Computing 3D shape parameters for face animation

#Face tracking techniques are used to find features on a user's face, such as eyes, mouth, nose, and so forth. A camera captures frames containing the face, and the techniques examine the face to find the facial features. With some techniques, various two-dimensional (2D) feature points first are found on the face. Once the 2D feature points have been found, then 3D shape parameters can be found. These 3D shape parameters may include the 3D shape of a user's head, the 3D head pose, and the 3D position of the 2D points observed on the image frame.

#One application of these face tracking techniques is to take the frames containing the user's face and model the facial expressions of the user. In other words, the way in which the user moves his face, such as lifting his eyebrows, smiling, and moving his mouth, is modeled. This modeling involves converting what is seen in the frames captured by the camera into movements of the face. This face model can be used to animate the user's face in a computing environment or deduce the meaning of a user's facial expression.

#One difficulty, however, is that different people have different facial features. For example, some people have larger mouths than others, some have eyes that are far apart, and some have eyes that are close together. If the actual shape of the user's head is not taken into account, then the facial features of the user can easily be misread.

#Referring now to the drawings in which like reference numbers represent corresponding parts throughout:

#FIG. 1 is a block diagram illustrating a general overview of embodiments of the 3D shape parameter computation system and method implemented in a computing environment.

#FIG. 2 is a flow diagram illustrating the general operation of embodiments of the 3D shape parameter computation system and method shown in FIG. 1.

#In the following description of embodiments of a 3D shape parameter computation system and method reference is made to the accompanying drawings, which form a part thereof, and in which is shown by way of illustration a specific example whereby embodiments of the 3D shape parameter computation system and method may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the claimed subject matter.

#I. System Overview

#Embodiments of the 3D shape parameter computation system and method compute update to 3D head shape parameters from 2D feature points obtained from images captured over a period of time. The dimension of the problem is lowered from 3D to 2D because 2D feature points are used instead of image pixels. This means there are fewer data points to work with, as image pixels are more numerous. This reduces the computational complexity considerably and allows the 3D head shape parameter updates to be computed in real time.