Head-Mounted Display For Augmented Reality Application

In recent years, Augmented Reality technology developed on the basis of Virtual Reality technology has become a hot research topic in the field of computer graphics and images processing. The development of mobile computing technology gave birth to a new developing technology called mobile augmented reality, in another word, augmented reality based mobile terminals. Mobile terminals, especially the rapid development of smart phones, enable them with a lot of capabilities on graphics processing, and their unique portability drive many researchers focus on the development of augmented reality system based on intelligent terminals. In the meanwhile, due to the unique hardware architecture, in the course of using some issues begin to show up. For example, mobile screen cannot render immersion, which is necessary in augmented reality gaming applications. Another case, although many smart phones are equipped with sensing devices such as gyroscopes, accelerometers and cameras, during use the cell phone needs to hand-held which is inconvenient. What’s worse, new interactive technology like head-tracking required sensors to obtain head movements data, which is sensors integrated in cell phone cannot provide.To solve problems above, this paper designed a smart phone based Head-Mounted Display. This head-mounted display does not only have merits like: high resolution, portability, long battery life, etc. According to the requirements of augmented reality system, it can acquire head movement data and external image information, then convert the data by data fusion to quaternion and then sent to the host. The main consents of this paper are as follows:1) Functional analysis of Head-Mounted Display was taken, and on this basis, the whole system design was proposed, including hardware platform and software platform. Then, the core devices were selected through several kinds, and software function and structure were introduced in detail.2) On the basis of the overall design, the HMD hardware platform was completed. In this part, several core module circuits were introduced in detail, including acquisition module, camera module, Bluetooth module, OLED micro-control module, the HDMI to VGA module, power module and crystal module.3) On the basis of hardware design, drivers of HMD were designed, including the head movement data acquisition module, image acquisition module and the OLED display module. In addition, the paper was focusing on the head movement data processing program, using extended Kalman filter method, which was converted into the form of quaternions.4) Completed a smart phone based augmented reality programming, mainly introducing the visual tracking matching module, graphics rendering, virtual information presentation and interaction module software design.5) Testing and validation were fulfilled of the HMD oriented in AR applications, the testing contents mainly include playing effect tests, model superimposed function tests and interactive tests.Through all those tests, the results showed that the HMD designed in this paper met all the requirements. In addition, key technologies for AR oriented HMD are summarized in this paper and future outlook is also given.