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- Activate Ruler Tool by Tools > Measurement > Ruler
Draw a line to calibrate on the scale which is a part of the image.
Note For more accurate results, it is recommended to use a calibration line as long as possible.
- Right-click on the calibration line and select Calibrate
- Enter the length of the calibration line in a physical unit in the dialog shown and select OK
The calibration line is shown in a physical unit now, and all next measurement that will be drawn will be shown in a physical unit.
Note The measurement calibration Measurements can only be done calibrated for images individually, so you should calibrate multiple uncalibrated images separately if you have more than one uncalibrated imagea calibration done for an uncalibrated image does not apply to other uncalibrated images.