面向3DGIS渲染逼真度的方法研究

为了提高3DGIS中的仿真逼真度，引入目前最流行的延迟渲染技术，并结合基于物理的双向反射分布函数（BRDF）光照模型、屏幕环境光遮蔽（SSAO）和高动态范围光照（HDR）技术，提出了一种新的3DGIS渲染方法-BSHRF。该方法中，基于物理渲染的BRDF光照模型提高了3DGIS中的材质效果；SSAO技术利用较少的计算量，大大提高了场景真实度的光照细节；HDR技术将图像的逼真度再次提升一个层次。最后，为了验该方法的可行性与先进性，在3DGIS软件平台Gaea Explorer上，应用BSHRF方法对植被场景和三维建筑场景分别进行渲染，并从渲染效果与效率两个方面，与当前流行的3DGIS软件Google Earth和ArcScene进行对比。实验结果表明，BSHRF方法在不损失渲染效率的情况下，能够得到更好的渲染逼真度。

A Method of Rendering Fidelity on 3DGIS

The visualization of the traditional 3DGIS is relatively backward and difficult to meet the needs of some practical applications. To improve the simulation fidelity of 3DGIS, we apply the most popular deferred shading technology to the 3DGIS and combine with the physical BRDF illumination model, SSAO and HDR technology, to propose a new 3DGIS rendering method (named as BSHRF). The physical BRDF illumination model improves the material effect of 3DGIS. The SSAO technology improves the light details of scene reality using cheap computing; the HDR technology raises the image fidelity one level again. Finally, to validate the proposed method is feasible and advanced, the vegetation scene and 3D building scene are rendered respectively using the BSHRF method in a 3DGIS software platform Gaea explorer, and the BSHRF method is compared with the current popular 3DGIS software Google Earth and ArcScene from two aspects of the rendering quality and efficiency. The results show that the BSHRF method can get a better rendering fidelity under the condition of no loss of rendering efficiency.