Relief Processing Research Based On Poisson Equation

As a kind of art, reliefs exist widely in the world around us, which is used in various fields, for example, on coinage, branding products and sculptural decoration. Relief production is a time and labor consuming work which is needed to be finished by skilled carver. Reverse engineering provides technical support for new development of relief production. Relief processing faces three problems. Firstly, since the acquired relief model from real world is a set of points, we need to convert it to mesh which is more widely used in computer graphics. Secondly, since the base surface that relief lies on is unknown, designing a simple and effective relief extraction method is a challenging work. Thirdly, how to make new reliefs by editing tools. Relief editing is different from traditional single model editing, because the relief needs to attach the base surface when edited which serves a strong constraint to relief editing.Based on poisson equation, we have solved the above three problems. Morever, using GPU to accelerate the construction and solution of poisson equation, we have improved the efficiency of relief processing. Our work contains three parts. Firstly, parallel relief reconstruction algorithm based on poisson equation. The contribution is that it is much faster than the traditional surface reconstruction algorithms. It executes entirely on GPU and is almost 10 times faster than previous CPU algorithm which satisfies the demand of real time reconstruction for modern set of points. Secondly, we have proposed a relief extraction algorithm based on poisson equation. Notice former methods are lack of either automaticity or unification, we have thought out a novel solution based on poisson equation. It can extract reliefs which may lie on a smooth or textured input surface automatically. Thirdly, a range of parallel relief editing tools, also based on poisson equation is provided, permitting global transformations (translation, rotation, and scaling) of the whole relief, as well as local modifications to the relief.We have tested our relief processing pipeline on several models. The experiments have proved that it can reconstruct relief mesh from point clouds acquired by laser scanner, extract real relief parts and apply it to new surfaces. By editing the position and shape of relief, we can reduce the time of relief production and make more precise results than traditional manual methods.