scholarly journals The Effects of Multiple Factors on Elderly Pedestrians’ Speed Perception and Stopping Distance Estimation of Approaching Vehicles

2020 ◽  
Vol 12 (13) ◽  
pp. 5308 ◽  
Author(s):  
Jiaming Shi ◽  
Changxu Wu ◽  
Xiuying Qian
Keyword(s):  
Distance Estimation ◽  
Weather Conditions ◽  
Accurate Estimation ◽  
Natural Conditions ◽  
Stopping Distance ◽  
Video Clips ◽  
Multiple Factors ◽  
Lighting Conditions ◽  
Speed Perception ◽  
Road Crossing

To make safe road-crossing decisions, it is necessary for pedestrians to accurately estimate the speed and stopping distance of approaching vehicles. Accordingly, the objective of our study was to examine the effects of multiple factors, such as weather conditions, context time (day or night), and illuminance of the roads, on older pedestrians’ (>60 years old) speed perception and stopping distance estimation of approaching vehicles. The participants in this study included 48 older participants who were asked to estimate the speed and stopping distance of approaching vehicles based on 12 s video clips that were selected from natural conditions. The results revealed that actual speeds, weather, context time, and lighting conditions played important roles in the performance of the participants. Compared with young adults, older pedestrians were found to have smaller accurate estimation intervals that varied by multidimensional influencing factors and thus resulted in missing road-crossing opportunities at lower vehicles’ speeds and increasing road-crossing dangers at higher speeds. The older pedestrians’ performance with respect to speed perception and stopping distance estimation is modeled using a regression model with a complex level of tasks. These models can be used by engineers when establishing speed limits and lighting conditions in the areas with senior residents.

scholarly journals Practical limitations of lane detection algorithm based on Hough transform in challenging scenarios

2021 ◽  
Vol 18 (2) ◽  
pp. 172988142110087
Author(s):  
Qiao Huang ◽  
Jinlong Liu
Keyword(s):  
Hough Transform ◽  
Detection Rate ◽  
Real Life ◽  
Weather Conditions ◽  
Autonomous Driving ◽  
Detection Algorithm ◽  
Lane Detection ◽  
Search Range ◽  
Range Restriction ◽  
Lighting Conditions

The vision-based road lane detection technique plays a key role in driver assistance system. While existing lane recognition algorithms demonstrated over 90% detection rate, the validation test was usually conducted on limited scenarios. Significant gaps still exist when applied in real-life autonomous driving. The goal of this article was to identify these gaps and to suggest research directions that can bridge them. The straight lane detection algorithm based on linear Hough transform (HT) was used in this study as an example to evaluate the possible perception issues under challenging scenarios, including various road types, different weather conditions and shades, changed lighting conditions, and so on. The study found that the HT-based algorithm presented an acceptable detection rate in simple backgrounds, such as driving on a highway or conditions showing distinguishable contrast between lane boundaries and their surroundings. However, it failed to recognize road dividing lines under varied lighting conditions. The failure was attributed to the binarization process failing to extract lane features before detections. In addition, the existing HT-based algorithm would be interfered by lane-like interferences, such as guardrails, railways, bikeways, utility poles, pedestrian sidewalks, buildings and so on. Overall, all these findings support the need for further improvements of current road lane detection algorithms to be robust against interference and illumination variations. Moreover, the widely used algorithm has the potential to raise the lane boundary detection rate if an appropriate search range restriction and illumination classification process is added.

A Survey of Approaches for Estimating Meteorological Visibility Distance Under Foggy Weather Conditions

2020 ◽  
pp. 65-92 ◽  
Author(s):  
Faouzi Kamoun ◽  
Hazar Chaabani ◽  
Fatma Outay ◽  
Ansar-Ul-Haque Yasar
Keyword(s):  
Intelligent Transportation Systems ◽  
Situational Awareness ◽  
Wide Spectrum ◽  
Distance Estimation ◽  
Weather Conditions ◽  
Transportation Systems ◽  
Driver Assistance Systems ◽  
Research Issues ◽  
Visibility Distance ◽  
Assistance Systems

The immaturity of fog abatement technologies for highway usage has led to growing interest towards developing intelligent transportation systems that are capable of estimating meteorological visibility distance under foggy weather conditions. This capability is crucial to support next-generation cooperative situational awareness and collision avoidance systems as well as onboard driver assistance systems. This chapter presents a survey and a comprehensive taxonomy of daytime visibility distance estimation approaches based on a review and synthesis of the literature. The proposed taxonomy is both comprehensive (i.e., captures a wide spectrum of earlier contributions) and effective (i.e., enables easy comparison among previously proposed approaches). The authors also highlight some open research issues that warrant further investigation.

scholarly journals Two-hop distance estimation in wireless sensor networks

2017 ◽  
Vol 13 (2) ◽  
pp. 155014771668968 ◽  
Author(s):  
Sunyong Kim ◽  
Sun Young Park ◽  
Daehoon Kwon ◽  
Jaehyun Ham ◽  
Young-Bae Ko ◽  
...  
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Estimation Error ◽  
Estimation Method ◽  
Distance Estimation ◽  
Wireless Sensor ◽  
Estimation Methods ◽  
Accurate Estimation ◽  
Distance Information ◽  
Wide Range

In wireless sensor networks, the accurate estimation of distances between sensor nodes is essential. In addition to the distance information available for immediate neighbors within a sensing range, the distance estimation of two-hop neighbors can be exploited in various wireless sensor network applications such as sensor localization, robust data transfer against hidden terminals, and geographic greedy routing. In this article, we propose a two-hop distance estimation method, which first obtains the region in which the two-hop neighbor nodes possibly exist and then takes the average of the distances to the points in that region. The improvement in the estimation accuracy achieved by the proposed method is analyzed in comparison with a simple summation method that adds two single-hop distances as an estimate of a two-hop distance. Numerical simulation results show that in comparison with other existing distance estimation methods, the proposed method significantly reduces the distance estimation error over a wide range of node densities.

scholarly journals Simulation Modeling of Aerial Work Completed by Helicopters in the Construction Industry Focused on Weather Conditions

2021 ◽  
Vol 13 (24) ◽  
pp. 13671
Author(s):  
Andrej Bisták ◽  
Zdenka Hulínová ◽  
Michal Neštiak ◽  
Barbara Chamulová
Keyword(s):  
Simulation Model ◽  
National Parks ◽  
Simulation Modeling ◽  
Simulation Models ◽  
Weather Forecast ◽  
Weather Conditions ◽  
Natural Conditions ◽  
Dominant Feature ◽  
Numerical Weather Forecast ◽  
The Given

The aim of this research was to develop a simulation model of the works carried out by helicopters, which are used in the construction of buildings under harsh natural conditions. This work identified that even technologies that we do not normally encounter, such as aerial work using helicopters, can have a major impact on ensuring the requirement of sustainability within the overall environmental and economic context. In the environment of protected landscape areas and national parks, in particular, where all sites are sensitive to human intervention, the use of helicopters in construction functions is an irreplaceable aid. Preparations for aerial work are very demanding and require the use of more sophisticated tools to achieve optimal results consistent within the paradigm of long-term sustainability. Simulation modeling is one such option, thanks to the considerable advancements made in information technology. A simulation model of aerial work was compiled within the presented work, and its functionality was verified using specific examples that confirmed in full the suitability of using simulations in the preparation of aerial work within construction. A detailed analysis of helicopter operations showed that an algorithm that accounts for future weather conditions at the construction site, and specifically focused on the conditions at the given altitude above the ground, should be a dominant feature of simulation models. It is exceptionally important that such data be known within the preparations for aerial work as accurately as possible, and, as such, this article describes the process of obtaining meteorological information for simulation models in detail using a numerical weather forecast and the reliability of data obtained in this manner. Based on the results obtained during this research, the proposed simulation model can be recommended as a suitable tool in the preparation of buildings. Its use is especially important if construction takes place under difficult natural conditions, where work cannot be carried out without the use of helicopters. We perceive the simulation model as a potential tool for digitizing construction preparations in the age of Industry 4.0.

scholarly journals The Calculated Circadian Effects of Light Exposure from Commuting

2021 ◽  
Vol 11 (24) ◽  
pp. 11846
Author(s):  
Yihan Lu ◽  
Wenye Hu ◽  
Wendy Davis
Keyword(s):  
Circadian Rhythms ◽  
Light Exposure ◽  
Weather Conditions ◽  
Health Problems ◽  
Spectral Irradiance ◽  
Metropolitan Region ◽  
Circadian Regulation ◽  
Lighting Conditions ◽  
Indoor Lighting ◽  
Daylight Exposure

Light entrains human circadian rhythms, but increased time spent indoors and decreased daylight exposure may disrupt human circadian regulation and cause health problems. Much research is focused on improving indoor lighting conditions to minimize the adverse circadian impact of electric lights, and few studies investigate the circadian impact of daylight during the incidental time that people spend outdoors. For instance, when people commute from home to work, they are exposed to daylight. The purpose of this study is to investigate daylight’s impact on commuters’ circadian rhythms. Measurements of the illuminance and the spectral irradiance distribution (SID) of daylight were taken for three modes of commuting: driving, riding on trains, and walking; and under different weather conditions, on different days, and at different locations throughout the summer and autumn in the Sydney metropolitan region in Australia. With the SID data, three metrics were calculated to estimate the circadian impacts: α-opic irradiance, circadian stimulus (CS), and equivalent melanopic lux (EML). The results suggest that driving or walking on sunny or cloudy days and riding trains on sunny days are beneficial for the commuters’ circadian synchronization.

scholarly journals Spatial resolution of unmanned aerial vehicles acquired imagery as a result of different processing conditions

2021 ◽  
Vol 67 (3) ◽  
pp. 148-154
Author(s):  
Jaroslav Kubišta ◽  
Peter Surový
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Spatial Resolution ◽  
Light Condition ◽  
Weather Conditions ◽  
Flight Speed ◽  
Lighting Conditions ◽  
Aerial Vehicles ◽  
Flight Height ◽  
The Impact ◽  
Imagery Data

Abstract Increasing availability of Unmanned aerial vehicles (UAV) and different software for processing of UAV imagery data brings new possibilities for on-demand monitoring of environment, making it accessible to broader spectra of professionals with variable expertise in image processing and analysis. This brings also new questions related to imagery quality standards. One of important characteristics of imagery is its spatial resolution as it directly impacts the results of object recognition and further imagery processing. This study aims at identifying relationship between spatial resolution of UAV acquired imagery and variables of imagery acquiring conditions, especially UAV flight height, flight speed and lighting conditions. All of these characteristics has been proved as significantly influencing spatial resolution quality and all subsequent data based on this imagery. Higher flight height as well as flight speed brings lower spatial resolution, whereas better lighting conditions lead to better spatial resolution of imagery. In this article we conducted a study testing various heights, flight speeds and light conditions and tested the impact of these parameters on Ground Resolved Distance (GRD). We proved that from among the variables, height is the most significant factor, second position is speed and finally the light condition. All of these factors could be relevant for instance in implementation of UAV in forestry sector, where imagery data must be often collected in diverse terrain conditions and/or complex stand (especially vertical) structure, as well as different weather conditions.

scholarly journals Visual Information Requirements for Remotely Supervised Autonomous Agricultural Machines

2020 ◽  
Vol 10 (8) ◽  
pp. 2794 ◽  
Author(s):  
Uduak Edet ◽  
Daniel Mann
Keyword(s):  
Visual Information ◽  
Weather Conditions ◽  
Relevant Information ◽  
Field Of View ◽  
Graphical Display ◽  
Live Video ◽  
Video Footage ◽  
Video Clips ◽  
The Look ◽  
Agricultural Machines

A study to determine the visual requirements for a remote supervisor of an autonomous sprayer was conducted. Observation of a sprayer operator identified 9 distinct “look zones” that occupied his visual attention, with 39% of his time spent viewing the look zone ahead of the sprayer. While observation of the sprayer operator was being completed, additional GoPro cameras were used to record video of the sprayer in operation from 10 distinct perspectives (some look zones were visible from the operator’s seat, but other look zones were selected to display other regions of the sprayer that might be of interest to a sprayer operator). In a subsequent laboratory study, 29 experienced sprayer operators were recruited to view and comment on video clips selected from the video footage collected during the initial ride-along. Only the two views from the perspective of the operator’s seat were rated highly as providing important information even though participants were able to identify relevant information from all ten of the video clips. Generally, participants used the video clips to obtain information about the boom status, the location and movement of the sprayer within the field, the weather conditions (especially the wind), obstacles to be avoided, crop conditions, and field conditions. Sprayer operators with more than 15 years of experience provided more insightful descriptions of the video clips than their less experienced peers. Designers can influence which features the user will perceive by positioning the camera such that those specific features are prominent in the camera’s field of view. Overall, experienced sprayer operators preferred the concept of presenting visual information on an automation interface using live video rather than presenting that same information using some type of graphical display using icons or symbols.

scholarly journals Underwater Wireless Sensor Networks: Estimation of Acoustic Channel in Shallow Water

2020 ◽  
Vol 10 (18) ◽  
pp. 6393
Author(s):  
Elma Zanaj ◽  
Ennio Gambi ◽  
Blerina Zanaj ◽  
Deivis Disha ◽  
Nels Kola
Keyword(s):  
Sensor Networks ◽  
Capacity Utilization ◽  
Environmental Parameters ◽  
Specific Area ◽  
Weather Conditions ◽  
Accurate Estimation ◽  
Underwater Sensor Networks ◽  
Acoustic Channel ◽  
Communication Capacity ◽  
Component Material

Underwater sensor networks (UWSN) include a large number of devices and sensors which are positioned in a specific area to carry out monitoring in cooperation with each other as well as data collection. In this paper it has been studied and simulated the performance of an extremely important parameter for communication in UWSN such as the acoustic channel capacity as function of water temperature and salinity arise. The performance’s knowledge on acoustic channel may be improved with a deep study of its dependence by season, weather conditions or environmental parameters variation. If an accurate estimation of the acoustic communication capacity utilization for a given area is required, we must consider also the bottom materials of this area. The simulation results presented in this study through an improved algorithm, will help to understand better the underwater acoustic channel performance as a function of all these factors. This is of particular importance for acoustic modems designing, in order to implement suitable functionalities able to adapt the data transmission capacity of the acoustic link to the structure of the oceanic bottom and its component material.

Classification of Building Images in Video Sequences

2014 ◽  
pp. 64-68
Keyword(s):  
Fuzzy Rule ◽  
Weather Conditions ◽  
Severe Weather ◽  
Video Sequences ◽  
Rule Based ◽  
Region Detection ◽  
Lighting Conditions ◽  
Illumination Changes ◽  
Outdoor Environments

A technique for detection of building images in real-world video sequences is presented. The proposed technique uses information extracted from video features to improve precision in classification results. It combines fuzzy rule-based classification with a method for changing region detection in outdoor environments, which is invariant to extreme illumination changes and severe weather conditions. It has been tested on sequences under various lighting conditions. Satisfactory and promising results have been achieved.

scholarly journals ASSESMENT OF THE INFLUENCE OF UAV IMAGE QUALITY ON THE ORTHOPHOTO PRODUCTION

2015 ◽  
Vol XL-1/W4 ◽  
pp. 1-8 ◽  
Author(s):  
D. Wierzbicki ◽  
M. Kedzierski ◽  
A. Fryskowska
Keyword(s):  
Large Scale ◽  
Digital Terrain Model ◽  
Image Data ◽  
Weather Conditions ◽  
Noticeable Increase ◽  
Terrain Model ◽  
Digital Terrain ◽  
Lighting Conditions ◽  
Terrain Models ◽  
Uav Image

Over the past years a noticeable increase of interest in using Unmanned Aerial Vehicles (UAV) for acquiring low altitude images has been observed. This method creates new possibilities of using geodata captured from low altitudes to generate large scale orthophotos. Because of comparatively low costs, UAV aerial surveying systems find many applications in photogrammetry and remote sensing. One of the most significant problems with automation of processing of image data acquired with this method is its low accuracy. This paper presents the following stages of acquisition and processing of images collected in various weather and lighting conditions: aerotriangulation, generating of Digital Terrain Models (DTMs), orthorectification and mosaicking. In the research a compact, non-metric camera, mounted on a fuselage powered by an electric motor was used. The tested area covered flat, agricultural and woodland terrains. Aerotriangulation and point cloud accuracy as well as generated digital terrain model and mosaic exactness were examined. Dense multiple image matching was used as a benchmark. The processing and analysis were carried out with INPHO UASMaster programme. Based on performed accuracy analysis it was stated that images acquired in poor weather conditions (cloudy, precipitation) degrade the final quality and accuracy of a photogrammetric product by an average of 25%.

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