How to set an LUT-Scale for intensity measurement of RGB-Images

NIR Perfusion-2.tif (90.8 KB)
I have a problem with intensity measurements in RGB Images. I get heat map / LUT images with the corresponding scale bar from my medical measurement device (part of it in the attached image, since it is patient data I needed to cut it so don’t wonder why it looks so nonsense).
I now need to measure the intensity in a self defined ROI in this image. Perfect would be if I could set the given LUT scale in image J and use this for measurement of the ROI.

I already tested the following

  • it can not be converted from LUT to greyscale intensity since its an RGB and LUT is not created in Image J
  • Calibration Bar does not work in my Fiji (newest version) on the RGB image, transfer to 8-bit color results in loss of information and gives crap with the Calibration Bar
  • split into 3 channels works and intensity is measured in gray scale (256 steps per channel) but splitted it makes no sense anymore. I added the values, but if only on channel is high I can not distinguish just by values if my measurement is blue / red or whatever.

Has anybody an idea? Or know which tool to use?

Hello Anja -

The best thing would be if you could get your medical measurement
device to give “intensity” images without any applied heat map. Then
you wouldn’t have to jump through these hoops.

But, if you’re stuck with these kinds of images, please take a look
at Nico’s macro in this post of the “Quantify from RGB color coding”

Thanks, mm

1 Like

Thanks! You made my day!