The Study Of Consistent Illumination In Visual-Based Augmented Reality

Augmented reality is a new domain which is developed on visual reality. It is a technology that merges the virtual objects into the real world. Virtual reality emphasizes on the user's immersion in a completely virtual world, while augmented reality pays attention to the mixture of real and virtual objects. With the development of the relative technologies, augmented reality is used into movie, entertainment, architecture, medical treatment, education, and so on.The early study of augmented reality is mainly about registration. By recent years, with the development of registration, more and more research has been put on the visual acceptance of AR scenes. One of the methods to solve this problem is the consistent illumination between real and virtual objects. At present, most illumination methods get the illumination informations of the real scenes by using special equipments, for example, HDR cameras with fish-eye lens. The results of these methods may be excellent, but the cost will be considerable because the equipments are too expensive. So these methods are not suitable for applications in ordinary conditions.This paper first introduces the structure of augmented reality and registration technology. Then we expound the consistent illumination technology and put forward a new consistent illumination method - dynamic light map based illumination method. This method uses the images of an ordinary camera instead of special equipments to get the incident light distribution in different normals of the real scene. Then the light map is created by the illumination of different normals in the real world, and is updated according to every new frame. Given a light map, we can draw the AR scenes with consistent illumination, regardless the lighting condition of the real world is changing or not.This paper makes a further research on the vision-based augmented reality, and realises an augmented reality system on visual studio 2005. By experimenting on this system, we prove that our registration method and illumination method are real-time and effective.