Abstract: Procedural textures usually require spending time testing parameters to realize the diversity of appearances. This paper introduces the idea of a procedural texture preview: A single static image summarizing in a limited pixel space the appearances produced by a given procedure. Unlike grids of thumbnails our previews present a continuous image of appearances, analog to a map. The main challenge is to ensure that most appearances are visible, are allocated a similar pixel area, and are ordered in a smooth manner throughout the preview. To reach this goal, we introduce a new layout algorithm accounting simultaneously for these criteria. After computing a layout of appearances, we rely on by-example texture synthesis to produce the final preview. We demonstrate our approach on a database of production-level procedural textures. © 2012 Wiley Periodicals, Inc.

Abstract: Simultaneous visualization of multiple continuous data attributes in a single visualization is a task that is important for many application areas. Unsurprisingly, many methods have been proposed to solve this task. However, the behavior of such methods during the exploration stage, when the user tries to understand the data with panning and zooming, has not been given much attention. In this paper, we propose a method that uses procedural texture synthesis to create zoom-independent visualizations of three scalar data attributes. The method is based on random-phase Gabor noise, whose frequency is adapted for the visualization of the first data attribute. We ensure that the resulting texture frequency lies in the range that is perceived well by the human visual system at any zoom level. To enhance the perception of this attribute, we also apply a specially constructed transfer function that is based on statistical properties of the noise. Additionally, the transfer function is constructed in a way that it does not introduce any aliasing to the texture. We map the second attribute to the texture orientation. The third attribute is color coded and combined with the texture by modifying the value component of the HSV color model. The necessary contrast needed for texture and color perception was determined in a user study. In addition, we conducted a second user study that shows significant advantages of our method over current methods with similar goals. We believe that our method is an important step towards creating methods that not only succeed in visualizing multiple data attributes, but also adapt to the behavior of the user during the data exploration stage. © 2012 Wiley Periodicals, Inc.

Abstract: Procedural shading has been a versatile and popular tool for off-line rendering for decades. With the ever increasing speed and computational capabilities of modern GPUs, it is now becoming possibl ...

Abstract: Realistic rendering of the organ surface appearance is necessary for high quality surgery simulator. It can greatly enhance visual realism and hence the overall quality of the VR simulators can be improved. This paper studied the realistic rendering methods of the organ surface, including organ texture synthesis, texture mapping and lighting computation for modeling mucous-covering of organ surfaces. Two different organ texture synthesis methods were presented: procedural texture generation based on Perlin noise, and applying an example synthesis based on an Ashikhmin algorithm. All kinds of organ textures were synthesized effectively. With regard to the visibility of seams and reducing the distortion, the created textures can be mapped to 3D mesh geometry by mesh parameterization. Blending between the different textures of patches reduced discontinuities. A kind of lighting computation method was described for modeling translucent mucous covering, in which incoming light is decomposed into its two components of surface reflection and sub-surface scattering that are then deal with respectively. Experimental results show that the proposed method is both feasible and effective.

Abstract: In this paper, we demonstrate the use of tiling with noise to generate rich procedural textures. We introduce the idea of storing tiles which consist of only the gradients stored at the integer lattice points and constructing a texture on the GPU from these tiles. We also introduce the idea of using mipmapped tiles to store gradients for turbulence. Finally we demonstrate a novel use of mipmaps to generate infinite aperiodic textures with varying frequency patterns.

Abstract: A procedural pattern generation process, called multi-scale “assemblage” is introduced. An assemblage is defined as a multi-scale composition of “multi-variate” statistical figures, that can be kernel functions for defining noise-like texture basis functions, or that can be patterns for defining structured procedural textures. This paper presents two main contributions: 1) a new procedural random point distribution function, that, unlike point jittering, allow us to take into account some spatial dependencies among figures and 2) a “multi-variate” approach that, instead of defining finite sets of constant figures, allows us to generate nearly infinite variations of figures on-the-fly. For both, we use a “statistical shape model”, which is a representation of shape variations. Thanks to a direct GPU implementation, assemblage textures can be used to generate new classes of procedural textures for real-time rendering by preserving all characteristics of usual procedural textures, namely: infinity, definition independency (provided the figures are also definition independent) and extreme compactness. © 2012 Wiley Periodicals, Inc.