Posted by
Michael Schmid on
May 07, 2010; 5:01pm
URL: http://imagej.273.s1.nabble.com/Setting-Brightness-Contrast-range-does-not-change-slider-range-tp3688374p3688375.html
Hi Lewis,
for an image with values between -2 and 600000, a range of 0-100 is
an extreme case. When I set these values, the brightness and contrast
sliders are at the very right end, and any action on the sliders is
too coarse for a sensible adjustment.
I guess that most users don't have such extreme data and want the
sliders to work on the full data range, not on that of the last 'Set'
operation,
I a case like yours, for display I would try to get rid of the
outliers or at least to limit their values (Process>Math>Max, with,
e.g. 1000) - assuming that these are not meaningful values but just
bad pixels.
You could also use the Versatile Wand plugin with a tolerance of,
e.g., 100 (not including holes). Click on some 'normal' pixels and
then click 'auto' - it should give you a nice display (-1 to 31 in
your test image)
http://imagejdocu.tudor.lu/doku.php?
id=plugin:segmentation:versatile_wand:start
Michael
________________________________________________________________
On 7 May 2010, at 18:15, J. Lewis Muir wrote:
> In ImageJ 1.43u, when I set the display range of an image via the Set
> button in the B&C dialog, the sliders seem to stay on the old
> range, but
> I expected them to be switched to the newly specified range. Is this
> behavior intended?
>
> For example:
>
> 1. Open this image in ImageJ (after unzipping it):
>
>
http://www.imca.aps.anl.gov/~jlmuir/tmp/sls-pilatus-6m.tif.zip>
> 2. Click Image > Adjust > Brightness/Contrast...
>
> 3. Click the Set button
>
> 4. Enter a minimum of 0 and a maximum of 100; click OK
>
> 5. Drag the Brightness or Contrast slider
>
> As you can see, the step size is huge and the range is somehow
> reverted
> back to the old range. I expected the step size to be scaled for the
> new range of 0-100 and the range of the sliders to be for the 0-100
> range.
>
> Thanks,
>
> Lewis