On 4 Apr., 06:53, "Terry Duell" <[email protected]> wrote:
> > On Sun, 03 Apr 2011 21:12:00 +1000, kfj <[email protected]> wrote: > > convolution in the 'time' domain (btw. where is time in a 2D > > matrix ;-) > Sorry A terminology mix up on my part. For this sort of stuff I should be > using the terms 'spatial' and 'frequency' domain, although 'time' domain > seems to be applied quite a lot to that which isn't the frequency domain > regardless of the nature of the problem. I think time can be considered > the same as distance in this sort of stuff. It's from signal-processing one-dimensional signals, which usually vary with time - like sounds. That's where the whole Fourier stuff started out, decomposing periodic phenomena into harmonics. > > And I still believe those sharp discontinuities and minimum-to-maximum > > jumps in your source image may be part of the problem, never mind you > > can recover the source image precisely. > > Things are now looking a bit more like they should. > I found some basic errors in the way I was doing convolution and > deconvolution in freq domain in Octave. I had forgotten that special > syntax is needed for element by element multiply and divide when dealing > with arrays/matrices. A bit more RTFM needed! > I also 'toned' down the test image a tad. > The sharp image can now be recovered (almost) exactly, and applying the > same PSF to the sharp recovers the blurred image (almost) exactly. > The 'brightness' of the recovered images (the pixel values) don't come > back exactly as they go in, but the ratios seem to be the same. > In the attached images I have rescaled the derived images to have the same > max values as the originals. Well done! Once the simple test case works, you can at least hope more complex signals will yield as well - maybe not perfectly, but to a degree. Best of luck. I'll be off on a holiday - who knows maybe you'll have it all sorted by the time I'm back! Kay -- 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
