[Hdri] correction for barrel distortion

[Martin Moeck]

No luck with Photoshop lens corrections. This is like poor freehand drawing. All gridlines are not vertical or horizontal, but warped in interesting ways. 
 
Each square with barrel distortion has to be corrected individually. Greg needs to do take care of this right now :) This community needs a tool to shift pixels in a Radiance image around. Input could be a black and white grid image showing the barrel distortion. Output would be the image with straight lines. 
 
Greg, I can help you with the command line :) :
 
pcomb -f barrel.cal barrelgrid.pic original.hdr > corrected.hdr
 
See, Greg, we are already halfway there :)
 
Martin

________________________________

From: hdri-bounces at www.radiance-online.org on behalf of Kirk Thibault
Sent: Tue 1/17/2006 3:52 PM
To: Hdri at www.radiance-online.org
Subject: Re: [Hdri] correction for barrel distortion


HDRShop will permit you to manually specify the exposure increment between each image in a LDR sequence.

------------------------------

Kirk L. Thibault, Ph.D.
kthibault at biomechanicsinc.com

p.  215.271.7720
f.   215.271.7740
c.  267.918.6908

skype. kirkthibault




On Jan 17, 2006, at 1:38 PM, Fitzsimmons, Rob wrote:


	I could be wrong, but don't HDR creators need the original camera shot with exif information? Doing Photoshop adjustments would lose that info. I'm pretty sure Photosphere needs this, but I don't know if HDRShop does.
	 
	Rob F

		-----Original Message-----
		From: Kirk Thibault [mailto:kthibault at biomechanicsinc.com] 
		Sent: Tuesday, January 17, 2006 9:03 AM
		To: hdri at www.radiance-online.org
		Subject: Re: [Hdri] correction for barrel distortion
		
		
		Martin,

		Photoshop CS2 has a Lens Correction filter that will help correct chromatic aberration, vignetting and barrel/pincushion distortion.  Filter>Distortion>Lens Correction

		However, I opened a HDR image (*.hdr) and the Filter>Distortion menu option was not available, leading me to believe that it will not operate directly on HDR 32 bit images.  Thus, it would seem that you would apply it to your LDR sequence images before converting to a HDR image.  The filter permits the applied settings to be saved, so you could open one image, applying the correction and then save the settings for the subsequent application to the rest of the image sequence, permitting automation in a batch action.  If your sequence is taken with a tripod and the images are registered prior to correction, I would guess that applying the same correction through saved settings should displace the same pixels in each image and preserve image registration.

		I just upgraded to CS2 so I haven't played with it yet.

		kirk

		

		On Jan 17, 2006, at 10:11 AM, Martin Moeck wrote:


			Assume you have a barrel distortion image like the one shown at
			 
			http://www.dcresource.com/reviews/nikon/coolpix5400-review/
			 
			towards the bottom of the page. 
			 
			1) Are there software tools or algorithms available to correct these images before they are converted into an HDR image?
			 
			2) If not, is there a simple way to correct the HDR image for barrel distortion?
			 
			Martin Moeck
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