Display of shadows via see-through display

An optical see-through head-mounted display system, comprising:

• a see-through display screen;
• an image production system configured to display an image on the see-through display screen;
• an image sensor configured to acquire an image of a real-world background scene viewable through the see-through display screen;
• a logic subsystem;
• and
• a data-holding subsystem comprising instructions executable by the logic subsystem to
• display an image of an object on the see-through display screen;
• and
• while displaying the image of the object, display an image of a shadow cast by the object onto the real-world background scene by
• acquiring via the image sensor the image of the real-world background scene viewable through the see-through display screen,
• determining a location of the shadow in the image of the real-world background scene,
• rendering the image of the real-world background scene to form an enhanced image of the real-world background scene in which a brightness of the real-world background scene in the enhanced image of the real-world background scene in a region adjacent to the shadow is increased compared to a brightness within the shadow, and
• displaying the enhanced image of the real-world background scene on the see-through display screen over and aligned with the real-world background scene.

On an optical see-through head-mounted display system comprising a see-through display screen, a camera, and a neutral density filter, a method of displaying an image of an object and an image of a shadow of the object over a real-world background scene viewable through the see-through display screen, the method comprising:

• displaying on the see-through display screen the image of the object;
• reducing an amount of ambient light passing through the see-through display screen via the neutral density filter;
• and
• while displaying the image of the object, displaying an image of a shadow of the object onto the real-world background scene by
• acquiring via the camera an image of the real-world background scene viewable through the see-through display screen,
• determining a location of the shadow in the image of the real-world background scene,
• rendering the acquired image of the real-world background scene to form an enhanced image of the real-world background scene by
• increasing a brightness of the real-world background scene in the enhanced image of the real-world background scene in non-shadow regions of the image and not increasing a brightness within the shadow, and
• displaying the enhanced image of the real-world background scene on the see-through display screen over and aligned with the real-world background scene such that light is added to the non-shadow regions.