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Real-time spatial modeling to detect and track resources on construction sites
For more than 10 years the U.S. construction industry has experienced over 1,000
fatalities annually. Many fatalities may have been prevented had the individuals and
equipment involved been more aware of and alert to the physical state of the environment
around them. Awareness may be improved by automatic 3D (three-dimensional) sensing
and modeling of the job site environment in real-time. Existing 3D modeling approaches
based on range scanning techniques are capable of modeling static objects only, and thus
cannot model in real-time dynamic objects in an environment comprised of moving
humans, equipment, and materials. Emerging prototype 3D video range cameras offer
another alternative by facilitating affordable, wide field of view, automated static and
dynamic object detection and tracking at frame rates better than 1Hz (real-time).
This dissertation presents an imperical work and methodology to rapidly create a
spatial model of construction sites and in particular to detect, model, and track the position, dimension, direction, and velocity of static and moving project resources in real-time, based on range data obtained from a three-dimensional video range camera in a
static or moving position. Existing construction site 3D modeling approaches based on
optical range sensing technologies (laser scanners, rangefinders, etc.) and 3D modeling
approaches (dense, sparse, etc.) that offered potential solutions for this research are
reviewed. The choice of an emerging sensing tool and preliminary experiments with this
prototype sensing technology are discussed. These findings led to the development of a
range data processing algorithm based on three-dimensional occupancy grids which is
demonstrated in detail. Testing and validation of the proposed algorithms have been
conducted to quantify the performance of sensor and algorithm through extensive
experimentation involving static and moving objects. Experiments in indoor laboratory
and outdoor construction environments have been conducted with construction resources
such as humans, equipment, materials, or structures to verify the accuracy of the
occupancy grid modeling approach. Results show that modeling objects and measuring
their position, dimension, direction, and speed had an accuracy level compatible to the
requirements of active safety features for construction. Results demonstrate that video
rate 3D data acquisition and analysis of construction environments can support effective
detection, tracking, and convex hull modeling of objects. Exploiting rapidly generated
three-dimensional models for improved visualization, communications, and process
control has inherent value, broad application, and potential impact, e.g. as-built vs. as-planned comparison, condition assessment, maintenance, operations, and construction
activities control. In combination with effective management practices, this sensing
approach has the potential to assist equipment operators to avoid incidents that result in
reduce human injury, death, or collateral damage on construction sites.Civil, Architectural, and Environmental Engineerin
Análise antropométrica da cabeça humana para dimensionamento de capacetes balísticos
Orientadora : Profª. Drª. Maria Lucia L. R. OkimotoTese (doutorado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia Mecânica. Defesa: Curitiba, 29/08/2014Inclui referênciasÁrea de concentração: Fenômenos de transporte e mecânica dos sólidosResumo: As medidas da cabeça humana analisadas para dimensionar artefatos que a protegerão de possíveis acidentes estão associadas apenas à sua circunferência, largura e comprimento máximo. Porém, ao analisar a cabeça em uma imagem tridimensional, percebe-se uma geometria muito mais complexa, fazendo com que esses parâmetros possam ser inadequados ou insuficientes na categorização de sua antropometria. Na área militar, estudos relatam que aproximadamente a metade das mortes nos campos de batalhas é devida a projéteis deflagrados na cabeça do soldado. Isso leva a pensar que, em muitos momentos, a vítima não usava, no momento do incidente, o capacete balístico. No entanto, outros estudos mostram que este artefato após poucos minutos, em uso contínuo, torna-se pesado e instável para muitos usuários. Dessa forma, este trabalho objetivou a pesquisa das possíveis variáveis dimensionais, na região do assentamento e fixação do capacete balístico, fazendo correlações com outras dimensões utilizadas atualmente. Diagnosticou-se através de análise fotogramétrica que a altura da cabeça humana, que ainda hoje não havia sido analisada, é maior que a do artefato em questão, capacete balístico modelo PASGT (Personal Armor System Ground Troops). Sendo assim, ao dimensionar o tamanho de capacete adequado ao usuário, através do perímetro máximo de sua cabeça, essa medida não é a mesma quando verificada a circunferência na região de assentamento do capacete. Dessa maneira, foi estruturado um experimento, por escaneamento tridimensional, para comprovar o resultado preliminar discutido anteriormente. Nele, verificou-se que em 58% dos casos o usuário precisaria de um capacete de tamanho menor que o especificado pelo método atual. Ou seja, o atual método de seleção do tamanho de capacete ao usuário não condiz com a necessidade do mesmo.
Palavras-chave: Cabeça Humana. Antropometria. Capacete Balístico. Fotogrametria e Escaneamento tridimensional.Abstract: The measures examined of the human head, used to scale artifacts that protect it from possible accidents, are only associated with its circumference, width and maximum length. However, when analyzing the head in a three-dimensional image, it has a more complex geometry, so that these measures may be inadequate or insufficient in categorizing its anthropometry. In military field, studies report that approximately half of the deaths in the battle fields is due to projectiles triggered in the mind of the soldier. This suggests that in many instances the victim would not use the ballistic helmet. However, other studies show that this artifact, after a few minutes in continuous use, becomes heavy and unstable for many users. Thus, this study aimed to survey the possible dimensional variables in the settlement and attachment of ballistic helmet region, making correlations with other measures currently used. It was diagnosed by the height photogrammetric analysis of the human head, which still had not been analyzed, that it is larger than the device in question. Thus, by scaling the appropriate size to the helmet user, the measure for this is not the same when found in the region of origin of the helmet. Thus, another experiment was generated by three-dimensional scanning, to confirm the preliminary results discussed above. In this experiment, it was found that in 58% of cases the user would need a smaller helmet than the size specified by the current method. That means that the current method of selecting the helmet size the user does not match the need of it.
Key words: Human Head. Complex Geometry. Anthropometry. Ballistic Helmet and Photogrammetry
Processing Range Data for Reverse Engineering and Virtual Reality
Optical 3-D sensors are used as tools for reverse engineering and virtual reality to digitize the surface of real three-dimensional objects. We discuss an almost fully automatic method to generate a surface description based on a mesh of curved or flat triangles. The method includes mesh reduction, smoothing, and reconstruction of missing data. The generated meshes feature minimum curvature variations and are therefore especially suited for visualization and rapid prototyping.