[ELGIS] POLL: 12 bit JPEG compression in TIFF

[Peter Hopfgartner]

I'll start next week some tests on this topic. I would like to
include epsilon for wavelet compression. This might get similar
results as ECW. 

Peter 

--------Micha Silver  wrote-------- 

Subject: Re: [ELGIS] POLL: 12 bit JPEG compression in TIFF 

Date: 12.08.2011 12:07 

  
> 
> On 02/08/2011 12:01, Peter Hopfgartner wrote: On
> > 08/02/2011 09:01 AM, Mathieu Baudier wrote:
> >   I do not know of any direct drawback,
> > > > except that internal libjpeg and
> > > >  libtiff/libgeotiff are used, instead of the system shared libs.
> > > >  Frank Warmerdam advised against using the internal
> > > libtiff back in October 2010:
> > >  http://lists.osgeo.org/pipermail/el/2010-October/000119.html [1]
> > >  (the same would probably apply for libjpeg I guess)
> > >  We could think about a separate gdal, e.g. gdal-il,
> > package with internal libs, with bigTIFF and 12 bit enabled. BTW,
> > UbuntuGIS is using internal libs, too.
> >  
> 
> Hi Peter: 
> 
> I did a quick (amateur) test of jpeg 12 this morning and I must say I
> was surprised with the results. I started with a 1.4 GB tiff ortho
> photo, which I also have as an ECW image. The ECW is about 64MB. 
> 
> I used the OSGeo4W installation of gdal with the libjpeg that
> supports 12 bit, and I made two compressed tiffs. The regular jpeg
> compression came down to about 75 MB, a bit larger than the ECW, but
> it's quality was a bit fuzzy with color changes in the pixels. (Of
> course ECW is also lossy, introducing changes in the pixel coloring,
> but keeping \"sharpness\"). 
> 
> The 12 bit jpeg-compressed tiff came down to about 120 MB, only twice
> the size of the ECW, but it was almost indistinguishable from the
> original tiff! Both in coloring and sharpness. That was very
> impressive, I must say. 
> 
> I don't know where the jpeg2000 format is going (if anwhere). For now
> this 12-bit jpeg compression looks like an ideal alternative to
> struggling with the closed ECW format on one hand, or the unwieldy
> file sizes of uncompressed tiff on the other. 
> 
> Best, Micha 
> 
>   Peter
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> > 
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> >  
> 
>     

Links:
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[1] http://lists.osgeo.org/pipermail/el/2010-October/000119.html
[2] mailto:el at lists.osgeo.org
[3] http://lists.osgeo.org/mailman/listinfo/el
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