scholarly journals Thinking Through Form

Screenworks ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elisabeth Brun
Keyword(s):  
Camera Position ◽  
Experimental Video

3xShapes of Home (2020) is a 7 minute experimental video, exploring how essayist film practice may be a way to think topographically, that is: to think conceptually through non-verbal techniques such as camera movement, camera position, montage and algorithm, about place forms and place structures, and their projective powers for the imagination of place. The video is part of a larger study on the Essay Film as Topography. 3xShapes of Home won the Ivan Juritz Prize for Creative Experiment 2020.

Effect of Field Setup on Accuracy of Traffic Data Collection Using Machine Vision Technology

2002 ◽  
Vol 1804 (1) ◽  
pp. 62-66 ◽  
Author(s):  
Sunita Nadella ◽  
Lloyd A. Herman
Keyword(s):  
Machine Vision ◽  
Focal Length ◽  
Reference Points ◽  
Specific Reference ◽  
Traffic Data ◽  
Video Traffic ◽  
Vertical Angle ◽  
Traffic Data Collection ◽  
Camera Position ◽  
Parameter Ranges

Video traffic data were collected in 24 combinations of four different camera position parameters. A machine vision processor was used to detect vehicle speeds and volumes from the videotapes. The machine vision results were then compared with the actual vehicle volumes and speeds to give the percentage errors in each case. The results of the study provide a procedure with which to establish camera position parameters with specific reference points to help machine vision users select suitable camera positions and develop appropriate measurement error expectations. The camera position parameters that were most likely to produce the least overall volume and speed errors, for the specific site and field setup with the parameter ranges used in this study, were the low height of approximately 7.6 m (25 ft), with an upstream orientation (traffic moving toward the camera), a 50-mm (midangle) focal length, and a 15° vertical angle.

scholarly journals DL-based segmentation of endoscopic scenes for mitral valve repair

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Matthias Ivantsits ◽  
Lennart Tautz ◽  
Simon Sündermann ◽  
Isaac Wamala ◽  
Jörg Kempfert ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Minimally Invasive ◽  
Mitral Valve Repair ◽  
Video Stream ◽  
Field Of View ◽  
Valve Repair ◽  
Distance Measurements ◽  
Anatomical Structures ◽  
Endoscopic Video ◽  
Camera Position

AbstractMinimally invasive surgery is increasingly utilized for mitral valve repair and replacement. The intervention is performed with an endoscopic field of view on the arrested heart. Extracting the necessary information from the live endoscopic video stream is challenging due to the moving camera position, the high variability of defects, and occlusion of structures by instruments. During such minimally invasive interventions there is no time to segment regions of interest manually. We propose a real-time-capable deep-learning-based approach to detect and segment the relevant anatomical structures and instruments. For the universal deployment of the proposed solution, we evaluate them on pixel accuracy as well as distance measurements of the detected contours. The U-Net, Google’s DeepLab v3, and the Obelisk-Net models are cross-validated, with DeepLab showing superior results in pixel accuracy and distance measurements.

scholarly journals POST-EARTHQUAKE 3D BUILDING MODEL (LOD2) GENERATION FROM UAS IMAGERY: THE CASE OF VRISA TRADITIONAL SETTLEMENT, LESVOS, GREECE

2020 ◽  
Vol XLIV-4/W3-2020 ◽  
pp. 165-172
Author(s):  
K. Chaidas ◽  
G. Tataris ◽  
N. Soulakellis
Keyword(s):  
Laser Scanner ◽  
Building Model ◽  
Levels Of Detail ◽  
Building Models ◽  
Digital Elevation ◽  
3D Building Model ◽  
Modelling Techniques ◽  
Camera Position ◽  
Elevation Model ◽  
Comparison Of The Results

Abstract. In recent years 3D building modelling techniques are commonly used in various domains such as navigation, urban planning and disaster management, mostly confined to visualization purposes. The 3D building models are produced at various Levels of Detail (LOD) in the CityGML standard, that not only visualize complex urban environment but also allows queries and analysis. The aim of this paper is to present the methodology and the results of the comparison among two scenarios of LOD2 building models, which have been generated by the derivate UAS data acquired from two flight campaigns in different altitudes. The study was applied in Vrisa traditional settlement, Lesvos island, Greece, which was affected by a devastating earthquake of Mw = 6.3 on 12th June 2017. Specifically, the two scenarios were created by the results that were derived from two different flight campaigns which were: i) on 12th January 2020 with a flying altitude of 100 m and ii) on 4th February 2020 with a flying altitude of 40 m, both with a nadir camera position. The LOD2 buildings were generated in a part of Vrisa settlement consisted of 80 buildings using the footprints of the buildings, Digital Surface Models (DSMs), a Digital Elevation Model (DEM) and orthophoto maps of the area. Afterwards, a comparison was implemented between the LOD2 buildings of the two different scenarios, with their volumes and their heights. Subsequently, the heights of the LOD2 buildings were compared with the heights of the respective terrestrial laser scanner (TLS) models. Additionally, the roofs of the LOD2 buildings were evaluated through visual inspections. The results showed that the 65 of 80 LOD2 buildings were generated accurately in terms of their heights and roof types for the first scenario and 64 for the second respectively. Finally, the comparison of the results proved that the generation of post-earthquake LOD2 buildings can be achieved with the appropriate UAS data acquired at a flying altitude of 100 m and they are not affected significantly by a lower one altitude.

scholarly journals A novel method of photogrammetry measurements of study models in orthodontics

2019 ◽  
Vol 147 (1-2) ◽  
pp. 10-16
Author(s):  
Marijana Arapovic-Savic ◽  
Mihajlo Savic ◽  
Mirjana Umicevic-Davidovic ◽  
Adriana Arbutina ◽  
Nenad Nedeljkovic ◽  
...  
Keyword(s):  
Information Technologies ◽  
3D Models ◽  
3D Scanner ◽  
Mean Values ◽  
Digital Representations ◽  
Perspective Distortion ◽  
Tooth Width ◽  
Significant Difference ◽  
Novel Method ◽  
Camera Position

Introduction/Objective. Rapid developments in information technologies lead to the wider use of digital representations of dental study models in orthodontics. Most popular way of digitizing the models is to use a 3D scanner and then perform measurements on 3D models, which requires additional and expensive hardware and software resources. In this paper we present an alternative approach based on the use of photogrammetry in the newly developed OrthoPhoto4D software that calculates and corrects perspective distortion errors. Methods. We measured individual tooth width for 24 teeth, 12 two-teeth segments as well as inter-molar and inter-canine distances on 50 models. Measurements are performed in OrthoPhoto4D software that uses four photographs of each model for measurements, uses QR codes for automation, calculates the camera position and corrects perspective distortion-caused errors in measurements. Obtained measurements are compared to ones obtained from models generated by structured light 3D scanner. Results. Statistical analysis strongly indicates that there is no significant difference between the two methods. The recorded differences also have no clinical impact as they have mean values of 0.2 mm for individual tooth widths, approximately 0.2 mm for two teeth segments, and under 0.3 mm for both intercanine and inter-molar distances. All recorded differences fall within the expected measurement error. Conclusion. We concluded that the described photogrammetry measurements performed in OrthoPhoto4D can be used in diagnosis and therapy planning.

scholarly journals Impacts of stochastic models on real-time 3D UAV mapping

2014 ◽  
Vol XL-1 ◽  
pp. 35-44
Author(s):  
M. Alqurashi ◽  
J. Wang
Keyword(s):  
Stochastic Model ◽  
Real Time ◽  
Stochastic Models ◽  
Feature Matching ◽  
Critical Role ◽  
Image Feature ◽  
Mapping Process ◽  
Camera Orientation ◽  
Camera Position

In UAV mapping using direct geo-referencing, the formation of stochastic model generally takes into the account the different types of measurements required to estimate the 3D coordinates of the feature points. Such measurements include image tie point coordinate measurements, camera position measurements and camera orientation measurements. In the commonly used stochastic model, it is commonly assumed that all tie point measurements have the same variance. In fact, these assumptions are not always realistic and thus, can lead to biased 3D feature coordinates. Tie point measurements for different image feature objects may not have the same accuracy due to the facts that the geometric distribution of features, particularly their feature matching conditions are different. More importantly, the accuracies of the geo-referencing measurements should also be considered into the mapping process. In this paper, impacts of typical stochastic models on the UAV mapping are investigated. It has been demonstrated that the quality of the geo-referencing measurements plays a critical role in real-time UAV mapping scenarios.

scholarly journals Avaliação de uma Nova Abordagem para o Ensino de Química

2020 ◽  
Vol 6 (12) ◽  
pp. 355
Author(s):  
Júnior Olair CHAGAS ◽  
Fabiana Aparecida LOBO ◽  
José Luiz GONÇALVES
Keyword(s):  
High School ◽  
Kinetic Theory ◽  
High School Teachers ◽  
Online Video ◽  
Kinetic Theory Of Gases ◽  
School Teachers ◽  
Daily Lives ◽  
Specific Approach ◽  
Video Sharing ◽  
Experimental Video

RESUMONeste trabalho é relatado o processo de elaboração e aplicação de um roteiro de atividade prática para professores do ensino médio como uma forma de estratégia didática para o ensino da teoria cinética dos gases na disciplina de química. Esta estratégia foi caracterizada por uma abordagem específica, aula expositiva do conteúdo seguida do vídeo experimental para a discussão do tópico. Optou-se por utilizar o Youtube por ser uma das plataformas mais acessadas por qualquer estudante. Escolheu-se um vídeo que continha um experimento claro e objetivo correlacionado com o conteúdo acima citado. Em seguida, elaborou-se o vídeo da aula prática que conteve com uma breve contextualização no cotidiano dos alunos, seguida do vídeo experimental do Youtube e por fim algumas perguntas discursivas. Os resultados indicam que a abordagem do vídeo experimental apresenta uma vantagem significativa sobre as aulas teóricas, reforçando a importância da utilização de práticas experimentais extras na sala.Ensino de Química. Aula prática. Teoria dos gases. Termodinâmica. Vídeo experimental.ABSTRACTIn this work, the process of elaborating and applying a script of practical activity for high school teachers is reported as a form of didactic strategy for teaching the kinetic theory of gases in the discipline of chemistry. This strategy was characterized by a specific approach, expository class of content followed by the experimental video for the discussion of the topic. We decided to use YouTube as it is one of the most online video-sharing platform accessed by any student. A video was chosen which contained a clear and objective experiment correlated with the above-mentioned content. Then, the video of practical class was elaborated, which contained a brief contextualization in the students' daily lives, followed by experimental YouTube video and finally some discursive questions. The results indicate that the experimental video approach has significant advantage over the analytical classes, reinforcing the importance of using extra experimental practices in classroom.Chemistry teaching. Practical class. Gas theory. Thermodynamics. Experimental vídeo.RESUMENEn este trabajo se reporta el proceso de elaboración y aplicación de un guión de actividad práctica para profesores de secundaria como una forma de estrategia didáctica para la enseñanza de la teoría cinética de los gases en la asignatura de la química. Esta estrategia se caracterizó por un enfoque específico, una clase expositiva del contenido seguida del video experimental para la discusión del tema. Optamos por utilizar Youtube ya que es una de las plataformas más visitadas por cualquier estudiante. Se eligió un video que contenía un experimento claro y objetivo correlacionado con el contenido mencionado anteriormente. Luego, se elaboró el video de la clase práctica, que contenía una breve contextualización en la vida cotidiana de los estudiantes, seguido del video experimental de YouTube y finalmente algunas preguntas discursivas. Los resultados indican que el enfoque de video experimental presenta una ventaja significativa sobre las clases teóricas, lo que refuerza la importancia de utilizar prácticas experimentales adicionales en el aula.Enseñanza de la Química. Clase práctica. Teoría de los gases. Termodinámica. Video experimental.SOMMARIOIn questo lavoro viene riportato il processo di elaborazione e applicazione di uno script di attività pratica per insegnanti di scuola secondaria come una forma di strategia didattica per l'insegnamento della teoria cinetica dei gas in materia di chimica. Questa strategia è stata caratterizzata da un approccio specifico, una classe espositiva del contenuto seguita da un video sperimentale per la discussione dell'argomento. Abbiamo scelto di utilizzare YouTube in quanto è una delle piattaforme più visitate da qualsiasi studente. È stato scelto un video che conteneva un esperimento chiaro e oggettivo correlato ai contenuti sopra menzionati. Quindi è stato prodotto il video della lezione pratica, che conteneva una breve contestualizzazione nella vita quotidiana degli studenti, seguito dal video sperimentale di YouTube e infine da alcune domande discorsive. I risultati indicano che l'approccio video sperimentale ha un vantaggio significativo rispetto alle lezioni, rafforzando l'importanza dell'utilizzo di pratiche sperimentali aggiuntive in classe.Insegnamento di chimica. Lezione pratica. Teoria dei gas. Termodinamica. Video sperimentale.

scholarly journals Special Behaviors in One Pedestrian Flow Experiment

2017 ◽  
Vol 4 (3) ◽  
pp. 243
Author(s):  
Junlan Chen ◽  
Wei Wei ◽  
Jinlian Wu
Keyword(s):  
Critical Phenomena ◽  
Critical Density ◽  
Maximum Density ◽  
Pedestrian Flow ◽  
Flow Experiment ◽  
Experimental Video ◽  
Type 3

<p><em>We organize one pedestrian flow experiment with 278 participants, and the maximum density reaches 9 ped/(m^2). The experiment is filmed by one UAV, and in the experimental video, we find some interesting behaviors. Five types of these behaviors are classified and introduced: 1</em><em>)</em><em> oppression near the boundaries; 2</em><em>)</em><em> impact on the boundaries; 3</em><em>)</em><em> special moves; 4</em><em>)</em><em> absentmindedness; 5</em><em>)</em><em> other events. The numbers of Type 1 and 2 behaviors can be counted, while the frequencies of Type 3 and 4 behaviors can be roughly estimated. At one critical density, the results of Type 1, 2, 3, 4 behaviors qualitatively change. This value is about 7~8 ped/(m^2), which indicates the possible existence of critical phenomena in pedestrian flow.</em></p>

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