CLAHE update, speed up

[Stephan Saalfeld]

Dear friends of ImageJ/Fiji,

we implemented the fast version of the Contrast Limited Adaptive
Histogram Equalization

http://pacific.mpi-cbg.de/wiki/index.php/Enhance_Local_Contrast_(CLAHE)

>From user perspective, the only difference to the old implementation is
a new checkbox in the parameter dialog to toggle between fast and slow
version.  Default is fast.  In the faster implementation, the local
contrast adjustment is not calculated for each single pixel
independently but for adjacent cells of the given block-size only.  The
transfer function for locations in between is interpolated.  This is the
approach as described in the original publication for close to real time
video enhancement.

You will notice, that the result is not exactly the same as in the exact
per-pixel evaluation but relatively close.  It is convenient to find
appropriate parameters with the fast version and finally apply it with
the accurate version.

The update is available through the Fiji-Updater

http://pacific.mpi-cbg.de/wiki/index.php/Update_Fiji

or as a standalone jar for ImageJ's plugins folder

http://fly.mpi-cbg.de/saalfeld/download/clahe_.jar

Sources are published under GPL2 and tracked in the mpicbg git
repository

http://pacific.mpi-cbg.de/cgi-bin/gitweb.cgi?p=mpicbg.git;a=tree;f=mpicbg/ij/clahe

Best regards,
Stephan

[Stephan Saalfeld]

Hi Gabriel,

thanks for the bug report.  I forgot to include the respective Util
class into the standalone plugin jar, because, in my installation, there
was the library included...

Fixed.  Please download again:

http://fly.mpi-cbg.de/saalfeld/download/clahe_.jar

Best,
Stephan




On Fri, 2010-08-13 at 09:41 +0100, Gabriel Landini wrote:

> On Thursday 12 August 2010, you wrote:
> >
> > or as a standalone jar for ImageJ's plugins folder
> >
> > http://fly.mpi-cbg.de/saalfeld/download/clahe_.jar
>
> Hi Stephan,
> I copied the jar to my ./plugins/Filters folder and I get this error:
> Probably there is something missing in the jar file?
>
> java.lang.NoSuchMethodError: mpicbg.util.Util.memset([BB)V
> at mpicbg.ij.clahe.FastFlat$Apply.<init>(FastFlat.java:98)
> at mpicbg.ij.clahe.FastFlat$RGBApply.<init>(FastFlat.java:271)
> at mpicbg.ij.clahe.FastFlat.run(FastFlat.java:561)
> at mpicbg.ij.clahe.FastFlat.run(FastFlat.java:425)
> at mpicbg.ij.clahe.FastFlat.run(FastFlat.java:334)
> at mpicbg.ij.clahe.PlugIn.run(PlugIn.java:147)
> at mpicbg.ij.clahe.PlugIn.run(PlugIn.java:133)
> at ij.IJ.runUserPlugIn(IJ.java:183)
> at ij.IJ.runPlugIn(IJ.java:150)
> at ij.Executer.runCommand(Executer.java:124)
> at ij.Executer.run(Executer.java:61)
> at java.lang.Thread.run(Thread.java:619)
>
> Cheers
>
> Gabriel