Hi Terry, Terry Duell wrote:
> I had initially thought that as well, but advice on the subject from > a signal processing group essentially said that the PSF will not be > uniform hence there won't be a good result. I was probably not doing > it correctly. That had been my first comment, too, if you remember ;^> Still you would expect a not perfect, but improved image in such a case... > At that stage of proceedings I had been working only within fourier space. Ah, so your attempt had been mostly a B' = B / (B/A) which is A.... > I tried two ways. The first was to split the main image into a > number of subimages equal in size to that from which I derived my > PSF, then applied the PSF to each and finally joined the results > together Doable, but due to border effects one should use overlapping fields and use weighting in the addition. > The second approach was to pad with zeros. That was automagically > done by Octave, so assume it was done properly, also assuming I knew > what I was doing when applying the Octave functions! Assuming this is indeed correct, the problem then for sure was that your PSF was not 'general' enough and needs some smoothing. As a start you should transform your PSF back to normal space and look at it. For motion blur, it should mainly be all zero except a line that tracks the movement during the exposure... > For a little while now I have been working on an alternate approach > which attempts to account for non uniform blurring (Whyte et al), > and will continue down this path until I have it working to the > point that I can judge whether it is an approach for this problem, > or it defeats me. Looking forward to read about your results! > I will no doubt come back to where I left off, as the idea of being > able to directly derive a PSF from sharp/blurred pair, seems to be > such a good start to a solution, and try your ideas. Well, in principle this works quite well, it is what we use to correct astronomical images for seeing (atmospheric distortions). We have two sets of images (a set is typically 100 images) that are taken strictly simultaneous. One of them can be corrected using statistical methods (Speckle imaging), so we get the 'sharp' image for this set. Then for each of the images in the set we can derive the PSF from the 'true' image and the blurred one, then apply the PSF to the simultaneous image in the other set. But this also only works if we have several PSFs to average, and still needs subtle noise calibration. Cheers, Pit -- Dr. Peter "Pit" Suetterlin http://www.astro.su.se/~pit Institute for Solar Physics Tel.: +34 922 405 590 (Spain) [email protected] +46 8 5537 8507 (Sweden) [email protected] -- You received this message because you are subscribed to the Google Groups "Hugin and other free panoramic software" group. A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/hugin-ptx
