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 224
 225 <h1>Module feature Methods</h1>
 226 <p class="navigation-index">[<a href="feature.html#GetImageChannelFeatures">GetImageChannelFeatures</a>]</p>
 227
 228 <h2><a href="http://www.imagemagick.org/api/MagickCore/feature_8c.html" id="GetImageChannelFeatures">GetImageChannelFeatures</a></h2>
 229 <div class="doc-section">
 230
 231 <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>
 232
 233 <pre class="text">
 234   channel_features=GetImageChannelFeatures(image,1,exception);
 235   contrast=channel_features[RedChannel].contrast[0];
 236 </pre>
 237
 238 <p>Use MagickRelinquishMemory() to free the features buffer.</p>
 239
 240 <p>The format of the GetImageChannelFeatures method is:</p>
 241
 242 <pre class="code">
 243   ChannelFeatures *GetImageChannelFeatures(const Image *image,
 244     const size_t distance,ExceptionInfo *exception)
 245 </pre>
 246
 247 <p>A description of each parameter follows:</p>
 248
 249 <h5>image</h5>
 250 <p>the image.</p>
 251
 252 <h5>distance</h5>
 253 <p>the distance.</p>
 254
 255 <h5>exception</h5>
 256 <p>return any errors or warnings in this structure.</p>
 257
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