Scene-specific classifier for effective and efficient team sport players detection from a single calibrated camera

Parisot, Pascaline [UCL] De Vleeschouwer, Christophe [UCL]

This paper considers the detection of players in team sport scenes observed with a still or motion-compensated camera. Background-subtracted foreground masks provide easy-to-compute primary cues to identify the vertical silhouettes of moving players in the scene. However, they are shown to be too noisy to achieve reliable detections when only a single viewpoint is available, as often desired for reduced deployment cost. To circumvent this problem, our paper investigates visual classification to identify the true positives among the candidates detected by the foreground mask. It proposes an original approach to automatically adapt the classifier to the game at hand, making the classifier scene-specific for improved accuracy. Since this adaptation implies the use of potentially corrupted labels to train the classifier, a semi-naive Bayesian classifier that combines random sets of binary tests is considered as a robust alternative to boosted classification solutions. In final, our validations on two publicly released datasets prove that our proposed combination of visual and temporal cues supports accurate and reliable players’ detection in team sport scenes observed from a single viewpoint.