Laser Lines are used in various machine vision applications. Examples include laser triangulation, laser light sectioning and many more.
Machine vision applications of Laser Lines
Laser triangulation or Laser light sectioning
Laser triangulation, also called laser light sectioning, is the most common application of a laser line. It is a 3D measuring technique for determining a profile at a predefined incident section. The imaging camera is mounted directly perpendicular to the scanned object. It measures the lateral displacement and distortion of the incident laser line projected at an angle onto the object. The recorded camera image contains all of the height information obtained from the section defined by the incident laser beam, which is then decoded to provide the 3D height profile as the object passes through the laser line camera detection system.
The depth of the measuring area and its resolution are determined by the triangulation angle between the planes of the dissecting laser line and the optical axis of the camera lens, with deeper angles of the dissecting incident laser line producing the greatest range in recordable height variations.
Laser Speckle is a common problem for this application. Laser speckle might be reduced by changing the measurement setup or choosing a special low noise laser line. More here.
Laser diffraction measurements
One of the most popular applications in laser measurement are laser diffraction measurements. This technique uses telecentric laser beams (that means beams with minimal divergence such as the Laser Diode Collimators Flatbeam®) and can e.g. be used to evaluate the diameter of an object by analyzing the Fresnel diffraction pattern of the shadow edge. [more]
Particle Measurement
Particle counting and measuring is another important application which uses laser lines or laser spots. In the most simple setup a detector registers the light reflected by a particle passing through the laser beam.
Most Laser Line Generators/ Focus Generators are also available as low-noise laser sources series LNC. More details about these lasers can be found here.
Please note: Lasers of series 13LR are not suitable for particle measurements, since the laser line consists of a chain of small dots.
Width and gap measurement
Other applications make use of the smallness of a laser diode emitter. With a typical emitter size of 1 µm x 3 µm, singlemode laser diodes combined with long focal optics result in large laser beams with very small divergence (typical 0.03 mrad). These laser sources are used for width and gap measurements, using simply the shadow, or in more sophisticated cases the diffraction pattern of the object placed into the beam.
Lasers for Machine Vision
Schäfter + Kirchhoff offers various Laser Line Generators, Laser Focus Generators and Laser Diode Collimators for Machine Vision. You can find the adequate laser module here.