< Previous | Contents | Manuals Home | Boris FX | Next >
Limitations of Auto-Masking
Auto-masking is a tool and image issues may make it inapplicable.
Chief among these is lighting changes, especially where the changing orientation of the lights, tracked plane, and camera cause large highlights to appear on the tracked plane, with resulting changes not only in luminance but in saturation as well. In a non- occluded shot, you normally deal with this by periodically re-keying the search pattern, but this is not an option when there is an occluding object as it "burns in" the image of the occluding object. If the main illumination compensation control is turned on, auto- mask performs additional processing to try to compensate for the lighting change, but this has limited effectiveness on significant illumination changes.
You may also see flagged pixels start to appear more and more near sharp edges in the image, where slight changes in planar position correspond to large changes in pixel values. You should be sure to use Detail: High mode, and you may be able to mitigate this by increasing the Coverage value.
If auto-mask isn't able to work with your footage, you'll need to use animated roto masks or layered trackers.
©2024 Boris FX, Inc. — UNOFFICIAL — Converted from original PDF.