(1) Short for return on investment, ROI is an accounting formula used to obtain an actual or perceived future value of an expense or investment.
(2) Short for region of interest, it is a term most commonly used in reference to a “machine vision” field of view (i.e. digital camera, scanner, medical x-ray equipment, etc.).
(3) Short for region of interest (ROI) coding it is a function supported by JPEG2000 it enables a non-uniform distribution of the image quality between a selected region (the ROI) and the rest of the image (background).