I'm trying to figure out the best way to track hands as though a person in front of a kiosk were using a mouse (or two).
My strategy so far is to grab an image when the Quartz composition launches from a web cam. Using a trick I saw in PhotoBooth, you can then compare the current frame of captured video to the background and find the difference -- that gives you a quick mask of something entering the screen. Next, I would up contrast and saturation, to exaggerate differences. By comparing a frame from a moment before with a current frame, I could then discover motion. The trick is to get the "most moved" area and perhaps the smallest area -- assuming that a finger is going to be smaller than a head, and is going to have more movement (not always true -- but the user should get the hang of it in short order). So I would need to figure out, not only the difference between the prior image and the current image for what has moved -- I need to use a false color to get an idea that that tan blob over there (a hand) has moved more than the blue jacket. I'm not completely sure how to do that. It sort of overlaps some of the other color-lookup discussions, where you don't want to check the color of each strand of hair, because lighting conditions can quickly change -- you want to "blob" the median values of a region. AFTER you discover the motion of a common region, you can track perhaps a highlight of the most moved point (like a finger). Luminosity would be valuable to use the Outline sketch effects to define regions, and then again for highlighting that gives dimension. I'm thinking out loud -- maybe someone has come up with a much easier strategy to turn a camera into a mouse. I've seen these with video displays at malls and I'm pretty sure they are using InfraRed on the camera to ignore their own projection. I may need to get a real video camera and hack it to grab only infrared -- I'd love advice on that. I know there is some patch that allows for finding the pixel in a row or column with the greatest or least value. With so many new patch's I've lost track of it -- but, after I can somehow visually create an image with the "most moved" regions, then I can find an x and y position and use that as though it were a mouse. CIKernel functions that do these operations I'm assuming would be faster -- so if anyone can point me to prior work or a way to do this, I'd love it. _______________________________________________ Do not post admin requests to the list. They will be ignored. Quartzcomposer-dev mailing list ([email protected]) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/quartzcomposer-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
