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Head-up display uses lidar to warn drivers of impending dangers

A heads-up display for vehicles using lidar and augmented reality could improve road safety for drivers, researchers said.

Developed by a team from the University of Cambridge, the University of Oxford and University College London (UCL), the technology allows drivers to see through objects and alert them to potential hazards.

Lidar, a technology used in autonomous vehicles to build models of their environment, uses the time it takes to reflect pulses of laser light from surfaces and send them back to the sensor to measure distances. In this case, the data is used to create ultra HD holographic representations of objects on the road. The information is then sent directly to the driver’s eyes, instead of the 2D windshield projections used in most head-up displays.

While the technology has not yet been tested in a car, early tests – based on data collected from a busy central London street – showed the holographic images appearing in the driver’s field of view to match their actual position reality).

This can be particularly useful when objects such as road signs, for example, are hidden by large trees or trucks, allowing the driver to intuitively see through visual obstacles.

“Head-up displays are integrated into connected vehicles and usually project information such as speed or fuel levels directly onto the driver’s windshield, who must keep his eyes on the road,” said lead author of the Optics Express paper.

Jana Skirnewskaja, a PhD candidate in Cambridge’s Engineering Department. “However, we wanted to go a step further by displaying real objects as panoramic 3D projections.” The researchers scanned a busy street on the UCL campus in central London with a lidar array.

Millions of pulses were emitted from different positions along the street, and the lidar data was then combined with point cloud data, building a 3D model.

“This way we can merge the scans and build an entire scene, capturing not only trees, but cars, trucks, people, signs and everything else you’d see on a typical city street,” said co-author Dr Phil Wilkes.

“Although the data we captured came from a stationary platform, it resembles the sensors in the next generation of autonomous or semi-autonomous vehicles.”

When the 3D model of the street was ready, the researchers transformed objects on the street into holographic projections.

The lidar data, in the form of point clouds, was processed by separation algorithms to identify and extract target objects. Another algorithm was used to convert the target objects into computer-generated diffraction patterns, which were used to project 3D holographic objects into the driver’s field of view.

The optical setup is capable of projecting multiple layers of holograms using advanced algorithms. The holographic projection can appear in different sizes and is aligned with the position of the depicted real object on the street.

For example, a hidden street sign would appear as a holographic projection relative to the actual position behind the obstruction and act as a warning mechanism.

In the future, the researchers hope to fine-tune their system by personalizing the layout of the head-up displays and have developed an algorithm that can project different layers of different objects.

These layered holograms can be freely placed in the driver’s viewing area. In the first layer, for example, a traffic sign can be projected smaller at a greater distance. In the second layer, a warning sign can be displayed at a smaller distance in a larger format.

“This layering technique provides an augmented reality experience and provides a natural warning to the driver,” said Skirnewskaja. “Each individual can have different preferences for their display options.

For example, the driver’s vital health signals can be projected to a desired location of the head-up display. “Panoramic holographic projections can be a valuable addition to existing safety measures by showing road objects in real time. Holograms warn the driver, but do not distract.”

The researchers are now working on miniaturizing the optical components used in their holographic setup so that they fit inside a car. Once installation is complete, vehicle testing will be conducted on public roads in Cambridge.