Grayscale calibration


I had a question regarding grayscale calibration. I’ll try to explain my problem as clearly as possible.

AIM - To develop a macro for looking at defect distribution across multiple scan volumes using ImageJ.


  • I am looking at different scan volumes of different samples made from the same material. The scans have been done at different times (also sometimes before and after CT scanning machine repair), therefore there might be a difference in grayscale distribution across the scan volumes.

  • Do a defect distribution study on the different scan volumes.


  • I am worried that the auto-threshold technique I will be using (Huang) might not capture defects to the same degree in each of the different scan volumes, because of the variation in grayscale distribution across the different scan volumes.


  • Is there a way of removing this issue? Are any plugins available in ImageJ which allows for grayscale calibration across different scans?

I have added a couple of images which I would like to calibrated. For example, I would like image B to be calibrated to the grayscale distribution of image A.

A.tiff (3.8 MB)
B.tiff (3.7 MB)

Hoping others have had to deal with this issue.

Thank you in advance,


Could anyone provide any ideas about the methods they use? It would be really helpful.

Thank you.
Kind regards,