I got:
apt: command [sudo -H apt-get install -y libopencv-nonfree2.4] failed
When using rosdep
rosdep install --from-paths src --ignore-src --rosdistro=indigo -y
To solve it:
sudo add-apt-repository --yes ppa:xqms/opencv-nonfree
sudo apt-get update
sudo apt-get install libopencv-nonfree-dev
The rosdep key was opencv2-nonfree
.
when there is some version of opencv already installed on your system, this solution might not be working.
prompting something like this: