[ELGIS] POLL: 12 bit JPEG compression in TIFF

Mathieu Baudier mbaudier at argeo.org
Fri Aug 12 05:50:12 EDT 2011


What about the compression rates of the standard TIFF compressions? (Already
available)

On 12 Aug 2011 11:36, "Micha Silver" <micha at arava.co.il> wrote:

On 02/08/2011 12:01, Peter Hopfgartner wrote:
>
> On 08/02/2011 09:01 AM, Mathieu Baudier wrote:
>>...

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
> _______________________________________________
> el mailing list
> el at lists.osgeo.org ...
This mail was received via Mail-SeCure System.



_______________________________________________
el mailing list
el at lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/el
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/el/attachments/20110812/ba0e4bcd/attachment.html


More information about the el mailing list