French companies Lynred and Saint-Gobain Sekurit have developed a windshield that incorporates visible and thermal cameras side-by-side for detecting pedestrians in varying visibility conditions.

The windshield, with an enhanced sensing-system, aims to help car makers improve the reliability of collision mitigation systems by detecting pedestrians in adverse visibility conditions, particularly at night, when more than 75% of pedestrian fatalities occur. It will also reduce incidences of false positive alarms – cars automatically braking when there is no danger, creating a risk of rear-end collisions.

Saint-Gobain Sekurit and Lynred demonstrated their visible and thermal sensing suite integrated into a windshield during AutoSens in Brussels this month. This sensing-system is the first to enable thermal imaging through standard windshield glass; detecting and classifying pedestrians at up to 140m in all weather and lighting conditions.

This co-development is in response to automotive vehicle safety standards requiring autonomous emergency braking (AEB) and pedestrian autonomous emergency braking (PAEB) systems to work reliably day and night, at speeds up to 100km/h for lead car crashes avoidance and up to 65km/h for pedestrians. Within four years of public approval of the regulation, the US National Highway Traffic Safety Administration’s (NHTSA) notice for proposed rulemaking will require light vehicles to be equipped with these systems.

Europe’s Road Safety Policy Framework 2021-2030, and its Vision Zero approach, is also requiring better vehicle construction to improve road and pedestrian safety.

Globally, approximately 1.3 million people die each year as a result of road traffic accidents. According to the American Automobile Association (AAA), in the USA alone it is estimated that AEB systems with pedestrian detection functionality could reduce annual vehicle-pedestrian accidents by up to 5000 a year.

“One of our main objectives is to provide tier-one suppliers with the critical building blocks to produce a thermal camera system under €100 that can connect to the AEB system,” said Sebastien Tinnes, global market leader at Lynred. “By halving the cost of thermal image sensors used by car makers today, they will have an affordable thermal sensor to enable them to comply to NHTSA rulemaking more readily across all car ranges.”

In a summary of test results, the AAA concluded that most pedestrian AEB systems have been ineffective at night. One challenge for car manufacturers is glass appears non-transparent (mirror-like) on the infra-red spectrum. Thermal imaging does not work through glass, which until now has precluded its integration into windshields, the optimal area for obstacle detection in AEB systems.

“Our long-standing expertise in safety systems for windshields and our best-in-class glass material shaping knowledge are essential to ensuring the best optical performance for reliable camera detection both night and day,” said Adil Jaafar, global innovation manager at Saint-Gobain Sekurit. “Alongside Lynred, we are pleased to contribute to the development of this innovation for the safety of all occupants, while improving the mobility experience.”

Saint-Gobain Sekurit developed a crystal-based technology to create a transparent area within the windshield, aligning both the visible and thermal cameras. The crystal is Federal Motor Carrier Safety Administration (FMCSA) compliant and is integrated while retaining the original performance of the wiper system and the thermal comfort of the passenger compartment.

Lynred provided a VGA (640×480 resolution) thermal sensor equipped with Umicore lenses and configured the camera data input with the pedestrian detection algorithm.

Conventionally, thermal sensors have been placed behind the grille, exposing them to mud, dirt shocks and other elements. Positioning visible and thermal sensing systems behind the windshield increases the reliability of AEB by improving visibility in all scenarios.

Advantages include distinguishing pedestrians from other animate or inanimate objects, thus reducing false positive alarms, and functioning in all weather and lighting conditions. The close proximity of both sensors results in easier visible and thermal image fusion thus providing enhanced detection performance. Better road vision results from higher placement of the sensing system. And sensors are protected from obstructive elements to optimise operating time.

Having demonstrated the technical and economic viability of this windshield for PAEB systems, each company plans to gear up their respective technologies for industrial-scale production with a view to commercialising the final product to be integrated into windshields in 2027.

Saint-Gobain Sekurit (www.saint-gobain-sekurit.com) designs and manufactures glazing systems for OEMs. Lynred (www.lynred.com) designs and makes infra-red technologies for aerospace, defence and commercial markets.