1 | initial version |
The ROI you have is (per images) the region where all pixels have been correctly rectified. IE, the ROI is made by:
This is why ROI are not the same on left and right images, and you have to specify them to the Stereo algorithm (at least Block Matching) and not directly apply them to the images before stereo reconstruction (images won't be aligned anymore if you do that and an error will be thrown as the images won't have the same size anymore...)
This is my understanding of the ROI, but for a formal definition, you should probably say that this is the biggest included (aligned to the axes) rectangle containing only valid pixels after stereo rectification.