparisons were executed across the three Test Systems. Accuracy was evaluated at the attempt and transaction levels. Attempt-level results are based on all available comparison scores Transactional results are based on the strongest comparison score of the six available in most recognition transactions.
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Accuracy Terminology
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Accuracy Results Fujitsu FMR, FNMR, T-FMR, and T-FNMR Hitachi, IrisGuard FMR, FNMR, T-FMR, and T-FNMR
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DET Curves
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Reference [1] http://en.wikipedia.org/wiki/Iris_recognitionhttp://en.wikipedia.org/wiki/Iris_recognition [2] http://www.cl.cam.ac.uk/~jgd1000/http://www.cl.cam.ac.uk/~jgd1000/ [3] http://www.biometricgroup.com/http://www.biometricgroup.com/ [4] J. G. Daugman, “How iris recognition works,” IEEE Trans. Circuits Syst. Video Technol., vol. 14, no. 1, pp. 21–30, Jan. 2004. [5] J. G. Daugman, "Probing the uniqueness and randomness of IrisCodes: Results from 200 billion iris pair comparisons." Proceedings of the IEEE, vol. 94, no. 11, pp 1927-1935, 2006. [6] J. G. Daugman, "Demodulation by complex-valued wavelets for stochastic pattern recognition." Int'l Journal of Wavelets, Multi-resolution and Information Processing, vol. 1, no. 1, pp 1-17, 2003. [7] International Biometric Group, “Comparative Biometric Testing, Round 6 Public Report”, 2006.
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