Image Processing Toolbox User's Guide Previous page   Next Page

Displaying Binary Images

In MATLAB, a binary image is of class logical. Binary images contain only 0's and 1's. Pixels with the value 0 are displayed as black; pixels with the value 1 are displayed as white.

To display a binary image, using either imshow or imtool, specify the image matrix as an argument. For example, this code reads a binary image into the MATLAB workspace and then displays the image. This documentation uses the variable name BW to represent a binary image in the workspace


Changing the Display Colors of a Binary Image

You might prefer to invert binary images when you display them, so that 0 values are displayed as white and 1 values are displayed as black. To do this, use the NOT (~) operator in MATLAB. (In this figure, a box is drawn around the image to show the image boundary.) For example:


You can also display a binary image using the indexed image colormap syntax. For example, the following command specifies a two-row colormap that displays 0's as red and 1's as blue.


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