Glossary · Machine vision
Working distance
Also known as: Object distance, WD
German: Arbeitsabstand
In machine vision and optics, working distance is the distance between the front of the lens (or the sensor housing) and the object surface being imaged or measured; together with focal length and sensor size it determines the field of view.
- Machine vision
In one sentence
Working distance is the space between the front of the lens and the object; with focal length and sensor size it sets the field of view.
Example
The working distance of 300 mm leaves enough room for the robot gripper to pass under the camera.
How it applies
- Engineering: Working distance is often fixed by the machine design: space for tools, part handling and protection of the lens. Lenses and lighting are chosen to fit it.
- Commissioning: Changing the working distance changes focus, field of view and, for low-angle lighting, the lighting effect. Mounting brackets should hold the distance fixed.
- Documentation: The documentation team should state the working distance with its reference points (lens front or housing, object surface) and tolerances, because data sheets differ in how they measure it.
Working distance vs. minimum distance
Working distance is an optical setup value. Minimum distance in machine safety is the distance between a protective device and the hazard zone. Both are called distance in German too (Arbeitsabstand, Mindestabstand) but have unrelated purposes.