基于全景图像的阴影算法研究与实现

Research and Implementation of Shadow Algorithm Based on Panoramic Image

基于图像光照技术(IBL)是目前增强现实常见的光照渲染方式,利用IBL的已知条件之一——全景图设计出一种模型阴影生成算法,使其可与IBL技术无缝衔接。首先,使用HDR全景图模拟真实场景中的光照分布;其次,识别三维模型顶点对周围环境光照的可见性区域,同时使用黎曼积分将可见区域光照影响数据化,生成阴影贴图;最后,利用屏幕空间环境光遮蔽技术(SSAO),模拟物体褶皱处的间接光照。实验表明,所提出的阴影生成算法能够得到逼真的阴影效果,同时可以完美嵌入到IBL技术中。

Image-Based lighting (IBL) is a lighting rendering method for augmented reality, uses the panorama, one of the known conditions of IBL, to design a shadow generation algorithm, which can be seamlessly connected with IBL. Firstly, uses HDR panorama to simulate the illumina. tion in real scenes. Secondly, analyzes the visibility area of the model vertices to the surrounding environment illumination, and uses Rie. mann integral to digitize the visible area to generate shadow maps. Finally, uses Screen Space Ambient Light Masking (SSAO) to simulates shadow of object’s wrinkles. The experiment shows that the proposed shadow generation algorithm can obtain realistic shadow effects, and can be perfectly embedded into the IBL technology.