image - measuRing: How does R determine the ring width without calibration?

Question

I have a question about the measuRing package. As I read in the description on cran.r-project.org, R determines the ring widths in mm. How does R know how many mm correspond to a certain distance on my image? I haven't read about a calibration or anything like that. Or does this information have to be hidden in metadata? I only have a scale bar on my image, but I don't think R recognizes it, or? Best regards

question from:https://stackoverflow.com/questions/66060044/measuring-how-does-r-determine-the-ring-width-without-calibration

Answer 1

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