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Unread 12-01-2010, 00:17
jhersh jhersh is offline
National Instruments
AKA: Joe Hershberger
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Re: Vision tracking: Did they get it right?

Quote:
Originally Posted by TD-Linux View Post
- While the ellipse detection only uses luminance data for detecting edges, it does so by allocating memory, mixing the image down, processing it, then freeing the memory. I don't know how efficient vxworks' malloc is, but this seems like a rather bad idea.
You are absolutely correct. And no... malloc on VxWorks is not amazingly fast or anything. It is a bad idea and any patch you'd like to submit to address the issue would be greatly appreciated. I hear the AxisCamera2010 does the same thing, but with C++ new! (hint hint)

Quote:
Originally Posted by TD-Linux View Post
- The tracking algorithm only samples the image once, then bases all further turning on the gyro without sampling any more images. There are both problems with this approach, as well as problems in the implementation. I won't elaborate on this point, as it probably deserves its own separate thread.
This is intentional... when you are moving, your image is usually very blury, meaning that you are unlikely to be able to find high contrast edges. By using the gyro, you are able to get higher bandwidth data to move you pretty close to your target. Since your target is not moving, you will likely be pointed very close to the target when the gyro is at the detected angle and the next update will be a minor adjustment.

This method is more reliable and typically faster when homing in on stationary targets.

If you'd like to discuss it further, feel free to start another thread.

-Joe
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