Re: New User - ImageJ use with Sea Surface Temperature Images

Posted by Rodrigo Gonçalves-4 on Feb 11, 2010; 2:30pm
URL: http://imagej.273.s1.nabble.com/New-User-ImageJ-use-with-Sea-Surface-Temperature-Images-tp3689433p3689434.html

Dear Kelly, Gabriel and others,

I have a similar situation but with other fluid: the atmosphere; and images representing ozone concentrations, for example from this image:
http://www.nasa.gov/images/content/160657main_OZONE_large.jpg

which uses the same palette as this image:
http://saferenvironment.files.wordpress.com/2008/12/ozone_hole.jpg

But, as Gabriel has pointed out, since this is a palette maped image, I guess it would be necessary to "convert/recalibrate the false colour to grayscale". Otherwise when I make a Plot Profile I get a plot which looks like a ascending zigzag line (plot attached).

My question is, how can this conversion/recalibration be performed without loosing information?

Thanks a lot to everybody that shares their knowledge and time in this list.

Rodrigo

________________________
Dr. Rodrigo J. Goncalves
Estación de Fotobiología Playa Unión
www.efpu.org.ar
________________________

--- El lun, 2/8/10, Gabriel Landini <[hidden email]> escribió:

De: Gabriel Landini <[hidden email]>
Asunto: Re: New User - ImageJ use with Sea Surface Temperature Images
A: [hidden email]
Fecha: lunes, 8 de febrero de 2010, 09:59 pm

On Monday 08 February 2010 19:48:37 you wrote:
> On Mon, Feb 8, 2010 at 7:43 AM, D Kelly O'Day wrote:
> > I'm a new ImageJ user interested in analysis of sea surface temperature
> > (sst) images.
[...]
> > How do I go about "subtracting" one image's ssta from another?

> Assuming that they are the same size, just use Process/Image Calculator and
> select the Subtract option.

Hmm... no,  because one cannot apply arithmetic operations between false
colour gif images (which are palette mapped) and expect a sensible result.

You probably need to convert/recalibrate the false colour to greyscale based
on the scale provided and only then do operations between the new images.

Cheers,
G.
 



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