Calibration
To measure a distance on a 2D image, the image must be calibrated first.
If you add a measurement to an uncalibrated 2D image, calibration will automatically start when you click Measure 
.
Click a first point and a second point of the reference measurement.
Enter the Reference value of the indicated measurement to calibrate the image. Click Apply.
The calibration measurement is shown on the image and the calibration object 
is added to the 2D measurement group on the Annotation tab of the smart panel.
Now it is possible to add measurements.
Note
If you calibrate an image that was created with an USB image sensor, you can immediately create measurements on all the images that were captured with this USB intraoral sensor or PSP device.
Editing a calibration
To edit the value of the calibration measurement, open the Annotation tab 
on the smart panel, click 
next to the calibration object and select Edit calibration value. Enter the new Reference value.
To edit the calibration, drag the control points to adjust the position of the calibration object in the viewer. All measurement values are updated accordingly.
To move the label of the calibration measurement, drag it.