Augmented reality 3D display using head-mounted projectors and transparent retro-reflective screen

Abstract

A 3D augmented reality display is proposed that can provide glass-free stereo parallax using a highly transparent projection screen. The proposed display is based on a transparent retro-reflective screen and a pair of laser pico projectors placed close to the viewer's head. The retro-reflective screen directs incident light towards its source with little scattering so that each of the viewer's eyes only perceives the content projected by the associated projector. Each projector displays one of the two components (left or right channel) of stereo content. The retro-reflective nature of screen provides high brightness compared to the regular diffused screens. The partially patterned retro-reflective material on clear substrate introduces optical transparency and facilitates the viewer to see the real-world scene on the other side of screen. The working principle and design of the proposed see-through 3D display are presented. A tabletop prototype consisting of an in-house fabricated 60x40cm 2 see-through retro-reflective screen and a pair of 30 lumen pico-projectors with custom 3D printed housings is demonstrated. Geometric calibration between projectors and optimal viewing conditions (eye box size, eye-to-projector distance) are discussed. The display performance is evaluated by measuring the brightness and crosstalk for each eye. The screen provides high brightness (up to 300 cd/m 2 per eye) using 30 lumens mobile projectors while maintaining the 75% screen transparency. The crosstalk between left and right views is measured as <10% at the optimum distance of 125-175 cm, which is within acceptable range.

Next Generation Augmented Reality Displays

“…6c. The part with beads provide the retroreflective character and the clear region between the blobs provide the transparency [9,10]. Augmency Inc, which is a spin-off from our lab, has been developing products based on head-mounted projector and transparent AR screens.…”

Light-efficient augmented reality 3D display using highly transparent retro-reflective screen

“…Since a full retro-reflective surface (i.e. retro-fabric, retro-sticker sheet) can provide higher light efficiency [14,15], we optimize the amount of transparency and retro-reflectivity by partially depositing retroreflective glass microspheres on the clear substrate as square shaped tiny islands. The smaller size of individual islands smooths pattern features and makes it irresolvable by human eye at working distance from screen [13].…”

“…The amount of brightness perceived by each eye was measured using experimental values of retro-reflective coefficient [13,14]. When a projector illuminates diffused screens, the incident light is scattered in the full hemisphere.…”

Wearable Augmented Reality Displays

“…The display provides bright stereoscopic content on a transparent retro-reflective screen. The display uses a pair of laser sourced pico-projector positioned close to viewer's eyes, where each projector illuminates the screen with a single view of stereoscopic content [6]. Due to the retro-reflective nature of the screen, the respective projector light is reflected back and the eye positioned close to projector perceives very bright content displayed on screen.…”

“…The general problems with wearable augmented reality displays (particularly near-to-eye displays) are the restricted field of view, low light efficiency and involvement of bulky optical elements. In this paper, as an alternative to near-to-eye displays, we present the wide field of view, compact and light-efficient displays based on head worn pico-projectors andretro-reflective screensthat have been recently developed in our group for 2D/3D augmented reality applications [1][2][3][4][5][6][7]. First, we introduce a compact head-worn display assembled around a regular cap.…”