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 222
 223 <h1>Module feature Methods</h1>
 224 <p class="navigation-index">[<a href="feature.html#GetImageChannelFeatures">GetImageChannelFeatures</a>]</p>
 225
 226 <h2><a href="http://www.imagemagick.org/api/MagickCore/feature_8c.html" id="GetImageChannelFeatures">GetImageChannelFeatures</a></h2>
 227 <div class="doc-section">
 228
 229 <p>GetImageChannelFeatures() returns features for each channel in the image in each of four directions (horizontal, vertical, left and right diagonals) for the specified distance.  The features include the angular second moment, contrast, correlation, sum of squares: variance, inverse difference moment, sum average, sum varience, sum entropy, entropy, difference variance,  difference entropy, information measures of correlation 1, information measures of correlation 2, and maximum correlation coefficient.  You can access the red channel contrast, for example, like this:</p>
 230
 231 <pre class="text">
 232   channel_features=GetImageChannelFeatures(image,1,exception);
 233   contrast=channel_features[RedChannel].contrast[0];
 234 </pre>
 235
 236 <p>Use MagickRelinquishMemory() to free the features buffer.</p>
 237
 238 <p>The format of the GetImageChannelFeatures method is:</p>
 239
 240 <pre class="code">
 241   ChannelFeatures *GetImageChannelFeatures(const Image *image,
 242     const size_t distance,ExceptionInfo *exception)
 243 </pre>
 244
 245 <p>A description of each parameter follows:</p>
 246
 247 <h5>image</h5>
 248 <p>the image.</p>
 249
 250 <h5>distance</h5>
 251 <p>the distance.</p>
 252
 253 <h5>exception</h5>
 254 <p>return any errors or warnings in this structure.</p>
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