Metrology is the scientific study of measurements. As technology becomes more advanced, the number of ways in which measurements can be made increases as well, and with much higher accuracy and precision than ever before.

Optics for Metrology & 3D Measurement

Making accurate measurements optically relies on imaging systems consisting of lenses with extremely low perspective or parallax error and illumination systems that light an object of interest and its environment appropriately. Telecentric lenses are a type of imaging lens that almost completely eliminate parallax error as well as image distortion. As such, telecentric lenses typically yield the most accurate dimensional measurements of all imaging lens types. Similarly, telecentric illumination is ideal for metrology applications as it results in extremely high-edge contrast images when used as backlight.

While extremely accurate for making measurements, telecentric lenses are typically larger and heavier machine vision lenses, which may be unsuitable for harsh environments subjected to shock and vibration. To maintain high-performance precision and reliability in these environments, non-telecentric fixed focal length imaging lenses are ruggedized to resist pixel shift from shock and vibration. While telecentric lenses eliminate perspective error, these lenses do not and are used for stereoscopic imaging. For 3D measurement applications including Time-of-Flight imaging, scheimpflug scanning, and LIDAR, laser patterns projected onto the sample object are imaged by a machine vision lens and manipulated into point cloud-like data structures which provide additional context about localized height or depth.