This set of m-files demonstrates how the M2DP algorithm works in principle. M2DP takes one point cloud as input, and outputs a 192 by 1 vector as the point cloud descriptor. To run the demo, simply start Matlab and run demo.m. If it is the first time you use this code, please run mex CountVote2D.c in Matlab. Demo video can be found at https://www.youtube.com/watch?v=o87MGK8qQaY Acknowledgment: The algorithm described in the code was published in: Li He, Xiaolong Wang and Hong Zhang, "M2DP: A Novel 3D Point Cloud Descriptor and Its Application in Loop Closure Detection", IROS 2016. Please cite this paper if you use the code to generate your results.