Inspection of lidar sensors: Eye-safety and working range

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The development of lidar sensors improves rapidly. Various concepts (flash lidar, MEMS-based lidar, scanning lidar) become more capable, smaller and more precise. The steps forward in development as well as increasing total numbers raise the demands for inspection and quality management. DIOPTIC builds specific optical inspection systems for measuring lidar systems. Two typical tasks are measurements of eye-safety and working range.

Inspection system to evaluate the eye-safety of lidar sensors

Eye-safety

The requirements for eye-safety of laser systems are defined by the norm EN 60825-1 and limits given therein. Accordingly, the pulse energy of lidar systems in automotive applications must be limited to protect skin and eyes at all time. However, even small mechanical maladjustments might lead to an unintended focus of light and thus exceed the limits. In detail, the appraisal ‘eye-safe‘ depends not only on the laser power but also on the pulse time, beam properties, scan rate, accommodation of the eye and size of the eye’s pupil. The accommodation has the effect of a magnifier that varies the resulting intensity on the retina. Changing the size of the pupil equals changing the size of the aperture to allow more or less light to reach the retina. In order to ensure eye-safety at any time, the intensity on the retina may not exceed the limits in any case. This measurement technique allows a much more detailed view than the standard evaluation described in EN 60825-1. DIOPTIC develops customized systems that are capable of evaluating eye-safety of lidar sensors. Furthermore, DIOPTIC supports its customers in both development and production of automatic measurement systems for optical key parameters.

optical systems can be used to build compact range testing systems lidar sensors

Working range inspection

The working range of lidar sensors is an important parameter for many applications and depends on the reflective characteristics of the object, the pulse energy of the emitter and the sensitivity of the receiver. In detail, the maximum range of a lidar is influenced by noise in the electronic components, the quality of optical adjustment and also the field of view. Objects with a high reflectivity might be recognized comfortably in 200 m while a diffuse reflecting object is not visible further than 60 m. Safe recognition of distant objects is a big task for sensor development and the inspection of sensors. Using a target simulator, the range of lidar sensors can be tested and measured for objects with various reflection types. A tailored optical system allows to map inspection ranges up to several hundred meters into a compact table system. So even large sensor ranges can easily be checked under reproducible circumstances.

If you are interested, find more details about our division inspection systems and have a look at our project examples for inspection systems.

Contact us to realize compact inspections for the range of your lidar system.

To get advice, contact: PhD Niklas Andermahr | Phone: +49 6201 650 40-13