A new, patented, autostereoscopic display is described that enables a viewer to view 3D TV or computer graphics images without the need to wear special glasses or other head-wear. Unlike autostereoscopic systems based upon lenticular lenses this new display does not create reverse 3D effects and maintains 3D images despite movement of the viewers head and eyes. The 50' image size is achieved by using back projection and two projectors, one to produce the image for each eye. This increases the average image brightness and allows the system to operate in a normally lit room. In order to ensure that the viewer's left eye always sees the L image, and the right eye the R image, regardless of the exact position of the viewer's head and eyes, the system uses an eye-tracking technique. A video camera within the display images the viewer's head and image analysis hardware and software locates and tracks their eyes, automatically adjusting the position of the projected L and R images to keep them in the correct alignment for optimum 3D viewing. As a result the viewers head has the freedom to move from side to side or vertically, without losing the 3D effect.