[ImageJ-devel] LUT ranges

[Curtis Rueden]

Hi Aivar,

To ensure we continue tracking the problems with LUT ranges that you
describe, I filed a ticket:
http://trac.imagej.net/ticket/2032

Regards,
Curtis


On Tue, May 14, 2013 at 1:56 PM, Aivar Grislis <grislis at wisc.edu> wrote:

> This e-mail discusses some issues regarding what I would call the LUT
> range, the min/max value that a LUT is mapped to.
>
> My motivation comes from SLIM Plugin:  In SLIM Plugin the min/max LUT
> range is used to colorized fitted pixels and also to control the range of
> generated histograms.  Suppose a user has fitted some data that has been
> gathered for multiple spectral channels.  It would be useful to be able to
> combine all of the channels when setting min/max, to see how the channels
> relate to each other, and also to be able to set an individual channel
> min/max independently, to zoom in on an individual channel.  I can discuss
> further upon request.
>
> IJ1 only supported one min/max range per image, so only a combined
> channels LUT range is possible.  IJ2 supports more than one, but it's
> limited:
>
> IJ2 currently supports individual RealLUTConverters and hence individual
> min/max ranges only for the special-cased CHANNEL Axis. Having individual
> RealLUTConverters is essential to the way RGB images are rendered (you need
> separate red, green, and blue converters).  However being able to specify
> separate ranges is actually not important in that case.
>
> (Currently there's a bug in DefaultDatasetView
> http://trac.imagej.net/ticket/1866 . For RGB images each channel
> converter is autoscaled independently, which only distorts the colors.  You
> want to set the same scale for all.  Here's a thought experiment:  Suppose
> you have an all-blue image with one gray pixel.  The only red in the entire
> image is in that gray pixel.  You don't want to autoscale that red
> component value so it becomes the maximal value possible.  See the attached
> image for 1866.)
>
> For more flexibility I'd suggest adding two new properties to the Axis
> class:  One would be whether it supports multiple LUTs.  The other would be
> whether LUT ranges should be combined.
>
> The default would be for both properties to be false.  We'd have to ensure
> they are both true in the RGB, CHANNEL Axis situation. Otherwise a
> programmer could tweak these settings before the dataset is displayed,
> especially when setting up a custom Axis type.
>
> Thanks!
> Aivar
>
>
>
>
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