User Manual

 Division Quartic: Provides a more accurate simulation of Quartic radial lens curvature.
This causes the low and high order distortion values to be solved for.
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Lower Order Radial Distortion: This slider is available for all simulations. It
determines the quadratic lens curvature.
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Higher Order Radial Distortion: This slider is available only for Quartic simulations.
Determines the quartic lens curvature.
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Tangential Distortion X/Y: These sliders are available only for Tangential
simulations. Determines skew distortion.
Track Filtering
The Camera Tracker can produce a large number of automatically generated tracks. Rather
than spending a lot of time individually examining the quality of each track, it is useful to have
some less time-intensive ways to filter out large swaths of potentially bad tracks. The following
input sliders are useful for selecting large amounts of tracks based on certain quality metrics,
and then a number of different possible operations can be made on them. For example, weaker
tracks can selected and deleted, yielding a stronger set of tracks to solve from. Each filter can
be individually enabled or disabled.
Minimum Track Length (Number of Markers)
Selects tracks that have a duration shorter than the slider’s value. Short tracks usually don’t get
a chance to move very far and thus provide less perspective information to the solver than a
longer track, yet both short and long tracks are weighted evenly in the solve process, making
long tracks more valuable to the solver. Locators corresponding to shorter tracks are also less
accurately positioned in 3D space than those corresponding to longer tracks. If the shot has a
lot of long tracks, it can be helpful to delete the short tracks. For typical shots, using a value in
the range of 5 to 10 is suggested. If there are not a lot of long tracks (e.g., the camera is quickly
rotating, causing tracks to start and move off frame quickly), using a value closer to 3 is
recommended.
Maximum Track Error
Selects tracks that have an average track error greater than the slider’s value. When tracking,
tracks are automatically terminated when their track error exceeds some threshold. This auto
termination controls the maximum track error, while this slider controls the average track error.
For example, tracks following the foliage in a tree tend to be inaccurate and sometimes may be
detected by their high average error.
Maximum Solve Error
Selects tracks that have a solve error greater than the slider’s value. One of the easiest ways to
increase the accuracy of a camera solve is to select the 20% of the tracks with the highest solve
error and simply delete them (although this can sometimes make things worse).
Select Tracks Satisfying Filters
Selects the tracks within the scene that meet the above Track Filtering values. Note that when
this button is pressed, the tracks that satisfy the filter values are displayed in the Selected
Tracks area of the Solve tab and are colored in the viewer. This button is useful when Auto
Select Tracks While Dragging Sliders is turned off or if the selection, for example, was
accidentally lost by mis-clicking in the viewer.
Auto Select Tracks While Dragging Sliders
When this is ticked on, dragging the above sliders (Minimum Track Length, Maximum Track
Error, Maximum Solve Error) will cause the corresponding tracks to be interactively selected in
the viewer.
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