Do I need to rectify if camera planes are aligned?

Question

If I am taking images from a pair of cameras whose principle axis(in both the cameras) is perpendicular to the baseline do I need to rectify the images?Typical example would be bumblebee stereo cameras.

Answer 1

If you can also guarantee that:

• the camera axes are parallel (maybe so if bought as a single package like the bumblebee)
• you have no lens distortion (probably not)
• all the other internal camera parameters are identical
• your measurement axis is parallel to your baseline

then you might be able to skip image rectification. Personally I wouldn't.

Just think about lens distortion. Even assuming everything else is equal and aligned, this might mess things up. Suppose a feature appears on the edge in one image and a the centre of the other. At the edge it might be distorted a few pixels away, while at the centre it appears where it should. Without rectification, your stereoscopic calculation (which assumes straight lines from object to sensor) is going to give you bad results.