scholarly journals Modeling stepped leaders using a time-dependent multidipole model and high-speed video data

2015 ◽  
Vol 120 (6) ◽  
pp. 2419-2436 ◽  
Author(s):  
Sumedhe Karunarathne ◽  
Thomas C. Marshall ◽  
Maribeth Stolzenburg ◽  
Nadeeka Karunarathna ◽  
Richard E Orville
Keyword(s):  
High Speed ◽  
Video Data ◽  
Time Dependent ◽  
High Speed Video

APPLICATION OF THE EARLY DAMAGE DIAGNOSTICS TECHNIQUE TO EXAMINATION OF THE AVIATION PANEL

2019 ◽  
Vol 85 (6) ◽  
pp. 53-63 ◽  
Author(s):  
I. E. Vasil’ev ◽  
Yu. G. Matvienko ◽  
A. V. Pankov ◽  
A. G. Kalinin
Keyword(s):  
Acoustic Emission ◽  
Damage Detection ◽  
High Speed ◽  
Early Stage ◽  
Video Data ◽  
High Speed Video ◽  
Damage Diagnostics ◽  
Subsurface Defect ◽  
Sensitive Coating ◽  
Early Damage

The results of using early damage diagnostics technique (developed in the Mechanical Engineering Research Institute of the Russian Academy of Sciences (IMASH RAN) for detecting the latent damage of an aviation panel made of composite material upon bench tensile tests are presented. We have assessed the capabilities of the developed technique and software regarding damage detection at the early stage of panel loading in conditions of elastic strain of the material using brittle strain-sensitive coating and simultaneous crack detection in the coating with a high-speed video camera “Video-print” and acoustic emission system “A-Line 32D.” When revealing a subsurface defect (a notch of the middle stringer) of the aviation panel, the general concept of damage detection at the early stage of loading in conditions of elastic behavior of the material was also tested in the course of the experiment, as well as the software specially developed for cluster analysis and classification of detected location pulses along with the equipment and software for simultaneous recording of video data flows and arrays of acoustic emission (AE) data. Synchronous recording of video images and AE pulses ensured precise control of the cracking process in the brittle strain-sensitive coating (tensocoating)at all stages of the experiment, whereas the use of structural-phenomenological approach kept track of the main trends in damage accumulation at different structural levels and identify the sources of their origin when classifying recorded AE data arrays. The combined use of oxide tensocoatings and high-speed video recording synchronized with the AE control system, provide the possibility of definite determination of the subsurface defect, reveal the maximum principal strains in the area of crack formation, quantify them and identify the main sources of AE signals upon monitoring the state of the aviation panel under loading P = 90 kN, which is about 12% of the critical load.

scholarly journals Ultra-high speed video observations of intracloud lightning flash initiation

2021 ◽  
Author(s):  
Maribeth Stolzenburg ◽  
Thomas C. Marshall ◽  
Sampath Bandara ◽  
Brian Hurley ◽  
Raymond Siedlecki
Keyword(s):  
Electric Field ◽  
Visible Light ◽  
Exposure Time ◽  
High Speed ◽  
Video Data ◽  
Lightning Flash ◽  
Field Change ◽  
High Speed Video ◽  
Video Observations ◽  
Electric Field Change

AbstractThis study describes results from video observations of five intracloud flashes located ≤ 20 km from the camera and recorded with 6.1 µs exposure time and 6.66 µs frame intervals. Video data are supported with electric field change (E-change) and VHF measurements, with emphasis on the flash initiating event (IE) and initial breakdown (IB) stage. In four of the five flashes, the IE is accompanied by weak luminosity, ≤ 5% above background, lasting for 300–500 µs. Two of these four IEs were positive Narrow Bipolar Events (NBEs) with VHF powers of 43 and 990 W; these are the first (known) data showing visible light detected with a positive NBE. Two other IEs with weak luminosity had powers of 0.5 and 1 W, and the IE with no detected luminosity had a VHF power of 3 W. A typical IB cluster consists of several narrow pulses and one classic pulse in E-change data (along with many VHF pulses), and each example flash has 2–10 IB clusters in the first 5–50 ms. The luminosity of IB clusters was substantially greater than IE luminosity, ranging from 10 to 40% above background in four examples, while for one flash with 10 IB clusters, the luminosity range was 35–360% above background (average 190%). Luminosity durations of IB clusters were 520–1750 µs with average 1210 µs. For both IEs and IB clusters, increases in the detected luminosity were closely timed with substantial VHF emissions and decreased when VHF emissions weakened.

scholarly journals A system for tracking whisker kinematics and whisker shape in three dimensions

2019 ◽  
Author(s):  
Rasmus S. Petersen ◽  
Andrea Colins Rodriguez ◽  
Mathew Hywel Evans ◽  
Dario Campagner ◽  
Michaela S. E. Loft
Keyword(s):  
High Speed ◽  
Imaging System ◽  
Video Data ◽  
Three Dimensions ◽  
3D Analysis ◽  
Imaging Data ◽  
Neural Basis ◽  
High Speed Imaging ◽  
High Speed Video ◽  
Whisker System

AbstractQuantification of behaviour is essential for systems neuroscience. Since the whisker system is a major model system for investigating the neural basis of behaviour, it is important to have methods for measuring whisker movements from behaving animals. Here, we developed a high-speed imaging system that measures whisker movements simultaneously from two vantage points. We developed an algorithm that uses the ‘stereo’ video data to track multiple whiskers by fitting 3D curves to the basal section of each target whisker. By using temporal information to constrain the fits, the algorithm is able to track multiple whiskers in parallel with low error rate. We used the output of the tracker to produce a 3D description of each tracked whisker, including its 3D orientation and 3D shape, as well as bending-related mechanical force. In conclusion, we present an automatic system to track whiskers in 3D from high-speed video, creating the opportunity for comprehensive 3D analysis of sensorimotor behaviour and its neural basis.Author summaryThe great ethologist Niko Tinbergen described a crucial challenge in biology to measure the “total movements made by the intact animal”. Advances in high-speed video and machine analysis of such data have made it possible to make profound advances. Here, we target the whisker system. The whisker system is a major experimental model in neurobiology and, since the whiskers are readily imageable, the system is ideally suited to machine vision. Rats and mice explore their environment by sweeping their whiskers to and fro. It is important to measure whisker movements in 3D, since whiskers move in 3D and since the mechanical forces that act on them are 3D. However, the problem of automatically tracking whiskers in 3D from video has generally been regarded as prohibitively difficult. Our innovation here is to extract 3D information about whiskers using a two-camera, high-speed imaging system and to develop computational methods to infer 3D whisker state from the imaging data. Our hope is that this study will facilitate comprehensive, 3D analysis of whisker behaviour and, more generally, contribute new insight into brain mechanisms of perception and behaviour.

scholarly journals Camera sensor platform for high speed video data transmission using a wideband electro-optic polymer modulator

2019 ◽  
Vol 27 (3) ◽  
pp. 1877
Author(s):  
Xiaoyang Cheng ◽  
Feng Qiu ◽  
Andrew M. Spring ◽  
Masaru Sasaki ◽  
Tsubasa Kashino ◽  
...  
Keyword(s):  
Data Transmission ◽  
High Speed ◽  
Video Data ◽  
High Speed Video ◽  
Electro Optic ◽  
Sensor Platform ◽  
Camera Sensor
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