Re: Biased/stretched LUTs in ImageJ

Posted by Michael Doube on Nov 21, 2008; 6:22pm
URL: http://imagej.273.s1.nabble.com/doesn-t-recognize-ratio-command-tp3694424p3694430.html

John

You may find window and level (W&L) useful.  If you apply a LUT to a
32-bit image, the LUT is 'stretched' to the current W&L.  So, if you
have a gradient of 32-bit values somewhere in your image, the LUT is
applied to it - and the image pixels - 'automatically'.  You can make a
gradient by going File->New->Image... and selecting 32-bit and ramp.

Mike

John Oreopoulos wrote:

> Hi,
>
> I have a calculated image formed by the ratiometic combination of two
> other images. I want to preserve the resulting pixel intensities in the
> calculated image
> which is 32-bit. I have several calculated images like these and their
> pixel intensities vary widely. I'd like to display these images with a
> colored look up table
> but be able to stretch LUT to bias the contrast to certain values for
> each image in a similar manner to what was done in Figure 3 and Figure 5
> of the
> following paper:
>
> Parasassi, T., E. Gratton, W.M. Yu, P. Wilson, and M. Levi, 1997.
> Two-photon fluorescence microscopy of Laurdan generalized polarization
> domains in model and natural membranes. Biophysical Journal 72: 2413-2429.
>
> When I take my calculated images and add a colored calibration bar for
> the LUT, I can adjust the brightness and contrast to get the desired
> effect, but the
> pixel intensities no longer match the original calculated image. Is
> there a way to do this properly in ImageJ without altering my pixel
> intensities?
>
> John Oreopoulos