Raspicam and OpenCV instructions

December 21, 2013 by
Filed under: Development, Hardware, Linux, Robots 

I have previously gotten the opencv and python bindings to work via the 2.3 opencv system and facial recognition did work, but the system is bugged out and I could only get 64x64px image size.

I followed these instructions to get the raspicam to work with opencv and simplecv

http://tothinkornottothink.com/post/59305587476/raspberry-pi-simplecv-opencv-raspicam-csi-camera

However, there where some minor details wrong with it so here is a short list of the updates to the installation instructions on that page.

I noticed a few problems as I saw it with the above instructions, or possibly I didn’t read the instructions well enough. That said, very good info! Thank you!

Here are the issues I had:

The opencv_2.4.5.sh script pulls in libopencv-dev which in turn pulls in the entire libopencv2.3 from raspbian repositories, which in turn meant that simplecv was still using libopencv2.3.

apt-get remove libopencv-core2.3

Once that is removed, python-opencv is also removed and simplecv will not even run anymore. Adding the following will add the path to where the python cv bindings are.

export PYTHONPATH=/usr/local/lib/python2.7/site-packages/

And finally, the LD_PRELOAD to actually use the correct uv4l libraries.

export LD_PRELOAD=/usr/lib/uv4l/uv4lext/armv6l/libuv4lext.so

Once this is done, you should no longer get the munmap errors etc, and large resolution should work:

SimpleCV:1> cam = Camera(0, {“width”:640, “height”:480})

SimpleCV:2> cam.live()

etc.

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