Applications of computer-graphics animation for motion-perception research

The advantages and limitations of using computer animated stimuli in studying motion perception are presented and discussed. Most current programs of motion perception research could not be pursued without the use of computer graphics animation. Computer generated displays afford latitudes of freedom and control that are almost impossible to attain through conventional methods. There are, however, limitations to this presentational medium. At present, computer generated displays present simplified approximations of the dynamics in natural events. Very little is known about how the differences between natural events and computer simulations influence perceptual processing. In practice, the differences are assumed to be irrelevant to the questions under study, and that findings with computer generated stimuli will generalize to natural events

An Investigation of How Lighting and Rendering Technology Affects Filmmaking Relative to Arnold’s Transition to a GPU-Based Path-Tracer

Computer Graphic (CGI) technology enables artists to explore a broad spectrum of approaches and styles, from photorealistic to abstract, expanding the boundaries of traditional aesthetic choices. Recent years have witnessed of 3D-CGI production shift towards greater physical fidelity driven by technological developments as well as consumer demand for realistic visuals; this trend can be found across various creative fields like film, video games, and virtual reality experiences with high-quality textures, lighting, rendering, and physics simulations providing enhanced levels of immersion for users. Arnold is one of the famous rendering engines assisting artists to be more creative while producing photorealistic images. Moreover, Arnold renders the engine as one of the main path-tracing renderers and contributes significantly to more fantastic photorealistic productions. Also, Arnold renders not only Support CPU render but also support GPU rendering to take full advantage of faster computation times and real-time interactivity, among many other advantages. Because of that, this study investigates how new technology like developed GPUs helps artists and filmmakers better comprehend 3D rendering solutions that impact their workflows. On the other hand, philosophically exploring the relationship between making a creative decision and technology within 3D photorealistic rendering reveals an intricate yet dynamic relationship that informs the creative processes of both independent artists and small studios alike. This interaction serves as a reminder that Art is driven forward by its creator\u27s creative energy rather than simply technological capabilities; artists and studios can continue pushing limits by embracing this complex dialogue between creativity and tech, opening new paths within digital Art\u27s fast-evolving realm

Improving elevation perception with a tool for image-guided head-related transfer function selection

This paper proposes an image-guided HRTF selection procedure that exploits the relation between features of the pinna shape and HRTF notches. Using a 2D image of a subject's pinna, the procedure selects from a database the HRTF set that best fits the anthropometry of that subject. The proposed procedure is designed to be quickly applied and easy to use for a user without previous knowledge on binaural audio technologies. The entire process is evaluated by means of an auditory model for sound localization in the mid-sagittal plane available from previous literature. Using virtual subjects from a HRTF database, a virtual experiment is implemented to assess the vertical localization performance of the database subjects when they are provided with HRTF sets selected by the proposed procedure. Results report a statistically significant improvement in predictions of localization performance for selected HRTFs compared to KEMAR HRTF which is a commercial standard in many binaural audio solutions; moreover, the proposed analysis provides useful indications to refine the perceptually-motivated metrics that guides the selection

A tool for generating three dimensional animation on computers

Ankara : The Department of Graphic Design and the Institute of Fine Arts of Bilkent Univ. , 1991.Thesis (Master's) -- Bilkent University, 1991.Includes bibliographical references leaves 31-32.In this work, a three dimensional computer animation system has been designed to be employed in schools, for the training of art students on basic three dimensional animation techniques. Puppet Theater, as we have called the system, utilizes the flexibility and effectiveness of the low-end hardware, namely IBM PC™ computers supported with Targa 16™ graphics board and gives special emphasis to user friendliness. It Is basically a software to design three dimensional objects and choreograph the object data in the computer's memory, before rendering the resulting scenery with shading methods. The system is the result of reflecting the recent advances in the field of computer graphics and pushing the potentials of the existing platform. Software is Implemented in C language, thus the code is transportable. A custom designed object oriented windowing system called WODNTW is used as the user Interface. This open windowing system supports pull-down menus, interactive buttons, scalable windows and other popular user interface elements.Türün, Cemil ŞinasiM.S

Parallel hierarchical global illumination

Solving the global illumination problem is equivalent to determining the intensity of every wavelength of light in all directions at every point in a given scene. The complexity of the problem has led researchers to use approximation methods for solving the problem on serial computers. Rather than using an approximation method, such as backward ray tracing or radiosity, we have chosen to solve the Rendering Equation by direct simulation of light transport from the light sources. This paper presents an algorithm that solves the Rendering Equation to any desired accuracy, and can be run in parallel on distributed memory or shared memory computer systems with excellent scaling properties. It appears superior in both speed and physical correctness to recent published methods involving bidirectional ray tracing or hybrid treatments of diffuse and specular surfaces. Like progressive radiosity methods, it dynamically refines the geometry decomposition where required, but does so without the excessive storage requirements for ray histories. The algorithm, called Photon, produces a scene which converges to the global illumination solution. This amounts to a huge task for a 1997-vintage serial computer, but using the power of a parallel supercomputer significantly reduces the time required to generate a solution. Currently, Photon can be run on most parallel environments from a shared memory multiprocessor to a parallel supercomputer, as well as on clusters of heterogeneous workstations

Breaking the Rayleigh-Plateau instability limit using thermocavitation within a droplet

We report on the generation of liquid columns that extend far beyond the traditional Rayleigh-Plateau instability onset. The columns are driven by the acoustic pressure wave emitted after bubble collapse. A high-speed video imaging device, which records images at a rate of up to 105 fps, was employed to follow their dynamics. These bubbles, commonly termed thermocavitation bubbles, are generated by focusing a midpower (275 mW) continuous wavelength laser into a highly absorbing liquid droplet. A simple model of the propagation of the pressure wavefront emitted after the bubble collapse shows that focusing the pressure wave at the liquid-air interface drives the evolution of the liquid columns. Control over the aspect ratio of the liquid column is realized by adjusting the cavitation bubble's size, beam focus position, and droplet volume. © 2013 by Begell House, Inc

CATRA: Interactive Measuring and Modeling of Cataracts

We introduce an interactive method to assess cataracts in the human eye by crafting an optical solution that measures the perceptual impact of forward scattering on the foveal region. Current solutions rely on highly-trained clinicians to check the back scattering in the crystallin lens and test their predictions on visual acuity tests. Close-range parallax barriers create collimated beams of light to scan through sub-apertures, scattering light as it strikes a cataract. User feedback generates maps for opacity, attenuation, contrast and sub-aperture point-spread functions. The goal is to allow a general audience to operate a portable high-contrast light-field display to gain a meaningful understanding of their own visual conditions. User evaluations and validation with modified camera optics are performed. Compiled data is used to reconstruct the individual's cataract-affected view, offering a novel approach for capturing information for screening, diagnostic, and clinical analysis.Alfred P. Sloan Foundation (Research Fellowship)United States. Defense Advanced Research Projects Agency (Young Faculty Award

A Method of Rendering CSG-Type Solids Using a Hybrid of Conventional Rendering Methods and Ray Tracing Techniques

This thesis describes a fast, efficient and innovative algorithm for producing shaded, still images of complex objects, built using constructive solid geometry ( CSG ) techniques. The algorithm uses a hybrid of conventional rendering methods and ray tracing techniques. A description of existing modelling and rendering methods is given in chapters 1, 2 and 3, with emphasis on the data structures and rendering techniques selected for incorporation in the hybrid method. Chapter 4 gives a general description of the hybrid method. This method processes data in the screen coordinate system and generates images in scan-line order. Scan lines are divided into spans (or segments) using the bounding rectangles of primitives calculated in screen coordinates. Conventional rendering methods and ray tracing techniques are used interchangeably along each scan-line. The method used is detennined by the number of primitives associated with a particular span. Conventional rendering methods are used when only one primitive is associated with a span, ray tracing techniques are used for hidden surface removal when two or more primitives are involved. In the latter case each pixel in the span is evaluated by accessing the polygon that is visible within each primitive associated with the span. The depth values (i. e. z-coordinates derived from the 3-dimensional definition) of the polygons involved are deduced for the pixel's position using linear interpolation. These values are used to determine the visible polygon. The CSG tree is accessed from the bottom upwards via an ordered index that enables the 'visible' primitives on any particular scan-line to be efficiently located. Within each primitive an ordered path through the data structure provides the polygons potentially visible on a particular scan-line. Lists of the active primitives and paths to potentially visible polygons are maintained throughout the rendering step and enable span coherence and scan-line coherence to be fully utilised. The results of tests with a range of typical objects and scenes are provided in chapter 5. These results show that the hybrid algorithm is significantly faster than full ray tracing algorithms