183 research outputs found

    Image enhancement from a stabilised video sequence

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    The aim of video stabilisation is to create a new video sequence where the motions (i.e. rotations, translations) and scale differences between frames (or parts of a frame) have effectively been removed. These stabilisation effects can be obtained via digital video processing techniques which use the information extracted from the video sequence itself, with no need for additional hardware or knowledge about camera physical motion. A video sequence usually contains a large overlap between successive frames, and regions of the same scene are sampled at different positions. In this paper, this multiple sampling is combined to achieve images with a higher spatial resolution. Higher resolution imagery play an important role in assisting in the identification of people, vehicles, structures or objects of interest captured by surveillance cameras or by video cameras used in face recognition, traffic monitoring, traffic law reinforcement, driver assistance and automatic vehicle guidance systems

    The Design Fabrication and Flight Testing of an Academic Research Platform for High Resolution Terrain Imaging

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    This thesis addresses the design, construction, and flight testing of an Unmanned Aircraft System (UAS) created to serve as a testbed for Intelligence, Surveillance, and Reconnaissance (ISR) research topics that require the rapid acquisition and processing of high resolution aerial imagery and are to be performed by academic research institutions. An analysis of the requirements of various ISR research applications and the practical limitations of academic research yields a consolidated set of requirements by which the UAS is designed. An iterative design process is used to transition from these requirements to cycles of component selection, systems integration, flight tests, diagnostics, and subsystem redesign. The resulting UAS is designed as an academic research platform to support a variety of ISR research applications ranging from human machine interaction with UAS technology to orthorectified mosaic imaging. The lessons learned are provided to enable future researchers to create similar systems

    Multi-Lane Perception Using Feature Fusion Based on GraphSLAM

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    An extensive, precise and robust recognition and modeling of the environment is a key factor for next generations of Advanced Driver Assistance Systems and development of autonomous vehicles. In this paper, a real-time approach for the perception of multiple lanes on highways is proposed. Lane markings detected by camera systems and observations of other traffic participants provide the input data for the algorithm. The information is accumulated and fused using GraphSLAM and the result constitutes the basis for a multilane clothoid model. To allow incorporation of additional information sources, input data is processed in a generic format. Evaluation of the method is performed by comparing real data, collected with an experimental vehicle on highways, to a ground truth map. The results show that ego and adjacent lanes are robustly detected with high quality up to a distance of 120 m. In comparison to serial lane detection, an increase in the detection range of the ego lane and a continuous perception of neighboring lanes is achieved. The method can potentially be utilized for the longitudinal and lateral control of self-driving vehicles

    Evaluating the accuracy of vehicle tracking data obtained from Unmanned Aerial Vehicles

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    Abstract This paper presents a methodology for tracking moving vehicles that integrates Unmanned Aerial Vehicles with video processing techniques. The authors investigated the usefulness of Unmanned Aerial Vehicles to capture reliable individual vehicle data by using GPS technology as a benchmark. A video processing algorithm for vehicles trajectory acquisition is introduced. The algorithm is based on OpenCV libraries. In order to assess the accuracy of the proposed video processing algorithm an instrumented vehicle was equipped with a high precision GPS. The video capture experiments were performed in two case studies. From the field, about 24,000 positioning data were acquired for the analysis. The results of these experiments highlight the versatility of the Unmanned Aerial Vehicles technology combined with video processing technique in monitoring real traffic data

    STS-81 Space Shuttle Mission Report

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    STS-81 was the fifth of nine planned missions to dock with the Russian Mir Space Station and the fourth crewmember transfer mission. The double Spacehab module was carried for the second time, and it housed experiments that were performed by the crew and logistics equipment that was transferred to the Mir

    Optic Flow from Unstable Sequences containing Unconstrained Scenes through Local Velocity Constancy Maximization

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    A comparison study of biologically inspired propulsion systems for an autonomous underwater vehicle

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    The field of Autonomous Underwater Vehicles (AUVs) has increased dramatically in size and scope over the past two decades. Application areas for AUVs are numerous and varied; from deep sea exploration, to pipeline surveillance to mine clearing. However, one limiting factor with the current technology is the duration of missions that can be undertaken and one contributing factor to this is the efficiency of the propulsion system, which is usually based on marine propellers. As fish are highly efficient swimmers greater propulsive efficiency may be possible by mimicking their fish tail propulsion system. The main concept behind this work was therefore to investigate whether a biomimetic fish-like propulsion system is a viable propulsion system for an underwater vehicle and to determine experimentally the efficiency benefits of using such a system. There have been numerous studies into biomimetic fish like propulsion systems and robotic fish in the past with many claims being made as to the benefits of a fish like propulsion system over conventional marine propulsion systems. These claims include increased efficiency and greater manoeuvrability. However, there is little published experimental data to characterise the propulsive efficiency of a fish like propulsive system. Also, very few direct experimental comparisons have been made between biomimetic and conventional propulsion systems. This work attempts to address these issues by directly comparing experimentally a biomimetic underwater propulsion system to a conventional propulsion system to allow for a better understanding of the potential benefits of the biomimetic system. This work is split into three parts. Firstly, the design and development of a novel prototype vehicle called the RoboSalmon is covered. This vehicle has a biomimetic tendon drive propulsion system which utilizes one servo motor for actuation and has a suite of onboard sensors and a data logger. The second part of this work focuses on the development of a mathematical model of the RoboSalmon vehicle to allow for a better understanding of the dynamics of the system. Simulation results from this model are compared to the experimental results and show good correlation. The final part of the work presents the experimental results obtained comparing the RoboSalmon prototype with the biomimetic tail system to the propeller and rudder system. These experiments include a study into the straight swimming performance, recoil motion, start up transients and power consumption. For forward swimming the maximum surge velocity of the RoboSalmon was 0.18ms-1 and at this velocity the biomimetic system was found to be more efficient than the propeller system. When manoeuvring the biomimetic system was found to have a significantly reduced turning radius. The thesis concludes with a discussion of the main findings from each aspect of the work, covering the benefits obtained from using the tendon drive system in terms of efficiencies and manoeuvring performance. The limitations of the system are also discussed and suggestions for further work are included

    Eye movements and natural tasks in an extended environment

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    Eye movements can be thought of as a window onto pre-conscious thought. Patterns of visual fixations over time as well as space can reveal cognitive strategies that are not amenable to conscious control or verbalization. A spatial analysis of an eye movement trace usually emphasizes the role that eye movements have in moving the retinal image of an object of interest from the periphery to the fovea for closer inspection. It is generally believed that a sequence of fixations across a region of space builds up the perception of a high-resolution field of view everywhere. Recent studies have shown that this perception is largely illusory. The visual-perceptual system prefers to maintain a limited internal representation of physical objects in the world and uses the environment as an external source of information, accessing the information only at the time it is needed. The goal of this research effort was to investigate the role that eye movements have in the performance of everyday tasks in a natural environment. A series of four experiments were conducted that represent an attempt to step away from the classical psychophysical approach of studying eye movements widiin the confines and contaol of the laboratory. There exists little precedence for this kind of approach, partly because past research efforts have emphasized a linear systems method to render the analysis tractable, and partly because the technology that is required to perform these experiments has not existed until recently. The hardware that was developed by the Visual Perception Laboratory at RIT specifically addresses the portability concerns that are crucial for successfully studying eye movements during natural tasks in a non-linear extended environment. A model was developed to describe the temporal sequencing of eye movements in terms of a hierarchical structure of goal-oriented tasks, with individual fixations considered the lowest level of the hierarchy. The analysis gives evidence for the sequencing of eye movements based on a desire to maximize the efficiency of task performance over time by anticipating future activities. The purpose of this sequencing is to enhance interaction with the world under conditions of limited memory representations rather than to create the perception of a high-resolution field of view

    Computer Vision and Image Understanding xxx

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    Abstract 12 A compact visual representation, called the 3D layered, adaptive-resolution, and multi-13 perspective panorama (LAMP), is proposed for representing large-scale 3D scenes with large 14 variations of depths and obvious occlusions. Two kinds of 3D LAMP representations are 15 proposed: the relief-like LAMP and the image-based LAMP. Both types of LAMPs con-16 cisely represent almost all the information from a long image sequence. Methods to con-17 struct LAMP representations from video sequences with dominant translation are 18 provided. The relief-like LAMP is basically a single extended multi-perspective panoramic 19 view image. Each pixel has a pair of texture and depth values, but each pixel may also have 20 multiple pairs of texture-depth values to represent occlusion in layers, in addition to adap-21 tive resolution changing with depth. The image-based LAMP, on the other hand, consists of 22 a set of multi-perspective layers, each of which has a pair of 2D texture and depth maps, 23 but with adaptive time-sampling scales depending on depths of scene points. Several exam-24 ples of 3D LAMP construction for real image sequences are given. The 3D LAMP is a con-25 cise and powerful representation for image-based rendering. 2
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