From 2D HUDs to Augmented Reality

Traditional head-up displays have been around for years – showing speed or basic icons on the windshield. These are essentially 2D projections at a fixed spot. AR HUDs take it a step further: they project images that appear to be out in the real world at a meaningful distance (say 100-200 feet ahead) and often align with real objects[88]. For example, instead of an arrow floating in the corner of your windshield, an AR HUD might paint a big arrow right on the intersection where you need to turn, as if it’s on the pavement[89].

Technically, AR HUDs use a larger projection area and clever optics so that the graphics seem far out in front of the car, not up close on the glass. This is important because your eyes don’t have to refocus between the road and the HUD – the AR images are projected at a virtual distance (e.g. 200 yards), making them appear to float out in the environment[88]. Audi noted that by projecting at a far image plane, “the eyes do not need to refocus between the real environment and the HUD image”, which reduces strain and makes the info feel naturally integrated[90].

In effect, AR HUDs merge the digital and real worlds for the driver. They can highlight things like lane markings, show navigation cues that trace the actual roadway, and display alerts exactly where relevant (e.g., highlighting a pedestrian on the side if sensors detect one, or outlining the car ahead if adaptive cruise is engaged).