Carnegie Mellon University
Object Detection Using the Statistics of Parts

Henry Schneiderman and Takeo Kanade
International Journal of Computer Vision, 2002.

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In this paper we describe a trainable object detector and its instantiations for detecting faces and cars at any size, location, and pose. To cope with variation in object orientation, the detector uses multiple classifiers, each spanning a different range of orientation. Each of these classifiers determines whether the object is present at a specified size within a fixed-size image window. To find the object at any location and size, these classifiers scan the image exhaustively. Each classifier is based on the statistics of localized parts. Each part is a transform from a subset of wavelet coefficients to a discrete set of values. Such parts are designed to capture various combinations of locality in space, frequency, and orientation. In building each classifier, we gathered the class-conditional statistics of these part values from representative samples of object and non-object images. We trained each classifier to minimize classification error on the training set by using Adaboost with Confidence-Weighted Predictions (Shapire and Singer, 1999). In detection, each classifier computes the part values within the image window and looks up their associated class-conditional probabilities. The classifier then makes a decision by applying a likelihood ratio test. For efficiency, the classifier evaluates this likelihood ratio in stages. At each stage, the classifier compares the partial likelihood ratio to a threshold and makes a decision about whether to cease evaluation ?labeling the input as non-object - or to continue further evaluation. The detector orders these stages of evaluation from a low-resolution to a high-resolution search of the image. Our trainable object detector achieves reliable and efficient detection of human faces and passenger cars with out-of-plane rotation.

object detection, object recognition, face detection, car detection, pattern recognition, machine learning, computer vision

Sponsor: Advanced Research and Development Activity (ARDA)
Grant ID: MDA904-00-C-2109
Associated Center(s) / Consortia: Vision and Autonomous Systems Center and Medical Robotics Technology Center
Associated Lab(s) / Group(s): Human Identification at a Distance and Face Group
Associated Project(s): Object Recognition Using Statistical Modeling, Face Detection Databases, Face Detection

Text Reference
Henry Schneiderman and Takeo Kanade, "Object Detection Using the Statistics of Parts," International Journal of Computer Vision, 2002.

BibTeX Reference
   author = "Henry Schneiderman and Takeo Kanade",
   title = "Object Detection Using the Statistics of Parts",
   journal = "International Journal of Computer Vision",
   year = "2002",