Toward a computational theory for motion understanding: The expert animators model

Artificial intelligence researchers claim to understand some aspect of human intelligence when their model is able to emulate it. In the context of computer graphics, the ability to go from motion representation to convincing animation should accordingly be treated not simply as a trick for computer graphics programmers but as important epistemological and methodological goal. In this paper we investigate a unifying model for animating a group of articulated bodies such as humans and robots in a three-dimensional environment. The proposed model is considered in the framework of knowledge representation and processing, with special reference to motion knowledge. The model is meant to help setting the basis for a computational theory for motion understanding applied to articulated bodies

Non-Rigid Puzzles

Shape correspondence is a fundamental problem in computer graphics and vision, with applications in various problems including animation, texture mapping, robotic vision, medical imaging, archaeology and many more. In settings where the shapes are allowed to undergo non-rigid deformations and only partial views are available, the problem becomes very challenging. To this end, we present a non-rigid multi-part shape matching algorithm. We assume to be given a reference shape and its multiple parts undergoing a non-rigid deformation. Each of these query parts can be additionally contaminated by clutter, may overlap with other parts, and there might be missing parts or redundant ones. Our method simultaneously solves for the segmentation of the reference model, and for a dense correspondence to (subsets of) the parts. Experimental results on synthetic as well as real scans demonstrate the effectiveness of our method in dealing with this challenging matching scenario

PLOT3D user's manual

PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files

MPI Informatics building model as data for your research

In this report we describe the MPI Informatics building model that provides the data of the Max-Planck-Institut f\"{u}r Informatik (MPII) building. We present our motivation for this work and its relationship to reproducibility of a scientific research. We describe the dataset acquisition and creation including geometry, luminaires, surface reflectances, reference photographs etc. needed to use this model in testing of algorithms. The created dataset can be used in computer graphics and beyond, in particular in global illumination algorithms with focus on realistic and predictive image synthesis. Outside of computer graphics, it can be used as general source of real world geometry with an existing counterpart and hence also suitable for computer vision

A graphical, scalable and intuitive method for the placement and the connection of biological cells

We introduce a graphical method originating from the computer graphics domain that is used for the arbitrary and intuitive placement of cells over a two-dimensional manifold. Using a bitmap image as input, where the color indicates the identity of the different structures and the alpha channel indicates the local cell density, this method guarantees a discrete distribution of cell position respecting the local density function. This method scales to any number of cells, allows to specify several different structures at once with arbitrary shapes and provides a scalable and versatile alternative to the more classical assumption of a uniform non-spatial distribution. Furthermore, several connection schemes can be derived from the paired distances between cells using either an automatic mapping or a user-defined local reference frame, providing new computational properties for the underlying model. The method is illustrated on a discrete homogeneous neural field, on the distribution of cones and rods in the retina and on a coronal view of the basal ganglia.Comment: Corresponding code at https://github.com/rougier/spatial-computatio

Effectively Utilizing Computer-Aided Design Technology: The Role of Individual Difference Variables

Computer graphics and computer-aided design (CAD) technology is rapidly changing design and manufacturing in American industry. This paper sets forth a model of the individual difference factors which may impact task performance and affective reactions to the use of CAD technology. A standardized, scorable engineering task was developed which utilizes CAD technology, and a number of individual difference variables were examined with reference to the task. Results indicate that cognitive skills were strongly related to\u27 CAD engineering performance, user confidence, and perceived task difficulty. Experience and attitudinal variables were not found to be related to the measured outcomes Implications for employee selection and suggestions for future research are not provided

Linking focus and context in three-dimensional multiscale environments

The central question behind this dissertation is this: In what ways can 3D multiscale spatial information be presented in an interactive computer graphics environment, such that a human observer can better comprehend it? Toward answering this question, a two-pronged approach is employed that consists of practice within computer user-interface design, and theory grounded in perceptual psychology, bound together by an approach to the question in terms of focus and context as they apply to human attention. The major practical contribution of this dissertation is the development of a novel set of techniques for linking 3D windows to various kinds of reference frames in a virtual scene and to each other---linking one or more focal views with a view that provides context. Central to these techniques is the explicit recognition of the frames of reference inherent in objects, in computer-graphics viewpoint specifications, and in the human perception and cognitive understanding of space. Many of these techniques are incorporated into the GeoZui3D system as major extensions. An empirical evaluation of these techniques confirms the utility of 3D window proxy representations and orientation coupling. The major theoretical contribution is a cognitive systems model that predicts when linked focus and context views should be used over other techniques such as zooming. The predictive power of the model comes from explicit recognition of locations where a user will focus attention, as well as applied interpretations of the limitations of visual working memory. The model\u27s ability to predict performance is empirically validated, while its ability to model user error is empirically founded. Both the model and the results of the related experiments suggest that multiple linked windows can be an effective way of presenting multiscale spatial information, especially in situations involving the comparison of three or more objects. The contributions of the dissertation are discussed in the context of the applications that have motivated them

Geometric Algebra: An Introduction with Applications in Euclidean and Conformal Geometry

This thesis presents an introduction to geometric algebra for the uninitiated. It contains examples of how some of the more traditional topics of mathematics can be reexpressed in terms of geometric algebra along with proofs of several important theorems from geometry. We introduce the conformal model. This is a current topic among researchers in geometric algebra as it is finding wide applications in computer graphics and robotics. The appendices provide a list of some of the notational conventions used in the literature, a reference list of formulas and identities used in geometric algebra along with some of their derivations, and a glossary of terms

Subjective and Objective Quality Assessment for in-the-Wild Computer Graphics Images

Computer graphics images (CGIs) are artificially generated by means of computer programs and are widely perceived under various scenarios, such as games, streaming media, etc. In practical, the quality of CGIs consistently suffers from poor rendering during the production and inevitable compression artifacts during the transmission of multimedia applications. However, few works have been dedicated to dealing with the challenge of computer graphics images quality assessment (CGIQA). Most image quality assessment (IQA) metrics are developed for natural scene images (NSIs) and validated on the databases consisting of NSIs with synthetic distortions, which are not suitable for in-the-wild CGIs. To bridge the gap between evaluating the quality of NSIs and CGIs, we construct a large-scale in-the-wild CGIQA database consisting of 6,000 CGIs (CGIQA-6k) and carry out the subjective experiment in a well-controlled laboratory environment to obtain the accurate perceptual ratings of the CGIs. Then, we propose an effective deep learning-based no-reference (NR) IQA model by utilizing multi-stage feature fusion strategy and multi-stage channel attention mechanism. The major motivation of the proposed model is to make full use of inter-channel information from low-level to high-level since CGIs have apparent patterns as well as rich interactive semantic content. Experimental results show that the proposed method outperforms all other state-of-the-art NR IQA methods on the constructed CGIQA-6k database and other CGIQA-related databases. The database along with the code will be released to facilitate further research