Study finds microscale concave interfaces could be useful to autonomous vehicles

A new study has looked into the science behind microscale concave interfaces (MCI). This type of structure reflects light and can produce rainbows which are potentially useful optical phenomena. The goal of this study was to learn how the technology works. The paper outlines how light interacts with an MCI, hoping to open the door for potential uses down the road.

One potential use for MCI is to improve the ability of autonomous vehicles to recognize traffic signs. Recognizing traffic signs is vitally important as an autonomous vehicle has to recognize when to merge, stop, and determine the speed limit on any particular piece of road. Researchers from multiple institutions were involved in the study and focus on a retro-reflective material made up of polymer microspheres attached to the sticky side of clear tape.

The microspheres were partially embedded in the tape, and the part that stuck out from the tape formed the MCI. Researchers shined white light on the film, which forms concentric rainbow rings when reflected by the MCI. Researchers also shined single-color laser light in red, green, blue at the MCI to create a pattern of dark and bright rings.

Experiments also found shining an IR laser at the MCI also produced signals made up of concentric rings. Patterns formed by the different types of light hitting the MCI were visible on LIDAR, which detects infrared light, and on cameras designed to detect visible light. The study results could mean significant improvements for autonomous vehicle systems, including current autopilot systems, which have challenges when it comes to recognizing traffic signs in real-world conditions.

The researchers believe that smart traffic signs made from the material used in their study could provide their own signal for autonomous vehicles fitted with LIDAR and other camera systems making the signs easier to recognize and identify. The team says the MCI is an ideal target for LIDAR cameras because it produces a consistent signal. Currently, project researchers are attempting to license the technology.