Calibrate to physical units

You need: the curator dataset role or higher. Calibration changes what every stored measurement means, which is why it is not bundled with annotation work — see Roles and permissions.

Until an image is calibrated, its measurements are in pixels. Read Calibration for the concept.

Steps

1. Switch to Calibrate mode and open the calibration drawer.
2. Start a scale measurement from that calibration's drawer button.
3. Draw the known distance across a reference in the image — a scale bar, a ruler, a calibration target.
4. Enter what that distance is in physical units.
5. Confirm. Object statistics should now report in your unit rather than in pixels.

Esc cancels a measurement in progress.

Measure-scale across a scale bar → enter the real distance → object stats flip from px to mm.

Per-dataset defaults

Calibrating every image by hand does not scale, and for a consistent acquisition setup it is redundant. Set a dataset default when every image was captured at the same working distance with the same optics; individual images can still override it.

Calibrate before you quantify at scale

Metrics computed before calibration are in pixels. Recalibrating afterwards is supported — measurements are also stored pixel-natively, so nothing has to be re-derived from the imagery — but it is far less confusing to establish the scale first.

Next: Quantify and export