cocoamacosisight

Exposure Lock in iSight


I am creating object-detection program on Mac. I want to use iSight in manual exposure mode to improve detection quality.

I tried iGlasses & QTKit Capture to do that and it worked but program runs very slowly and unstable. So I want to try other solution.

In PhotoBooth.app, iSight seemed to be run in fixed exposure mode so there might be a way to do that. I read QTKit Capture documents and OpenCV documents but I couldn't find the answer.

If you have any ideas, please tell me. Thank you.


Solution

  • QTKit Capture, as easy as it is to use, lacks the ability to set manual camera parameters like gain, brightness, focus, etc. If you were using a Firewire camera, I'd suggest looking into the libdc1394 library, which gives you control over all these values and more if you're using an IIDC Firewire camera (like the old external iSight). I use this library for video capture from, and control of, CCD cameras on a robotics platform.

    However, I'm guessing that you're interested in the internal iSight camera, which is USB. Wil Shipley briefly mentions control of parameters on internal USB iSights in his post "Frozen in Carbonite", but most of the Carbon code he lays out controls those values in IIDC Firewire cameras.

    Unfortunately, according to this message in the QuickTime mailing list by Brad Ford, it sounds like you can't programmatically control anything but saturation and sharpness on builtin iSights through the exposed interfaces. He speculates that iGlasses is post-processing the image in software, which is something you could do using Core Image filters.