Re: zoom into float image data?

[amacphee(at)my-deja.com]

Excelent! I've had a quick look at your xstretch.pro and I think it will
do the trick.

Many thanks; this has been the fastest, most direct solution I have
received to a question in any newsgroup!
Andrew

In article <MPG.143bd9b381532cab989c3e@news.frii.com>,
  davidf@dfanning.com (David Fanning) wrote:
> Andrew (amacphee@my-deja.com) writes:
>
> > I've got arrays of float where the interesting data lies in a small
> > range. For example, the raw data ranges from -123.45 to 5678.9,
> > whilst the interesting stuff lies between 123.4 and 125.6. For each
set
> > the interesting data is not necesserily in the same range.
> >
> > I'm trying to write something that:
> > 1) displays the image bytescaled;
> > 2) uses xloadct to stretch the colour table to home in on the
> > interesting data;
> > 3) re-bytescales the data with new min and max values determined
from
> > the scaling of the colour table.
> > 4) Iterate 3 and 4 until I've zoomed in on the interesting data.
> >
> > I thought I could use the numbers on the stretch bars in xloadct as
> > feedback to re-bytescale my input data, but these numbers aren't
> > returned by xloadct. I then thought I could use tvlct to read the
rgb
> > values after stretching, then use e.g. min(where(r>0)) and
> > max(where(r<255)) to find how much I had stretched the table.
However, I
> > expect I would need to do the same for green and blue and I can't
see
> > then how this would correspond to the 'stretch' numbers in xloadct
if
> > the colour table wasn't linear in all three colours.
> >
> > Then I wondered if anyone else had gone around this loop and maybe
had
> > come up with a far slicker, tried and trusted solution :-)
>
> I think my XStretch program is made to order. :-)
>
>    http://www.dfanning.com/programs/xstretch.pro
>
> You will need XColors too, if you want to change color
> tables:
>
>    http://www.dfanning.com/programs/xcolors.pro
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting
> Phone: 970-221-0438 E-Mail: davidf@dfanning.com
> Coyote's Guide to IDL Programming: http://www.dfanning.com/
> Toll-Free IDL Book Orders: 1-888-461-0155
>


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