3.2 HUD Terminology

Figure 4 and Figure 5 illustrate the terminology used in this document.

Head-up Display (HUD)

A transparent display that presents data in the driver's normal line of sight by creating a virtual image.

Augmented Reality (AR)

Superimposes a computer-generated image on a user's view of the real world, thus providing a composite view.

Virtual Image (VI)

An image that appears to “float” at some focal distance in space.

Virtual Image Distance (VID)

The focal distance where the virtual image appears to reside. The apparent distance between the viewer’s eyes and the virtual image created by the HUD optics. Typically, the virtual image is created well beyond the windshield of the car.

Field of View (FOV)

The angle subtended at the driver’s eyes by the virtual image presented by the HUD.

Horizontal Field of View (HFOV)

The horizontal angle (along x-axis) subtended from the driver’s eyes to the virtual image.

Vertical Field of View (VFOV)

The vertical angle (along y-axis) subtended from the driver’s eyes to the virtual image.

Combiner

A partially reflective element of the optical chain that reflects light towards the viewer and allows outside light to pass through.

Eyebox

The area in which the HUD virtual image is viewable by the driver.