Glossary · Machine vision
Structured light
Also known as: Fringe projection, Pattern projection
German: Strukturiertes Licht
In 3D vision, structured light is a measuring method that projects known patterns, such as stripes or dot grids, onto the object and computes surface shape from how the camera sees the patterns deformed by the surface.
- Machine vision
In one sentence
Structured light projects known stripe or dot patterns onto an object and computes its 3D shape from how the patterns deform.
Example
A structured light sensor above the bin captures a point cloud of randomly piled parts so the robot can choose which part to pick next.
How it applies
- Engineering: Structured light gives dense, accurate 3D data of a stationary scene within one or a few captures. Multi-pattern methods need the scene to be still during capture; shiny and dark surfaces are challenging. Blue or infrared projectors are sometimes used to reduce the effect of ambient light.
- Commissioning: Projector and camera are calibrated together; ambient light and vibration affect results.
- Documentation: The documentation team should document the measuring volume, accuracy, cycle time and conditions of validation, plus the projector light class or laser class if applicable.
Structured light vs. laser triangulation
Both use triangulation. Laser triangulation projects a single line and needs relative motion; structured light projects area patterns and captures a whole area without motion.