General logarithmic image processing convolution

The logarithmic image processing model (LIP) is a robust mathematical framework, which, among other benefits, behaves invariantly to illumination changes. This paper presents, for the first time, two general formulations of the 2-D convolution of separable kernels under the LIP paradigm. Although both formulations are mathematically equivalent, one of them has been designed avoiding the operations which are computationally expensive in current computers. Therefore, this fast LIP convolution method allows to obtain significant speedups and is more adequate for real-time processing. In order to support these statements, some experimental results are shown in Section V

The Computer Graphics Scene in the United States

We briefly survey the major thrusts of computer graphics activities, examining trends and topics rather than offering a comprehensive survey of all that is happening. The directions of professional activities, hardware, software, and algorithms are outlined. Within hardware we examine workstations, personal graphics systems, high performance systems, and low level VLSI chips; within software, standards and interactive system design; within algorithms, visible surface rendering and shading, three-dimensional modeling techniques, and animation. Note: This paper was presented at Eurographics\u2784 in Copenhagen, Denmark

Optical illusion shape texturing using repeated asymmetric patterns

Illusory motions refer to the phenomena in which static images composed of certain colors and patterns lead to the illusion of motions. This paper presents an approach for generating illusory motions on 3D surfaces which can be used for shape illustration as well as artistic visualization of line fields on surfaces. Our method extends previous work on generating illusory motions in the plane, which we adapt to 3D surfaces. In addition, we propose novel volume texture of repeated asymmetric patterns (RAPs) to visualize bidirectional flows, thus enabling the visualization of line fields in the plane and on the surface. We demonstrate the effectiveness of our method with applications in shape illustration as well as line field visualization on surfaces. For the design of optical illusion art, it is a tough case to arrange the distribution of RAP. However, we provide a semi-automatic algorithm to help users design flow direction. Finally, this technique applies to the design of street art and user could easily set the perspective effect and flow motion for illustration.This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: http://link.springer.com/journal/371. The publisher, Springer-Verlag, has issued an Erratum [correction] to this article as it appears in their publication due to a publishing error on their part. "In the original article Fig. 5 was published twice, once as Fig. 5 and once again as Fig. 3 by mistake." The figures are correct in the author's final Accepted Manuscript as archived here.Keywords: Repeated asymmetric patterns (RAP), Illusory motion, Line field, Optical illusion artKeywords: Repeated asymmetric patterns (RAP), Illusory motion, Line field, Optical illusion ar

5D Covariance Tracing for Efficient Defocus and Motion Blur

The rendering of effects such as motion blur and depth-of-field requires costly 5D integrals. We dramatically accelerate their computation through adaptive sampling and reconstruction based on the prediction of the anisotropy and bandwidth of the integrand. For this, we develop a new frequency analysis of the 5D temporal light-field, and show that first-order motion can be handled through simple changes of coordinates in 5D. We further introduce a compact representation of the spectrum using the co- variance matrix and Gaussian approximations. We derive update equations for the 5 × 5 covariance matrices for each atomic light transport event, such as transport, occlusion, BRDF, texture, lens, and motion. The focus on atomic operations makes our work general, and removes the need for special-case formulas. We present a new rendering algorithm that computes 5D covariance matrices on the image plane by tracing paths through the scene, focusing on the single-bounce case. This allows us to reduce sampling rates when appropriate and perform reconstruction of images with complex depth-of-field and motion blur effects

Futurist sculpting: modeling movement in 3D

Futurist Sculpting is a collection of techniques for representing dynamic motion in a static three-dimensional model. These techniques allow digital artists to use animation as a new modeling tool. The idea of Futurist Sculpting is inspired by the works of the Italian Futurist artists and it aims to achieve the same goal as the one described by Umberto Boccioni, âÂÂto find a form that would be like a remembered motion, the product of time but permanent in space.â However, Futurist Sculpting extends BoccioniâÂÂs idea to the new medium of 3D animation and modeling, introducing the techniques of Motion Snapshot, Surface Differentiation, and Motion Elasticity. Motion Snapshot has evolved from the idea that multiple key poses captured at different stages of motion can successfully portray the idea of movement. Surface Differentiation was developed to remove redundancy of overlaping geometry introduced by snapshots occuring with high spatial frequency. Exploded Snapshot creates a geometric blur effect and extends application of Motion Snapshots to motion of deforming objects. The Motion Elasticity technique stretches the object to represent a partial volume through which it is moving. As a proof of concept all of the Futurist Sculpting techniques were implemented in Maya. The techniques should be viewed as a set of tools for the artists. The user can choose any one of them to apply to any animation, but he needs to understand their applications and limitations too

Real-time impluse-based rigid body simulation and rendering

The purpose of this thesis is to develop and demonstrate a physically based rigid body simulation with a focus on simplifications to achieve real-time performance. This thesis aims to demonstrate that by improving the efficiency with simplified calculations of possible bottlenecks of a real-time rigid body simulation, the accuracy can be improved. A prototype simulation framework is implemented to evaluate the simplifications. Finally, various real-time rendering features are implemented to achieve a realistic look, and also to imitate the game-like environment where real-time rigid body simulations are mostly utilized. A series of demonstration experiments are used to show that our simulator does, in fact, achieve real-time performance, while maintaining satisfactory accuracy. A direct comparison of this prototype with a commercially available simulator verifies that the simplified approach improves the efficiency and does not damage the accuracy under our test conditions. Integration of rendering elements like advanced shading, shadowing, depth of field and motion blur into our real-time framework also enhanced the perception of simulation outcomes

Frequency Analysis and Sheared Reconstruction for Rendering Motion Blur

International audienceMotion blur is crucial for high-quality rendering but is also very expensive. Our first contribution is a frequency analysis of motion-blurred scenes, including moving objects, specular reflections, and shadows. We show that motion induces a shear in the frequency domain, and that the spectrum of moving scenes is usually contained in a wedge. This allows us to compute adaptive space-time sampling rates, to accelerate rendering. For uniform velocities and standard axis-aligned reconstruction, we show that the product of spatial and temporal bandlimits or sampling rates is constant, independent of velocity. Our second contribution is a novel sheared reconstruction filter that tightly packs the wedge of frequencies in the Fourier domain, and enables even lower sampling rates. We present a rendering algorithm that computes a sheared reconstruction filter per pixel, without any intermediate Fourier representation. This often permits synthesis of motion-blurred images with far fewer rendering samples than standard techniques require