Noise Percentage and ROIs

Hello everyone,
I’m an italian engineering student and I’m using imageJ/Fiji for my university thesis.
I have two questions and I hope someone can help me:

  • While using the program, my professor asked me to show the percentage of the noise I removed from the images. Are there any commands/macros I can use to do so?
  • In some images I’m using ROIs and I was wondering if there are some commands/macros in order to tell the program not to apply filters in that area.
    In case of macros, can someone gave me an example? I’m not that good at coding.
    I’m sorry if my English is not that good, but I hope that I was able to explain myself.
    Thank you in advance
    Eugenia

Hello future Dr. Falvo,
As always keep a copy of the original image in safe keeping. Then when you are finished processing the image you are working with, you can use Process > Image Calculator macro to compare the original to the finished image. From that you can extract which ever information you require.
Good Luck,
Bob

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Thank you for your answer!

Hi Bob,
I’m trying to do what you suggested: while I’m using the Image Calculator macro, which operation (the possibilities are: add, substract, multiply, divide, and, or, xor, min, max, average, difference, copy, transparent-zero) should I use? After this, where can I extract the required informations?
Thank you in advance
Eugenia

Hello again,

When you use the Image Calculator, put the original image in first slot, then the finished image in the second slot and highlight ‘Difference’. The result will be a third image which is comprised of the differences between the images. The ‘lighter’ the parts of the result will be the more of a difference between the original and the finished image. Then go to Analyze > Historgram the result image, and press the data button for a sheet listing the pixel level and number of the “Difference” pixels. Then do as you wish with the results. Put into a report, spreadsheet, etc…. And you are done.

Have a Great New Year, and play with the Fiji software to get a feel for it. You would not believe all that you can do with it besides image.

Bob

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Thank you again!

Have a Great New Year,
Eugenia

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