1. A computer-implemented method for estimating head pose, comprising: initiating tracking of a sequence of images received from a depth camera; receiving a first sequence of images from the depth camera wherein the images correspond to a first side of a human subject's head; generating a head mesh that estimates head pose for each of the first sequence of images; determining that that the subject's head has rotated to a threshold angle in the first direction; receiving a second sequence of images from the depth camera wherein the images correspond to a second side of the subject's head; generating a head mesh that estimates head pose for each of the second sequence of images; merging the head meshes to create a 3D model of the head of the subject; and displaying the 3D model; wherein generating a head mesh for a received sequence of images comprises: establishing a reference frame from one of images received from the depth camera; extracting a reference head mesh from the reference frame; for each additional received image in the sequence of images: extracting a second head mesh from a second received image, the second received image being received after the reference frame; and computing the relative rotation and translation in three dimensions between the second head mesh and the reference head mesh.