Computer Graphics and Visualisation

The appliances of methods in computer graphics span from simulations, computer aided education to digital photography and entertainment. Some fundamental problems of computer graphics and visualisations are investigated, such as the complexities of illumination in virtual scenes, different aspects of modeling and animating virtual environments and processing the main aspects which differ various imaging formats. Particular methods and technologies related to computer graphics and visualization are developed. The insight is given to how graphics can be generated and manipulated, and computed based to some specific applications. A large number of novel visualisation techniques are summarized. Geometric primitives are a staple of computer graphics. They provide artists with shapes that are easy to understand and create, yet they can be easily combined and modified into more complex structures. A new 2D geometric primitive is derived represent¬ing a smooth curved shape that blends two circles of any radii, and is controlled with a few parameters which have immediate geometric interpretations. The applications of shapes, surfaces and curves in computer graphics are introduced in the initial six chapters of the book. Also, the concept of curve segment is introduced after relaxing the definition of digital straight segment and it is used to decompose a digital curve into a sequence of curve segments. 3D scene modeling has long been a fundamental problem in computer graphics. With the popularity of consumer-level RGB-D cameras, there is a growing interest in digitizing real-world indoor 3D scenes. However, modeling indoor 3D scenes remains a challenging problem because of the complex structure of interior objects and poor quality of RGB-D data acquired by consumer-level sensors. Various methods have been proposed to tackle these challenges. An overview of recent advances in indoor scene modeling techniques is presented in Chapter 7 of the book, as well as public datasets and code libraries which can facilitate experiments and evaluation. The following eight chapters of the book present various visualization techniques to improve practical appliances of computer graphics, such as surface waves of the jet, electrical resistance tomography, videoconferencing and cranio-maxillofacial (CMF) surgery. An overview of image enhancement techniques based on the use of Particle Swarm Optimization is presented in the final chapter of the book. A variety of mappings between a sphere and a disc and between a disc and a square, as well as combinations of both, are used in computer graphics applications, resulting in mappings between spheres and squares. Many options exist for each type of mapping; to pick the right methods for a given application requires knowledge about the nature and magnitude of mapping distortions. An overview of forward and inverse mappings between a unit sphere, a unit disc, and a unit square is provided. Quality measure¬ments relevant for computer graphics applications are derived from tools used in the field of map projection, and a comparative analysis of the mapping methods is given. A novel, direct ray-tracing method for rendering Catmull-Clark subdivision surfaces is presented. This method resolves an intersection with Bezier patches without performing of polygon tessellation as done in most traditional renderers. The instability analysis of the liquid jet issuing into ambient air was conducted with an emphasis placed upon the evolution of surface waves of the jet. An experiment was designed to visualize the microscopic morphology on the surface of a liquid jet. A spectral method was proposed to measure wavelength from the obtained jet images. An iterative back projection method (i-BP) has been developed to improve the resolution of reconstructed images produced by electrical resistance tomography (ERT). This solution is based on an iterative calculation of the electrical fields and it is possible to reconstruct clearer images than those reconstructed by the conventional back projection method without divergence. Numeri¬cal simulations and experiments using a simple model are performed in this study. The numerical simulations show that clear images are reconstructed both near the wall and at the center by i-BP. Face-to-face videoconferencing system is considered that uses a Kinect camera at each end of the link for 3D modeling and an ordinary 2D display for output. The Kinect camera allows a 3D model of each participant to be transmitted; the (assumed static) background is sent separately. Furthermore, the Kinect tracks the receiver’s head, allowing our system to render a view of the sender depending on the receiver’s viewpoint. The resulting motion parallax gives the receivers a strong impression of 3D viewing as they move, yet the system only needs an ordinary 2D display. The recent development of light field cameras has received growing interest, as their rich angular information has poten