Archived posting to the Leica Users Group, 2007/06/12
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hello, Don thanks for your kind comments. Neat image offers (almost too many options) for noise reduction and sharpening in 3 different bands and a selection of whether to do it in RGB or YCrCb - the second option means you can sharpen in the luminance channel alone and avoid most of the sharpen artefacts found with other programs. The options, as far as I understand the fundamental idea of it, are low, medium and high-pass filters and when you set to "conservative" sharpening this probably prevents clipping around the respective Nyquist frequencies or cut-off points for the respective filters, or it tapers the flanks of the spectra more strongly. I also suspect that the noise filters are in reject mode with a mix-back function and that sharpening is purely pass - only the programmer knows, and he must be good. On the other hand, it may be some clever use of FK filtering (frequency /wavenumber) or a deconvolution process, or a complex random noise attenuation program, but one thing is clear to me, whoever worked it out hasn't been looking at pictures, it's all physics and math that ALSO works on images. In spectral analysis, digital technologies couldn't care less whether it's a signal, a frequency or a colour - it's all just numbers. I only wish I had had something as efficient as Neat Image for cleaning up noisy seismic data. http://www.neatimage.com/ Cheers Douglas Don Dory wrote: > The end result is very nice indeed. When you say you sharpened in three > frequencies I would appreciate a little more information on that. > > On 6/11/07, Douglas Sharp <douglas.sharp@gmx.de> wrote: >> >> So many lovely lilies!!! >> Motivation enough to go deep into my "back catalogue" of flowers to dig >> up some of my own. >> >> A little abstract, and far removed from a garden context - hope you like >> them. >> >> >> http://gallery.leica-users.org/v/DMS/New-Old-Pictures/_MG_1143_edited-2.jpg.html >> >> >> >> http://gallery.leica-users.org/v/DMS/New-Old-Pictures/_MG_1182_edited-3.jpg.html >> >> >> >> http://gallery.leica-users.org/v/DMS/New-Old-Pictures/_MG_1091_edited-6.jpg.html >> >> >> >> http://gallery.leica-users.org/v/DMS/New-Old-Pictures/_MG_1136_edited-3.jpg.html >> >> >> >> Comments welcome >> Douglas >> (before anyone asks - yes, there was a fair amountIMG: of Photoshopping >> involved) >> >> >> >> > >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> > > >