A Survey of Procedural Noise Functions Lagae, A.; Lefebvre, S.; Cook, R. ...
Computer graphics forum,
December 2010, Volume:
29, Issue:
8
Journal Article
Peer reviewed
Open access
Procedural noise functions are widely used in computer graphics, from off‐line rendering in movie production to interactive video games. The ability to add complex and intricate details at low memory ...and authoring cost is one of its main attractions. This survey is motivated by the inherent importance of noise in graphics, the widespread use of noise in industry and the fact that many recent research developments justify the need for an up‐to‐date survey. Our goal is to provide both a valuable entry point into the field of procedural noise functions, as well as a comprehensive view of the field to the informed reader. In this report, we cover procedural noise functions in all their aspects. We outline recent advances in research on this topic, discussing and comparing recent and well‐established methods. We first formally define procedural noise functions based on stochastic processes and then classify and review existing procedural noise functions. We discuss how procedural noise functions are used for modelling and how they are applied to surfaces. We then introduce analysis tools and apply them to evaluate and compare the major approaches to noise generation. We finally identify several directions for future work.
ETC2 is a widely-used texture compression format in Android devices and applications, so efficient ETC2 encoding can reduce application development time. We present QuickETC2-HQ, a set of improved ...ETC2 encoding techniques for real-time, high-quality texture compression. Our modifications to the luma-based approximations used in etcpak 1.0, the state-of-the-art encoder which integrated the QuickETC2 method, allow the execution of additional compression modes and more accurate error comparisons. As a result, the image quality of QuickETC2-HQ is improved compared to that of etcpak 1.0 and is comparable to that of the reference encoder, ETCPACK 2.74, with the fast mode. In terms of performance, QuickETC2-HQ is orders of magnitude faster than ETCPACK, making it practical for real-time application execution and offline production builds of applications.
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•A set of improved ETC2 encoding techniques for real-time, high-quality texture compression.•Solving several quality issues appeared in real-time ETC2 encoding (e.g., block artifacts, blurring, posterization, etc.).•Orders of magnitude faster than the reference ETCPACK encoder.
The tribological characteristics of sliding surfaces have been remarkably improved by surface texturing. Surface texturing can be beneficial in many ways; for example, it can reduce friction and ...wear, increase load carrying capacity, and increase fluid film stiffness. The design process for surface texturing is highly correlated to the particular functions of any application for which texturing is required. Texture quality is greatly affected by manufacturing methods, therefore, it is important to have a detailed understanding of the related parameters of any technique.
The use of surface texturing to improve the cutting performance of tools is a relatively new application. These textures improve cutting performance by enhancing lubricant availability at the contact point, reducing the tool-chip contact area, and trapping wear debris. Reductions in crater and flank wear, friction force, cutting forces, and cutting temperature are the main benefits obtained by this technique. To date, surface texturing has been successfully used in drilling, milling, and turning operations.
This article provides an overview of the techniques that have been used in industry and research platforms to manufacture micro-/nano-textures for tribological applications, and it examines the effects of surface textures on cutting tool performance.
Texture mapping as a fundamental task in 3D modeling has been well established for well-acquired aerial assets under consistent illumination, yet it remains a challenge when it is scaled to large ...datasets with images under varying views and illuminations. A well-performed texture mapping algorithm must be able to efficiently select views, fuse and map textures from these views to mesh models, at the same time, achieve consistent radiometry over the entire model. Existing approaches achieve efficiency either by limiting the number of images to one view per face, or simplifying global inferences to only achieve local color consistency. In this paper, we break this tie by proposing a novel and efficient texture mapping framework that allows the use of multiple views of texture per face, at the same time to achieve global color consistency. The proposed method leverages a loopy belief propagation algorithm to perform an efficient and global-level probabilistic inferences to rank candidate views per face, which enables face-level multi-view texture fusion and blending. The texture fusion algorithm, being non-parametric, brings another advantage over typical parametric post color correction methods, due to its improved robustness to non-linear illumination differences. The experiments on three different types of datasets (i.e. satellite dataset, unmanned-aerial vehicle dataset and close-range dataset) show that the proposed method has produced visually pleasant and texturally consistent results in all scenarios, with an added advantage of consuming less running time as compared to the state of the art methods, especially for large-scale dataset such as satellite-derived models.
This paper introduces a texture representation suitable for recognizing images of textured surfaces under a wide range of transformations, including viewpoint changes and nonrigid deformations. At ...the feature extraction stage, a sparse set of affine Harris and Laplacian regions is found in the image. Each of these regions can be thought of as a texture element having a characteristic elliptic shape and a distinctive appearance pattern. This pattern is captured in an affine-invariant fashion via a process of shape normalization followed by the computation of two novel descriptors, the spin image and the RIFT descriptor. When affine invariance is not required, the original elliptical shape serves as an additional discriminative feature for texture recognition. The proposed approach is evaluated in retrieval and classification tasks using the entire Brodatz database and a publicly available collection of 1,000 photographs of textured surfaces taken from different viewpoints.
Real-world underwater images suffer from quality degeneration caused by the scattering and absorption of light propagation. The damage of the detailed textures in underwater images shows the negative ...effect of detection and recognition. To recovery the image visibility and sharpness for the above applications, a new image enhancement method is proposed for extracting the image textures. To enhance the image textures with high quality, we propose a multiscale fusion enhancement. Two new fusion inputs are built on different color methods. One input is devoted to improve the sharpness by contrast-based dark channel prior dehazing in the red-green-blue (RGB) model. The other input is designed based on multiple morphological operation and color compensation from the opponent color in the CIE <inline-formula> <tex-math notation="LaTeX">1976~L^{\ast}a^{\ast}b^{\ast} </tex-math></inline-formula> color space (CIELAB) model. This input is used to enhance the counter brightness and adjust the color distribution. The dominant features of the two inputs are merged. Therefore, the contrast of the fusion output is enhanced adaptively to recover the final enhanced result. Compared with the state-of-the-art methods, our results reveal that the proposed method can enrich the image textures based on an impressive visual perception of contrast, saturation, and sharpness. Moreover, our method also shows strong robustness in challenge scenes and improves the performance of several underwater applications.
In drylands, the coexistence of grasses and woody plants has been attributed to soil-water resource partitioning. Soil texture and precipitation seasonality can influence the amount and distribution ...of water in the soil, and their interaction may play an important role in determining the relative importance of grasses and woody plants. We investigated the influence of this interaction on plant functional types across a broad range of precipitation regimes and soil textures in western North America by analyzing plant-cover data collected at 2,084 plots that included the widespread shrub big sagebrush (Artemisia tridentata Nutt.). We characterized how the significance of the inverse-texture effect varies across soil conditions by quantifying relationships between precipitation and foliar cover on finer- vs. coarser-textured soils across a range of potential texture divisions represented by sand content. We found evidence of the inverse-texture effect for every plant functional type (except for cheatgrass) that we examined with at least one component of precipitation (annual, warm, or cold season), and provide the first evidence for this effect in locations with cold-season-dominated precipitation regimes. The texture and precipitation combinations that exhibited the inverse-texture effect varied with plant functional type, presumably because of effects of soil texture on water availability at different soil depths with season. Furthermore, we found an inverse-texture effect that was remarkably similar for shrub cover with cold-season precipitation and grass cover with warm-season precipitation. These results provide new insight into how the inverse-texture effect interacts with precipitation seasonality to influence plant functional type composition in drylands, and further suggest that quantifying the soil-texture division at which the inverse-texture effect is relevant under a given set of environmental conditions may provide support for the effect across dryland plant communities.
Coherence enhancing shock filters combine shock filtering with the orientation estimation of the structure tensors thus enhancing the coherent flow-like structures. The basic operations defined here ...are dilation and erosion that take place in the zones of influence. However, in order to achieve the goal of texture enhancement, in the proposed method, the authors have extended this notion to define an opening and closing based shock filter. Subsequently, the open–close filtered image is employed to locate and highlight the bright and dark texture features over the entirety of the image. Combining these feature images with the original image in a specific way will produce an image with texture features enhanced. Furthermore, we have performed these operations at different scales to achieve better enhancement of the texture features. The method has been formulated, implemented and tested over a number of synthetic and natural texture images and the experimental results establish the efficacy of the proposed method in enhancing the prominent texture parts in the image proportionately more than the non-prominent texture parts.
Palmprint attracts increasing attention thanks to its several advantages. 1st-order textures have been widely used for palmprint recognition; unfortunately, high-order textures, although they are ...also discriminative, were ignored in the existing works. 2nd-order textures are first employed for palmprint recognition in this paper. 1st-order textures are convolved with the filters to extract 2nd-order textures that can refine the texture information and improve the contrast of the feature map. Then 2nd-order textures are used to generate 2nd-order Texture Co-occurrence Code (2TCC). The sufficient experiments demonstrate that 2TCC yields satisfactory accuracy performance on four public databases, including contact, contactless and multi-spectral acquisition types. Moreover, in order to further improve the discrimination and robustness of 2TCC, we propose Multiple-order Texture Co-occurrence Code (MTCC), in which 1st-order Texture Co-occurrence Code (1TCC) and 2TCC are fused at score level. 1TCC is good at describing minor wrinkles; while 2TCC does well in describing principal textures. Thus the combination of both can describe the palmprint features more comprehensively. MTCC achieves remarkable accuracy performance when compared with the state-of-the-art methods on all public databases.
A new contact stiffness model for the rough surface with different machining textures is established. The studied surface consists of regular surface machining texture in the global scale and ...stochastic micro-asperities in the local scale. The proposed model improves upon previous work that considers only the effect of stochastic asperities and completely ignores that of the machining textures generated by different machining methods. The analytical expression to calculate the contact stiffness of the studied textured surface is derived and numerical results are obtained via the finite element method. A high-precision test bench to measure the interface contact stiffness of the workpiece with different surface textures is designed. The measured results and simulated results are directly compared to demonstrate the validity of the proposed method. The effects of different texture types and surface roughness values on the contact stiffness of the proposed textured surface are analyzed. The proposed method provides a research basis for the accurate calculation of nonlinear contact stiffness and dynamic characteristics of the surface with complex texture topography.
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