dmen's profile - activity

I am tracking an infrared LED with a simple contour check - it works great. However the LED has a switch and can be turned off - I am needing to know if the switch went off or if the LED just moved out of view of the camera.

I thought I could do something simple with just checking position, but if the led is moved fast off screen, then the last tracked point I get from my detector is on screen... maybe I can just use something like an edge buffer where if the last point is within the buffer range, it's likely off screen now, and not turned off.

I am trying to match a user created drawing (in realtime if possible) against one of three library images. They are simple images, as shown, but are also somewhat similar... I am unsure of the best algorithm to use and after doing a few hours research I thought I'd ask here.

Capturing from a webcam and using the simple blob detector to find a blob of white pixels - I use threshold to make a binary image that should contain just the single blob I need, and I only need it's x,y position in the image. Is there a faster way to do this?

I found this code, that uses AS3 but is faster than anything I've seen thus far. Could it be easily ported? It uses floodFill and getColorBoundsRect - I know openCV has floodFill but not sure about the other. http://play.blog2t.net/fast-blob-dete...

Hi, thanks for the info! To remove background noise I did a threshold on the image to filter out non white pixels. At least in testing I'm only seeing the one blob I need.

But yeah, for false positives... the Kalman filter could work. However part of my problem is that I don't think I get data fast enough for that to work? I think I get around ten frames per second from the QuickCam. I'm going to try and modify a better camera (logitech c920) and see if I can get faster input.

Doing a project at work and we need to have a user hold a stick. We need to track one end of this stick in real time and place a 3D particle system at that point. A HD webcam will record to a video that the user will receive.

My plan to do this: Unity as the 3D engine, it has an OpenCV plugin, and can use multiple cameras. We will place an IR LED at the end of the stick. I think to use two webcams - one modified to see just IR - I removed the IR filter and added a piece of floppy disk over the CCD and it sees IR well. I will use simple blob detector to track the IR point and get X,Y position. Then use that to position particle system in the actual video being recorded by a second, HD webcam.

Hoping for a little guidance now. I need the tracking to be spot on as possible. I'd love to not use two cameras though, but I'm not sure about tracking accuracy though. Color is out as I can't know what the user will wear, other people around, etc. IR seems good... but couple problems.

I have it working now tracking the IR but the camera can see some daylight, reflections of IR etc. and I don't know how to get just that one point I need? Would I need to get a min/max area or something and then only that blob size will work? So user would have to be correct distance from camera?

Any help much appreciated.