What is Structured Light?
Structured light is the projection of a light pattern (plane, grid, or more complex shape) at a known angle onto an object. This technique can be very useful for imaging and acquiring dimensional information. The most often used light pattern is generated by fanning out a light beam into a sheet-of-light. When a sheet-of-light intersects with an object, a bright line of light can be seen on the surface of the object. By viewing this line of light from an angle, the observed distortions in the line can be translated into height variations.
Acquiring 2-dimensional information
Scanning the object with the light constructs 3-D information about the shape of the object. This is the basic principle behind depth perception for machines, or 3D machine vision. In this case, structured lighting is sometimes described as active triangulation.
Since structured lighting can be used to determine the shape of an object in machine vision applications, it can also help recognize and locate an object in an environment. These features make structured lighting useful in assembly lines implementing process control or quality control. These methods use structured lighting for alignment and inspection purposes. Structured light systems can drastically transform a manufacturing plant by decreasing process variation, reducing production time, allowing automation of assembly lines, increasing precision, and generally decreasing overall cost. Although other types of light can be used for structured lighting, laser light is the best choice when precision and reliability are important.
Structured Light Applications
Coherent's Lasiris™ uniform intensity laser projectors are especially useful for structured light applications, including Machine Vision, Inspection, and Alignment.
Machine vision is a combination of structured lighting, a detector, and a computer to precisely gather and analyze data. For example, it is used on robots as 3-D guiding systems to place or insert a part on a car, such as a windshield wiper or a door.
Structured light lasers used in inspection minimize process variation by drawing attention to parts that do not conform to specifications. They can pick out vegetables with blemishes from food processor lines or can ensure that the right colored capsule goes in the correct bottle in drug packaging lines.
Another laser application is alignment. In computer assembly, a laser system can help an operator determine if a computer chip is perfectly positioned on a circuit board.
Lasiris™ lasers can be useful for contour mapping of parts, surface defect detection, depth measurements, guidelines, edge detection, and alignment. Coherent has standard laser configurations available off-the-shelf for a wide variety of applications, but lasers can also be custom manufactured for OEM clients, designed for specific applications.
Companies that are interested in integrating laser technology for machine vision and industrial inspection into the manufacturing process should involve our engineers at the design stage.