User Manual

Sometimes with troublesome shots, it can help to drop down to a simpler motion model—for
example, when many track points are clustered on one side of the tracked region or when
tracking a small region where there are not many trackable pixels.
Output
Controls what is output from the Planar Tracker node while in the Track operation mode.
 Background: Outputs the input image unchanged.
 Background - Preprocessed: The Planar Tracker does various types of preprocessing
on the input image (e.g., converting it to luma) before tracking. It can be useful to see
this when deciding which track channel to choose.
 Mask: Outputs the pattern as a black and white mask.
 Mask Over Background: Outputs the pattern mask merged over the background.
Track Channel
Determines which image channel in the background image is tracked. It is good to pick a
channel with high contrast, lots of trackable features, and low noise. Allowed values are red,
green, blue, and luminance.
Tracking Controls
These controls are used to control the Tracker. Note that while tracking, only track to a new
frame if the current frame is already tracked or it is the reference frame.
 Track to start: Tracks from the current frame backward in time to the start (as
determined by the current render range).
 Step tracker to previous frame: Tracks from the current frame to the previous frame.
 Stop tracking: Stops any ongoing tracking operations.
 Step tracker to next frame: Tracks from the current frame to the next frame.
 Track to end: Tracks from the current frame forward in time to the end (as determined
by the current render range).
 Trim to start: Removes all tracking data before the current frame.
 Delete: Deletes all tracking data at all times. Use this to destroy all current results and
start tracking from scratch.
 Trim to end: Removes all tracking data after the current frame. This can be useful, for
example, to trim the end of a track that has become inaccurate when the pattern starts
to move off frame.
Show Splines
This button to the right of the “Trim to end” button opens the Spline Editor and shows the
splines associated with the Planar Tracker node. This can be useful for manually deleting points
from the Track and Stable Track splines.
Right-Click Here for Track Spline
While tracking, a spline containing 4 x 4 matrices at each keypoint is created. This is known as
the “Track spline” or just “Track” for short. These matrices completely describe the distortions
of the tracked pattern.
Chapter – 107 Tracker Nodes 2410