GPU-Accelerated nearest neighbor search for 3d registration

Abstract. Nearest Neighbor Search (NNS) is employed by many computer vision algorithms. The computational complexity is large and constitutes a challenge for real-time capability. The basic problem is in rapidly processing a huge amount of data, which is often addressed by means of highly sophisticated search methods and parallelism. We show that NNS based vision algorithms like the Iterative Closest Points algorithm (ICP) can achieve real-time capability while preserving compact size and moderate energy consumption as it is needed in robotics and many other domains. The approach exploits the concept of general purpose computation on graphics processing units (GPGPU) and is compared to parallel processing on CPU. We apply this approach to the 3D scan registration problem, for which a speed-up factor of 88 compared to a sequential CPU implementation is reported

GANHO DE DESEMPENHO DO FEMA UTILIZANDO PROGRAMAÇÃO PARALELA E ÁRVORES DE PARTICIONAMENTO ESPACIAL

This paper presents an application with data structures and GPU to get better performances in FEMa algorithm. At first, a binary partition Kd-Tree is constructed from a dataset, after his building, the search algorithm of the K nearest neighbours (K-NN) is applied in the Kd-Tree to all sample in the test dataset. After get the result of nearest samples search, the step of classification begin applying the Finite Element Method basis to get the result. Another approach is to utilize cuda codes in algorithm, so that it can be parallelized and run in GPU to obtain a gain of performance in the code runtime.O presente estudo apresenta a  utilização de estruturas de dados e GPU como uma melhoria de desempenho do algoritmo de classificação FEMa. Primeiramente, à partir de um datasets  é criada uma árvore de partição binária do tipo Kd-Tree e após sua construção, aplicado o algoritmo de busca dos K vizinhos mais próximos (K-NN) na Kd-Tree para cada amostra de teste apresentada na fase de classificação. Após ter o resultado da busca das amostras mais próximas, é feita a etapa de classificação do FEMa aplicando uma base dos Métodos dos Elementos Finitos (FEM), para trazer o resultado. Outra abordagem é utilizar códigos CUDA no algoritmo do FEMa, para que o mesmo seja paralelizado e executado em GPU’s, para obter um ganho de desempenho no tempo de execução

Rendering Geometry with Relief Textures

International audienceWe propose to render geometry using an image based representation. Geometric information is encoded by a texture with depth and rendered by rasterizing the bounding box geometry. For each resulting fragment, a shader computes the intersection of the corresponding ray with the geometry using pre-computed information to accelerate the computation. Great care is taken to be artifact free even when zoomed in or at grazing angles. We integrate our algorithm with reverse perspective projection to represent a larger class of shapes. The extra texture requirement is small and the rendering cost is output sensitive so our representation can be used to model many parts of a 3D scene

Streaming Ray Tracer on GPU

Současné GPU je možné snadno použít jako vysoce výkonné stream procesory a představují tak lákovou platformu pro implementaci raytracingu. V první části práce stručně přibližuji základy raytracingu, programovatelnou pipeline moderních GPU a možnosti jejího využití. V druhé části popisuji algoritmy využité pro implementaci jednoduchého raytraceru a rozebírám experimenty s ním provedené.Current consumer GPUs can be used as high performance stream processors and are a tempting platform to be used to implement raytracing. In this paper I briefly present raytracing principles and methods used to accelerate it, modern GPUs programmable pipeline and examples of its use. I describe stream processing in general and available interfaces enabling the usage of GPU as stream processor. Then I present my GPU raytracer implementation, used algorithms and experiments I have made.

Developing an efficient algorithm for computing Solar Radiation Pressure

The main goal for this master's degree final thesis is to propose an alternative way of computing solar radiation pressure. Solar radiation pressure is the impact of the photons emitted by the Sun onto a satellite. This impact generates acceleration that is important to model satellite's motion

New parametric surface and rendering algorithm

Orientador: Francisco de Assis Magalhães Gomes NetoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação CientíficaResumo: O principal foco da Computação Gráfica é o armazenamento e renderização de objetos tridimensionais computacionalmente. Objetos reais são modelados e apresentados visualmente para os usuários. Esse processo de geração da imagem a ser exibida para o usuário é chamado de renderização. Existem vários modelos que podem ser utilizados, com suas vantagens e desvantagens, e vários métodos para renderizar tais modelos. No trabalho atual um novo modelo de superfícies curvas paramétricas é introduzido juntamente com um algoritmo de renderização que, diferentemente dos algoritmos para os modelos de superfícies curvas paramétricas atuais, não depende de métodos numéricos e aproximações, sendo capaz de identificar intersecções entre um raio e a superfície com um número constante de operações. Durante o desenvolvimento do modelo proposto foram utilizadas a função de interpolação de Hermite e uma função de interpolação quadrática em partes muito pouco explorada na literatura, com comparações entre ambas. A função quadrática em partes possibilitou que o algoritmo proposto fosse executado em tempo constante ao reduzir a ordem das equações envolvidas no problema, o que não foi possível com a interpolação de Hermite. Por fim, restrições do algoritmo proposto foram analisadas e possíveis novas linhas de pesquisa foram levantadas para tentar eliminá-las. Um programa que implementa o algoritmo proposto também foi codificado, e alguns objetos foram modelados usando a superfície propostaAbstract: Computer graphic's main goal is to store and render tridimensional objects computationally. Real objects are modeled and presented visually to the user. This proccess of generating the image to be shown to the user is called "rendering". There are many models that can be used, with advantages and disadvantages, and many methods to render such models. In the present work a novel model of curved parametric surfaces is introduced along with a rendering algorithm that, unlike current methods, doesn't deppend on numerical methods, being able to identify ray/surface intersections with a constant number of operations. During the research, the Hermite interpolation was used, as well as a partitioned quadratic interpolation with almost no presence in the literature. The quadratic function has allowed the proposed algorithm to run in constant time by reducing the order of equations involved in the problem, something that was not possible with the Hermite interpolation. At last, the proposed algorithm's restrictions were analysed and possible new lines of research were suggested to try and remove such restrictions. A program that implements the proposed algorithm was also coded, and some objects were modeled using the proposed surfaceMestradoMatematica AplicadaMestre em Matemática AplicadaCAPE

Fast Rendering of Forest Ecosystems with Dynamic Global Illumination

Real-time rendering of large-scale, forest ecosystems remains a challenging problem, in that important global illumination effects, such as leaf transparency and inter-object light scattering, are difficult to capture, given tight timing constraints and scenes that typically contain hundreds of millions of primitives. We propose a new lighting model, adapted from a model previously used to light convective clouds and other participating media, together with GPU ray tracing, in order to achieve these global illumination effects while maintaining near real-time performance. The lighting model is based on a lattice-Boltzmann method in which reflectance, transmittance, and absorption parameters are taken from measurements of real plants. The lighting model is solved as a preprocessing step, requires only seconds on a single GPU, and allows dynamic lighting changes at run-time. The ray tracing engine, which runs on one or multiple GPUs, combines multiple acceleration structures to achieve near real-time performance for large, complex scenes. Both the preprocessing step and the ray tracing engine make extensive use of NVIDIA\u27s Compute Unified Device Architecture (CUDA)