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Unread 03-08-2009, 08:53
Greg McKaskle Greg McKaskle is offline
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Re: 1D/2D Barcodes with Camera (Micro QR, Semacode, etc.)

All of the algorithms that search will benefit from a search area that is smaller. They will work faster and are less likely to find false positives in the scene. I believe that one of the 2D bars is commonly used for full scene, but I don't have experience with how robust it is.

The fiducial dialog in that package is a bit more specialized to robotics than what NI Vision contains, but I think that you can use the Characterization functions with skewed templates in the same way. If you have access to a computer with last years files on them, flip through the NI Vision Concepts manual. It was installed in Program Files/National Instruments/Vision/Documentation. It contains a chapter on each of the major techniques implemented in NI Imaq. Each of the search functions has their strengths and weaknesses, and it is useful to know a bit about your options.

Characterization uses mask comparisons and I'm pretty sure it supports scaling and rotation variation. The aspect skew is accomplished by adding skewed templates. If this were going to be used extensively for FRC, we'd add a training dialog that'd generate the skewed images automatically. If the characterization doesn't support rotation or scaling, then those would need to be generated too, or we'd move to other techniques such as geometric edge detection.

Greg McKaskle