XP009 parallax rangfinder

[Karl]

Since FirePaste and FPD both have cameras, we can use these for parallax rangefinding.

Here's a simple experiment that proves that we can use FireSIght to rangefind with two images

taken at different Z-heights. No Z-probe here!

https://github.com/firepick1/fpd-vision/tree/master/XP009-Parallax-Range

[Joshua Pritt]

Holy crap balls! This is what I was imagining when I thought about the original idea to calibrate. I hope this works out great.

--
You received this message because you are subscribed to the Google Groups "FirePick" group.
To unsubscribe from this group and stop receiving emails from it, send an email to firepick+unsubscribe@googlegroups.com.
To post to this group, send email to fire...@googlegroups.com.
Visit this group at https://groups.google.com/group/firepick.
For more options, visit https://groups.google.com/d/optout.

[Karl]

What I like about this method is that it works with arbitrary images having sufficiently "distinguishable features".

It should also work well with images of crap balls as long as the imaged objectives are "sufficiently coplanar"

with respect to the camera. :D

[Karl]

Further investigation with the parallax method reveals some interesting challenges.

FNR appears to work well with dense and highly irregular features. Notably, natural

wood grain qualifies as such and is what made the initial investigation a success.

However, FNR does NOT work well if there are regular or sparse features. For example,

FNR fails on grids as well as blank sheets of paper. It will also fail on, for example, PCBs

with LED arrays, etc.

This isn't as bad as it seems, since we can construct a parallax calibration page that works 

as well as wood grain. Here is an example of such a page:

https://github.com/firepick1/fpd-vision/blob/master/XP009-Parallax-Range/dashes.pdf

Attached are the matched images, near and far. You will notice that the matched areas

are not the same (look at the border), since FNR is matching a full size template to an image

that has shrunk slightly. The parallax calibration page works because the features to be matched

(i.e., dashes) are large enough that they are still recognizable when shrunk. Good FNR calibration

pages are therefore tolerant of scale changes.