Proxel Lens Corrector

Started Aug 28, 2006 | Discussions thread
KL Matt Veteran Member • Posts: 5,885
Re: PTLens update

Hi John,

Thanks very much for the detailed report and examples.

It's an automation plugin rather than a filter, I understand that
this is what allows the canvas size change. It gives me a huge
advantage in central resolution of corrected fisheye images
compared with any other correction tool I've tried.

If I understand correctly, Proxel stretches the corners instead of shrinking the middle for barrel distortion, right? So theoretically, the very center of the image will have almost exactly the same resolution and sharpness as the original before any correction. The corners will also have the same resolution, but a percentage of those pixels will have been interpolated. With PTlens, it appears the center is shrunk, forcing more original pixels into the space of fewer "converted" pixels in the middle and leaving the edges relatively unmolested exept for the fact that the resolution of the entire image is lessened due to the subsequent cropping that is necessary.

So for barrel distortion, Proxel does indeed sound like it would preserve center resolution and sharpness, at the expense of edge sharpness (but not resolution). But what about pincushion distortion? Won't Proxel expand the middle of the image to fill up the top and bottom, interpolating most heavily right in the middle of the image? Can this degrade center sharpness? Or does Proxel swich to the other (i.e. shrink-the-corners) method for pincushion (I assume this would be better for center sharpness, although leading to overall lower resolution)?

To me, the PTLens method, although lowering resolution, sounds like it should provide overall sharper results. Apparently this is not your experience? I always thought up-resing was worse for sharpness than down-resing.

I think I need to do some experiments of my own!


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