建立一个透明物体上有污点的模型，可以模拟玻璃上有污点的图象-Rendering of clean transparent objects has been well studied in computer graphics. However, real-world transparent

objects are seldom clean—their surfaces have a variety of contaminants such as dust, dirt, and lipids. These

contaminants produce a number of complex volumetric scattering effects that must be taken into account when

creating photorealistic renderings. In this paper, we take a step toward modeling and rendering these effects. We

make the assumption that the contaminant is an optically thin layer and construct an analytic model following

results in radiative transport theory and computer graphics. Moreover, the spatial textures created by the different

types of contamination are also important in achieving visual realism. To this end, we measure the spatially

varying thicknesses and the scattering parameters of a number of glass panes with various types of dust, dirt, and

lipids. We also develop a simple interactive synthesis tool to create novel instances of the me