Laser Profilometry

Laser measurement systems include a CMOS camera and a laser light source. The operating principle is based on a laser beam projected on the surface of the target material under measurement. This beam or part of it is then reflected onto a detector, shifting its position in the receiver as its location varies in the object surface.

The information collected is then used to measure height, width, area, slope, and other complex surface features. Innerspec´s know-how in metal sector NDT applications has enabled the development of special lasers surface profile measurement systems and signal processing algorithms to minimize bright surface reflections in varying ambient lighting conditions. These laser profiling systems are ideal for a variety of applications where non-contact measurement is critical to ensure surface and geometry quality levels with very tight tolerances in industrial operating conditions. 3D Laser Profiling is based on Triangulation and makes use of embedded FPGA processing for high speed acquisition in industrial manufacturing processes.

Laser Triangulation

Laser Triangulation is a novel machine vision NDT technique able to convert data acquired in 2D images into 3D information through the projection of a laser profile on the material surface. The laser beam created by the illumination source is set at an angle with the high-speed camera sensor known as α. This angle is fixed and accurately optimized for each application based on accuracy and field of view requirements. α is then used to reconstruct the acquired image by digitizing the 2D profile and transforming it into 3D data with additional ´depth´ information.

Laser Profiling

Laser Profiling

Laser Illumination

Inspection of metallic shiny and reflecting surfaces can be challenging due to reflecting surfaces. Innerspec´s laser sensors are equipped with a special filter and signal processing algorithms so that they are insensitive to highly emitting objects such as glowing metals enabling high repeatability rates regardless of external lighting conditions.

Depending on laser radiation level and wavelength, laser profiling systems can be harmful for humans. Thus, industrial laser surface profile measurement systems must have low power levels or laser exposure to humans must be avoided through other means. Innerspec´s laser profiling systems have been designed to avoid harm to eyes during momentary exposure. Nonetheless, laser beams should not be looked at with bare eye deliberately. Laser protective eyewear is normally not necessary with our standard laser profiling systems and these do not represent a hazard for skin or materials burn.

Standoff Distance (D)

Laser measurement systems have an ideal operating position, known as the standoff distance (D). In this location, the reflected information is centred in the detector FOV (Field of view) and the laser is found at its exact focal point. Sensors standoff distance can be customized for each application depending on accuracy, geometry restrictions and vertical range required.

Laser Measurement: standoff distance

Standoff distance

FPGA Image processing

Making use of embedded FPGA for image processing, laser measurement systems can carry out the different tasks in the data acquisition chain at very high speeds of up to 4000 profiles per second allowing high speed materials inspection. The measurement process with our laser profiling cameras comprises the following steps and can be customized to comply with specific customer quality codes:

  • Accurate acquisition of surface profiles
  • Profile filtering and rebuilding
  • Feature extraction and reference points identification
  • Selection of target features and construction of surface feature profiles
  • Alarm type and levels selection

When and how should Laser Profiling be used?

  • To carry out laser surface profile measurements at high speeds.
  • To detect longitudinal type defects and lateral positioning between welded parts.
  • To secure in-plane positioning and mismatch levels in welded blanks.
  • When direct measurements of surface features are required.
  • When direct contact with the part is not feasible.
  • In combination with other NDT techniques to enhance inspection reliability.

Find out our Laser Measurement Systems: temate® Si-WB and Rollmate®.

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