Shooting for Head Tracking

Here are some touch points if you are shooting a scene and will later track one or more actor's head or other body parts.

• Use a reasonably tight shot of the head: the smaller the actor's head in frame, the harder to track it.
• Use a shorter focal length lens—by shooting from up close there will be more perspective to get 3-D.
• Keep shutter time short to avoid blurring tracking dots into oblivion
• Maintain accurate focus
• If you are tracking multiple heads, or a head plus the background camera, consider how you will set their relative scale, ie a distance measurement for each.
• Use high-resolution progressive-scan source.
• Try to maintain more than a dozen trackable points on the head at all times.
• Trackers must be on parts of the head that don't move relative one another—corners of the eyes, nose, ears, ...
• Don't use trackers on the jaw, mouth, eyebrows, or mobile portions of the cheeks.
• Consider tracking tiny facial details on the face and head.
• Consider drawing some dots on the actor, especially in areas that will later be replaced
• Usually supervised tracking is required

You can track the moving features of the actor's face independently using SynthEyes's motion-capture capabilities, if you use two cameras. See the manual.