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Unread 12-02-2007, 16:25
Ankush Dhar Ankush Dhar is offline
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Camera tracking between two lights

Before i ask my question, i wnat to state all that i know already, to see if anyone can correct my understanding of how the camera works.

I believe that the Camera takes in the green light and outputs a blob which is usually contained in a rectangular frame. If the camera only sees 1 light then it will have a high resoulution pixels and actually know that it is looking at only one camera

But in the case of two cameras, is it true that it still converts the two lights as 1 blob in the same rectangular frame or does it adjust the width because it can sense the distance between the two lights?

In any case, what does the camera do to find the point to track? does it calculate the mid point and take that location? And if it does, what is the consistency of the midpoint. For example if it sees more of one light than the other, than the other, does the midpoint for this case is different than the midpoint if the camera had seen the same amount of light from the two tracking lights.


But reading the forums, i heard that if there are two tracking lights, it actually shows the space between the two lights by no colour pixel to define the size apart from the two lights. If thats true, then is it possible to tell the camera to pick which half of the blob?

lol, i know i have tons of questions, if anyone has any information through a site, can they please send me the link, and if anyone knows few answers, it will be awsome if you can answer them!

Regards

Ankush Dhar
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Unread 12-02-2007, 16:40
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Re: Camera tracking between two lights

Well I've been really into the double camera stuff, and here's the simple answer:

The way we did it, each camera is completely independent, and works without knowing that the other camera is there. They both will convert both lights into a single blob. It would be up to you to write any calculations to find the location of the light.

http://kevin.org/frc/CMUcam2_demo.wmv Shows how the camera deals with multiple lights. The centroid is based on the number of pixels and the the concentration of pixels. So for example if you see two lights, one at an extreme angle and the other dead on, there will be a blob encasing both lights, but the confidence will be low and the centroid will be closer to the high concentration of pixels.

If you want to differentiate the two lights you'll either need to use the Virtual Window function (see the CMU Commands manual), Or get a full pixelmap (not recommended).
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Unread 12-02-2007, 23:44
Ankush Dhar Ankush Dhar is offline
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Re: Camera tracking between two lights

I see, so the centre point is not constant?

If i may ask, what is this "double camera" thing, is it that you have 2 cameras searching for one light each?

Thanks for the links, i will check them out tomorrow morning,

Regards

Ankush Dhar
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