<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>A demo of the mean-shift clustering algorithm — scikits.learn v0.6.0 documentation</title> <link rel="stylesheet" href="../../_static/nature.css" type="text/css" /> <link rel="stylesheet" href="../../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../../', VERSION: '0.6.0', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../../_static/jquery.js"></script> <script type="text/javascript" src="../../_static/underscore.js"></script> <script type="text/javascript" src="../../_static/doctools.js"></script> <link rel="shortcut icon" href="../../_static/favicon.ico"/> <link rel="author" title="About these documents" href="../../about.html" /> <link rel="top" title="scikits.learn v0.6.0 documentation" href="../../index.html" /> <link rel="up" title="Examples" href="../index.html" /> <link rel="next" title="Spectral clustering for image segmentation" href="plot_segmentation_toy.html" /> <link rel="prev" title="Segmenting the picture of Lena in regions" href="plot_lena_segmentation.html" /> </head> <body> <div class="header-wrapper"> <div class="header"> <p class="logo"><a href="../../index.html"> <img src="../../_static/scikit-learn-logo-small.png" alt="Logo"/> </a> </p><div class="navbar"> <ul> <li><a href="../../install.html">Download</a></li> <li><a href="../../support.html">Support</a></li> <li><a href="../../user_guide.html">User Guide</a></li> <li><a href="../index.html">Examples</a></li> <li><a href="../../developers/index.html">Development</a></li> </ul> <div class="search_form"> <div id="cse" style="width: 100%;"></div> <script src="http://www.google.com/jsapi" type="text/javascript"></script> <script type="text/javascript"> google.load('search', '1', {language : 'en'}); google.setOnLoadCallback(function() { var customSearchControl = new google.search.CustomSearchControl('016639176250731907682:tjtqbvtvij0'); customSearchControl.setResultSetSize(google.search.Search.FILTERED_CSE_RESULTSET); var options = new google.search.DrawOptions(); options.setAutoComplete(true); customSearchControl.draw('cse', options); }, true); </script> </div> </div> <!-- end navbar --></div> </div> <div class="content-wrapper"> <!-- <div id="blue_tile"></div> --> <div class="sphinxsidebar"> <div class="rel"> <a href="plot_lena_segmentation.html" title="Segmenting the picture of Lena in regions" accesskey="P">previous</a> | <a href="plot_segmentation_toy.html" title="Spectral clustering for image segmentation" accesskey="N">next</a> | <a href="../../genindex.html" title="General Index" accesskey="I">index</a> </div> <h3>Contents</h3> <ul> <li><a class="reference internal" href="#">A demo of the mean-shift clustering algorithm</a></li> </ul> </div> <div class="content"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="a-demo-of-the-mean-shift-clustering-algorithm"> <span id="example-cluster-plot-mean-shift-py"></span><h1>A demo of the mean-shift clustering algorithm<a class="headerlink" href="#a-demo-of-the-mean-shift-clustering-algorithm" title="Permalink to this headline">ΒΆ</a></h1> <p>Reference: K. Funkunaga and L.D. Hosteler, “The Estimation of the Gradient of a Density Function, with Applications in Pattern Recognition”</p> <img alt="auto_examples/cluster/images/plot_mean_shift.png" class="align-center" src="auto_examples/cluster/images/plot_mean_shift.png" /> <p><strong>Python source code:</strong> <a class="reference download internal" href="../../_downloads/plot_mean_shift.py"><tt class="xref download docutils literal"><span class="pre">plot_mean_shift.py</span></tt></a></p> <div class="highlight-python"><div class="highlight"><pre><span class="k">print</span> <span class="n">__doc__</span> <span class="kn">import</span> <span class="nn">numpy</span> <span class="kn">as</span> <span class="nn">np</span> <span class="kn">from</span> <span class="nn">scikits.learn.cluster</span> <span class="kn">import</span> <span class="n">MeanShift</span><span class="p">,</span> <span class="n">estimate_bandwidth</span> <span class="c">################################################################################</span> <span class="c"># Generate sample data</span> <span class="n">np</span><span class="o">.</span><span class="n">random</span><span class="o">.</span><span class="n">seed</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span> <span class="n">n_points_per_cluster</span> <span class="o">=</span> <span class="mi">250</span> <span class="n">n_clusters</span> <span class="o">=</span> <span class="mi">3</span> <span class="n">n_points</span> <span class="o">=</span> <span class="n">n_points_per_cluster</span><span class="o">*</span><span class="n">n_clusters</span> <span class="n">means</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([[</span><span class="mi">1</span><span class="p">,</span><span class="mi">1</span><span class="p">],[</span><span class="o">-</span><span class="mi">1</span><span class="p">,</span><span class="o">-</span><span class="mi">1</span><span class="p">],[</span><span class="mi">1</span><span class="p">,</span><span class="o">-</span><span class="mi">1</span><span class="p">]])</span> <span class="n">std</span> <span class="o">=</span> <span class="o">.</span><span class="mi">6</span> <span class="n">clustMed</span> <span class="o">=</span> <span class="p">[]</span> <span class="n">X</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">empty</span><span class="p">((</span><span class="mi">0</span><span class="p">,</span> <span class="mi">2</span><span class="p">))</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">n_clusters</span><span class="p">):</span> <span class="n">X</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">r_</span><span class="p">[</span><span class="n">X</span><span class="p">,</span> <span class="n">means</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">+</span> <span class="n">std</span> <span class="o">*</span> <span class="n">np</span><span class="o">.</span><span class="n">random</span><span class="o">.</span><span class="n">randn</span><span class="p">(</span><span class="n">n_points_per_cluster</span><span class="p">,</span> <span class="mi">2</span><span class="p">)]</span> <span class="c">################################################################################</span> <span class="c"># Compute clustering with MeanShift</span> <span class="n">bandwidth</span> <span class="o">=</span> <span class="n">estimate_bandwidth</span><span class="p">(</span><span class="n">X</span><span class="p">,</span> <span class="n">quantile</span><span class="o">=</span><span class="mf">0.3</span><span class="p">)</span> <span class="n">ms</span> <span class="o">=</span> <span class="n">MeanShift</span><span class="p">(</span><span class="n">bandwidth</span><span class="o">=</span><span class="n">bandwidth</span><span class="p">)</span> <span class="n">ms</span><span class="o">.</span><span class="n">fit</span><span class="p">(</span><span class="n">X</span><span class="p">)</span> <span class="n">labels</span> <span class="o">=</span> <span class="n">ms</span><span class="o">.</span><span class="n">labels_</span> <span class="n">cluster_centers</span> <span class="o">=</span> <span class="n">ms</span><span class="o">.</span><span class="n">cluster_centers_</span> <span class="n">labels_unique</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">unique</span><span class="p">(</span><span class="n">labels</span><span class="p">)</span> <span class="n">n_clusters_</span> <span class="o">=</span> <span class="nb">len</span><span class="p">(</span><span class="n">labels_unique</span><span class="p">)</span> <span class="k">print</span> <span class="s">"number of estimated clusters : </span><span class="si">%d</span><span class="s">"</span> <span class="o">%</span> <span class="n">n_clusters_</span> <span class="c">################################################################################</span> <span class="c"># Plot result</span> <span class="kn">import</span> <span class="nn">pylab</span> <span class="kn">as</span> <span class="nn">pl</span> <span class="kn">from</span> <span class="nn">itertools</span> <span class="kn">import</span> <span class="n">cycle</span> <span class="n">pl</span><span class="o">.</span><span class="n">figure</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="n">pl</span><span class="o">.</span><span class="n">clf</span><span class="p">()</span> <span class="n">colors</span> <span class="o">=</span> <span class="n">cycle</span><span class="p">(</span><span class="s">'bgrcmykbgrcmykbgrcmykbgrcmyk'</span><span class="p">)</span> <span class="k">for</span> <span class="n">k</span><span class="p">,</span> <span class="n">col</span> <span class="ow">in</span> <span class="nb">zip</span><span class="p">(</span><span class="nb">range</span><span class="p">(</span><span class="n">n_clusters_</span><span class="p">),</span> <span class="n">colors</span><span class="p">):</span> <span class="n">my_members</span> <span class="o">=</span> <span class="n">labels</span> <span class="o">==</span> <span class="n">k</span> <span class="n">cluster_center</span> <span class="o">=</span> <span class="n">cluster_centers</span><span class="p">[</span><span class="n">k</span><span class="p">]</span> <span class="n">pl</span><span class="o">.</span><span class="n">plot</span><span class="p">(</span><span class="n">X</span><span class="p">[</span><span class="n">my_members</span><span class="p">,</span><span class="mi">0</span><span class="p">],</span> <span class="n">X</span><span class="p">[</span><span class="n">my_members</span><span class="p">,</span><span class="mi">1</span><span class="p">],</span> <span class="n">col</span><span class="o">+</span><span class="s">'.'</span><span class="p">)</span> <span class="n">pl</span><span class="o">.</span><span class="n">plot</span><span class="p">(</span><span class="n">cluster_center</span><span class="p">[</span><span class="mi">0</span><span class="p">],</span> <span class="n">cluster_center</span><span class="p">[</span><span class="mi">1</span><span class="p">],</span> <span class="s">'o'</span><span class="p">,</span> <span class="n">markerfacecolor</span><span class="o">=</span><span class="n">col</span><span class="p">,</span> <span class="n">markeredgecolor</span><span class="o">=</span><span class="s">'k'</span><span class="p">,</span> <span class="n">markersize</span><span class="o">=</span><span class="mi">14</span><span class="p">)</span> <span class="n">pl</span><span class="o">.</span><span class="n">title</span><span class="p">(</span><span class="s">'Estimated number of clusters: </span><span class="si">%d</span><span class="s">'</span> <span class="o">%</span> <span class="n">n_clusters_</span><span class="p">)</span> <span class="n">pl</span><span class="o">.</span><span class="n">show</span><span class="p">()</span> </pre></div> </div> </div> </div> </div> </div> <div class="clearer"></div> </div> </div> <div class="footer"> <p style="text-align: center">This documentation is relative to scikits.learn version 0.6.0<p> © 2010, scikits.learn developers (BSD Lincense). 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