Specify ROIs

Specify ROI as Binary Mask

You can create a binary mask by selecting pixels based on intensity values or position, or by using binary segmentation techniques.

Create ROI Shapes

ROI objects represent ROIs as geometric and hand-drawn shapes.

Create Binary Mask Using an ROI Function

This example shows to create a binary mask using one of the ROI creation functions, such as drawcircle, with the mask creation function createMask.

Filter ROIs

Overview of ROI Filtering

To filter a region of interest (ROI), first define a mask to separate the ROI from the background, then apply the filter to the ROI only.

Sharpen Region of Interest in an Image

This example shows how to use masked filtering to increase the sharpness of a specific region of interest.

Apply Custom Filter to Region of Interest in Image

This example shows how to define your own function and mask to filter a region of interest.

Fill Region of Interest in an Image

The process of filling a region of interest involves replacing all pixels in the region by interpolating inward from the boundary of the region.

Create Interactive ROIs Using Events and Callback Functions

Subsample or Simplify a Freehand ROI

This example shows how to subsample or reduce the number of points in a Freehand ROI object.

Rotate Image Interactively Using Rectangle ROI

This example shows how to rotate an image by using a Rectangle ROI with a callback function that calls imrotate when you move the ROI.

Use Polyline to Create Angle Measurement Tool

This example shows how to create an interactive tool that displays the angle between three vertices in a polyline ROI.

Measure Distances in an Image

This example shows how to use line ROIs to measure distances in an image.

Use Wait Function After Drawing ROI

This example shows how to define a custom wait function that blocks the MATLAB® command line until you finish positioning a rectangle.