This package provides a C++ implementation of the algorithm describedin the following article:A Topological Approach to Hierarchical Segmentation using Mean ShiftSylvain Paris and Fr閐o DurandProceedings of the IEEE conference on Computer Vision and Pattern Recognition2007http://people.csail.mit.edu/sparis/#cvpr07Most of the code is released under the MIT license. Some old files areunder the BSD license.The code have been developed and tested under Linux using GCC. Weprovide a simple makefile that compiles everything. No optimizationoptions beyond "-O3" have been included to prevent portabilityproblems. We use the GNU Scientific Library to compute PCA:http://www.gnu.org/software/gsl/* How to use the program?*************************It is a command line program with following arguments:mean_shift file_name range_sigma time_sigma space_sigma persistence_threshold- file_name: To segment images, provide the file name of the input  picture. Only PPM files are supported. To segment a video, provide  the name of a file with the following syntax:  . the first line contains the path to the frame files    (e.g. /home/user/movie/)  . the following lines contain the file names of the frames, one name    per line, only PPM format (e.g. frame000.ppm)- range_sigma: The Gaussian parameter used on the color axes. We use  the CIE-Lab color space. The L values range between 0 and 100. Try  values between 5 and 10 for this parameter.- time_sigma: The Gaussian parameter used on the time axis. Available  only when segmenting videos. Try values between 5 and 15 for this parameter.- space_sigma: The Gaussian parameter used on the x and y axes. Try  values between 4 and 256 for this parameter.- persistence_threshold: See our article for this parameter. Try  values between 0 and 5.    The program prints statistics and timings in the terminal. It alsocreates the following files:- partial.ppm: The segmentation obtained only by classifying the grid  nodes. Black pixels are still unlabeled.- full.ppm: The final segmentation with color-coded clusters.- boundaries.ppm: The boundaries of the final segmentation. The  boundary persistence is coded with gray values (dark is low, bright  is high).    * How to set up the program?****************************Before compiling the program, you can choose between:- segmenting images or videos,- comparing intensities or CIE-Lab colors,- using a regular array, a sparse array, or mixed strategy,- and applying PCA or not.These settings are available though the "config.h" file. Here are afew notes:- To ensure a strict hierarchical cluster structure, you need to  comment lines 62 and 71.- To get the full hierarchy up to the persistence level specified on  the command line, uncomment line 75. The cluster IDs are coded on  three bytes: red-green-blue. The finest level is output. The file  "hierarchy.txt" indicates in which order to merge the segments,  e.g. "3 --> 10" means "cluster 3 has to be merged with cluster 10,  3 disappears".- If your feature space is large, choose a sparse data structure  (line 52) and consider using PCA (lines 57 and 58).