孙博文 孙健 唐贝贝

摘 要：增强现实中的光照一致性是使虚拟物体获得真实感的重要手段，它能使计算机生成的虚拟物体很好的融合到真实场景当中。为了更好的实现增强现实系统中的光照一致性，对现有的光源检测算法进行改进，提出一种基于单标记的实时场景光源检测算法。该方法通过采集识别标记在各个方位的亮度信息确定出光源的方向;通过识别标记和虚拟物体之间的亮度对比确定光源的亮度;通过获取标记物上未喷墨部分的颜色，确定光源的颜色。实验证明，在满足增强现实应用的实时性和稳定性的同时，使用本文的光源检测算法所估计出的虚拟光源与真实光源方向之间的角度差值平均在4.3度，并可以使虚拟物体正确的产生阴影。

关键词：光源检测;光照一致性;虚实融合;增强现实

DOI：10.15938/j.jhust.2018.06.024

中图分类号： TP316.2

文献标志码： A

文章编号： 1007-2683（2018）06-0133-05

Abstract：The illumination coherence in augmented reality is an important means that makes virtual objects get realistic. It can make the computer-generated virtual objects blend into the real scene. In order to archieve the illumination coherence of augmented reality this paper modifies the present algorithm and proposes a algorithm based on single tag. This new method collects the brightness of the identification marking in any direction to make sure which direction the light source might be; it compares the brightness of the identification marking with the brightness of the virtual objects to ensure the brightness of the light source; it determines the color of the light source by getting the color of the marker portion of no inkjet. Experiments show that in meet the real-time and stability at the same time，the average angle between the virtual light source which is estimated by using the algorithm in this paper and the true source is 4.3 degrees，and the virtual objects can correctly cast shadows.

Keywords：lighting detection; illumination coherence; combination of virtual and real objects; argument reality

0 引 言

增强现实[1]augmented reality，AR）是虚拟现实技术的拓展，通过把计算机生成的虚拟对象与真实环境融为一体的方式来增强用户对真实环境的理解和体验[2]。目前，增强现实在医疗卫生、军事仿真、工业维修、教育娱乐等方向均具有广泛的应用前景。高度真实感的AR效果主要体现在几何一致性、光照一致性和时间一致性等三个方面[3]，其中几何一致性是指真实场景和虚拟物体有正确的位置、透视和遮挡关系;光照一致性是指虚拟物体与真实场景之间有正确的阴影、明暗等光照匹配关系;时间一致性是指真实物体与虚拟物体的运动相互协调。……