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     <title>ImageMagick: Connected Components Labeling</title>
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 <p class="lead magick-description">Connected-component labeling (alternatively connected-component analysis, blob extraction, region labeling, blob discovery, or region extraction) uniquely labels connected components in an image.  The labeling process scans the image, pixel-by-pixel from top-left to bottom-right, in order to identify connected pixel regions, i.e. regions of adjacent pixels which share the same set of intensity values.  For example, let's find the objects in this image:</p>
 <ul>
   <a href="../images/objects.gif"><img src="../images/objects.gif" width="256" height="171" class="image-slices" alt="purse"></a>
 </ul>
 <p>To identify the objects in this image, use this command:</p>
 <pre>
 convert objects.gif -connected-components 4 -auto-level -depth 8 objects.png
 </pre>
 <p>The detected objects are uniquely labeled starting with 1.  Use auto leveling to visualize the detected objects:</p>
 <ul>
   <a href="../images/objects.png"><img src="../images/objects.png" width="256" height="171" class="image-slices" alt="Objects"></a>
 </ul>
 <p>Note, the <code>-connected-components</code> option requires ImageMagick version 6.8.9-10 or later.</p>
 <p>Object statistics is useful to review.  To display them, use this command:</p>
 <pre>
 convert objects.gif -define connected-components:verbose=true -connected-components 4 objects.png
 </pre>
 <p>Five objects were detected with these statistics:</p>
 <pre>
 Objects (id: bounding-box centroid area mean-color):
   0: 256x171+0+0 +119.2,+80.8 33117 gray(0)
   2: 120x135+104+18 +159.5,+106.5 8690 gray(255)
   3: 50x36+129+44 +154.2,+63.4 1529 gray(0)
   4: 21x23+0+45 +8.8,+55.9 409 gray(255)
   1: 4x10+252+0 +253.9,+4.1 31 gray(255)
 </pre>
 <p>Use <code>-connected-components 8</code> to visit 8 neighbors rather than 4.  By default, neighbor colors must be exact to be part of a unique object. Use <a href="command-line-options.html#fuzz">-fuzz</a> to include pixels that are <var>close</var> in color.</p>
 <p>You might want to eliminate small objects by merging them with their larger neighbors.  If so, use this command:</p>
 <pre>
 convert objects.gif -define connected-components:area-threshold=410 -connected-components 4 \
   -auto-level objects.jpg
 </pre>
 <p>Here are the expected results.  Notice, how the small objects are now merged with the background.</p>
 <p class="img-responsive center-block">
   <a href="../images/objects.jpg"><img src="../images/objects.jpg" width="256" height="171" class="image-slices" alt="Objects"></a>
 </p>
 <p>Use the <a href="command-line-options.html#fuzz">-fuzz</a> option to identify objects that are made up of pixels similiar in color (e.g. <code>-fuzz 3%</code>).</p>
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	<title>ImageMagick: Connected Components Labeling</title>
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	<meta name="description" content="ImageMagick® is a software suite to create, edit, compose, or convert bitmap images. It can read and write images in a variety of formats (over 200) including PNG, JPEG, JPEG-2000, GIF, WebP, Postscript, PDF, and SVG. Use ImageMagick to resize, flip, mirror, rotate, distort, shear and transform images, adjust image colors, apply various special effects, or draw text, lines, polygons, ellipses and Bézier curves.">
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	<p class="lead magick-description">Connected-component labeling (alternatively connected-component analysis, blob extraction, region labeling, blob discovery, or region extraction) uniquely labels connected components in an image. The labeling process scans the image, pixel-by-pixel from top-left to bottom-right, in order to identify connected pixel regions, i.e. regions of adjacent pixels which share the same set of intensity values. For example, let's find the objects in this image:</p>
	<ul>
	<a href="../images/objects.gif"><img src="../images/objects.gif" width="256" height="171" class="image-slices" alt="purse"></a>
	</ul>
	<p>To identify the objects in this image, use this command:</p>
	<pre>
	convert objects.gif -connected-components 4 -auto-level -depth 8 objects.png
	</pre>
	<p>The detected objects are uniquely labeled starting with 1. Use auto leveling to visualize the detected objects:</p>
	<ul>
	<a href="../images/objects.png"><img src="../images/objects.png" width="256" height="171" class="image-slices" alt="Objects"></a>
	</ul>
	<p>Note, the <code>-connected-components</code> option requires ImageMagick version 6.8.9-10 or later.</p>
	<p>Object statistics is useful to review. To display them, use this command:</p>
	<pre>
	convert objects.gif -define connected-components:verbose=true -connected-components 4 objects.png
	</pre>
	<p>Five objects were detected with these statistics:</p>
	<pre>
	Objects (id: bounding-box centroid area mean-color):
	0: 256x171+0+0 +119.2,+80.8 33117 gray(0)
	2: 120x135+104+18 +159.5,+106.5 8690 gray(255)
	3: 50x36+129+44 +154.2,+63.4 1529 gray(0)
	4: 21x23+0+45 +8.8,+55.9 409 gray(255)
	1: 4x10+252+0 +253.9,+4.1 31 gray(255)
	</pre>
	<p>Use <code>-connected-components 8</code> to visit 8 neighbors rather than 4. By default, neighbor colors must be exact to be part of a unique object. Use <a href="command-line-options.html#fuzz">-fuzz</a> to include pixels that are <var>close</var> in color.</p>
	<p>You might want to eliminate small objects by merging them with their larger neighbors. If so, use this command:</p>
	<pre>
	convert objects.gif -define connected-components:area-threshold=410 -connected-components 4 \
	-auto-level objects.jpg
	</pre>
	<p>Here are the expected results. Notice, how the small objects are now merged with the background.</p>
	<p class="img-responsive center-block">
	<a href="../images/objects.jpg"><img src="../images/objects.jpg" width="256" height="171" class="image-slices" alt="Objects"></a>
	</p>
	<p>Use the <a href="command-line-options.html#fuzz">-fuzz</a> option to identify objects that are made up of pixels similiar in color (e.g. <code>-fuzz 3%</code>).</p>
	</div>
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	<p><a href="connected-components.html#">Back to top</a> •
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