Colour adjustment

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Colour adjustment

Postby rolle » Tue Jan 20, 2009 7:34 am

I just updated PTAssembler to version 4.1 and made some test runs. The program seems to be much faster than 3.1. Everything else worked fine but the colour adjustment between adjacent images does not seem to work.

Version 3.1 did a nice work in adjusting the brightness and colour but 4.1 didn't seem to adjust them at all, in spite of the alternative being selected.

Have I missed something?
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Re: Colour adjustment

Postby maxlyons » Tue Jan 20, 2009 9:37 am

rolle wrote:I just updated PTAssembler to version 4.1 and made some test runs. The program seems to be much faster than 3.1. Everything else worked fine but the colour adjustment between adjacent images does not seem to work.

Version 3.1 did a nice work in adjusting the brightness and colour but 4.1 didn't seem to adjust them at all, in spite of the alternative being selected.


PTAssembler uses PTMender (by default) for stitching. PTMender does not perform color/brightness adjustment. You can still use color/brightness adjustment if you use PTStitcher as the stitching program (See the Files/Dirs tab of the preferences screen). However, PTStitcher is slower than PTMender because it is incapable of producing "cropped TIFF" output.

Max
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Postby rolle » Wed Jan 21, 2009 2:48 am

Thanks for the info. I usually take my panoramas with fixed exposure so PTMender will do fine.

My oldest panoramas are taken in Auto mode, however, and for these I seem to need PTstitcher.

Images with serious vignetting I usually stitch to layered psd files without masks. I then correct vignetting separately for each layer using circular gradient masks. With this technique very precise matches can be achieved (especially in the sky) because the shades of the layers can easily be compared. I then manually paint the seams with the images in difference blending mode.

I have tried to correct the vignetting before stitching the images but the exact level of correction is hard to define and some differences, especially in the sky, can in most cases be seen. Smartblend seems to be good in hiding minor vignetting problems, however.

Some kind of colour matching (and possibly vignetting correction) for PTmender would be very nice to have. Since morphing selected control points always produces perfect alignment, the colour correction would completely eliminate all manual steps, even for less perfect images.

I hope we will see these features implemented in future versions of PTassembler.
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Postby maxlyons » Wed Jan 21, 2009 10:37 am

rolle wrote:Some kind of colour matching (and possibly vignetting correction) for PTmender would be very nice to have. Since morphing selected control points always produces perfect alignment, the colour correction would completely eliminate all manual steps, even for less perfect images.


It has been a while since I checked, but I don't think PTMender supports morphing either.

I hope we will see these features implemented in future versions of PTassembler.


I hope to add some color/brightness adjustment logic to PTAStitcher at some point.

Max
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Postby rolle » Thu Jan 22, 2009 2:14 am

It has been a while since I checked, but I don't think PTMender supports morphing either.


I checked the morphing with my very first panorama taken with a cheap pocket camera with severe lens distortion. The images fit very poorly together. When I selected morphing, I first got wavy warps in regular patterns (brick walls, windows etc.) when using automatically generated control points. When a small nuber of control points were used, the result was surprisingly good. In a layered psd image a clear (but narrow) black band passing through the control points could be seen in layer difference mode.

PTMender seems to morph both images at each seam.

Rolle
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