ROI (Region of Interest)    

The ROI is the green box that appears on the screen when you select certain tools.   Some of the tools work on the entire image and others allow you to define where you want them to work.  The ROI box allows you to tell that tool where to work.  The ROI box can be placed anywhere on the Viewer window and can be resized and rotated as needed.


When the ROI box is selected it will turn red and 10 smaller boxes will be placed around the ROI so you can resize and rotate it. 

If you hold CTRL down when resizing the ROI will maintain a perfectly square shape.

If you hold Shift while rotating it will rotate in 15 degree increments.


If you right-click inside the ROI it will display the ROIEntity edit page.  Selecting the Entity tab allows you to adjust the colors, thickness, handle size and visibility of the ROI box.  You can also select a Coordinate System - this controls how the ROI understands where it is on the screen.

Selecting the Rectangle tab allows you to enter specific values for the ROI rectangle used, including center X, Y, width, height, angle and aspect of width/height. After entering your values, click Apply then Close. Note the angle is in radians. You can uses the ellipses edit buton and convert eg if you want 17 deg type 17*PI/180 and hit calculate  The ROI will be adjusted according to the selections.