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Vision enhancement

Poor visibility is frequently cited as a contributing cause of crashes. We have combined lidar and radar sensors with head-up display technology and onboard geospatial databases, creating a system that allows drivers to operate safely in low-visibility conditions, or even in the complete white-out of a Minnesota blizzard.

The head-up display, currently deployed on snowplows and transit buses, displays relevant information superimposed on the driver’s field of view, including information about the vehicle’s location and any vehicles or other obstacles which affect vehicle operation. By referencing the vehicle and the driver’s eye position within an accurate digital map, it is possible to accurately recreate the field of view from the driver’s perspective.

As the vehicle moves along the highway, the vehicle’s position (from the DGPS system) is used to query the geospatial database. The resulting data is fed to the HUD’s graphics processor, which integrates it into a visual representation and computes the projection perspective needed for registration with the driver’s eyes. In other words, as the vehicle moves, the system transforms the objects from the real time accessible database on the vehicle and projects them into the field of view based on a coordinate system centered at the driver’s eyes.

The system allows the vehicle operator to see the ‘computed’ road boundaries projected and superimposed upon the ‘actual’ road boundaries, even if the road itself is obscured by snow, rain, or darkness. Icons representing radar-sensed obstacles are projected into the HUD image to provide the driver with correct cueing information (apparent position and apparent size) to determine distance and location of the obstacles in the field of view.

Video clips of Head-Up Display (HUD) development

Various stages in the development of the HUD system are illustrated in these video clips from early research projects.

September 1997

Local TV news segment on what we were doing with DGPS several years back, developing a system for truck drivers in the event of driver impairment (such as fatigue).

November 1999

Local Twin Cities news segment showing snowplows and an early prototype version of the HUD when we were first starting the Field Operational Test. Taped just before the official announcement date for the Field Operational Test (the vibrations of the HUD on the bouncing truck have since been removed).

October 2000

Test run showing how the projected lane boundaries line up with the true lane boundaries for a moving snowplow on a clear day with radar off.

October 2000

Test run showing how the projected lane boundaries line up with the true lane boundaries for a moving snowplow at night with radar on, showing how vehicles in front of the plow are accurately tracked.*

*Note: Only one radar was mounted at the time and so only vehicles in the front forward central 12 degree field of view are tracked. This video illustrates that the system correctly does not generate false positives from radar echoes returning from other road furniture adjacent to the roadway itself. This is accomplished by creating a 'filter' using the same accurate DGPS (a dual frequency unit) and accurate road geospatial database (i.e. a real time accessible digital map on board the vehicle) that is used to generate the projected lane boundaries on the HUD.

December 2001

Improved HUD display at night, tracking moving vehicles and lane boundaries. The snowplow is moving along a highway approaching an intersection. In the HUD, rectangles with a width equivalent to a truck (widest vehicle normally on the road) are drawn when triggered by radar on the plow. For a while, iconic representations of guard-rails appear on the right and a representation for Jersey barriers appears on the left. These are necessary so that plow operators know that they are there during poor visibility conditions.

At the intersection, the signals turn red and as a result the headway to the vehicle just ahead of the plow is reduced. The radar icon turns red when the vehicle is 50 feet or less from the plow. The traffic signals then turn green and traffic begins to flow normally again.

In the distance, the projected digital map is drawn as green from 350 ft. and out. This is a cue to the driver that this is the maximum range of the radar. Vehicles beyond 350 ft are not sensed by the system and therefore cannot be drawn there.