Structured light projection, also known as fringe projection or stripe projection, is a technique used in 3D metrology to capture and measure the surface geometry of an object. It involves projecting a pattern of stripes onto the object's surface. The resulting stripe patterns exhibit distortions due to the surface contours of the object. A sensor captures these distortions, and based on that, 3D data is generated.
The process of structured light projection begins with a projector that projects a pattern of narrow, parallel stripes onto the surface of the object to be measured. These stripe patterns are typically projected in a vertical or slanted direction to illuminate different areas of the surface. Depending on specific requirements, the projector position and the properties of the stripes (width, intensity, color) can be adjusted.
Once the stripes are projected onto the surface, the distortions are captured. A sensor, such as a camera, is used to capture the reflected or deformed stripe patterns. The sensor captures the projected pattern and registers the distortions caused by the surface contours of the object. The captured images are then transferred to the evaluation software.
In the evaluation software, the captured images are analyzed to extract 3D information. By processing the stripe patterns and calculating the distortions, the software reconstructs the surface geometry of the object. This process often involves mapping the 2D images to a 3D coordinate system and converting the distortions into actual 3D coordinates.
The resulting 3D data can provide various information about the object, such as surface profiles, shape deviations, distances, or volumes. This data can be used for part inspection, quality assurance, or dimensional verification.
Structured light projection offers several advantages in 3D metrology. It enables the rapid and non-contact capture of surface geometries of large and complex objects. The accuracy of the measurements depends on the resolution of the sensor used and the quality of the projector. Modern structured light projection systems can deliver highly accurate results and are suitable for a variety of applications, including reverse engineering, quality control, part measurement, and surface inspection.