1. A method of operating a display device having a see-through display screen, the method comprising: displaying on the see-through display screen an image of an object; and while displaying the image of the object, displaying an image of a shadow cast by the object onto the background scene by acquiring an image of a background scene, determining a location of the shadow in the image of the background scene, rendering an enhanced image of the background scene by increasing a relative brightness in a region adjacent to the shadow compared to a brightness within the shadow, and displaying the enhanced image of the background scene.