Reconstructing vectorised photographic images

We address the problem of representing captured images in the continuous mathematical space more usually associated with certain forms of drawn ('vector') images. Such an image is resolution-independent so can be used as a master for varying resolution-specific formats. We briefly describe the main features of a vectorising codec for photographic images, whose significance is that drawing programs can access images and image components as first-class vector objects. This paper focuses on the problem of rendering from the isochromic contour form of a vectorised image and demonstrates a new fill algorithm which could also be used in drawing generally. The fill method is described in terms of level set diffusion equations for clarity. Finally we show that image warping is both simplified and enhanced in this form and that we can demonstrate real histogram equalisation with genuinely rectangular histograms

Adaptive image vectorisation and brushing using mesh colours

We propose the use of curved triangles and mesh colours as a vector primitive for image vectorisation. We show that our representation has clear benefits for rendering performance, texture detail, as well as further editing of the resulting vector images. The proposed method focuses on efficiency, but it still leads to results that compare favourably with those from previous work. We show results over a variety of input images ranging from photos, drawings, paintings, all the way to designs and cartoons. We implemented several editing workflows facilitated by our representation: interactive user-guided vectorisation, and novel raster-style feature-aware brushing capabilities

Data capture from engineering drawings

Call number: LD2668 .T4 1985 S574Master of Scienc

Arbitrary topology meshes in geometric design and vector graphics

Meshes are a powerful means to represent objects and shapes both in 2D and 3D, but the techniques based on meshes can only be used in certain regular settings and restrict their usage. Meshes with an arbitrary topology have many interesting applications in geometric design and (vector) graphics, and can give designers more freedom in designing complex objects. In the first part of the thesis we look at how these meshes can be used in computer aided design to represent objects that consist of multiple regular meshes that are constructed together. Then we extend the B-spline surface technique from the regular setting to work on extraordinary regions in meshes so that multisided B-spline patches are created. In addition, we show how to render multisided objects efficiently, through using the GPU and tessellation. In the second part of the thesis we look at how the gradient mesh vector graphics primitives can be combined with procedural noise functions to create expressive but sparsely defined vector graphic images. We also look at how the gradient mesh can be extended to arbitrary topology variants. Here, we compare existing work with two new formulations of a polygonal gradient mesh. Finally we show how we can turn any image into a vector graphics image in an efficient manner. This vectorisation process automatically extracts important image features and constructs a mesh around it. This automatic pipeline is very efficient and even facilitates interactive image vectorisation

Three-dimensional anatomical atlas of the human body

A thesis submitted in partial fulfillment of the requirements for the degree of Doctor in Information Management, specialization in Geographic Information SystemsAnatomical atlases allow mapping the anatomical structures of the human body. Early versions of these systems consisted of analogic representations with informative text and labelled images of the human body. With the advent of computer systems, digital versions emerged and the third dimension was introduced. Consequently, these systems increased their efficiency, allowing more realistic visualizations with improved interactivity. The development of anatomical atlases in geographic information systems (GIS) environments allows the development of platforms with a high degree of interactivity and with tools to explore and analyze the human body. In this thesis, a prototype for the human body representation is developed. The system includes a 3D GIS topological model, a graphical user interface and functions to explore and analyze the interior and the surface of the anatomical structures of the human body. The GIS approach relies essentially on the topological characteristics of the model and on the kind of available functions, which include measurement, identification, selection and analysis. With the incorporation of these functions, the final system has the ability to replicate the kind of information provided by the conventional anatomical atlases and also provides a higher level of functionality, since some of the atlases limitations are precisely features offered by GIS, namely, interactive capabilities, multilayer management, measurement tools, edition mode, allowing the expansion of the information contained in the system, and spatial analyzes

Introduction to applied photogrammetry and cartography for civil engineering

Los ingenieros civiles, a lo largo de sus carreras, deberían manejar información cartográfica, que se obtiene principalmente mediante técnicas de fotogrametría. Este trabajo tiene como objetivo prácticamente introduciendo la técnica de fotogrametría aérea digital, con el propósito de compartir los métodos utilizados para obtener la cartografía para planificar su trabajo. La formulación matemática no está dentro del alcance de este trabajo, ya que, en mi opinión, tiene poco que aportar a los ingenieros civiles y existen tratados muy complejos destinados a lectores más especializados en el campo. Este breve texto comienza por delinear algunos conceptos básicos de cartografía, centrándose en sistemas de referencia, que están cambiando hoy en día y deberían ser conocidos por civiles ingenieros antes de trabajar con datos cartográficos. La parte fundamental del texto se centra en la fotogrametría digital, y al enfatizar una vez más, en su simplicidad, pretende explicar, desde mi experiencia profesional, todo el proceso de trabajo desde el momento en que se solicita un vuelo fotogramétrico hasta la cartografía digital llega a las manos de los ingenieros para trabajar en ella, con sus precisiones y precisiones. Por lo tanto, este trabajo está destinado a proporcionar ayuda a los profesionales de ingeniería civil cuando evaluar y manejar datos cartográficos que, en mayor o menor grado, ser la base de su trabajo.Civil engineers, throughout their careers, should handle cartographical information, which is mainly obtained by photogrammetry techniques. This work aims at practically introducing the digital aerial photogrammetry technique, with the purpose of sharing the methods used to obtain cartography to plan their work. Mathematical formulation is not under the scope of this work, since, in my view, it has little to contribute to civil engineers and there exist very complex treaties aimed at more specialised readers in the field. This short text begins by outlining some basic cartography concepts, focusing on reference systems, which are changing nowadays and should be known by civil engineers before working with cartographical data. The text’s fundamental part focuses on digital photogrammetry, and by emphasizing once again on its simplicity, it aims at explaining, from my professional experience, all the work process from the moment when a photogrammetric flight is requested until digital cartography arrives into the hands of engineers to work on it, with its accuracies and precisions. Therefore, this work is intended to provide help to civil engineering professionals when valuating and handling cartographical data which, to a greater or lesser degree, would be the basis for their work

Image Processing Using FPGAs

This book presents a selection of papers representing current research on using field programmable gate arrays (FPGAs) for realising image processing algorithms. These papers are reprints of papers selected for a Special Issue of the Journal of Imaging on image processing using FPGAs. A diverse range of topics is covered, including parallel soft processors, memory management, image filters, segmentation, clustering, image analysis, and image compression. Applications include traffic sign recognition for autonomous driving, cell detection for histopathology, and video compression. Collectively, they represent the current state-of-the-art on image processing using FPGAs