Sigma/Foveon Questions
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From: nospam on 27 Apr 2010 16:24 In article <itlnZlEBky1LFwZd(a)kennedym.demon.co.uk>, Kennedy McEwen <rkm(a)nospam.demon.co.uk> wrote: > >> We start with 4Mp of red and blue, we end up with 12Mp of red and blue. > >> Irrespective of what else is used in the interpolation that is *STILL* > >> interpolation and upsizing. > > > >interpolation yes. no upsizing since it's already the correct size. > > No size change need occur when you upsize an image from 3Mp to 12Mp > either. the word upsize means a bigger size. up-size. just as downsize means smaller.
From: nospam on 27 Apr 2010 16:29 In article <9tagpWF9ny1LFw7+(a)kennedym.demon.co.uk>, Kennedy McEwen <rkm(a)nospam.demon.co.uk> wrote: > >> "Pixel" may have a number of meanings - there is the element in a JPEG > >> file which has three components (R, G & B), and there is the region on a > >> sensor which received light and turns it into an electrical signal. > > > >they're all spatial elements of an image. > > > Not necessarily. Pixel is derived from "picture element" not "spatial > element". yes it is, but it's spatial. it's the smallest part of an image, which is *not* one colour component, i.e., red. it's a monochrome sample, an rgb triplet, a cmyk quad, a hexachrome sextuplet, etc. foveon layers are unquestionably *not* separate pixels. the only people who claim they are is sigma, foveon and some of the users (not all, surprisingly). > There can be several picture elements, ie. pixels, at exactly > the same spatial co-ordinates of multispectral images. I work with some > images which have 128 pixels with exactly the same spatial coordinates! examples please.
From: dj_nme on 27 Apr 2010 20:22 nospam wrote: > In article <itlnZlEBky1LFwZd(a)kennedym.demon.co.uk>, Kennedy McEwen > <rkm(a)nospam.demon.co.uk> wrote: > >>>> We start with 4Mp of red and blue, we end up with 12Mp of red and blue. >>>> Irrespective of what else is used in the interpolation that is *STILL* >>>> interpolation and upsizing. >>> interpolation yes. no upsizing since it's already the correct size. >> No size change need occur when you upsize an image from 3Mp to 12Mp >> either. > > the word upsize means a bigger size. up-size. just as downsize means > smaller. It is a "filling in", not "up-sizing" that occurs. Bayer CFA demosaicing doesn't make the (in this limited example) the 3mp of green pixels (from the 12mp sensor) larger (ie: cover a bigger area, with bigger dimensions) in size, the "missing" green pixels from the rest of the 12mp image are filled out by the demosaicing algorithm.
From: nospam on 27 Apr 2010 20:45 In article <4bd77fd8$0$5421$afc38c87(a)news.optusnet.com.au>, dj_nme <dj_nme(a)optusnet.com.au> wrote: > >>>> We start with 4Mp of red and blue, we end up with 12Mp of red and blue. > >>>> Irrespective of what else is used in the interpolation that is *STILL* > >>>> interpolation and upsizing. > >>> interpolation yes. no upsizing since it's already the correct size. > >> No size change need occur when you upsize an image from 3Mp to 12Mp > >> either. > > > > the word upsize means a bigger size. up-size. just as downsize means > > smaller. > > It is a "filling in", not "up-sizing" that occurs. > Bayer CFA demosaicing doesn't make the (in this limited example) the 3mp > of green pixels (from the 12mp sensor) larger (ie: cover a bigger area, > with bigger dimensions) in size, the "missing" green pixels from the > rest of the 12mp image are filled out by the demosaicing algorithm. exactly.
From: Ray Fischer on 28 Apr 2010 02:06
Kennedy McEwen <rkm(a)kennedym.demon.co.uk> wrote: > Ray Fischer >>All pixels are "complete". > >But some pixels are more "complete" than others. That doesn't even make sense. -- Ray Fischer rfischer(a)sonic.net |