This is a list some common issues (and their solutions) that might cause installation or runtime errors.
The following OpenCV error might be displayed when trying to run tests or code that displays images:
OpenCV Error: Unsupported format or combination of formats () in threshold, file /tmp/opencv3-20160626-61731-v18vfg/opencv-3.1.0/modules/imgproc/src/thresh.cpp, line 1273
This happens due to a bug in an older version of OpenCV3 (3.1.0) where the cv::threshold function does not support 64-bit floats (doubles) in images.
The fix is to update your OpenCV installation to OpenCV version 3.2.0+.
brew update
brew upgrade opencv3
Probably need to download and install the latest version again. Sorry :( You can re-install OpenCV the same way as you originally installed it. Follow the same instructions with the latest version.