Image Calibration: Save, Attach and Reuse

Use a reliable reference

A calibration connects a length in image pixels to a known physical distance. Use a clearly defined scale bar or reference and confirm its stated unit before drawing the line.

Create and attach a calibration

1. Open the target image and zoom into the reference.
2. Draw the reference line, or inspect the line found by assisted detection.
3. Enter the known distance and unit, then verify the endpoints.
4. Save the calibration and attach it to the target image.

Saved does not always mean attached

A saved calibration is available for reuse. An attached calibration belongs to a particular image and can be used when that image continues into a supported measurement or scale-bar tool. Confirm the attachment on the target image rather than relying on the last calibration selected.

When to reuse a calibration

Reuse it only when the image scale is compatible, including acquisition scale and any resampling. Matching image dimensions or similar appearance are insufficient. If the pixel scale changed, recalibrate before reporting physical values.

If a measurement looks wrong

Check the unit, reference distance and endpoints first. Then confirm that the correct calibration is attached to this image. Compare a known feature before continuing a larger measurement task.

Continue your work

• Open the NotyCalibration tool page
• Add a scale bar
• Measure image features