IMAGE PROCESSING APPARATUS AND METHOD FOR FITTING A DEFORMABLE SHAPE MODEL TO AN IMAGE USING RANDOM FOREST REGRESSION VOTING

One embodiment of the invention provides an image processing method for use in fitting a deformable shape model to an acquired image. The deformable shape model specifies a set of target points whose motion is governed by the model. The method comprises, for each target point, generating a corresponding response image by: providing a feature detector to locate a given target point within the acquired image, wherein said feature detector includes a random forest comprising one or more decision trees; scanning a patch image across the acquired image to define multiple sampling locations with respect to the acquired image; for each sampling location of the patch image with respect to the acquired image, performing regression voting using the random forest to produce one or more votes for the location of the given target point within the acquired image; and accumulating the regression votes for all of the multiple sampling locations to generate said response image corresponding to the given target point. The method further includes then performing an optimization to determine positions for the set of target points within the acquired image based on the corresponding response images and subject to constraint by the deformable shape model.