Vision-tangible mixed reality (VTMR) is a further development of the traditional mixed reality. It provides an experience of directly manipulating virtual objects at the perceptual level of vision. In this paper, we propose a mixed reality system called “VTouch”. VTouch is composed of an optical see-through head-mounted display (OST-HMD) and a depth camera, supporting a direct 6 degree-of-freedom transformation and a detailed manipulation of 6 sides of the Rubik’s cube. All operations can be performed based on the spatial physical detection between virtual and real objects. We have not only implemented a qualitative analysis of the effectiveness of the system by a functional test, but also performed quantitative experiments to test the effects of depth occlusion. In this way, we put forward basic design principles and give suggestions for future development of similar systems. This kind of mixed reality system is significant for promoting the development of the intelligent environment with state-of-the-art interaction techniques.
Single point active alignment method is a widely used calibration method for optical-see-through head-mounted displays (OST-HMDs) since its appearance. It always requires high-accuracy alignment for data acquisition, and the collected data affect the calibration accuracy to a large extent. However, there are often many kinds of alignment errors occurring in the calibration process. These errors may contain random errors of manual alignment and system errors of the fixed eye-HMD model. To tackle these problems, we first leverage a random sample consensus approach to recurrently decrease the random error of the collected data sequence and use a region-induced data enhancement method to reduce the system error. We design a typical framework to enhance the data acquisition for calibration, sequentially reducing the random error and the system error. Experimental results show that the proposed method can significantly make the calibration more robust due to the elimination of sampling points with large errors. At the same time, the calibration accuracy can be increased by the proposed dynamic eye-HMD model that takes the eye movement into consideration. The improvement about calibration should be significant to promote the applications based on OST-HMDs.
The combination of health and entertainment becomes possible due to the development of wearable augmented reality equipment and corresponding application software. In this paper, we implemented a fast calibration extended from SPAAM for an optical see-through head-mounted display (OSTHMD) which was made in our lab. During the calibration, the tracking and recognition techniques upon natural targets were used, and the spatial corresponding points had been set in dispersed and well-distributed positions. We evaluated the precision of this calibration, in which the view angle ranged from 0 degree to 70 degrees. Relying on the results above, we calculated the position of human eyes relative to the world coordinate system and rendered 3D objects in real time with arbitrary complexity on OSTHMD, which accurately matched the real world. Finally, we gave the degree of satisfaction about our device in the combination of entertainment and prevention of cervical vertebra diseases through user feedbacks.