Re: IR images index scale not linear and disjunct help?!

Posted by terin on Nov 28, 2009; 5:39pm
URL: http://imagej.273.s1.nabble.com/IR-images-index-scale-not-linear-and-disjunct-help-tp3690302p3690305.html

Thank you for the reply, much appreciated.  I read about that so I did make a custom lookup table. Unless I did something wrong. This is what I did: I exported all the RGB values in order of the scale bar and then made a custom look up table in order of the scale bar.  It helped some, making the scale more linear but then right at the higher temperatures the scale bar is still disjunct even with the lookup table.  I will try to attach an image, maybe that would help.

Gabriel Landini wrote

On Saturday 28 November 2009, you wrote:
> to analyze the images using imagej.  Yet I am having trouble with the
> relationship between the index value and the temperature scale.  When I
>  make a profile plot of the scale bar the plot  is almost linear except at
>  very high temperatures when the index values drop to low values again
> (attached?).

Without seeing the image it is difficult to know what is going on, but I guess
that the intensity (a greyscale value generated by the profile plot) of a
colour (3 values) scale bar is not the right way to recreate the calibration.

You might have to create a new image where each rbg triplet value in the scale
bar corresponds to the index value of that triplet in the LUT.
Only then you could apply a calibration if you know what the indexes
correspond to.

G.