| Relief is a bump sculpture carved out of the plane. In recent years, with the development of the computer graphics and image processing technology, digital relief has been widely used as a new form of art and industrial production. The generation of digital relief has to balance a contradiction:thickness and appearance of the model (details and bump). Most of previous work focus on one aspect of model features while ensuring the thickness, which is not ideal for the retention of the whole appearance. This paper describes an improved method helping designers to generate bas-relief automatically from3D models. This method can compress a model into any thickness with a good retention of details and bump.This article is mainly based on some basic observation:as the relief is generally built on top of the flat background, it can be watched as a height field. So during the compressing process we can only deal with height of the scene in one direction rather than all directions. At the same time, we find that if given normal vector of the original model to each vertex in the parameterization, the rendered image has rugged details, which look like having3D visual effects.Relief designers input a3D model or scene and adjust the visual angle. Our approach is to use the domain features of gradient field to compress the gradient of the height field. In the entire process, we control the disturbance of vertex normal in accordance with the principle of bump mapping, which leads to rugged visual appearance under the conditions of not changing the texture and color information. In this way, the appearance features of the input model are well maintained. In addition, because of the "visual areas" based on low-level vision system, we add feature analysis into our method, taking precedence to keep the details and bump within the feature region.Finally, we show some groups of results. Compared with previous methods, bas-reliefs generated by our method are more vivid and distinct even in thin thickness. |
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