Analysis Of Video Data Research Articles

‘PhysTrack’: a Matlab based environment for video tracking of kinematics in the physics laboratory

In the past two decades, several computer software tools have been developed to investigate the motion of moving bodies in physics laboratories. In this article we report a Matlab based video tracking library, PhysTrack, primarily designed to investigate kinematics. We compare PhysTrack with other commonly available video tracking tools and outline its salient features. The general methodology of the whole video tracking process is described with a step by step explanation of several functionalities. Furthermore, results of some real physics experiments are also provided to demonstrate the working of the automated video tracking, data extraction, data analysis and presentation tools that come with this development environment. We believe that PhysTrack will be valuable for the large community of physics teachers and students already employing Matlab.

Peaches for Lunch: Creating and Using Visual Variables

ABSTRACTIn this article, I describe the process of systematically including nonverbal data in medical anthropology research. I demonstrate the process of visualizing and coding videotaped moments of life and show how we can analyze what is being done along with what is being said. I ground my discussion in toddler language socialization and then expand my observations to the realm of language pathologies. Aphasia from strokes, speech difficulties in neurologically based illnesses like Lou Gehrig’s disease, and the variety of communication challenges that face those on the autism spectrum can all be studied in interesting ways by including precise descriptions of nonverbal actions. I discuss the process of recording and coding the data with the software Observer XT 11.5 by Noldus. This method of collecting and analyzing video data can be used for many anthropological questions, in addition to those concerned with communication.

COMPASS: Continuous Open Mouse Phenotyping of Activity and Sleep Status.

Background Disruption of rhythms in activity and rest occur in many diseases, and provide an important indicator of healthy physiology and behaviour. However, outside the field of sleep and circadian rhythm research, these rhythmic processes are rarely measured due to the requirement for specialised resources and expertise. Until recently, the primary approach to measuring activity in laboratory rodents has been based on voluntary running wheel activity. By contrast, measuring sleep requires the use of electroencephalography (EEG), which involves invasive surgical procedures and time-consuming data analysis. Methods Here we describe a simple, non-invasive system to measure home cage activity in mice based upon passive infrared (PIR) motion sensors. Careful calibration of this system will allow users to simultaneously assess sleep status in mice. The use of open-source tools and simple sensors keeps the cost and the size of data-files down, in order to increase ease of use and uptake. Results In addition to providing accurate data on circadian activity parameters, here we show that extended immobility of >40 seconds provides a reliable indicator of sleep, correlating well with EEG-defined sleep (Pearson's r >0.95, 4 mice). Conclusions Whilst any detailed analysis of sleep patterns in mice will require EEG, behaviourally-defined sleep provides a valuable non-invasive means of simultaneously phenotyping both circadian rhythms and sleep. Whilst previous approaches have relied upon analysis of video data, here we show that simple motion sensors provide a cheap and effective alternative, enabling real-time analysis and longitudinal studies extending over weeks or even months. The data files produced are small, enabling easy deposition and sharing. We have named this system COMPASS - Continuous Open Mouse Phenotyping of Activity and Sleep Status. This simple approach is of particular value in phenotyping screens as well as providing an ideal tool to assess activity and rest cycles for non-specialists.

Low-power coprocessor for Haar-like feature extraction with pixel-based pipelined architecture

Intelligent analysis of image and video data requires image-feature extraction as an important processing capability for machine-vision realization. A coprocessor with pixel-based pipeline (CFEPP) architecture is developed for real-time Haar-like cell-based feature extraction. Synchronization with the image sensor’s pixel frequency and immediate usage of each input pixel for the feature-construction process avoids the dependence on memory-intensive conventional strategies like integral-image construction or frame buffers. One 180 nm CMOS prototype can extract the 1680-dimensional Haar-like feature vectors, applied in the speeded up robust features (SURF) scheme, using an on-chip memory of only 96 kb (kilobit). Additionally, a low power dissipation of only 43.45 mW at 1.8 V supply voltage is achieved during VGA video procession at 120 MHz frequency with more than 325 fps. The Haar-like feature-extraction coprocessor is further evaluated by the practical application of vehicle recognition, achieving the expected high accuracy which is comparable to previous work.

Identifying resilience axioms: Israeli experts on trauma resilience.

Author(s): Corzine, E; Figley, CR; Marks, RE; Cannon, C; Lattone, V; Weatherly, C | Abstract: This is a report of the process by which the Israeli expert panel on trauma resilience generated a set of axioms. The first part of the article discusses how the expert panel members were selected and polled to determine which among the membership were best qualified to be interviewed by the research team. The next section of the article describes the process by which 7 of the expert panelists were interviewed in Israel using professional video production equipment that generated over 8 hr of high quality video data for later analysis. The final section of the article describes the process by which each of the interviews were analyzed and indexed to generate a list of trauma resilience axioms and sent to interviewees for their review and editing. In addition to the list of axioms generated from their video interviews, the expert panelists were supplied with the video of their interview with Quick Time markers that linked each axiom with the exact point on the video interview. The article describes the final phase of the process: generating a final list of trauma resilience axioms for the expert panel to rate. The results of the expert panel’s ratings are described and establish 83 trauma resilience axioms which fall into 3 categories: those related to individuals, communities, and related contexts. The article then includes a discussion of the findings in terms of the potential utility of this approach for other projects with the goal of reaching consensus among experts.

You and me: The structural basis for the interaction of people with severe and profound intellectual disability and others.

Interaction between two people may be construed as a continuous process of perception and action within the dyad. A theoretical framework is proposed in this article that explains the concepts and processes which comprise the interaction process. The article explores the transactional nature of interaction, through analysis of narrative data from two dyads, each comprising a person with severe or profound intellectual and multiple disability and a service worker. The novel application of grounded theory to analyse video data of non-verbal communication data in order to develop the theoretical framework is reviewed. Previously, attuning has been identified as the key process that drives interaction. This article explores the other concepts of the theory proposed, namely, setting, being, stimulus, action, attention and engagement. The article concludes by contrasting this theory of the interaction process with other related concepts and suggests how application of the proposed framework may enhance practice.

Pedestrians' Crossing Behavior at Marked Crosswalks on Channelized Right-Turn Lanes at Intersections

Abstract: Unsignalized marked crosswalks are problematic locations from pedestrians’ safety perspective. Although the priority rule at such locations is clear; pedestrians have the absolute right of way over vehicles, driver often compete with pedestrians over the right of way which risks pedestrian safety and impose extra delays on pedestrians. In developing countries, as concluded in many previous studies, vehicles usually do not give right of way to pedestrians, leaving them with the only choice to wait until an accepted gap is available. In Gulf Cooperation Council (GCC) countries where vehicles are the predominant mode of travel, pedestrians are receiving lesser priority. Drivers usually hijack the right of way from pedestrians which often causes safety threats. Therefore, pedestrians loose the reason for crossing at these designed locations pushing them to cross at arbitrary locations increasing their safety risk. This paper investigates influencing factors on the crossing behavior of pedestrians at marked crosswalks located on dedicated right-turn lanes. A study site from Doha, Qatar was selected for video recording and data analysis. A sample of 235 pedestrian observations was used for waiting behavior, crossing speed, accepted gaps, and driver yielding behavior analysis. The results showed that the waiting behavior was independent of pedestrian characteristics and relied only on the traffic characteristics. In addition, the average crossing speed was 1.43m/s and the gender, distraction, and group significantly affected the crossing speed. Beside, the distracted pedestrians and pedestrians crossing in groups accepted significantly larger gaps compared to undistracted and individual pedestrians. Moreover, about 15% of drivers yielded for pedestrians, yielding was irrespective of gender and mainly affected by the crossing direction. Consequently, innovative strategies in terms of engineering measures and awareness are needed to improve pedestrian safety at these locations.

Interactions in engaged work teams: a qualitative study

PurposeThe aim of this study is to describe work-engaged teams in terms of interpersonal interaction.Design/methodology/approachSix teams (N = 31 individuals) were videotaped during a decision-making task, for one hour. Based on a priori defined categories, the authors coded the videos in terms of the degree of interaction between team members, the physical distance between members, the degree of team’s activation and the valence of their interaction. The videos were also coded in terms of motivational and affective processes. Team work engagement was assessed using questionnaires.FindingsHighly engaged team members work physically close and have an increment on their interactions up until the task’s temporal midpoint. They have an initial peak of activation and show more positive emotional valence in the first and the last moments of the task. The most interpersonal processes used are affective. The worst performing team had the highest initial interaction levels followed by an abrupt decrease both in their levels of interaction and in their levels of activation. Simultaneously, they present higher peaks of positive emotional valence.Practical implicationsAlthough engaged teams are essentially characterized by the presence of positive interactions, it is fundamental to alternate more “exited” and fun moments with more task focused ones and collective interaction moments with individual work.Originality/valueThis study answers to Kozlowski and Chao’s (2012) call for studying emergence in a more direct way, using qualitative analysis of video data.

Acoustics and hydrodynamics of a drop impact on a water surface

Hydrodynamic and acoustic processes associated with a drop impact on a water surface were studied experimentally. Acoustic signals were detected underwater (with a hydrophone) and in air (with a microphone), the flow pattern was recorded with a high-speed camera, and the surface perturbation was monitored with a laser detector. The dimensionless parameters of flows (Reynolds, Froude, and Weber numbers) induced by the impact varied with fall height within the ranges of 5000 < Re < 20000, 20 < Fr < 350, and 70 < We < 1000. The sequence of acoustic signals incorporated an impact pulse at the moment of contact between a drop and the surface and a series of acoustic packets attributable to the resonance emission of gas cavities. The top of the impact pulse, which was detected clearly in the entire fall height range, had a complex structure with short high-frequency and longer low-frequency oscillations. The total number and the parameters of emitted acoustic packets depended to a considerable extent on the fall height. The cases of lacking, one-time, and repeated emission of packets were noted in a series of experiments performed at a constant fall height. The analysis of video data showed that the signal variability was induced by considerable differences in the scenarios of water entry of a drop, which assumed an ovoid shape at the end trajectory segment, in the mentioned experiments.

Current and future methodologies for quantitative analysis of information transfer in sign language and gesture data.

State-of-the-art methods of analysis of video data now include motion capture and optical flow from video recordings. These techniques allow for biological differentiation between visual communication and noncommunicative motion, enabling further inquiry into neural bases of communication. The requirements for additional noninvasive methods of data collection and automatic analysis of natural gesture and sign language are discussed.

Use of video data for analysis of special transport movement

Special transport (for example ambulances, fire trucks, police cars) can ignore rules of the road in some cases. Modern transport models simulate the movement of conventional vehicles. However usually modern models don’t take into account, for example, ambulance moving onto oncoming lane. We need data about special transport moving for developing effective models. In this work we described a methodology, which can be used for obtaining data about special transport moving onto oncoming lane and road traffic from road cameras video. Methodology includes computer vision methods for vehicle moving detection. We demonstrate the work of our method in the task of analyzing the data of road cameras in St. Petersburg.

Evaluation of red RRFB implementation at freeway off-ramps and its effectiveness on alleviating wrong-way driving

Abstract: Wrong-way crashes are a major cause for safety concern along freeways and limited access facilities. This study investigated three different aspects of the use of Rectangular Rapid Flashing Beacons (RRFBs): 1) different settings of red RRFBs and their perceived effectiveness on reducing wrong-way driving based on a public opinion survey, 2) the effect of active red RRFBs on the behavior of drivers traveling on adjacent roadways via a before-and-after study, and 3) the effectiveness of red RRFBs on alleviating wrong-way driving on freeway off-ramps by analyzing the percentage of vehicles turning back after observing the red RRFB activation. Based on the public opinion survey results, the most informative warning red RRFB combination was determined and implemented in this study. The evaluation of the impact of red RRFB implementation (at six I-275 off-ramps in Tampa, FL, USA) on driving behaviors along adjacent arterials indicated that the implementation of red RRFBs did not adversely impact driving behaviors on adjacent arterials. To determine the effectiveness of red flashing beacons and RRFBs on alleviating wrong-way driving on freeway off-ramps, video recordings of red flashing beacons and RRFBs mounted on wrong-way signs were analyzed. Red RRFBs were deemed to be a more effective countermeasure to deter wrong-way driving than red flashing beacons. Six-months of video data were collected for red flashing beacons mounted on wrong-way signs, and video data collection for red RRFBs mounted on wrong-way signs is currently underway. For red flashing beacons, a high percentage of wrong-way drivers in this study made a U-turn and went back in the correct traffic flow direction upon realizing they were traveling in the wrong direction. It is expected that red RRFBs will be more effective on alleviating wrong-way driving due to their capabilities to inform drivers of wrong-way driving than those from red flashing beacons. The video data analysis for red RRFBs will be presented in a separate paper.

Разработка роботизированного летательного комплекса для мониторинга состояния линий электропередач

The prospects of putting in use a mobile robotic drone-aided system for monitoring the condition of power lines are considered. Monitoring and inspection of power lines are among the mandatory measures carried out by electric network companies in order to maintain uninterrupted operation of the power grid. During power grid operation, emergency tripping of high-voltage overhead power lines account for 25% of all disconnections in the power system. According to the existing practices, power lines are inspected by patrol linemen, who walk along the power line route for visually checking its condition. Inspections involving climbing/ascending over the power line supports are also carried out, which, however, are not always absolutely free from life-threatening risk. The condition of power lines passing in hard-to-reach-areas is inspected using a helicopter, which sometimes turns to be an economically unprofitable measure. It follows from the performed analysis that the main drawbacks of the existing facilities for monitoring the condition of power lines is that they provide insufficient information and that they are poorly adapted to operation under the conditions of a strong electromagnetic field. In addition, a helicopter is required to ascend these systems for monitoring a de-energized power line. The proposed project is aimed at achieving more reliable power line monitoring data and obtaining the possibility to perform remote visual inspection of the condition of power line wires. The proposed system is characterized by a number of new features. Thus, its design allows the system to be connected to the power line wires without the need to de-energize the line. In addition, the system and the input data processing algorithm reduce the information burden on the operator owing to the availability of video data analysis functions, which minimize the amount of background flow of video data. Unlike airplane-type unmanned flying vehicles, which need a specially prepared runway for takeoff and landing, the proposed system can lift off from any place, a feature that is of special importance for hard-to-reachplaces, e.g., in a mountainous terrain. The developed device can hover at the closest distance to wires and, if necessary, it can be put in contact with the power line wires. All these features make it possible to obtain a flow of high-quality information in different frequency spectra and foreshortenings of power line elements. Tests of the developed system have shown that the measurement data obtained from its mobile part feature high accuracy. In view of the fact that timely and reliable detection of flaws and unsatisfactory condition of power line wires and power line accessories is among the main problems faced by the modern electric power industry, the proposed system will find an extensive use in the industry.

Video monitoring reveals pulsating vents and propagation path of fissure eruption during the March 2011 Pu'u 'Ō'ō eruption, Kilauea volcano

Lava fountains are a common eruptive feature of basaltic volcanoes. Many lava fountains result from fissure eruptions and are associated with the alignment of active vents and rising gas bubbles in the conduit. Visual reports suggest that lava fountain pulses may occur in chorus at adjacent vents. The mechanisms behind such a chorus of lava fountains and the underlying processes are, however, not fully understood.The March 2011 eruption at Pu'u 'Ō'ō (Kilauea volcano) was an exceptional fissure eruption that was well monitored and could be closely approached by field geologists. The fissure eruption occurred along groups of individual vents aligned above the feeding dyke. We investigate video data acquired during the early stages of the eruption to measure the height, width and velocity of the ejecta leaving eight vents. Using a Sobel edge-detection algorithm, the activity level of the lava fountains at the vents was determined, revealing a similarity in the eruption height and frequency. Based on this lava fountain time series, we estimate the direction and degree of correlation between the different vents. We find that the height and velocity of the eruptions display a small but systematic shift in time along the vents, indicating a lateral migration of lava fountaining at a rate of ~11m/s from W to E. This finding is in agreement with a propagation model of a pressure wave originating at the Kilauea volcano and propagating through the dyke at ~10m/s from W to E. Based on this approach from videos only 30s long, we are able to obtain indirect constraints on the physical dyke parameters, with important implications for lateral magma flow processes at depth. This work shows that the recording and analysis of video data provide important constraints on the mechanisms of lava fountain pulses. Even though the video sequence is short, it allows for the confirmation of the magma propagation direction and a first-order estimation of the dyke dimensions.

COMPASS: Continuous Open Mouse Phenotyping of Activity and Sleep Status

Background: Disruption of rhythms in activity and rest occur in many diseases, and provide an important indicator of healthy physiology and behaviour. However, outside the field of sleep and circadian rhythm research, these rhythmic processes are rarely measured due to the requirement for specialised resources and expertise. Until recently, the primary approach to measuring activity in laboratory rodents has been based on voluntary running wheel activity. By contrast, measuring sleep requires the use of electroencephalography (EEG), which involves invasive surgical procedures and time-consuming data analysis. Methods: Here we describe a simple, non-invasive system to measure home cage activity in mice based upon passive infrared (PIR) motion sensors. Careful calibration of this system will allow users to simultaneously assess sleep status in mice. The use of open-source tools and simple sensors keeps the cost and the size of data-files down, in order to increase ease of use and uptake. Results: In addition to providing accurate data on circadian activity parameters, here we show that extended immobility of &gt;40 seconds provides a reliable indicator of sleep, correlating well with EEG-defined sleep (Pearson’s r &gt;0.95, 4 mice). Conclusions: Whilst any detailed analysis of sleep patterns in mice will require EEG, behaviourally-defined sleep provides a valuable non-invasive means of simultaneously phenotyping both circadian rhythms and sleep. Whilst previous approaches have relied upon analysis of video data, here we show that simple motion sensors provide a cheap and effective alternative, enabling real-time analysis and longitudinal studies extending over weeks or even months. The data files produced are small, enabling easy deposition and sharing. We have named this system COMPASS - Continuous Open Mouse Phenotyping of Activity and Sleep Status. This simple approach is of particular value in phenotyping screens as well as providing an ideal tool to assess activity and rest cycles for non-specialists.

Application of video microscopy in probing structures and dynamics of micromotor systems

Video microscopy has become an essential, real space experiment technique to study the structural and dynamical properties of microscopic particulate systems. On the one hand, video microcopy can be used to directly observe and record such particulate systems. On the other hand, combined with particle tracking technique, video microscopy enables quantitatively analysis of video data, and further calculation of the structures and dynamics of the studied microscopic systems. For example, video microscopy has been widely used in soft matter physics research. With the advantage of single particle resolution and the capability of longtime recording, video microscopy has led to great advances in our understudying of fundamental condensed matter physics phenomena such as crystallization, melting and glass transition. This paper reviews the applications of video microscopy in studying structures and dynamics of micromotor systems. Firstly, the experimental technique of the video microscopy is summarized. We introduce the hardware of video microscopy, which includes an optical microscope, a video camera and a personal computer. The video camera attached to the microscope records videos and the videos are stored in the computer for future image analysis. Then, the procedures of image analysis are detailed. Various methods to determine the positions of microscopic particles, i.e., particle tracking algorithms, are outlined. Suggestions on video acquisition are also discussed to enable better image analysis and particle tracking. The typical physical parameters to quantify the structures and dynamics of micromotor systems, such as radial distribution function g( r ) and mean square displacement (MSD), are introduced. Secondly, recent progress of the applications of video microscopy in micromotor systems are reviewed. Micromotors can move autonomously because they can convert chemical or other forms of energy (magnetic, electrical, photo- chemical, acoustic, thermal) to mechanical movement. Micromotors have attracted great attentions due to, (1) convenient experimental model of active matter in fundamental physics research; (2) great potential in applications such as chemical analysis and separations, repair of cracks in materials, pumping of fluids in microchannel, and prevention of membrane fouling. To review the applications of video microscopy in micromotor systems, we start with the investigation of the aggregation behavior of micromotors. The results show that both cluster and band phase exist in the micromotor system, and the formation of the cluster or band depends on the velocity of the micromotors. Then, the dynamics of micromotor in viscoelastic fluids are demonstrated. Of particular interest is the remarkable increase of rotational diffusion with increasing particle velocity for micromotor in viscoelastic fluids. The experimental studies of the dynamics of micromotor in confined environments are introduced. Two kinds of confined conditions are considered: A circle wall and an array of periodically arranged obstacles. For the first case, the probability of finding the micromotor at the confinement walls significantly increases compared to Brownian particles. For the second case, it is found that with increasing activity, the micromotor can steer to direction that is even perpendicular to the applied force. Finally, the application of video microscopy for the study of micromotor systems is summarized. The importance of the video microscopy for experimental study of the micromotor system is emphasized, and the limitations and the future of the video microscopy in micromotor research are also discussed.

Effects of economic classroom experiments on economic knowledge and reasoning in secondary education

This study explored whether and how economic classroom experiments may enhance the economic knowledge and the reasoning ability of 108 secondary school students. Economic classroom experiments are controlled interactive learning exercises by means of which students can learn to think as economists. Economic reasoning is conceptualized as the ability to identify a correct cause-and-effect relationship between variables. Students formulate an initial hypothesis by indicating two main variables from an economic context, determining associations between these, and formulating possible explanations. Subsequently, students test their hypothesis and try to establish the accuracy of their initial ideas. From the economic classroom experiments used in the study, students have to derive key variables, determine how these variables were related, and provide explanations. The goal of the study is to investigate whether actually participating in economic classroom experiments (n=36) is more beneficial to learning than either watching others perform economic classroom experiments (n=27) or merely analyzing the data produced by other students within such experiments (n=45). Contrary to expectations, students who observe experiments and students who analyze experimental data show higher and sustained gains in their knowledge of economic concepts than students who participate in the experiments. Moreover, experiment participation turns out to be less beneficial for the reasoning-ability of students than video observation and data analysis. Possible explanations for these findings are discussed.

Emergent reading comprehension: Social imagination and kindergarteners’ readings of a wordless picture book

In this cross-case analysis of six young children’s wordless book readings, we examine the ways in which participants use social understanding during the reading of a wordless book to understand the narrative story. Using a conceptually based coding scheme, we identified places in children’s readings in which they imagined the thoughts, feelings, and intentions of characters. We refer to this use of social understanding during reading as social imagination, as it is occurs not in an actual but in a vicarious context. The findings indicated that children who frequently engaged in imagining the minds of others produced more as well as more varied meaning units and often ‘became’ the characters during their wordless book reading. Multimodal analysis of video data show that children who used social imagination relatively more frequently had livelier readings, with extensive use of inflection, emotion, and voicing of characters as well as a sense of continual investment in the narrative event as it unfolded. The use of social imagination appears to be critical in making sense of a story. The cases presented here demonstrate how understanding the minds of others leads to more complex thinking during the reader-text transaction. Implications for classroom practice and research are discussed.

Automated video-based assessment of surgical skills for training and evaluation in medical schools.

Routine evaluation of basic surgical skills in medical schools requires considerable time and effort from supervising faculty. For each surgical trainee, a supervisor has to observe the trainees in person. Alternatively, supervisors may use training videos, which reduces some of the logistical overhead. All these approaches however are still incredibly time consuming and involve human bias. In this paper, we present an automated system for surgical skills assessment by analyzing video data of surgical activities. We compare different techniques for video-based surgical skill evaluation. We use techniques that capture the motion information at a coarser granularity using symbols or words, extract motion dynamics using textural patterns in a frame kernel matrix, and analyze fine-grained motion information using frequency analysis. We were successfully able to classify surgeons into different skill levels with high accuracy. Our results indicate that fine-grained analysis of motion dynamics via frequency analysis is most effective in capturing the skill relevant information in surgical videos. Our evaluations show that frequency features perform better than motion texture features, which in-turn perform better than symbol-/word-based features. Put succinctly, skill classification accuracy is positively correlated with motion granularity as demonstrated by our results on two challenging video datasets.

Protocol for Data Collection and Analysis Applied to Automated Facial Expression Analysis Technology and Temporal Analysis for Sensory Evaluation.

We demonstrate a method for capturing emotional response to beverages and liquefied foods in a sensory evaluation laboratory using automated facial expression analysis (AFEA) software. Additionally, we demonstrate a method for extracting relevant emotional data output and plotting the emotional response of a population over a specified time frame. By time pairing each participant's treatment response to a control stimulus (baseline), the overall emotional response over time and across multiple participants can be quantified. AFEA is a prospective analytical tool for assessing unbiased response to food and beverages. At present, most research has mainly focused on beverages. Methodologies and analyses have not yet been standardized for the application of AFEA to beverages and foods; however, a consistent standard methodology is needed. Optimizing video capture procedures and resulting video quality aids in a successful collection of emotional response to foods. Furthermore, the methodology of data analysis is novel for extracting the pertinent data relevant to the emotional response. The combinations of video capture optimization and data analysis will aid in standardizing the protocol for automated facial expression analysis and interpretation of emotional response data.