Image Processing Toolbox User's Guide

7. Determine the Number of Objects in the Image

After converting the image to a binary image, you can use the bwlabel function to determine the number of grains of rice in the image. The bwlabel function labels all the components in the binary image bw and returns the number of components it finds in the image in the output value, numObjects.

• [labeled,numObjects] = bwlabel(bw,4);
  
  numObjects 
  ans = 
  
     101
  

The accuracy of the results depends on a number of factors, including

• The size of the objects
• Whether or not any objects are touching (in which case they might be labeled as one object)
• The accuracy of the approximated background
• The connectivity selected. The parameter 4, passed to the bwlabel function, means that pixels must touch along an edge to be considered connected. For more information about the connectivity of objects, see Pixel Connectivity.

6. Create a Binary Version of the Image

8. Examine the Label Matrix

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