We have developed an eye-position tracking stereoscopic projector which employs image shifting optics. The display allows 3D images to be viewed without special glasses from any position along a lateral axis. Its image shifting device contains a plane parallel glass plate and is installed in a liquid crystal projector. Refraction produced by inclination of the glass plate shifts the optical axis of the projected image. Since the only moving part in the optics is the lightweight glass plate, the response of the image shifting device is both fast and precise enough for interactive 3D-CAD and virtual reality applications. To improve the system's interactive response, we have widened the stereoscopic viewing area by adding a device which causes the image to vibrate laterally. Also we use a new tracking algorithm which reduces the tracking error that would ordinarily be created by delay time. Experimental results confirm the success of these improvements.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.