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Dynamic threshold for detection

June 24, 2013 - 10:43am #1

Hi, is it possible to adjust some sort of threshold for detecting an image target? I notice by default when I am attemping to track an image  on my computer screen, it won't recognize it. But as I change the contrast of the image on-screen, it'll pick it up. So while it is tracking this image with high contrast, I am able to turn down the contrast to relatively low values and the sdk is still able to track it. I guess it seems like the sdk has to have a relatively higher confidence level to detect a target than it does to track it. I am wondering if there is a way to level this out. 

Dynamic threshold for detection

June 25, 2013 - 7:03am #7

Yeah, that is a possiblility. We are currently experimenting a number of things since this is new to the company. One thing I noticed is that i can change the video mode from

QCAR::CameraDevice::MODE_DEFAULT

 to

QCAR::CameraDevice::MODE_OPTIMIZE_QUALITY

I believe I noticed better detecting performance, but is that really doing anything?

Dynamic threshold for detection

June 24, 2013 - 3:54pm #6

Those are going to be challenging targets, both due to the lack of contrast and the fact that they are not flat. Can you place 2D targets in the region of the object to provide a reliable anchor for tracking (e.g. using context panels or placed targets )?

Dynamic threshold for detection

June 24, 2013 - 11:23am #5

I am trying to track a variety of objects that are sometimes single color but have smooth and sharp contours (scultures, statues, plaster designs, etc). I realize the quality of the tracking depends on sharp features which can be helped with a contrast of color and lighting contrast. 

Now, a person viewing such objects can visually pick out these features in these single color (typically white or off white) objects, but it is much more difficult for the sdk to without the aid of contrasting to emphasize the contrours. I hope this makes sense.

Dynamic threshold for detection

June 24, 2013 - 11:06am #4

All of that is handled by the SDK, there is no way to pre-process the image. What's the use case that you're trying to achieve?

Dynamic threshold for detection

June 24, 2013 - 11:02am #3

Is there a way, then, to filter the contrast of the camera feed through the api or ndk?

Dynamic threshold for detection

June 24, 2013 - 10:58am #2

There is no way to adjust the relative thresholds for detection vs tracking. But you are correct that tracking can often be sustained under condition that would render the target undetectable.

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