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Re: HDR

Posted by Burger Wilhelm on Apr 30, 2008; 9:46am
URL: http://imagej.273.s1.nabble.com/HDR-tp3696379p3696380.html

Hello,

while Wikipedia is certainly a convenient source to get started, for attempting a thorough implementation of HDRI concepts I want to recommend this excellent book by Reinhard et al., "High Dynamic Range Imaging: Acquisition, Display, and Image-Based Lighting" (Morgan Kaufmann):

http://www.amazon.com/High-Dynamic-Range-Imaging-Acquisition/dp/0125852630

Good luck,
Wilhelm


> -----Original Message-----
> From: ImageJ Interest Group [mailto:[hidden email]] On
> Behalf Of Michael Schmid
> Sent: Wednesday, April 30, 2008 11:26 AM
> To: [hidden email]
> Subject: Re: HDR
>
> Hi Andreas,
>
> there is a bit about HDR in the english Wikipedia, with a few
> links
>    http://en.wikipedia.org/wiki/High_dynamic_range_imaging
>
> Since almost everyone uses digital sensors now, I think a
> first step could be rather simple, get the correlation between
> non-saturated pixels values of two input images, and finding
> the pixel value offset and factor between the images. Then one
> could combine them, maybe with some "smooth transition", i.e.
> a weighted sum for pixel values that are reasonably well
> exposed on both images.
>
> ImageJ supports float images, so we need not care about special
> HDR formats unless we want to read HRD images already present
> in such formats.
>
> For the beginning, I think that we don't need all the procedures
> to map the high dynamic of a HDR image onto a smaller range for
> display - this looks like a the more difficult task.
>
> Best wishes,
>
> Michael
> ________________________________________________________________
> Michael Schmid                    email: [hidden email]
> Institut fuer Allgemeine Physik, Technische Universitaet Wien
> Wiedner Hauptstr. 8-10/134, A 1040 Wien, Austria
> Tel. +43 1 58801-13452 or -13453, Fax +43 1 58801 13499
> ________________________________________________________________
>
> On 30 Apr 2008, at 09:17, Andreas Jahnen wrote:
>
> > Hello,
> >
> > I will have a look at this in more detail as I would like
> to have HDR
> > functionallity in ImageJ as well.
> >
> > So far I have used HDR only as a user (pfstools, qtpfsgui) and I  
> > need to
> > dig into this in more detail. Currently, I think it is not that  
> > easy. You
> > need to at least support the file formats and have hdr functions
> > available. Can anybody recommend good documentation on HDR?
> >
> > I will keep you informed about my work... .
> >
> > So long,
> >                 Andreas
> >
> > -----------------------------------------------------------------
> > Andreas Jahnen  -  Ingenieur de Recherche
> > [hidden email]
> > -----------------------------------------------------------------
> > CRP Henri Tudor  -  http://santec.tudor.lu
> > 2A, rue Kalchesbrück
> > L-1852 Luxembourg
> > -----------------------------------------------------------------
> >
> > ImageJ Interest Group <[hidden email]> wrote on 29.04.2008  
> > 16:47:37:
> >
> >> I assume you're looking for HDR photos in the manner of
> Debevec?  I'm
> >> sure it would be fairly easy to implement this in ImageJ, but I
> >> haven't seen it done so far.  I've tried that method in Cinepaint  
> >> with
> >> good results, though just on test images and not technical
> examples.
> >>
> >> In ImageJ, we've used a manual approach to combine gel scans that
> >> start out sub-16bit.  The end results are worth it, but
> the method is
> >> very time-intensive and I would be very interested in an automated
> >> routine.
> >>
> >> Jonathan
> >>
> >>
> >>
> >> On Tue, Apr 29, 2008 at 1:29 AM, Przemko <[hidden email]>
> > wrote:
> >>> Sylvain Lacomble wrote:
> >>>
> >>>> Dear all,
> >>>>
> >>>> Has anyone tried to process HDR images with imageJ?
> >>>> This would be extremely useful!
> >>>> With my best wishes,
> >>>> Sylvain
> >>>>
> >>>>
> >>>>
> >>>>
> >>>  I would be very interested in HDR on ImageJ as well. I
> tried it on
> >>> Photoshop and one can get very nice Nomarski/Fluorescence
> overlays.
> > Under
> >>> normal conditions, Nomarski pictures are rather difficult
> to take  
> >>> but
> > HDR
> >>> makes it really simpler and much more realistic (WYSIWYG).
> >>>  Przemko
> >>>
> >>>  --
> >>>  Przemko Tylzanowski Ph.D.
> >>>  LSD & Joints
> >>>  O & N1, box 813- dark green
> >>>  University of Leuven
> >>>  Herestraat 49
> >>>  3000 Leuven, Belgium
> >>>
> >>>  phone: (32-16)34-61-96
> >>>  fax  : (32-16)34-62-00
> >>>
> >>>
> >>>
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>