Image-space simplifications have been used to accelerate the calculation of computer graphic images since the dawn of visual simulation. Texture mapping has been used to provide a means by which images may themselves be used as display primitives. The work reported by this paper endeavors to carry this concept to its logical extreme by using interpolated images to portray three-dimensional scenes. The special-effects technique of morphing, which combines interpolation of texture maps and their shape, is applied to computing arbitrary intermediate frames from an array of prestored images. If the images are a structured set of views of a 3D object or scene, intermediate frames derived by morphing can be used to approximate intermediate 3D transformations of the object or scene. Using the view interpolation approach to synthesize 3D scenes has two main advantages. First, the 3D representation of the scene may be replaced with images. Second, the image synthesis time is independent of the scene complexity. The correspondence between images, required for the morphing method, can be predetermined automatically using the range data associated with the images. The method is further accelerated by a quadtree decomposition and a view-independent visible priority. Our experiments have shown that the morphing can be performed at interactive rates on today’s high-end personal computers. Potential applications of the method include virtual holograms, a walkthrough in a virtual environment, image-based primitives and incremental rendering. The method also can be used to greatly accelerate the computation of motion blur and soft shadows cast by area light sources.

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This dissertation presents algorithms for restoring some of the major corruptions observed in archived film or video material. The two principal problems of impulsive distortion (Dirt and Sparkle or Blotches) and noise degradation are considered. There is also an algorithm for suppressing the inter--line jitter common in images decoded from noisy video signals. In the case of noise reduction and Blotch removal the thesis considers image sequences to be three dimensional signals involving evolution of features in time and space. This is necessary if any process presented is to show an improvement over standard two--dimensional techniques. It is important to recognize that consideration of image sequences must involve an appreciation of the problems incurred by the motion of objects in the scene. The most obvious implication is that due to motion, useful three dimensional processing does not necessarily proceed in a direction `orthogonal' to the image frames. Therefore, attention is giv...

Although image understanding and natural language processing constitute two major areas of AI, they have mostly been studied independently of each other. Only a few attempts have been concerned with the integration of computer vision and the generation of natural language expressions for the description of image sequences. The aim of our joint efforts at combining a vision system and a natural language access system is the automatic simultaneous description of dynamic imagery, i.e., we are interested in image interpretation and language processing on an incremental basis. In this contribution 1 we sketch an approach towards the integration of the Karlsruhe vision system called Actions and the natural language component Vitra developed in Saarbrücken. The steps toward realization, based

The classical approach to motion and structure estimation problem from two perspective projections consists of two stages: (i) using the 8-point algorithm to estimate the 9 essential parameters defined up to a scale factor, which is a linear estimation problem; (ii) refining the motion estimation based on some statistically optimal criteria, which is a nonlinear estimation problem on a five-dimensional space. Unfortunately, the results obtained using this approach are often not satisfactory, especially when the motion is small or when the observed points are close to a degenerate surface (e.g. plane). The problem is that the second stage is very sensitive to the initial guess, and that it is very difficult to obtain a precise initial estimate from the first stage. This is because we perform a projection of a set of quantities which are estimated in a space of 8 dimensions, much higher than that of the real space which is five-dimensional. We propose in this paper a novel approach by introducing...

The standard approach consists of two stages: (i) using the 8-point algorithm to estimate the 9 essential parameters defined up to a scale factor; (ii) refining the motion estimation based on some statistically optimal criteria, which is a nonlinear estimation problem on a five-dimensional space. Unfortunately, the results obtained are often not satisfactory. The problem is that the second stage is very sensitive to the initial guess, and that it is very difficult to obtain a precise initial estimate from the first stage. This is because we perform a projection of a set of quantities which are estimated in a space of 8 dimensions (by neglecting the constraints on the essential parameters), much higher than that of the real space which is five-dimensional. We propose in this paper a novel approach by introducing an intermediate stage which consists in estimating a 3 × 3 matrix defined up to a scale factor by imposing the rank-2 constraint (the matrix has seven independent parameters, and is known as the fundamental matrix). The idea is to gradually project parameters estimated in a high dimensional space onto a slightly lower space, namely from 8 dimensions to 7 and finally to 5. The proposed approach has been tested with synthetic and real data, and a considerable improvement has been observed. Our conjecture from this work is that the imposition of the constraints arising from projective geometry should be used as an intermediate step in order to obtain reliable 3D Euclidean motion and structure estimation from multiple calibrated images. The software is available from the Internet.

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application systems based on simple computer vision techniques. Especially, the practical approach recently focused on is to use multiple vision sensors with simple visual processing.

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The problems under consideration in this dissertation centre around the representation of visual spacetime, i.e., (visual) image intensity (irradiance) as a function of two-dimensional spatial position and time. In particular, the overarching goal is to establish a unified approach to representation and analysis of temporal image dynamics that is broadly applicable to the diverse phenomena in the natural world as captured in two-dimensional intensity images. Previous research largely has approached the analysis of visual dynamics by appealing to representations based on image motion. Although of obvious importance, motion represents a particular instance of the myriad spatiotemporal patterns observed in image data. A generative model centred on the concept of spacetime orientation is proposed. This model provides a unified framework for understanding a broad set of important spacetime patterns. As a consequence of this analysis, two new classes of patterns are distinguished that have previously not been considered directly in terms of their constituent spacetime oriented structure, namely multiplicative motions (e.g., translucency) and stochastic-related phenomena (e.g.,