Intensity Units

kwmcneel
kwmcneel
in Image-Pro General Discussions

Hi,

I'm reporting the results of non-mono line profile pixel intensity measurements. I'm having issues finding what the unit of measurement is. If there's a location to look this up or a canned definition, I would greatly appreciate getting a link or copy.

Thank you,

Kevin

Best Answers

  • NikitaRG
    NikitaRG
    edited July 2018 Answer ✓
    Hi Kevin,

    Please, take a look on Intensity Calibration check box in the Options group of the Line Profile tool. If disabled then the intensity calibration is not defined or enabled, but unchecked then intensity values are in gray scale. The intensity calibration tool could be found on Capture tab, Calibration group, Create button popup.

    Thanks,
    Nikita.
  • YuriG
    YuriG
    Answer ✓
    Kevin,

    If you use the same illumination conditions and stable light source, and you just need to compare results between different experiments, then you can do measurements without intensity calibration. In that case the values are just pixel gray intensities in 0-255 range: 0 - black and 255 - white (if you use 8-bit camera).
    In that case we are not talking about any units, as intensity is not calibrated.

    The above description is for "Mono" interpretation. You mentioned that you measure "non-mono" intensity. Is your intention to measure colors? Image-Pro 10 has ability to measure L*a*b* or XYZ colors on images and perform color calibration and color measurements using standard light sources (D50, D65,...) using color profiles. You can find it on the Measure tab, Color group. Let us know if that's what you want.

    Yuri

Answers

  • kwmcneel
    kwmcneel

    Hi Nikita,

    Our intensity calibration isn't set and we currently don't have a step tablet. We have standardized lighting and capture settings though. Can you describe how the intensity values are derived from the image?

    Thanks,

    Kevin

  • CraigW
    CraigW
    You need to come up with some way to relate the values that your camera captures to quantities that you are interested in.   Generally, you will need to provide a calibration source, capture an image of that, measure the pixel values at locations of known real-world quantities and then use the measured relationship to set up an Intensity Calibration (Capture tab, Calibration group, Create button popup).  Your camera or microscope manufacturer may have instructions and/or resources to assist in this effort.
  • kwmcneel
    kwmcneel
    Thank you! We are interpreting the green channel profile. I'll report it as gray scale intensity.

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