< Previous | Contents | Manuals Home | Boris FX | Next >
If your footage has a pixel aspect ratio greater than one, we advise using the image preprocessor’s output tab to resample it to 1:1 pixels while you are generating trackers. After the trackers are set and locked, you can remove the resampling.
Tip: Zoom in on dots or corners near the edge of your grid. Click and unclick the Red, Green, and Blue channel selectors at the bottom of the camera view, and see if the pattern appears to move. If so, that indicates Chromatic Aberration in the lens, and we suggest changing the Image Preprocessor’s Rez tab to switch
to G (green) while generating the trackers (by any method). If you’re really tricky, you could generate 3 different calibrations and use a compositing app to correct each channel individually to remove the aberrations.
Begin by clicking Shot/Create Lens Grid Trackers. Answer Yes to indicate that you have a checkerboard. Delete any spurious trackers, likely using the tracker panel's Delete mode. If necessary, add additional trackers around the edges if vignetting has caused them not to be recognized. Select all trackers (control-A) and lock them.
Tip : Instead of using Shot/Create Lens Grid Trackers, you can also auto-track using the Checkerboard neural net model on the Advanced Feature Control panel. Set the Minimum Track Length to zero or one, and raise the Maximum Tracker Count to several thousand. Use the Symmetry tracker type for additional supervised trackers. Blips all frames, then Link frames and Peel All.
Tip : Alternatively, use corner tracking. On the Advanced Feature Control panel, turn on Corner trackers. Set Small Blip Density and Big Blip Density to zero. Set the Minimum Track Length to zero or one, and raise the Maximum Tracker Count to several thousand. Turn on Auto Re-blip, and experiment with the Edge Width, especially for defocused grids. Blips all frames, then Link frames and Peel All.
Tip: After using the Checkerboard or corner tracking, use the Script/Lens/ Decluster Trackers script to automatically combine nearby trackers that result from poor grid images. Averaging is most useful for corner trackers, highest value for neural net trackers.
You can switch the camera view to display only dots, or turn off the image display, to check the trackers produced.
Note: the 3D tracker locations will not line up with the 2D tracker locations in the image. It isn't doing that kind of solve, the camera location isn't determined. The image of the dot will line up with the 2D tracker location; they will form the regular grid.
©2023 Boris FX, Inc. — UNOFFICIAL — Converted from original PDF.