Inadequate contrast ratio of road markings as an indicator for ADAS failure
Sprache des Titels:
Englisch
Original Buchtitel:
IRF World Congress 2024
Original Kurzfassung:
Road markings were reported as critical road safety features, equally needed for both
human drivers and for machine vision technologies utilised by advanced driver assistance
systems (ADAS) and in driving automation. Visibility of road markings is achieved because of
their colour contrasting with the roadway surface. During recent testing of an open-source
camera-based ADAS under several visibility conditions (day, night, rain, glare), significant
failures in trajectory planning were recorded and quantified. Consistently, better ADAS
reliability under poor visibility conditions was achieved with Type II road markings (i.e.
structured markings, facilitating moisture drainage) as compared to Type I road marking (i.e.
flat lines). To further understand these failures, analysis of contrast ratio of road markings,
which the tested ADAS was detecting for traffic lane recognition, was performed.
The highest contrast ratio (>0.5, calculated per Michelson equation) was measured at night
in the absence of confounding factors, with statistically significant difference of 0.1 in favour of
Type II road markings over Type I. Under daylight conditions, contrast ratio was reduced, with
slightly higher values measured with Type I. The presence of rain or wet roads caused the
deterioration of the contrast ratio, with Type II road markings exhibiting significantly higher
contrast ratio than Type I, even though the values were low (<0.1).
These findings matched the output of the ADAS related to traffic lane detection and
underlined the importance of road marking?s visibility. Inadequate lane recognition by ADAS
was associated with very low contrast ratio of road markings indeed. Importantly, specific
minimum contrast ratio value could not be found, which was due to the complexity of ADAS
algorithms that rely simultaneously on edge detection and recognition of other roadway
features. The results also indicate that while the issue of blinding by glare cannot be solved at
present with camera-based ADAS input, the visibility decrease due to rain could be
meaningfully alleviated by the use of Type II structured road markings. Hence, such road
markings should be installed to increase resiliency and dependability of road network, to
improve reliability of ADAS, and foremost to augment comfort and safety of human drivers.
Forschungs-