Capturing image from the IMAGING SOURCE DFM 22BUC03-ML board camera with unicap driver

edit

Hello,

I would like to get images from multiple IMAGING SOURCE DFM 22BUC03-ML board cameras in Python with openCv and the unicap driver supporting the call-back interface.

I am running Fedora 20 and installed OpenCV 2.4.7, as described in on the documentation.

>>> import cv2
>>> print cv2.__version__
2.4.7

I was not successful using the standart VideoCapture code:

cap = cv2.VideoCapture(0);
libv4l2: error setting pixformat: Device or resource busy
HIGHGUI ERROR: libv4l unable to ioctl S_FMT
libv4l2: error setting pixformat: Device or resource busy
libv4l1: error setting pixformat: Device or resource busy
HIGHGUI ERROR: libv4l unable to ioctl VIDIOCSPICT

I would like to try using the unicap driver with the the call-back interface. However, I could not find much information regarding how to use the unicap in openCv. I found following ticket: https://code.ros.org/trac/opencv/ticket/1112 suggesting a patch for the above mentioned camera.

Could you please give me some hints how can I capture an image from the camera with the unicap driver ? I suggest I have to (re)compile OpenCv using the patch or exchanging the cap_unicap.cpp file and use the WITH_UNICAP=ON flag. Is this true ? Can I use the unicap capturing from python ?