I once used this technique to make a 2D pseudo-lidar sensor from a camera mounted on a indoor vehicle, it worked fairly well when used on uniformly textured flooring. After transforming the camera input image using an IPT, you could do some basic trig to figure out the distances away from the camera to non-floor objects.
The title is missing a right parenthesis after the date <a href="https://www.xkcd.com/859" rel="nofollow">https://www.xkcd.com/859</a> . EDIT: I originally put one in this comment, but then realised that that would be even worse once the title was fixed ….
Great stuff. Would it kill this site to allow for even just the tiniest bit of context for why a 22 year old article is being posted? Also it looks like fmwconcepts.com has come up on Hacker News a few times for Fred's ImageMagick scripts. But has anyone found the code to do the perspective transformation discussed here?