1. A method for determining a pose of a subject comprising the steps of: organizing a plurality of images in a searchable tree structure, each image being associated with at least one parameter representing a pose, the step of organizing includes the steps of: determining a direction of maximal variation of the plurality of images; and separating the plurality of images into at least two subsets according to a comparison of each image to the direction of maximal variation; taking a picture of the subject to generate a sample image; traversing the searchable tree structure to locate one of the plurality of images which is closest to the sample image; and outputting the at least one parameter associated with the one of the plurality of images as the pose.