[Insight-users] Re: Problem with lossless JPEG compression in GDCMImageIO

[Jean-Pierre Roux]

Pechin Lo wrote:
> I'm using ITK 3.2.0
> Should I switch to 3.4 and try again?

I'm afraid it will not change a lot.
In the very last version a gdcm, for a few images, we have, after 
compression/decompression a few pixels that differs from +/-1 ...
Could you send me one of your 'binary images' that only consists of n 
and n+, to see if we can track the bug?
Thx
Jean-Pierre Roux
>
> On 9/25/07, *Mathieu Malaterre* <mathieu.malaterre at gmail.com 
> <mailto:mathieu.malaterre at gmail.com>> wrote:
>
>     On 9/25/07, Steve M. Robbins <steve at sumost.ca
>     <mailto:steve at sumost.ca>> wrote:
>     > On Mon, Sep 24, 2007 at 11:50:05PM +0200, Pechin Lo wrote:
>     > > After some tweaking around, I found out that JPEG compression
>     works provided
>     > > that the minimum difference between two pixels is 2.
>     > > For example, if I have an image that only consists of n and
>     n+1, the saved
>     > > image will only contains the value n.
>     > > However, if the image consists of value n and n+2, then the
>     saved image will
>     > > contains both n and n+2.
>     > > In other words, the image will stores fine if I multiply it by
>     a factor of
>     > > 2.
>     > >
>     > > Can someone please tell me why is this happening?
>     >
>     > I'm not familiar with the code in question, but is it possible
>     > that you're using a lossy JPEG compression?
>
>     Hi all,
>
>
>       Could you please let me know if you are using ITK 3.2 / ITK 3.4
>     or CVS ?
>
>     Thanks
>
>     --
>     Mathieu
>     Ps: 3.4 and CVS should *not* produce this weird behavior.
>
>
>
>
> -- 
> Pechin Lo Chien Pau
> Ph.d. Student
> Department of Computer Science (DIKU)
> University of Copenhagen
> Universitetsparken 1, Office S226
> DK-2100 Copenhagen, Denmark
> Phone: +45 3532 1433
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>
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