Programatically Plot ROI

[chinty]

How to plot line ROI programatically from center of circle 

[AmitShachaf]

Create a binary mask of the area you want include in the ROI.

Then you can convert the mask to ROI. 

Use IMAQ Mask to ROI.vi for that.

[Andrey_Dmitriev]

I would like to suggest to compute end points of the line (one point on the center of the circle, and another one - where you want), then use IMAQ Convert Line to ROI VI to convert coordinates to the ROI. Then you can group your Line ROI with existing with IMAQ Group ROIs VI (if needed) and apply ROI to the image.