Wavelet toolbox for complex images
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From: glen herrmannsfeldt on 5 Mar 2010 13:51 Jerry Avins <jya(a)ieee.org> wrote: > Sylvia wrote: >> I am searching for a robust wavelet based MATLAB toolbox that could be used >> for complex images. There are some good toolboxes available however they >> can only work for real images. > I know what complex numbers are, but what is a complex image? > Can it be reproduced by printing? I don't know about complex, but there are some cases in optics where phase information is important. If you represent amplitude and phase as a complex number then that would count. Holography, in some sense, stores both the amplitude and phase of the reflected beam, and holograms are difficult to reproduce by intensity based reproduction systems. -- glen
From: Jerry Avins on 5 Mar 2010 14:35 glen herrmannsfeldt wrote: > Jerry Avins <jya(a)ieee.org> wrote: >> Sylvia wrote: >>> I am searching for a robust wavelet based MATLAB toolbox that could be used >>> for complex images. There are some good toolboxes available however they >>> can only work for real images. > >> I know what complex numbers are, but what is a complex image? >> Can it be reproduced by printing? > > I don't know about complex, but there are some cases in optics > where phase information is important. If you represent amplitude > and phase as a complex number then that would count. > > Holography, in some sense, stores both the amplitude and phase > of the reflected beam, and holograms are difficult to reproduce > by intensity based reproduction systems. I used to make monochrome holograms using high-resolution black-and-white photographic plates. Those holograms recorded depth. On the other hand. Lippmann photographs used phase (in a way) to record color with the same monochromatic emulsion. I don't know of a process that does both in one image. Jerry -- It matters little to a goat whether it be dedicated to God or consigned to Azazel. The critical turning was having been chosen to participate. �����������������������������������������������������������������������
From: Eric Jacobsen on 5 Mar 2010 15:25 On 3/5/2010 12:35 PM, Jerry Avins wrote: > glen herrmannsfeldt wrote: >> Jerry Avins <jya(a)ieee.org> wrote: >>> Sylvia wrote: >>>> I am searching for a robust wavelet based MATLAB toolbox that could >>>> be used >>>> for complex images. There are some good toolboxes available however >>>> they >>>> can only work for real images. >> >>> I know what complex numbers are, but what is a complex image? Can it >>> be reproduced by printing? >> >> I don't know about complex, but there are some cases in optics >> where phase information is important. If you represent amplitude >> and phase as a complex number then that would count. >> >> Holography, in some sense, stores both the amplitude and phase >> of the reflected beam, and holograms are difficult to reproduce >> by intensity based reproduction systems. > > I used to make monochrome holograms using high-resolution > black-and-white photographic plates. Those holograms recorded depth. On > the other hand. Lippmann photographs used phase (in a way) to record > color with the same monochromatic emulsion. I don't know of a process > that does both in one image. > > Jerry Some image sources (e.g., radar) have underlying data that is complex-valued, and the image is generated, typically, by detecting the magnitude of the data, sometimes with an emphasis, log, or other detection map. Maybe a "complex image" is the underlying data before detection? -- Eric Jacobsen Minister of Algorithms Abineau Communications http://www.abineau.com
From: Jerry Avins on 5 Mar 2010 15:32
Eric Jacobsen wrote: > On 3/5/2010 12:35 PM, Jerry Avins wrote: >> glen herrmannsfeldt wrote: >>> Jerry Avins <jya(a)ieee.org> wrote: >>>> Sylvia wrote: >>>>> I am searching for a robust wavelet based MATLAB toolbox that could >>>>> be used >>>>> for complex images. There are some good toolboxes available however >>>>> they >>>>> can only work for real images. >>> >>>> I know what complex numbers are, but what is a complex image? Can it >>>> be reproduced by printing? >>> >>> I don't know about complex, but there are some cases in optics >>> where phase information is important. If you represent amplitude >>> and phase as a complex number then that would count. >>> >>> Holography, in some sense, stores both the amplitude and phase >>> of the reflected beam, and holograms are difficult to reproduce >>> by intensity based reproduction systems. >> >> I used to make monochrome holograms using high-resolution >> black-and-white photographic plates. Those holograms recorded depth. On >> the other hand. Lippmann photographs used phase (in a way) to record >> color with the same monochromatic emulsion. I don't know of a process >> that does both in one image. >> >> Jerry > > Some image sources (e.g., radar) have underlying data that is > complex-valued, and the image is generated, typically, by detecting the > magnitude of the data, sometimes with an emphasis, log, or other > detection map. Maybe a "complex image" is the underlying data before > detection? I wasn't skeptical. Finding new ideas to explore is a big part of the pleasure I get from hanging out here. Jerry -- It matters little to a goat whether it be dedicated to God or consigned to Azazel. The critical turning was having been chosen to participate. ����������������������������������������������������������������������� |