1,240 research outputs found

    Adaptive smoothness constraint image multilevel fuzzy enhancement algorithm

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    For the problems of poor enhancement effect and long time consuming of the traditional algorithm, an adaptive smoothness constraint image multilevel fuzzy enhancement algorithm based on secondary color-to-grayscale conversion is proposed. By using fuzzy set theory and generalized fuzzy set theory, a new linear generalized fuzzy operator transformation is carried out to obtain a new linear generalized fuzzy operator. By using linear generalized membership transformation and inverse transformation, secondary color-to-grayscale conversion of adaptive smoothness constraint image is performed. Combined with generalized fuzzy operator, the region contrast fuzzy enhancement of adaptive smoothness constraint image is realized, and image multilevel fuzzy enhancement is realized. Experimental results show that the fuzzy degree of the image is reduced by the improved algorithm, and the clarity of the adaptive smoothness constraint image is improved effectively. The time consuming is short, and it has some advantages

    Intelligent Computational Transportation

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    Transportation is commonplace around our world. Numerous researchers dedicate great efforts to vast transportation research topics. The purpose of this dissertation is to investigate and address a couple of transportation problems with respect to geographic discretization, pavement surface automatic examination, and traffic ow simulation, using advanced computational technologies. Many applications require a discretized 2D geographic map such that local information can be accessed efficiently. For example, map matching, which aligns a sequence of observed positions to a real-world road network, needs to find all the nearby road segments to the individual positions. To this end, the map is discretized by cells and each cell retains a list of road segments coincident with this cell. An efficient method is proposed to form such lists for the cells without costly overlapping tests. Furthermore, the method can be easily extended to 3D scenarios for fast triangle mesh voxelization. Pavement surface distress conditions are critical inputs for quantifying roadway infrastructure serviceability. Existing computer-aided automatic examination techniques are mainly based on 2D image analysis or 3D georeferenced data set. The disadvantage of information losses or extremely high costs impedes their effectiveness iv and applicability. In this study, a cost-effective Kinect-based approach is proposed for 3D pavement surface reconstruction and cracking recognition. Various cracking measurements such as alligator cracking, traverse cracking, longitudinal cracking, etc., are identified and recognized for their severity examinations based on associated geometrical features. Smart transportation is one of the core components in modern urbanization processes. Under this context, the Connected Autonomous Vehicle (CAV) system presents a promising solution towards the enhanced traffic safety and mobility through state-of-the-art wireless communications and autonomous driving techniques. Due to the different nature between the CAVs and the conventional Human- Driven-Vehicles (HDVs), it is believed that CAV-enabled transportation systems will revolutionize the existing understanding of network-wide traffic operations and re-establish traffic ow theory. This study presents a new continuum dynamics model for the future CAV-enabled traffic system, realized by encapsulating mutually-coupled vehicle interactions using virtual internal and external forces. A Smoothed Particle Hydrodynamics (SPH)-based numerical simulation and an interactive traffic visualization framework are also developed

    ๋ฌด์ธ ์ž์œจ์ฃผํ–‰ ์ฐจ๋Ÿ‰์„ ์œ„ํ•œ ๋‹จ์•ˆ ์นด๋ฉ”๋ผ ๊ธฐ๋ฐ˜ ์‹ค์‹œ๊ฐ„ ์ฃผํ–‰ ํ™˜๊ฒฝ ์ธ์‹ ๊ธฐ๋ฒ•์— ๊ด€ํ•œ ์—ฐ๊ตฌ

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    ํ•™์œ„๋…ผ๋ฌธ (๋ฐ•์‚ฌ)-- ์„œ์šธ๋Œ€ํ•™๊ต ๋Œ€ํ•™์› : ์ „๊ธฐ๊ณตํ•™๋ถ€, 2014. 2. ์„œ์Šน์šฐ.Homo Faber, refers to humans as controlling the environments through tools. From the beginning of the world, humans create tools for chasing the convenient life. The desire for the rapid movement let the human ride on horseback, make the wagon and finally make the vehicle. The vehicle made humans possible to travel the long distance very quickly as well as conveniently. However, since human being itself is imperfect, plenty of people have died due to the car accident, and people are dying at this moment. The research for autonomous vehicle has been conducted to satisfy the humans desire of the safety as the best alternative. And, the dream of autonomous vehicle will be come true in the near future. For the implementation of autonomous vehicle, many kinds of techniques are required, among which, the recognition of the environment around the vehicle is one of the most fundamental and important problems. For the recognition of surrounding objects many kinds of sensors can be utilized, however, the monocular camera can collect the largest information among sensors as well as can be utilized for the variety of purposes, and can be adopted for the various vehicle types due to the good price competitiveness. I expect that the research using the monocular camera for autonomous vehicle is very practical and useful. In this dissertation, I cover four important recognition problems for autonomous driving by using monocular camera in vehicular environment. Firstly, to drive the way autonomously the vehicle has to recognize lanes and keep its lane. However, the detection of lane markings under the various illuminant variation is very difficult in the image processing area. Nevertheless, it must be solved for the autonomous driving. The first research topic is the robust lane marking extraction under the illumination variations for multilane detection. I proposed the new lane marking extraction filter that can detect the imperfect lane markings as well as the new false positive cancelling algorithm that can eliminate noise markings. This approach can extract lane markings successfully even under the bad illumination conditions. Secondly, the problem to tackle, is if there is no lane marking on the road, then how the autonomous vehicle can recognize the road to run? In addition, what is the current lane position of the road? The latter is the important question since we can make a decision for lane change or keeping depending on the current position of lane. The second research is for handling those two problems, and I proposed the approach for the fusing the road detection and the lane position estimation. Thirdly, to drive more safely, keeping the safety distance is very important. Additionally, many equipments for the driving safety require the distance information. Measuring accurate inter-vehicle distance by using monocular camera and line laser is the third research topic. To measure the inter-vehicle distance, I illuminate the line laser on the front side of vehicle, and measure the length of the laser line and lane width in the image. Based on the imaging geometry, the distance calculation problem can be solved with accuracy. There are still many of important problems are remaining to be solved, and I proposed some approaches by using the monocular camera to handle the important problems. I expect very active researches will be continuously conducted and, based on the researches, the era of autonomous vehicle will come in the near future.1 Introduction 1.1 Background and Motivations 1.2 Contributions and Outline of the Dissertation 1.2.1 Illumination-Tolerant Lane Marking Extraction for Multilane Detection 1.2.2 Fusing Road Detection and Lane Position Estimation for the Robust Road Boundary Estimation 1.2.3 Accurate Inter-Vehicle Distance Measurement based on Monocular Camera and Line Laser 2 Illumination-Tolerant Lane Marking Extraction for Multilane Detection 2.1 Introduction 2.2 Lane Marking Candidate Extraction Filter 2.2.1 Requirements of the Filter 2.2.2 A Comparison of Filter Characteristics 2.2.3 Cone Hat Filter 2.3 Overview of the Proposed Algorithm 2.3.1 Filter Width Estimation 2.3.2 Top Hat (Cone Hat) Filtering 2.3.3 Reiterated Extraction 2.3.4 False Positive Cancelling 2.3.4.1 Lane Marking Center Point Extraction 2.3.4.2 Fast Center Point Segmentation 2.3.4.3 Vanishing Point Detection 2.3.4.4 Segment Extraction 2.3.4.5 False Positive Filtering 2.4 Experiments and Evaluation 2.4.1 Experimental Set-up 2.4.2 Conventional Algorithm for Evaluation 2.4.2.1 Global threshold 2.4.2.2 Positive Negative Gradient 2.4.2.3 Local Threshold 2.4.2.4 Symmetry Local Threshold 2.4.2.5 Double Extraction using Symmetry Local Threshold 2.4.2.6 Gaussian Filter 2.4.3 Experimental Results 2.4.4 Summary 3 Fusing Road Detection and Lane Position Estimation for the Robust Road Boundary Estimation 3.1 Introduction 3.2 Chromaticity-based Flood-fill Method 3.2.1 Illuminant-Invariant Space 3.2.2 Road Pixel Selection 3.2.3 Flood-fill Algorithm 3.3 Lane Position Estimation 3.3.1 Lane Marking Extraction 3.3.2 Proposed Lane Position Detection Algorithm 3.3.3 Birds-eye View Transformation by using the Proposed Dynamic Homography Matrix Generation 3.3.4 Next Lane Position Estimation based on the Cross-ratio 3.3.5 Forward-looking View Transformation 3.4 Information Fusion Between Road Detection and Lane Position Estimation 3.4.1 The Case of Detection Failures 3.4.2 The Benefit of Information Fusion 3.5 Experiments and Evaluation 3.6 Summary 4 Accurate Inter-Vehicle Distance Measurement based on Monocular Camera and Line Laser 4.1 Introduction 4.2 Proposed Distance Measurement Algorithm 4.3 Experiments and Evaluation 4.3.1 Experimental System Set-up 4.3.2 Experimental Results 4.4 Summary 5 ConclusionDocto

    1994 NASA-HU American Society for Engineering Education (ASEE) Summer Faculty Fellowship Program

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    Since 1964, the National Aeronautics and Space Administration (NASA) has supported a program of summer faculty fellowships for engineering and science educators. In a series of collaborations between NASA research and development centers and nearby universities, engineering faculty members spend 10 weeks working with professional peers on research. The Summer Faculty Program Committee of the American Society for Engineering Education supervises the programs. Objectives: (1) To further the professional knowledge of qualified engineering and science faculty members; (2) To stimulate and exchange ideas between participants and NASA; (3) To enrich and refresh the research and teaching activities of participants' institutions; (4) To contribute to the research objectives of the NASA center

    A Three-Dimensional Heads-Up Primary Navigation Reference Display for Paratroopers Performing High Altitude High Open Jumps

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    The Department of Defense (DoD) relies on the para-dropping of resources to meet different objectives in order to accomplish missions during peace-time, war-time, or military operations other than war. The resources dropped to the ground via parachute range from supplies and equipment to the most valued asset, people. Tactics have been developed to increase the safety of troops parachuting into areas of conflict. These tactics include high-altitude high-opening (HAHO) jumping and night jumping. HAHO jumping allows paratroopers to travel large distances in the air away from the path of the delivering aircraft. While night jumping, done with the aid of night vision goggles (NVGs), provides paratroopers with the cover of night. Both of these tactics aid in avoiding detection. These techniques, however, have their drawback: low cloud cover and fog can often delay mission accomplishment due to a lack of visibility. However, low cloud cover and foggy conditions also provide a tremendous aid in covert insertion missions and enhance the element of surprise. This research introduces a novel application combining three-dimensional graphics and GPS for a primary navigation reference for paratroopers. It uses three-dimensional graphics to realistically portray a paratrooper\u27s movement in the physical world, measured by GPS, as movement in a computer generated scene. This reference, presented as a heads-up display on the NGVs paratroopers already wear, facilitates mission accomplishment in cloudy and foggy conditions. Evaluation of a prototype system validates the effectiveness of such a three-dimensional navigation reference for paratroopers

    A framework based on Gaussian mixture models and Kalman filters for the segmentation and tracking of anomalous events in shipboard video

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    Anomalous indications in monitoring equipment on board U.S. Navy vessels must be handled in a timely manner to prevent catastrophic system failure. The development of sensor data analysis techniques to assist a ship\u27s crew in monitoring machinery and summon required ship-to-shore assistance is of considerable benefit to the Navy. In addition, the Navy has a large interest in the development of distance support technology in its ongoing efforts to reduce manning on ships. In this thesis, algorithms have been developed for the detection of anomalous events that can be identified from the analysis of monochromatic stationary ship surveillance video streams. The specific anomalies that we have focused on are the presence and growth of smoke and fire events inside the frames of the video stream. The algorithm consists of the following steps. First, a foreground segmentation algorithm based on adaptive Gaussian mixture models is employed to detect the presence of motion in a scene. The algorithm is adapted to emphasize gray-level characteristics related to smoke and fire events in the frame. Next, shape discriminant features in the foreground are enhanced using morphological operations. Following this step, the anomalous indication is tracked between frames using Kalman filtering. Finally, gray level shape and motion features corresponding to the anomaly are subjected to principal component analysis and classified using a multilayer perceptron neural network. The algorithm is exercised on 68 video streams that include the presence of anomalous events (such as fire and smoke) and benign/nuisance events (such as humans walking the field of view). Initial results show that the algorithm is successful in detecting anomalies in video streams, and is suitable for application in shipboard environments

    Investigating Key Techniques to Leverage the Functionality of Ground/Wall Penetrating Radar

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    Ground penetrating radar (GPR) has been extensively utilized as a highly efficient and non-destructive testing method for infrastructure evaluation, such as highway rebar detection, bridge decks inspection, asphalt pavement monitoring, underground pipe leakage detection, railroad ballast assessment, etc. The focus of this dissertation is to investigate the key techniques to tackle with GPR signal processing from three perspectives: (1) Removing or suppressing the radar clutter signal; (2) Detecting the underground target or the region of interest (RoI) in the GPR image; (3) Imaging the underground target to eliminate or alleviate the feature distortion and reconstructing the shape of the target with good fidelity. In the first part of this dissertation, a low-rank and sparse representation based approach is designed to remove the clutter produced by rough ground surface reflection for impulse radar. In the second part, Hilbert Transform and 2-D Renyi entropy based statistical analysis is explored to improve RoI detection efficiency and to reduce the computational cost for more sophisticated data post-processing. In the third part, a back-projection imaging algorithm is designed for both ground-coupled and air-coupled multistatic GPR configurations. Since the refraction phenomenon at the air-ground interface is considered and the spatial offsets between the transceiver antennas are compensated in this algorithm, the data points collected by receiver antennas in time domain can be accurately mapped back to the spatial domain and the targets can be imaged in the scene space under testing. Experimental results validate that the proposed three-stage cascade signal processing methodologies can improve the performance of GPR system

    Aspects of Synthetic Vision Display Systems and the Best Practices of the NASA's SVS Project

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    NASA s Synthetic Vision Systems (SVS) Project conducted research aimed at eliminating visibility-induced errors and low visibility conditions as causal factors in civil aircraft accidents while enabling the operational benefits of clear day flight operations regardless of actual outside visibility. SVS takes advantage of many enabling technologies to achieve this capability including, for example, the Global Positioning System (GPS), data links, radar, imaging sensors, geospatial databases, advanced display media and three dimensional video graphics processors. Integration of these technologies to achieve the SVS concept provides pilots with high-integrity information that improves situational awareness with respect to terrain, obstacles, traffic, and flight path. This paper attempts to emphasize the system aspects of SVS - true systems, rather than just terrain on a flight display - and to document from an historical viewpoint many of the best practices that evolved during the SVS Project from the perspective of some of the NASA researchers most heavily involved in its execution. The Integrated SVS Concepts are envisagements of what production-grade Synthetic Vision systems might, or perhaps should, be in order to provide the desired functional capabilities that eliminate low visibility as a causal factor to accidents and enable clear-day operational benefits regardless of visibility conditions

    The NASA SBIR product catalog

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    The purpose of this catalog is to assist small business firms in making the community aware of products emerging from their efforts in the Small Business Innovation Research (SBIR) program. It contains descriptions of some products that have advanced into Phase 3 and others that are identified as prospective products. Both lists of products in this catalog are based on information supplied by NASA SBIR contractors in responding to an invitation to be represented in this document. Generally, all products suggested by the small firms were included in order to meet the goals of information exchange for SBIR results. Of the 444 SBIR contractors NASA queried, 137 provided information on 219 products. The catalog presents the product information in the technology areas listed in the table of contents. Within each area, the products are listed in alphabetical order by product name and are given identifying numbers. Also included is an alphabetical listing of the companies that have products described. This listing cross-references the product list and provides information on the business activity of each firm. In addition, there are three indexes: one a list of firms by states, one that lists the products according to NASA Centers that managed the SBIR projects, and one that lists the products by the relevant Technical Topics utilized in NASA's annual program solicitation under which each SBIR project was selected
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