Laser Profile Mapping

What is it?

LTC has developed three-dimensional optical surface inspection systems for a broad spectrum of NDT and QC applications for both military and commercial customers. Laser-based profiling sensors act as high resolution, “laser calipers” ― taking a succession of single-point distance measurements as the sensor is scanned over the target surface. The result is a three-dimensional data cloud that can be displayed using our LaserViewer™ software. Features such as denting, ovality, pitting and corrosion can be accurately mapped and analyzed using our laser-based profiling sensors.

Laser profile mapping is one of the technologies used in by LTC's Laser MicroMap™ system, supported by our LaserViewer™ software.

Some of the advantages of LTC's Laser MicroMap™ profilometry systems include:

Quantitative

High-resolution

Three-dimensional images

Non-contact sensors

May be integrated with other NDT methods, such as eddy current

Modular and flexible

LTC builds standard rotary sensors for the inner surface inspection of tubes as small as 0.275 inch (7 mm) inner diameter, as well as standard fixed sensors for the inspection of flat plates, pipes and complex surfaces, with better than 0.0005 in (0.0127 mm) spatial and depth resolution.  We also provide custom-designed sensors for special applications.

How does it work?

LTC's laser profile sensors use optical triangulation to determine the distance between the sensor and the target surface. Optical triangulation requires a light source, imaging optics, and a photodetector. The light source and focusing optics generate a collimated or focused beam of light that is projected onto a target surface. An imaging lens captures the scattered light and focuses it onto a photodetector. The photodetector may be either a lateral-effect detector for high-speed measurement, or a CCD for environments with high background light. LTC typically uses lateral-effect detectors, which generate signals proportional to the position of the spot in its image plane. As the target surface distance changes, the imaged spot shifts due to parallax. The optical system is designed to maintain high accuracy when measuring challenging textures, such as contoured specular surfaces. To generate a three-dimensional image of the part surface, the sensor is scanned in two dimensions, thus generating a set of distance data that represents the surface topography of the part.

LTC builds both rotary and fixed laser profile sensors. Our rotary laser profile sensors are primarily used for the inspection of components such as boiler and heat exchanger tubes. Standard designs include sensors that can operate in tubes as small as 0.275 inch (7 mm) inner diameter. Our fixed laser profile sensors are intended for use in larger components such as pipes, flat surfaces and complex structures. These sensors are normally attached to robotic arms or other scanning mechanisms, such as our 3D Profiler.

Applications

LTC's three-dimensional optical surface inspection sensors are useful tools in a wide range of applications. Some of the applications LTC has produced systems for are listed below:

Mapping erosion in gun bores

Detection and measurement of corrosion and pitting

Space Shuttle thruster chip detection

Hall thruster erosion measurement

Dent measurement

Ovality measurement

Underwater mapping

Combined laser profilometry and eddy current

Replica characterization

For more information

More information regarding laser profile mapping and optical triangulation (Adobe Reader required.)

Also see our Technologies page for other laser-based NDT and QC methods.