Giovanni Visentini, Amit Gupta 2012 http://psrcentre.org/images/extraimages/40.%20312019.pdf
https://github.com/pierrepaleo/sift_pyocl
https://github.com/opencv/opencv/tree/master/modules/features2d/src/opencl
https://github.com/dphoyes/OpenCL-Structure-from-Motion
https://github.com/oneam/harris
-- CPU implementation of "Pixelwise View Selection for Unstructured Multi-View Stereo (Schönberger et al.)" (https://github.com/mitjap/pwmvs)
https://software.intel.com/en-us/articles/large-scale-3d-reconstruction-on-intel-platforms