providing a collection of images, the images having faces at various views: for each of a plurality of views, providing a prior probability that faces in images of the collection will be at that view based on a percentage of the faces in the images of the collection that are at that view;

providing detectors for determining whether a window of an image contains a face, each detector adapted to detect faces with a certain view;

providing a filter for each detector, the filter for filtering out windows based on a the prior probability associated with the view of the detector;

after the prior probabilities have been provided, receiving an image for detecting whether the image contains a face; and

for each window of the received image,

generating a score relating to a likelihood that the received image contains a face; and

for each detector,

applying the filter of the detector to filter out the window when the generated score does not satisfy a threshold score, such that the threshold score is higher for filters of detectors of views with lower prior probabilities and lower for filters of detectors of views with higher prior probabilities; and

applying the detector to the window when the window has not been filtered to identify a candidate window containing a face.