Warp so image appears undistorted when projected on cylinder?

PB
Posted By
Peter_Burghardt
Aug 1, 2008
Views
905
Replies
7
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Closed
I’m trying to warp an image so that it will appear undistorted when projected onto a horizontal cylinder. The projection is 1:1 — no magnification — so the image height is slightly less than the cylinder diameter. In a ray tracing the lines would all be parallel. I’ve made a couple of attempts at warping it manually, which showed that it could work, but I was wondering if there was a more accurate way to do it. Thanks!
Related Tags
appearance image warp

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F
Freeagent
Aug 1, 2008
Just trying to project my head around this: are you talking about transforming an original image so that it should look undistorted from a certain viewpoint when actually projected? Or is it the other way round – like a pole with a "projected poster" on it, wrapping around the surface?
P
Phosphor
Aug 1, 2008
You can do this with the Flexify plugin from FlamingPear.

<http://www.flamingpear.com/flexify.html>
PB
Peter_Burghardt
Aug 1, 2008
Freeagent : I don’t want to wrap the image around around the cylinder. I want to "pre-distort" it — some sort of non-linear warping, greatest at the top and bottom — so that it will appear undistorted when projected onto the horizontal cylinder.

Phos+for: Thanks for the link — i’ll take a look.

Peter
F
Freeagent
Aug 1, 2008
That’s what I was wondering about – would’t it depend on the viewpoint? The projector itself would "see" it as OK..?
F
Freeagent
Aug 1, 2008
OK, I think I know what you mean. I’m just having a Bad Brain Day, I’ll see you all tomorrow.

Phos’ plugin will take care of it.
JL
John_L_Waller
Aug 6, 2008
What is "Phos’plugin", and where is it?
PB
Peter_Burghardt
Aug 6, 2008
<http://www.flamingpear.com/flexify.html>

Thanks for the tip! I downloaded the trial and ran it, changing the Input to cylindrical and the Output to equirectangular. The result looks promising.

How to Master Sharpening in Photoshop

Give your photos a professional finish with sharpening in Photoshop. Learn to enhance details, create contrast, and prepare your images for print, web, and social media.

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