Re: Twin camera Overlapping/Staggering


Antonio F.G.
 

On Thu, Jun 10, 2021 at 11:14 AM, George Themelis wrote:
but people who used it say that software alignment (SPM) eliminates the error (which is not correct) and that they do not see a problem.
Yes, I am one of those people. I do not have any staggered rig, but I can prove the perspective issues of the staggering can be corrected to provide 0.0% vertical error (if the lenses have no significant distortion). In fact ANY misalignment can be corrected in theory to give zero vertical error.

I had a look to your error calculations. They seem correct, but they only show the errors in the unaligned image. The calculations do not prove that those errors could not be aligned.

As you correctly said in your report the effect of the staggering is a 2D perspective deformation. You told your rig is 75mm, and one camera is 25mm in front of the other, so the perspective angle is atan(25/75)=18.4°
If the only misalignment were the 18.4°, then the images would become perfectly aligned by applying exactly a 18.4° perspective deformation in the same direction to both of them. Of course there will be parts of the scene that will not overlap (as will the straight lines in the ground in your experiment), but this happens with any stereo pair, and it is routinely corrected by cropping. 
But enough theory, please send some examples of allegedly non-correctable pairs from your staggered rig, and see what can be done with them. They should have zero vertical errors, but will have a 18.4° perspective deformation. Not sure whether this will be noticeable or not, it probably depends on the type of scene.


By the way. Thank you for your very good description of the RX100 rig (only the statements about staggering errors are wrong:-). Should I consider give a try to Sony? (I am still an NX1000 guy:-).

Regards
    Antonio



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