Browsing by Author "Papanikolopoulos, Nikos"
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Item Autonomous Docking for an eROSI Robot Based on a Vision System with Points Clustering(2007-01-26) Min Jeong, Hyeun; Drenner, Andrew; Papanikolopoulos, NikosThis paper presents an autonomous docking system based on visual cues on a docking station. Autonomous docking is essential for large scale robotic teams to be delivered by larger robots, recovered, recharged, and redeployed for continuous operation. Using a computer vision based approach, we identify cues to line up for docking by extracting corner pixels and combining this information with color information. Potential target points are extracted and clustered using Euclidean distance in the image plane. Using these clusters of points the appropriate motion behavior is selected to reposition the robot into the desired position and orientation. This paper will present examples of this implementation using an eROSI robot which uses only vision to navigate.Item A Comprehensive System for Assessing Truck Parking Availability(Center for Transportation Studies, University of Minnesota, 2017-01) Morris, Ted; Murray, Dan; Fender, Kate; Weber, Amanda; Morellas, Vassilios; Cook, Doug; Papanikolopoulos, NikosCommercial heavy vehicle (CHV) drivers are required under federal Hours of Services (HOS) rules to rest and take breaks to reduce driving while fatigued. CHV drivers and operators must balance compliance to the HOS rules against on-time delivery requirements as well as shorter lead times to plan their trips, thereby making location and parking availability of rest area facilities more critical. Without timely, accurate parking availability information, drivers are left with the dilemma of continuing to drive fatigued, drive beyond HOS CHV operation limits, or park illegally on highway shoulders or ramps—all potential safety hazards. In this study, a multi-view camera system was designed and evaluated to detect truck parking space occupancy in real-time through extensive field operational testing. A system architecture was then developed to disseminate up-to-the-minute truck parking information through three separate information delivery systems: 1) Roadside Changeable Message Signs (CMS), 2) Internet/Website information portal, and 3) an onboard geolocation application. The latter application informs the driver of parking availability of one or more parking facilities that are downstream from their current direction of travel. All three notification mechanisms were evaluated during the field test. Survey studies were conducted to provide feedback from commercial heavy vehicle drivers and operators to better understand their perceptions of parking shortages and utility of the parking information delivery mechanisms. Overall, the system has proven to provide 24/7 around-the-clock per-space parking status with no need for manual interventions to correct detection errors, with per parking space accuracy typically equal to or exceeding 95 percent. The concept of operations field tests demonstrated the feasibility of the technical approach and the potential to alter freight borne trip behaviors by allowing drivers and carriers to plan stops and improve trip efficiency.Item A Real-Time Truck Availability System for the State of Wisconsin(Center for Transportation Studies, University of Minnesota, 2018-05) Morris, Ted; Henderson, Travis; Morellas, Vassilios; Papanikolopoulos, NikosIndependent of truck parking capacity shortages, obtaining reliable and timely information has been receiving considerable attention nationally as of late. The situation has been exacerbated by increasing levels of freightborne truck volumes along many regional and interstate corridors and the need for carriers and drivers to balance efficient transport with required periods to park and rest to minimize driver fatigue. Interstate 94, a nationally designated freight corridor, as it passes through the Upper Midwest, including Wisconsin, shares this problem. A multi-camera computer vision detection system was deployed at a state sponsored rest area truck parking facility 67 miles east of Minneapolis. A key aspect of the system is that it is a completely automated 24/7, non-intrusive, parking detection system; there is no need to intervene with manual resets or re-calibration procedures, and pavements are not disturbed. Secondly, a region-wide truck parking notification architecture, recognized as an emerging national standard, was integrated with the detection system to provide real-time roadside truck parking notifications upstream of the facilities, as well as notification to other third party stakeholders. The overall detection accuracy was between 90 and 95 percent during up-to-the minute, per-space parking status notifications.Item Video Detection and Classification of Pedestrian Events at Roundabouts and Crosswalks(Intelligent Transportation Systems Institute, Center for Transportation Studies, 2013-08) Morris, Ted; Li, Xinyan; Morellas, Vassilios; Papanikolopoulos, NikosA well-established technique for studying pedestrian safety is based on reducing data from video-based in-situ observation. The extraction and cataloging from recorded video of pedestrian crossing events has largely been achieved manually. Although the manual methods are generally reliable, they are extremely time-consuming. As a result, more detailed, encompassing site studies are not practical unless the mining for these events can be automated. The study investigated such a tool based on utilizing a novel image processing algorithm recently developed for the extraction of human activities in complex scenes. No human intervention other than defining regions of interest for approaching vehicles and the pedestrian crossing areas was required. The output quantified general event indicators—such as pedestrian wait time, and crossing time and vehicle-pedestrian yield behaviors. Such data can then be used to guide more detailed analyses of the events to study potential vehicle-pedestrian conflicts and their causal effects. The evaluation was done using an extensive set of multi-camera video recordings collected at roundabouts. The tool can be used to support other pedestrian safety research where extracting potential pedestrian-vehicle conflicts from video are required, for example at crosswalks at urban signalized and uncontrolled intersections.