scholarly journals Obstacle Detection Challenges of Camera Sensor Designed for ADAS

2020 ◽  
Vol 9 (11) ◽  
pp. 90-98
Keyword(s):  
Weather Conditions ◽  
Obstacle Detection ◽  
Good Resolution ◽  
Computational Load ◽  
Respective Solution ◽  
Camera Sensor

Camera is a very crucial sensor for ADAS which is commonly used in all the vehicles to assist driver by providing information about all the obstacles around the vehicle during a drive. The Camera sensor is a vision based sensor and it is highly preferred because of its advantages like excellent in classification, good resolution, very economical and small in size. Still this sensor is having some disadvantages like huge computational load, failed to detect obstacles due to poor light and weather conditions and even less capable to estimate the distance from the obstacle. In recent years so many research works were performed to overcome these challenges, for making the camera a robust sensor. In this paper, the challenges in detection faced by camera sensor were focused and their respective solution is discussed, which are required to improve the effectiveness in vision based detection.

scholarly journals Sensing Technology Survey for Obstacle Detection in Vegetation

2021 ◽  
Vol 1 (3) ◽  
pp. 672-685
Author(s):  
Shreya Lohar ◽  
Lei Zhu ◽  
Stanley Young ◽  
Peter Graf ◽  
Michael Blanton
Keyword(s):  
Autonomous Vehicles ◽  
Weather Conditions ◽  
Climatic Conditions ◽  
Obstacle Detection ◽  
Agricultural Field ◽  
Thermal Camera ◽  
Agricultural Vehicles ◽  
Sensing Systems ◽  
Sensing Technology ◽  
Hyperspectral Sensing

This study reviews obstacle detection technologies in vegetation for autonomous vehicles or robots. Autonomous vehicles used in agriculture and as lawn mowers face many environmental obstacles that are difficult to recognize for the vehicle sensor. This review provides information on choosing appropriate sensors to detect obstacles through vegetation, based on experiments carried out in different agricultural fields. The experimental setup from the literature consists of sensors placed in front of obstacles, including a thermal camera; red, green, blue (RGB) camera; 360° camera; light detection and ranging (LiDAR); and radar. These sensors were used either in combination or single-handedly on agricultural vehicles to detect objects hidden inside the agricultural field. The thermal camera successfully detected hidden objects, such as barrels, human mannequins, and humans, as did LiDAR in one experiment. The RGB camera and stereo camera were less efficient at detecting hidden objects compared with protruding objects. Radar detects hidden objects easily but lacks resolution. Hyperspectral sensing systems can identify and classify objects, but they consume a lot of storage. To obtain clearer and more robust data of hidden objects in vegetation and extreme weather conditions, further experiments should be performed for various climatic conditions combining active and passive sensors.

scholarly journals INSPEX: Optimize Range Sensors for Environment Perception as a Portable System

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4350 ◽  
Author(s):  
Julie Foucault ◽  
Suzanne Lesecq ◽  
Gabriela Dudnik ◽  
Marc Correvon ◽  
Rosemary O’Keeffe ◽  
...  
Keyword(s):  
Weather Conditions ◽  
Obstacle Detection ◽  
Ultra Wideband ◽  
Human Beings ◽  
Computational Capability ◽  
Perception System ◽  
Environment Perception ◽  
Wideband Radar ◽  
Multiple Sensing ◽  
Range Sensors

Environment perception is crucial for the safe navigation of vehicles and robots to detect obstacles in their surroundings. It is also of paramount interest for navigation of human beings in reduced visibility conditions. Obstacle avoidance systems typically combine multiple sensing technologies (i.e., LiDAR, radar, ultrasound and visual) to detect various types of obstacles under different lighting and weather conditions, with the drawbacks of a given technology being offset by others. These systems require powerful computational capability to fuse the mass of data, which limits their use to high-end vehicles and robots. INSPEX delivers a low-power, small-size and lightweight environment perception system that is compatible with portable and/or wearable applications. This requires miniaturizing and optimizing existing range sensors of different technologies to meet the user’s requirements in terms of obstacle detection capabilities. These sensors consist of a LiDAR, a time-of-flight sensor, an ultrasound and an ultra-wideband radar with measurement ranges respectively of 10 m, 4 m, 2 m and 10 m. Integration of a data fusion technique is also required to build a model of the user’s surroundings and provide feedback about the localization of harmful obstacles. As primary demonstrator, the INSPEX device will be fixed on a white cane.

scholarly journals Light Transmission in Fog: The Influence of Wavelength on the Extinction Coefficient

2019 ◽  
Vol 9 (14) ◽  
pp. 2843 ◽  
Author(s):  
Pierre Duthon ◽  
Michèle Colomb ◽  
Frédéric Bernardin
Keyword(s):  
Extinction Coefficient ◽  
Light Transmission ◽  
Small Difference ◽  
Droplet Size Distribution ◽  
Weather Conditions ◽  
Autonomous Driving ◽  
Obstacle Detection ◽  
Intelligent Vehicles ◽  
Adverse Weather Conditions ◽  
Adverse Weather

Autonomous driving is based on innovative technologies that have to ensure that vehicles are driven safely. LiDARs are one of the reference sensors for obstacle detection. However, this technology is affected by adverse weather conditions, especially fog. Different wavelengths are investigated to meet this challenge (905 nm vs. 1550 nm). The influence of wavelength on light transmission in fog is then examined and results reported. A theoretical approach by calculating the extinction coefficient for different wavelengths is presented in comparison to measurements with a spectroradiometer in the range of 350 nm–2450 nm. The experiment took place in the French Cerema PAVIN BPplatform for intelligent vehicles, which makes it possible to reproduce controlled fogs of different density for two types of droplet size distribution. Direct spectroradiometer extinction measurements vary in the same way as the models. Finally, the wavelengths for LiDARs should not be chosen on the basis of fog conditions: there is a small difference (<10%) between the extinction coefficients at 905 nm and 1550 nm for the same emitted power in fog.

scholarly journals A Study on Recent Developments and Issues with Obstacle Detection Systems for Automated Vehicles

2020 ◽  
Vol 12 (8) ◽  
pp. 3281 ◽  
Author(s):  
Xiaoyan Yu ◽  
Marin Marinov
Keyword(s):  
Urban Areas ◽  
Weather Conditions ◽  
Autonomous Driving ◽  
Extreme Weather ◽  
Obstacle Detection ◽  
Automated Vehicles ◽  
Detection Systems ◽  
Critical Issues ◽  
Recent Developments ◽  
Service Vehicles

This paper reviews current developments and discusses some critical issues with obstacle detection systems for automated vehicles. The concept of autonomous driving is the driver towards future mobility. Obstacle detection systems play a crucial role in implementing and deploying autonomous driving on our roads and city streets. The current review looks at technology and existing systems for obstacle detection. Specifically, we look at the performance of LIDAR, RADAR, vision cameras, ultrasonic sensors, and IR and review their capabilities and behaviour in a number of different situations: during daytime, at night, in extreme weather conditions, in urban areas, in the presence of smooths surfaces, in situations where emergency service vehicles need to be detected and recognised, and in situations where potholes need to be observed and measured. It is suggested that combining different technologies for obstacle detection gives a more accurate representation of the driving environment. In particular, when looking at technological solutions for obstacle detection in extreme weather conditions (rain, snow, fog), and in some specific situations in urban areas (shadows, reflections, potholes, insufficient illumination), although already quite advanced, the current developments appear to be not sophisticated enough to guarantee 100% precision and accuracy, hence further valiant effort is needed.

Some Biological Applications of High Voltage Electron Microscopy

1974 ◽  
Vol 32 ◽  
pp. 298-299
Author(s):  
Hans Ris
Keyword(s):  
High Voltage ◽  
Chromosome Structure ◽  
Nerve Fibers ◽  
Good Resolution ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
University Of Wisconsin ◽  
High Voltage Electron ◽  
One Year ◽  
The University

The High Voltage Electron Microscope Laboratory at the University of Wisconsin has been in operation a little over one year. I would like to give a progress report about our experience with this new technique. The achievement of good resolution with thick specimens has been mainly exploited so far. A cold stage which will allow us to look at frozen specimens and a hydration stage are now being installed in our microscope. This will soon make it possible to study undehydrated specimens, a particularly exciting application of the high voltage microscope.Some of the problems studied at the Madison facility are: Structure of kinetoplast and flagella in trypanosomes (J. Paulin, U. of Georgia); growth cones of nerve fibers (R. Hannah, U. of Georgia Medical School); spiny dendrites in cerebellum of mouse (Scott and Guillery, Anatomy, U. of Wis.); spindle of baker's yeast (Joan Peterson, Madison) spindle of Haemanthus (A. Bajer, U. of Oregon, Eugene) chromosome structure (Hans Ris, U. of Wisconsin, Madison). Dr. Paulin and Dr. Hanna are reporting their work separately at this meeting and I shall therefore not discuss it here.

Profile Imaging of Silicon Surface Reconstructions

1985 ◽  
Vol 43 ◽  
pp. 262-263
Author(s):  
O.L. Krivanek ◽  
G.J. Wood
Keyword(s):  
Electron Microscopy ◽  
Surface Structure ◽  
Structure Determination ◽  
Silicon Surface ◽  
Good Resolution ◽  
Surface Reconstructions ◽  
Bulk Structure ◽  
Point To Point ◽  
The Relationship

Electron microscopy at 0.2nm point-to-point resolution, 10-10 torr specimei region vacuum and facilities for in-situ specimen cleaning presents intere; ing possibilities for surface structure determination. Three methods for examining the surfaces are available: reflection (REM), transmission (TEM) and profile imaging. Profile imaging is particularly useful because it giv good resolution perpendicular as well as parallel to the surface, and can therefore be used to determine the relationship between the surface and the bulk structure.

Electron diffraction studies of amorphous and polycrystalline thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 118-119
Author(s):  
D J H Cockayne ◽  
D R McKenzie
Keyword(s):  
Thin Films ◽  
Electron Diffraction ◽  
Polycrystalline Materials ◽  
Good Resolution ◽  
Scattered Intensity ◽  
Radial Density ◽  
X Ray ◽  
Polycrystalline Thin Films ◽  
Nitrogen Ion ◽  
Diffraction Patterns

The study of amorphous and polycrystalline materials by obtaining radial density functions G(r) from X-ray or neutron diffraction patterns is a well-developed technique. We have developed a method for carrying out the same technique using electron diffraction in a standard TEM. It has the advantage that studies can be made of thin films, and on regions of specimen too small for X-ray and neutron studies. As well, it can be used to obtain nearest neighbour distances and coordination numbers from the same region of specimen from which HREM, EDS and EELS data is obtained.The reduction of the scattered intensity I(s) (s = 2sinθ/λ ) to the radial density function, G(r), assumes single and elastic scattering. For good resolution in r, data must be collected to high s. Previous work in this field includes pioneering experiments by Grigson and by Graczyk and Moss. In our work, the electron diffraction pattern from an amorphous or polycrystalline thin film is scanned across the entrance aperture to a PEELS fitted to a conventional TEM, using a ramp applied to the post specimen scan coils. The elastically scattered intensity I(s) is obtained by selecting the elastically scattered electrons with the PEELS, and collecting directly into the MCA. Figure 1 shows examples of I(s) collected from two thin ZrN films, one polycrystalline and one amorphous, prepared by evaporation while under nitrogen ion bombardment.

Evaluating Microbial Partitioning Differences Under Storm and Dry-Weather Conditions

2005 ◽  
Author(s):  
Gregory W. Characklis ◽  
Mackenzie J. Dilts ◽  
Otto D. Simmons ◽  
Leigh-Anne H. Krometis ◽  
Christina Likirdopulos ◽  
...  
Keyword(s):  
Weather Conditions ◽  
Microbial Partitioning

Technical textiles for protection against Arc-flash fire: Savesplash®

2020 ◽  
pp. 67-78
Author(s):  
Nandan Kumar ◽  
Sainath Shrikant Pawaskar
Keyword(s):  
Attenuation Factor ◽  
Threshold Energy ◽  
Single Layer ◽  
Weather Conditions ◽  
Electric Arc ◽  
Risk Category ◽  
Technical Textiles ◽  
Flash Fire ◽  
Level 3 ◽  
Arc Flash

Flash fire caused by electric arc is different than that caused by flammable liquids/fumes or combustible dusts. A suitable protective clothing for protection against electric arc-flash must be designed as per Indian weather conditions. Currently available garments are manufactured using two or three layers of woven/nonwoven combinations to achieve higher Hazard Risk Category (HRC) rating (level 3 and above). However, they are heavy and not comfortable to the end users. Savesplash® is a single layer inherent flame-retardant knitted fabric. Its arc rating was determined using ASTM standards. It achieved arc thermal performance value (ATPV) of 41 cal/cm2, breakopen threshold energy (E_BT) of 42 cal/cm2 and heat attenuation factor (HAF) of 94% when tested as per ASTM F1959/F1959M-14 which translated into an arc rating of 41 cal/cm2. This is equivalent to HRC level 4 ratings as per National Fire Protection Association’s NFPA 70E standard (USA). Further, cut and sewn gloves (HM-100) developed using Savesplash® fabric reinforced with leather on palm area achieved ATPV of 63 cal/cm2 and HAF of 94.5% when tested as per ASTM F2675/F2675M-13.

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