Calibration defines the relationship between the image and real-world dimensions.
Basic principle
Mark two points of a known dimension and enter its real value. For ordinary sources, the X and Y directions can be calibrated separately.
Choosing a reference
Whenever possible, use:
- the longest known dimension available,
- clearly identifiable endpoints,
- a dimension lying in the same plane as the geometry being measured.
A short reference is more sensitive to inaccurate point placement. An error of only a few pixels can become significant when measuring a large object.
Multiple references
Multiple independent references make it possible to verify calibration consistency and identify suspicious deviations.