Mobile Augmented Reality Based on Invisible Marker

This paper proposes an approach for implementing marker -based augmented reality (AR) on smartphone. Specifically, to resolve the obtrusiveness of visual markers, use of infrared (IR) markers that are not visible to the human eye is studied. The main idea is to use an additional external camera with IR functionality to track IR markers that are not detectable in smartphone camera. Additionally is to put a visual fiducial object at the place where the fields of view of the external camera and the smartphone camera are overlapping, which enables the external camera to track the geometric transform between the fiducial object and the IR markers. As a result, since the fiducial object is trackable with the smartphone camera, the smartphone camera pose relative to the IR markers can be computed by using the transform. To validate the feasibility of the proposed approach, a proof-of-concept system is implemented where a visual marker is used as fiducial object for the convenience of implementation. The system accuracy mainly depends on the transform accuracy. Thus, to improve the transform accuracy, two constraints are defined and evaluated: one is that both markers lie on the same plane and the other is that the 3D marker data is available. Through experiments, with the constraints, it is verified that virtual contents can be stably augmented on IR markers in smartphone camera images.