Obstacle

About: Obstacle is a research topic. Over the lifetime, 9517 publications have been published within this topic receiving 94760 citations. The topic is also known as: impediment & barrier.

Ultrasonic and Infrared Sensors Performance in a Wireless Obstacle Detection System

Abstract: Ultrasonic (US) and infrared (IR) sensors are broadly used in mobile applications for distance measurements. In this project, an obstacle detection system is built based on these two types of sensors. The system is intended for use by the elderly and people with vision impairment. The prototype developed has been tested to detect obstacles and shows accuracies of 95% to 99% for distance measurements if the sensor circuits are calibrated properly and their output linearized. The system also demonstrates good detection for different obstacle materials (e.g., wood, plastic, mirror, plywood and concretes) and colors. The minimum size of an obstacle that the system can detect is 5 cm x 5 cm.

Obstacle detection using a 2D LIDAR system for an Autonomous Vehicle

Abstract: Obstacle detection is a requirement for Advanced Driver Assistance Systems (ADAS) which are the precursors to autonomous vehicle systems. A number of sensor systems have been used before to perform obstacle detection. One particular sensor system is the LIDAR system which is noted for its accuracy in measuring distances. However, most commercially available LIDAR (Light Detection and Ranging) systems are expensive and computationally intensive. This research characterizes an inexpensive 2D LIDAR system using the LIDAR-Lite v1 for use in obstacle detection for autonomous vehicles. Since data acquisition occurs only in a single plane, the system should be computationally fast. The field of vision should be capable of up to 360 degrees. The data acquired was median-filtered and pre-processed by the merging and segmentation of data points. Obstacle detection was then performed via clustering. Results show that obstacles with widths of 1 meter can be detected at distances of 10 meters.

Running support system for vehicle

Abstract: There is provided a running support system for a vehicle, which supports running of a vehicle by using a radar and image recognition means as obstacle detecting means, and in which appropriate support control based on a result of detection performed by each control means is set. A result of obstacle detection performed by a millimeter wave radar (21) is checked against a result of obstacle detection performed by image recognition means (22). Then, a starting condition for the running support control is changed depending on whether an obstacle has been detected by both the millimeter wave radar (21) and the image recognition means (22), or an obstacle has been detected by only one of the millimeter wave radar (21) and the image recognition means (22). Thus, the control support is performed based on an inattentive condition of a driver.

Effect of a Shallow Water Obstruction on Long Wave Runup and Overland Flow Velocity

Abstract: A study is presented to examine the one-horizontal dimension effect of a shallow shelf obstacle on nonlinear long wave runup. Due to the large horizontal-vertical aspect ratio of this problem, it is not well suited for experimental analysis, and therefore this study is purely numerical. Simulations are performed for various incident wave conditions, obstacle height and widths, and final beach slopes. Many of the setups involve breaking, either through approaching the obstacle as a large breaking bore, incipient breaking on top of the obstacle, or breaking during the beach uprush. The general conclusion of this study is that, for highly nonlinear waves wave height/shelf water depth 0.5, the obstacle will always act to reduce the runup and the maximum overland velocity. However, for very small obstacle lengths, particularly for extremely large waves, this reduction may be practically inconsequential. Interestingly, for weakly nonlinear waves 0.1, due to front steepening over the obstacle, greater overland velocities can result from increasing obstacle length. Consistent with previous studies, it is found that the final beach slope is of primary importance for determining the runup.

Device and method for detection of moving obstacles

Abstract: A moving obstacle detecting device detects moving objects, may be applied in the field of autonomous vehicles, intelligent robots, video monitoring system and similar systems. The device includes an optical flow extracting unit 1 for extracting optical flows for the respective local regions in the measured images, an focus of expansion (F.O.E.) calculating unit for calculating an F.O.E. of a straight line extended by the extracted optical flows, and a moving obstacle detecting unit for analyzing a temporal change of the calculated F.O.E. to judge the presence of the moving obstacle when the temporal positional change is larger than a predetermined variation quantity.