A head-up display system includes a display unit including a projection unit configured to be positioned adjacent to a windshield, a display screen, and a controller. The projection unit is operable to project a current image generated by the controller onto a display screen. A position sensor is electrically coupled to the display unit and is operable to detect a position of an object with respect to the display unit. The controller is configured to dynamically update the current image based upon the position. A method of detecting an object is also disclosed.