Algorithm Study And Implement On PRT And Inverse Rendering Technology

PRT technology is a fast algorithm used to render complex scene which under natural light condition. It can speed up rendering by reducing the integral to a dot product of vectors or vector and matrix. We present a new BSDF model to describe translucent material. Then use this model into PRT algorithms and get a fast algorithm for rendering translucent object under complex light condition using non-linear wavelet. The method firstly computes a vector which contains BSDF element on each vertex of the scene, approximates these vectors using wavelet transform, and keeps some wavelet coefficients. Then the method approximates the environment map in the same wavelet basis by keeping only the largest terms to get a non-linear approximation of the environment-map. The algorithm is performed by multiplying a sparse light vector by sparse transport vectors, which can achieve real-time rendering speed if the viewpoint is constant. If the viewpoint changes, the method can achieve interactive rendering speed.Inverse rendering is a technology which recovers reflectance, model and lighting from images. In this research area, firstly we implement an algorithm which can recover normals of specular objects using structured lights. Secondly,we present a method for recovery of normals and surface reflectance of object from images taken with the light source translation. We classify the points of the surface into diffuse points and mix points according to their radiance values in the input images and recover the normals and reflectance of these points respectively. Finally, we improve and implement an algorithm which can recover the shape and surface reflectance of objects. The height function and reflectance is recovered when the light positions are known by minimize the error between the values of input image and the values computed by the BRDF model.