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Viola and Jones Object Detector. Ruxandra Paun EE/CS/CNS 148 - Presentation 04.28.2005. Fast!. 15 times faster than any previous approach 384 by 288 pixel images detected at 15 frames per second on a conventional 700 MHz Intel Pentium III. 3 key contributors:
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Viola and Jones Object Detector Ruxandra Paun EE/CS/CNS 148 - Presentation 04.28.2005
Fast! • 15 times faster than any previous approach • 384 by 288 pixel images detected at 15 frames per second on a conventional 700 MHz Intel Pentium III
3 key contributors: - a new image representation: the “Integral Image” - a simple and effective classifier, based on the AdaBoost learning algorithm - combining the classifiers in a “cascade” Robust Real-Time Face Detection
Classifier: using AdaBoost • 160,000 features for every sub-window • Very small number of these features can be combined to form an effective classifier • AdaBoost: constrain each week classifier to depend on a single feature • each stage of boosting = new week classifier selection = feature selection
The Cascade • combining successively more complex classifiers in a cascade structure • 38 stages
ROC curves: cascaded vs. monolithic classifier -> not significantly different accuracy -> but the cascade class. almost 10 times faster
Comparing Viola-Jones with Other Systems
More: Detecting Walking Pedestrians • Integrating image intensity with motion information • Efficient, detects pedestrians at small scales, and has a very low false positive rate • Works on low resolution images and under difficult weather conditions (rain, snow)