Implementation of multi-algorithm controllers for path determination in mobile robot systems

textRecent advancements in control systems, such as the ones used in missile technology in the military or autonomous vehicle development have motivated this study in an attempt to explore various control algorithms and their implementation relevant those applications. Both missile interceptor and autonomous vehicle technology require precise and responsive control system to accurately determine the projectile path of pursuer to strike a moving target or reach a static finish line.The objective of this study is to investigate the performance of several control techniques for a mobile robot to autonomously track and pursue a moving object. Computer model is developed to numerically predict the path taken by the pursuer as it tracks an object moving in regular or random manner. In the computer simulation, the robot's path is calculated using three different techniques: reactive controller, linear estimation, and artificial neural network. Fitness of each method may be determined by evaluating the controller against several factors, such as interception time, steady-state positional error, steady-state time (settling time) and algorithm complexity, listed in decreasing order of importance. A working experimental model is developed to validate the controller selection determined from the computer model simulation. In the experimental setting, the primary inputs to the robot are visual images from cameras. The experiments are carried out with the robot receiving visual inputs from two different perspectives, overhead and frontal vision. Robust image processing technique becomes a topic of significant importance for the system. To manipulate visual images in real-time from raw inputs to comprehensible data, while maintaining fast computational time is a challenge that is addressed in this study. The results from computer simulations show that artificial neural network is a more powerful control algorithm, capable of estimating the object's path more accurately than the other two controllers, resulting in smaller steady-state positional error. The experimental results confirm this conclusion as artificial neural network outperforms the reactive and linear controller by intercepting the object more quickly, i.e. shorter interception time.Mechanical Engineerin

Holoscopic 3D imaging and display technology: Camera/ processing/ display

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonHoloscopic 3D imaging “Integral imaging” was first proposed by Lippmann in 1908. It has become an attractive technique for creating full colour 3D scene that exists in space. It promotes a single camera aperture for recording spatial information of a real scene and it uses a regularly spaced microlens arrays to simulate the principle of Fly’s eye technique, which creates physical duplicates of light field “true 3D-imaging technique”. While stereoscopic and multiview 3D imaging systems which simulate human eye technique are widely available in the commercial market, holoscopic 3D imaging technology is still in the research phase. The aim of this research is to investigate spatial resolution of holoscopic 3D imaging and display technology, which includes holoscopic 3D camera, processing and display. Smart microlens array architecture is proposed that doubles spatial resolution of holoscopic 3D camera horizontally by trading horizontal and vertical resolutions. In particular, it overcomes unbalanced pixel aspect ratio of unidirectional holoscopic 3D images. In addition, omnidirectional holoscopic 3D computer graphics rendering techniques are proposed that simplify the rendering complexity and facilitate holoscopic 3D content generation. Holoscopic 3D image stitching algorithm is proposed that widens overall viewing angle of holoscopic 3D camera aperture and pre-processing of holoscopic 3D image filters are proposed for spatial data alignment and 3D image data processing. In addition, Dynamic hyperlinker tool is developed that offers interactive holoscopic 3D video content search-ability and browse-ability. Novel pixel mapping techniques are proposed that improves spatial resolution and visual definition in space. For instance, 4D-DSPM enhances 3D pixels per inch from 44 3D-PPIs to 176 3D-PPIs horizontally and achieves spatial resolution of 1365 × 384 3D-Pixels whereas the traditional spatial resolution is 341 × 1536 3D-Pixels. In addition distributed pixel mapping is proposed that improves quality of holoscopic 3D scene in space by creating RGB-colour channel elemental images

Photography and Social Life: An Ethnography of Chinese Amateur Photography Online

This dissertation explores the ‘middle-brow’ (Bourdieu, 1990) photography practices of contemporary Chinese people in the digital era and how they produce, circulate, and consume photographic images on and off the Internet. Through participant observation and interviews with Chinese photo hobbyists and professionals working in the visual-Internet industry based in London, Beijing, or in the virtual world, it asks how the marriage between photography and the Internet in China has been similar to, or distinct from, its counterparts in the rest of the world, consolidating a vernacular photo-scape that has emerged alongside China’s booming Internet economy and socio-economic transformation over the past forty years. The research further addresses the agencies of both individuals and images, which determine what people want from photography in today’s China and what photography wants from this new networked, mediated society. The dissertation moves across persons, communities, organisations, and real and virtual sites, making it a multi-sited ethnography that traces social relations and ‘the circulation of cultural meanings, objects, and identities in diffuse time-space’ (Marcus, 1995: 96). The thesis presents a panoramic picture of the everyday practices carried out by Chinese amateur photographers, who are often imagined and categorised as the country’s middle class. The study focuses on two main aspects. The first is the activity of amateur photography, including the conspicuous consumption of photographic equipment and participation in relevant events, as well as social behaviours on and off of Internet photography platforms. The second involves the judgement and appreciation of photographic images on sites such as Tuchong, focusing on various kinds of aesthetic strategies around and within photographic images. The combination of the two has helped photo hobbyists in China to shape their values, career paths, and new identities in the context of digitalisation and the rise of social media

Wide-Area Surveillance System using a UAV Helicopter Interceptor and Sensor Placement Planning Techniques

This project proposes and describes the implementation of a wide-area surveillance system comprised of a sensor/interceptor placement planning and an interceptor unmanned aerial vehicle (UAV) helicopter. Given the 2-D layout of an area, the planning system optimally places perimeter cameras based on maximum coverage and minimal cost. Part of this planning system includes the MATLAB implementation of Erdem and Sclaroff’s Radial Sweep algorithm for visibility polygon generation. Additionally, 2-D camera modeling is proposed for both fixed and PTZ cases. Finally, the interceptor is also placed to minimize shortest-path flight time to any point on the perimeter during a detection event. Secondly, a basic flight control system for the UAV helicopter is designed and implemented. The flight control system’s primary goal is to hover the helicopter in place when a human operator holds an automatic-flight switch. This system represents the first step in a complete waypoint-navigation flight control system. The flight control system is based on an inertial measurement unit (IMU) and a proportional-integral-derivative (PID) controller. This system is implemented using a general-purpose personal computer (GPPC) running Windows XP and other commercial off-the-shelf (COTS) hardware. This setup differs from other helicopter control systems which typically use custom embedded solutions or micro-controllers. Experiments demonstrate the sensor placement planning achieving \u3e90% coverage at optimized-cost for several typical areas given multiple camera types and parameters. Furthermore, the helicopter flight control system experiments achieve hovering success over short flight periods. However, the final conclusion is that the COTS IMU is insufficient for high-speed, high-frequency applications such as a helicopter control system

The use of technical metadata in still digital imaging by the newspaper industry

Newspapers are increasingly capturing images digitally. Included with these digital files is technical information about the conditions of the image and the conditions surrounding image capture. Technical metadata has the potential to be a valuable resource in image reproduction, management, and archiving. Nevertheless, even though digital devices capture a large amount of technical metadata, the use of such data in the digital imaging workflow is not widespread. The use of technical metadata requires a uniform set of technical metadata standards and an open encoding scheme to embed data. From their inception, image file formats, such as TIFF and JPEG, have allowed the inclusion of technical metadata tags. The Exif schema has extended the metadata inclusion capabilities of both of these formats. Additionally, XML has emerged as a standard for users to add metadata to image files. Consequently, organizations such as the World Wide Web Consortium and Adobe Systems all support XML. Moreover, organizations such as the Digital Imaging Group (DIG35) and the National Information Standards Organization (NISO) are defining standards for technical metadata inclusion. The purpose of this study was to answer two fundamental questions about technical metadata in the newspaper industry. First, it assessed the ability of technical metadata to improve the newspaper digital imaging workflow; and second, it determined how technical metadata could be used to preserve the integrity of newspaper digital images. This study examined five large newspaper organizations: The Chicago Tribune, The New York Times, The Rochester Democrat & Chronicle, USA Today, and The Washington Post. Based on interviews and questionnaire responses, each organization?s use of technical metadata in the digital imaging workflow was examined through case studies. Interviews were conducted with those individuals responsible for image capture, adjustment, database management, and output. Furthermore, participants were asked to rank the importance of selected fields of technical metadata through a questionnaire. It was found that the use of technical metadata classified by NISO as Basic Image Parameters, which includes file size, type, and compression, was universal in newspaper organizations. The use of Image Creation metadata was not widespread with the exception of two fields that established date and time of capture and assigned each image a unique identifier. Image Performance Assessment metadata, such as test targets, was not widely used except by The Rochester Democrat & Chronicle. Change History fell victim to the short cycle time in the newspaper industry, and for the most part, a history of change was kept at various handoffs in the digital workflow through versioning. The use of technical metadata to improve the digital workflow, to an extent, was at cross-purposes with newspapers? need to visually examine each image to determine its usefulness. However, software designed to visually present technical metadata through a well designed graphic user interface was popular. It appeared that technical metadata had the potential to benefit newspapers when repurposing images for other media. Additionally, large newspaper organizations were creating their own image databases; while the use of technical metadata in these archives was unclear, it would be prudent to include too much technical metadata, rather than too little. The foremost concern of all organizations was preservation of the editorial integrity of the image. Newspapers defined editorial integrity as the ability to capture as much detail of an event as possible, and then present that information to their readers in a truthful, unambiguous way. Research pointed out that image reproduction quality was only one of a series of variables that determined newspaper image quality. With the advent of digital photography, photographers are editing more in the field, and as a result they are making decisions regarding image content. The use of technical metadata has the potential to provide greater tractability of these outtakes. Additionally, the industry is moving toward the Camera Raw file format to acquire image data that is unprocessed by camera software. The adjustment of Camera Raw files through a GUI, and their subsequent conversion to another file format, represented a de facto use of technical metadata to preserve editorial integrity

Examining Police Officer Resistance to Change and Body-Worn Cameras

Police departments are adopting the body-worn camera as an important tool in the restoration of trust and accountability for police officers. Although body-worn cameras can be beneficial to their work, police officers might resist the use of cameras. The purpose of the current study was to examine whether experiences with technology or the perceived usefulness of body-worn cameras predict resistance to the cameras in order to determine where resistance to body-worn cameras possibly exists. The current study employed a quantitative design that examined 48 (n = 48) police officers’ responses about resistance to body-worn cameras in relationship to the following variables: experiences with technology, perceived usefulness (PU), and perceived ease of use of body-worn cameras (PEOU). A survey was delivered to participant police officers through a countywide email system. Data analysis included one-sample t-tests, correlational analyses, and multiple regressions. A statistically significant difference was found between officers’ levels of resistance to change and body-worn cameras in comparison to the scale midpoint. In relationship to resistance to body-worn cameras, statistically significant correlations existed between the variables of experiences with technology, PU, and PEOU. Additionally, the regression analyses showed experiences with technology, PU, and PEOU were statistically significant predictors of resistance to body-worn cameras. Police departments that invest in body-worn cameras should be aware that officers might resist cameras should deficiencies with technology experience, perceived usefulness, and perceived ease of use of the body-worn cameras exist