A traitor tracing scheme is a multi-receiver encryption scheme where malicious receiver coalitions aiming at building pirate decryption devices are deterred by the existence of a tracing algorithm: Using the pirate decryption device, the tracing algorithm can recover at least one member of the malicious coalition. All existing traitor tracing schemes rely either on rather inefficient generic co...

Black-on-white images can be represented either as a bitmap or as a vector outline. A bitmap represents an image as a grid of black or white pixels. A vector outline describes an image via an algebraic description of its contours, typically in the form of Bezier curves. The advantage of representing an image as a vector outline is that it can be scaled to any size without loss of quality. Outli...

Ray tracing has become established as one of the most important and popular rendering techniques for synthesizing photo-realistic images. However, the high quality images require long computation times and memory-consuming scene description. Parallel architectures with distributed memories are increasingly being used for rendering and provide more memory and CPU power. This paper describes a ne...

Packet tracing is a popular and efficient method for accelerating ray tracing. However, packet traversal techniques become inefficient when they are applied to path tracing since the secondary rays are incoherent. In this paper, we present a simple technique for improving the coherency of secondary rays. This technique uses the same sequence of random numbers for generating secondary rays for a...

An algorithm is presented for rapid traversal of octree data structures, in order to enhance the speed of ray tracing for scenes of high complexity. At each level of the octree, the algorithm generates the addresses of child voxels in the order they are penetrated by the ray. This requires only a few arithmetic operations and simple logical operations. A depth-first search of the tree is used t...

This paper examines existing bidirectional ray tracing algorithms and the bottlenecks and possible benefits compared to backward tracing methods. The results of the implementation of one algorithm is provided. The article addresses the problems in the implementation of this a system including accurate probability calculation and efficient ray generation.

This article presents an optimized ray tracing algorithm which improves standard existing algorithms by processing simultaneously a large set of rays and carrying out a single traversal of the spatial indexing of the scene with all rays. This allows hardware SIMD functionality to be used efficiently and produces coherent memory accesses. Furthermore, during the single traversal, rays are groupe...

Ray tracing programs are widely used to generate photo-realistic images, but the high computation time may discourage their implementation on single-processor machines; moreover, cost reduction of multi-processor general purpose architectures makes parallel rendering an attractive field of research. We propose a new algorithm which addresses the main issues of a parallel implementation of ray t...

Ray casting has become a fundamental step in many graphics algorithms es pecially in the area of global illumination Examples include using rays to calculate form factors for traditional radiosity track energy in particle tracing and trace possible transport paths in path tracing The appeal of ray casting is that it o ers a exible and intuitive way to query visibility within a scene and we expe...

Three methods for extraction and quantitative measurement of features in CT and MR images are examined: hand tracing, semi-automated tracing using the livewire graph search algorithm, and extraction using a geometrically constrained region growth algorithm. Extracted structures are evaluated in terms of volume, cross-sectional area, and major axis in plane. Reproducibility, time required for ex...