This panel contains all settings for the 2D tracking algorithms. Preset tracking settings can be configured in the panel header. These presets are based on tracking experience of real footage and provides good start values to begin working with a specific footage.
- Pattern Size, Search Size
Defines size of a newly created tracks.
- Motion Model
Defines which possible motions tracking feature has. This option should be set depending on which motion a particular feature has and it will make tracking most accurate for such a motion.
Location, Location & Rotation, Location & Scale, Location, Rotation & Scale, Affine
Is usually used to track a planar feature, but often Affine is a good enough approximation and may have more stable tracks.
Controls which patterns get tracked; to be more precise, the pattern from which frame is getting tracked. Here is an example which should make things clearer.
The tracker algorithm receives two images inside the search area and the position of a point to be tracked in the first image. The tracker tries to find the position of that point from the first image in the second image.
Now, this is how tracking of the sequence happens. The second image is always from a frame at which the position of marker is not known (next tracking frame). But a different first image (instead of the one that immediately precedes the second image in the footage) can be sent to the tracker.
An image created from a frame on which the track was keyframed. This configuration prevents sliding from the original position (because the position which best corresponds to the original pattern is returned by the tracker), but it can lead to small jumps and can lead to failures when the feature point is deformed due to camera motion (perspective transformation, for example).
- Previous Frame
Keyframes for tracks are creating every frames, and tracking between keyframed image and next image is used. In this configuration the pattern is tracking between two neighboring frames. It allows dealing with cases of large transformations of the feature point but can lead to sliding from the original position, so it should be controlled.
Enables a two pass tracking, where the first pass is a brute force tracking of location only, and the second pass will use tracking of the full motion model refining the first pass.
Means patterns will be normalized by their average intensity while tracking, to make them invariant to illumination changes. An example where this is useful is a scene where a marker moves in the shadow of an object.
Defines color channels which will be used by a tracking algorithm. Disabling some colors might increase the contrast to enhance the feature detection.
- Copy from Active Track
Copies all settings from active track. Allows to ease creation of new tracks with the same setting.
Tracking Extra Settings
See Track Weight.
This value defines the minimal correlation between a matched pattern and a reference to be considered a successful tracking. If the tracker is stops too early, decrease this value, or if the track is slipping too much when it should stop sooner, increase this value.
Can be used disable tracks when they become too close to the image boundary. This slider sets "too close" in pixels.
- Use Mask
Allows to use annotation tool to mask part of a pattern, narrowing down what the tracker algorithm is attempting to match across frames.
- Frames Limit
Controls how many frames can be tracked when the Track Sequence operator is called. So, each Track Sequence operation would track maximum Frames Limit frames. This also helps to notice a slide-off of tracks and correct them.
Marker settings only -- Can be used to control the speed of sequence tracking. This option does not affect the quality of tracking; it just helps to control if tracking happens accurately. In most cases tracking happens much faster than real-time, and it is difficult to notice when a track began to slide out of position. In such cases Speed can be set to Double or Half to add some delay between tracking two frames, so a slide-off would be noticed earlier and the tracking process can be canceled to adjust positions of tracks.