I have a frame taken from a video. The frame contains a face and I have the (x, y) locations of the features (corners of lips, edge of eyebrows, etc.) and the headpose vector (pitch, yaw, roll), which shows the direction that the face is looking in degrees ((0, 0, 0) would be at the camera).
I need to calculate distances between specific points in real (3D) space. How can I map the feature locations to 3D space?