A good 3D tracking result
is often footage dependant, therefore you may decide to use the
automatic or manual 3D tracker. In most cases, the automatic 3D
tracker gives good results. In some instances, such as when the
motion is confined to the axes, and there is little or no perspective
rotation, the manual tracker may be a better choice.
Here are some things
to keep in mind that can improve your 3D track:
- The 3D tracker works best when tracking
an image sequence that has a moving camera or environment. Masks
should be used to isolate the background and the objects in the
scene that have different motions. Masking objects cause them to
be ignored in the tracking process. You should also mask any logos
or watermarks in your image sequence.
- The 3D tracker analysis is based on point-like
and corner-like image features. Balls, spheres, lines, and smooth
surfaces are not considered.
- Crop out any black areas around your
image (such as letterbox areas). When cropping, it is very important
to keep the optical centre of the image in the centre, that is,
the crop should be symmetrical in both dimensions.
- To be able to convert the tracking results
correctly, the resolution and aspect ratio of the image being analysed
must match the resolution and aspect ratio set in the Action Setup menu.
- 3D tracking analyses each frame extensively
and with high resolution clips, the process can be lengthy. Unlike
2D tracking, however, you are not required to analyse full-resolution
clips. In many cases, analysing proxies will produce acceptable
3D tracking results, in a fraction of the time that would be required
for the full-resolution clips.
- If you have information about the camera
that shot the scene you want to track, such as the focal length
of the lens and the film back size, you can specify these details
to help the 3D tracking analysis.