Other Selection Methods :: Region-Based Processing (Image Processing Toolbox User's Guide)

Image Processing Toolbox User's Guide

Other Selection Methods

roipoly provides an easy way to create a binary mask. However, you can use any binary image as a mask, provided that the binary image is the same size as the image being filtered.

For example, suppose you want to filter the grayscale image I, filtering only those pixels whose values are greater than 0.5. You can create the appropriate mask with this command.

```
BW = (I > 0.5);
```

You can also use the poly2mask function to create a binary mask. Unlike the roipoly function, poly2mask does not require an input image. For more information, see the poly2mask reference page.

You can also use the roicolor function to define the region of interest based on a color or intensity range. For more information, see the reference page for roicolor.

Selecting a Polygon Filtering a Region