Research On Illumination Consistency Mixing Of Virtual And Actual Reality In Augmented Reality

Augmented reality, which enhances our understanding and experience to reality by the way of merging the synthetic object produced by computer graphics into the real scenes seamlessly, is the development of virtual reality. Achieving the mixture of synthetic object and real scenes is the goal of augmented reality, that is to say, synthetic object must consist to other real objects in terms of geometry and illumination when it is placed in real scenes. This thesis is focus on illumination consistency. The main research work of the paper is as follows:1. The research status and the development of augmented reality are introduced firstly, and the key technology of augmented reality is analyzed deeply. Then a more comprehensive study of illumination consistency algorithm is given and their strengths and weaknesses are compared. Some technology which related to real time illumination computing, such as lighting and material, illumination model and GPU, are introduced.2. Firstly, real world lighting conditions is analyzed, and more detailed comparison of existing research work in the respects of illumination acquisition and rendering results are given, and then it is concluded that using high dynamic range image to represent the complex lighting can get a more satisfactory results and meet high realistic demanding of augmented reality. Finally, the ways of acquisition real scene lighting are summary.3. Considering lacking in-depth study on the synthetic objects'reflective properties of the existing research, we adopt the Cook Torrance illumination model to accomplish the illumination computing in this thesis. The lighting coefficients of high dynamic range image is obtained in real time by using spherical harmonics,and the diffuse component of the illumination model is gotten in the Shader. And the specular component is simulated via the technology of environment maps, all computing task are accomplished in GPU.4. A modified Gaussian filter to simulate a realistic blooming effect is proposed in the paper, which is used for post processing effect of real time illumination computing. The refraction effect of synthetic object with transparent material is simulated and the scenes of mixing virtual and actual reality are rendered in real time, therefore, the global illumination effect is obtained and the rendering scenes are more realistic.