1. Introduction

2,3,6,7,10,11,12,17, With the development of display technologies, electronic display devices have to meet people’s higher requirements. Augmented reality (AR) displays, which allow the overlaying of digital information onto a direct view of the real world so that the two-dimensional (2D) or three-dimensional (3D) images are seamlessly combined with the real-world scene, have been widely of interest to researchers and the industry [ 1 4 ]. There has been great desire for AR in many applications, such as medical visualization, surgical training, flight simulation, and entertainment [ 5 8 ]. Basically, there are two types of AR displays, which are optical see-through AR displays and video see-through AR displays [ 9 13 ]. Optical see-through AR displays, compared to video see-through AR displays [ 14 15 ], can provide a non-obstructed visualization of the real environment that guarantees that the visual and proprioception information will be synchronized and maintains see-through vision to the real world, and therefore has attracted much research interest. Additionally, integral imaging (II), a 3D imaging technique which provides auto-stereoscopic images without the help of special glasses [ 16 18 ], is very suitable for displaying 3D images in the optical see-through AR display system. Moreover, the structure of II is very compact, which makes it suitable for the AR system to display 3D images.

Some works have been proposed to achieve AR display with 3D images, a method of using free-form optics to magnify the 3D images reconstructed by a micro-II display unit and to overlap the 3D images with the real world, was reported by Hua [ 19 ]; another useful way to transfer 3D images into the viewer’s eyes through total internal reflection in an optical waveguide was also proposed, and achieved a good transmittance of the real-world lights [ 20 ]. Researchers have also proposed to realize an AR display by folding virtual 3D images into space with a semi-transparent mirror [ 21 ]. However, AR systems using these methods are more suitable for near-eye displays because of the size limitation, known as one of the common shortcomings, of the display screen or view box. To achieve a more compact structure for an AR system, the use of a lens array holographic optical element (HOE) has been proposed [ 22 23 ], but the size of the lens array HOE only reached several centimeters [ 24 25 ].

In this paper we propose, for the first time, a reflective AR system using a mirror-based pinhole array (MBPA). The real-world scene is reflected by the mirror area of the MBPA, and the 3D images are reconstructed by a pinhole array-based II unit. Due to its compact form factor, the proposed AR display system has the advantages of lower cost, no distortions, and more importantly, ease of manufacturing large-sized display screens.