These m-files let you process interactively and multiply on image ROIs.
Updated 18 Apr 2005

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1) Goal: Draw & process multiple ROIs interactively within an image, which output area, mean, std, min, max, median and roicenter [x, y].

2) Usage: ROI(img, nroi), where 'img' is your image, and 'nroi' is a total number to ROIs to be processed. The opened image will be processed BY DEFAULT. A prefered procedure is as follows:

a) img = imread(...);
b) imh = imshow(img) and
c) ROI(img, nroi).

Alternatively, if there is no image in your WorkSpace, you MUST use square brackets to occupy the argument space for img, such as, ROI([],5), will let you open a new image and process with 5 ROIs.

3) Since getline('closed') is used to get the polygon interactively, please click left mouse button to select, and right button to finish up a ROI (Backspace to delete the lastest click). You may repeat this process till all ROIs were processed. For more infos, please may see help getline.

4) Results: ROI statistics are displayed on screen or output to a text file (optional).

5) The colors of line/text label are generated by 'jet' colormap, therefore, certain color may be too close to tell, especially when you select too many ROIs. In that case, you may need to edit the color after ROI processing. For more infos, please see

help jet

6) For your convenience, you may use the following m-scripts to clear your enviroments: 'dt', 'dl' and 'df' to delete all text characters, lines and figures, respectively.

7) This package includes 5 m-files: 'ROI.m', 'MultiROI.m', 'df.m', 'dl.m' and 'dt.m'.

Shanrong Zhang
Department of Radiology
University of Washington


Cite As

Shanrong Zhang (2024). ROI (, MATLAB Central File Exchange. Retrieved .

MATLAB Release Compatibility
Created with R13
Compatible with any release
Platform Compatibility
Windows macOS Linux
Find more on Read, Write, and Modify Image in Help Center and MATLAB Answers

Inspired by: ImROI

Inspired: mmROI (multiple images with multiple ROIs)

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Version Published Release Notes

Add one more m-file which has similar function to ROI, but use spline to smooth the roi edge.