Re: "Set Threshold" records incorrect values - 16bit images - Ubuntu

Posted by David Randell on Aug 27, 2008; 3:23pm
URL: http://imagej.273.s1.nabble.com/Set-Threshold-records-incorrect-values-16bit-images-Ubuntu-tp3695217p3695243.html

Gabriel Landini wrote:

> On Wednesday 27 August 2008, Ghislain Bugnicourt wrote:
>  
>> I could test the 'threshold set' option on various OS : (all from the same
>> ij140.x86.tar.gz file)
>>    
>
> Is this always the same machine?
>
>  
>>  - on Ubuntu 8.04, Knopix 5.1, Debian (I didn't look at the version),
>> Ubuntu 7.04, the problem appeared.
>>  - surprisingly, the problem did not appear on Fedora 4 (java version
>> 1.6.0_05).
>>  - I couldn't try on suse
>>    
>
> I could (11.0), and it does not happen.
>
>  
>> It implies that it is not a bug included into the tar.gz file, but rather a
>> java problem. As I said, I didn't find any java version that worked better
>> than another.
>>    
>
> So what happens if you run this macro with your image:
>
> setThreshold(445, 1000);
>
> What does the threshold window show?
> Could it be the slider resolution?
>
>  
>> List of all the java versions I tried on my computer : 1.5.0, 1.6.0_05,
>> 1.6.0_06, 1.6.0_07, and openjdk 1.6.
>>    
>
> Hm... this sounds very strange. What CPU do you have? There have been some
> weird things going on with multiple core cpus (but none currently I am aware
> of).
>
> Have you tried with an updated version of the ij.jar? 1.40 is not new (I have
> installed 1.41k) and what you see might not happen in an updated IJ.
>
> G.
>
>  

As it happens I am currently running ImageJ 1.41j and Java 1.6.0_05
under Ubuntu 8.04...

I first loaded your image several times and had no problems setting
threshold to min/max 107/500.

However, what I did notice was that after setting the threshold to
107/500 and repeating this setting several times using the same
threshold window on the same image, (i.e. repeatedly using the "Set"
button and then OK-ing this) the max min values then changed somewhat
arbitrarily.  Is this the same behaviour you have witnessed?

For 8-bit images it seems fine: but 16-bit images seem to generate this
odd behaviour.

Dave Randell