Stereoscopic Vision And Head Mounted Display Design For Augmented Reality

Augmented Reality (AR) is a new technology which is about overlaying the information including 2D and 3D on the real environment by computer technology. The essential purpose of AR is to make users feel themselve immersing in the computer generated environment which is made up by virtual digital information and real environment. AR can also enhance the user's cognitive abilities. It provides new ideas for many different applications, such as mechanical manufacturing and maintenance guide, entertainment and education, military field, medical surgery and training and so on.Binocular head-mounted display (HMD) has many advantages:the wonderful effect of mixing of virtual and actual reality, convenience for carrying and the possibility of being applied to multi-user interactive AR system. As a result, it is widely used in augmented reality systems. But nowadays the commercial binocular head-mounted display is expensive and the Prism Effect because of the mismatching between the distance of the binocular camera optical center and the wearer's pupil distance. Therefore, this thesis designed an adjustable binocular head-mounted display in contraposition of this problem.The specifics work as follows:(1) A stereo display based on stereo image pairs of virtual models using the position of virtual camera was discussed. According to the principle of stereo vision, we established a mathematical model in order to obtain the projection matrix P and model view matrix M of left-and-right eye. And then displaying the virtual model in corresponding position of the real scene, we repeated it for the virtual model in circles to get the stereo-virtual-model viewing.(2) Designing an adjustable binocular head-mounted display. The two cameras on HMD are connected on the stepper motor by the screw. The distance of two cameras can be modified though the stepper motor's positive and negative rotation to fix the user's pupil distance. At the same time, two cameras can be rotated 15°left and right to enhance users'visual range. (3) Designing the control system of stepper motor based on microcomputer. It includes MAX232 circuit design, crystal oscillator circuit design, watchdog reset circuit design, limit switch circuit design, switching power supply circuit design and stepper motor drive circuit design.(4) Microcomputer Unit (MCU) driver program and PC driver program design. MCU driver includes:main process, initialization process, interrupt process and control program. PC driver include:main control program and serial communication program.(5) Stereo magic book based on AR is designed for our adjusted HMD. With our HMD, user can get a view of some stereo model figures. In contrast, we can have a better stereo effect. With a large number of experiments, we know that the distance and angle between two cameras on the HMD are the key factor of stereo effect. We make a table on the data when each user get the best stereo-virtual-model viewing. This table is valuable for saving a lot of debugging time before using the HMD.