2011

Dust Removal Workflow
The dust removal workflow can be divided into three steps:
■ Dust Detection This automatically creates the defect matte by examining
the images, using motion vectors if available. This step is optional, as the
defect matte may be supplied to the tool as the second input. Even if no
defect matte is supplied, you may choose to bypass detection and perform
all labeling by hand. A single tolerance parameter controls the dust
detection, where a value of 0 means no dust is detected, and a value of
100 means all pixels are dust. You can tweak the value slightly from its
default of 50 to get a reasonable set of dust pixels. Two other parameters
control the expansion of the dust to make sure the whole dust object is
covered, not just the center.
■ Manual correction of the defect matte If any pixels have been incorrectly
labeled as dust or not dust in step 1, manual correction of the defect matte
can be performed by drawing appropriate shapes on the dust matte. These
locally change the detection and repair parameters within the geometric
region of the shape. Each object drawn has its own dust detection
parameters, which overrides the global (automatic) values used in step 1.
In addition, each object has other parameters to control how correction
is performed. Of course, drawing shapes is optional.
■ Defect repair Using the final defect matte, an image processing operation
is performed to fill in the corresponding pixels in the output image with
corrected pixels. This process uses motion vectors if they are available.
Your can choose between a spatial repair, which uses only the current
frame, or a temporal repair, the default, which uses neighboring frames
and motion vectors. Spatial repair should only be used in areas of the image
where the motion vectors are inaccurate or there are occlusions making it
difficult for the algorithm to find the corresponding correct pixel on
neighboring frames.
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