Mobile Mapping Systems gathers a lot of spatial data that can be used for inventory and analyses regarding road safety. The main purpose of this thesis is to propose a workflow for automatic classification and digitisation of objects in a point cloud gathered by a Mobile Mapping System.   The current method used for processing point clouds is performed manually which is cost-inefficient and time consuming due to the vast amount of data the point cloud contains.   Before defining the workflow, different software were reviewed for finding which ones to use for the classification. The software review showed that a combination of using Terrasolid and FME is suitable for performing the steps suggested in the classification and digitisation method.   The proposed workflow for performing automatic classification and digitisation is based on six different steps: Identify characteristics of the objects of interest, Filter the point cloud, Noise reduction, Identify objects, Digitise and Control. This method has been carried out on two examples, road signs and painted road lines. Attributes that have been used for classifying the objects involves intensity, colour value and spatial relations. The results showed that for digitising road signs, the method found 15 out of 16 signs (94%). For digitising the painted road lines, the results produced by the automatic function had an average misalignment of 3.8 centimetres in comparison to the initial point cloud. The thesis demonstrates that the carried out functions are less time demanding for the user, compared to the manual method carried out today. / Bilburen laserskanning samlar geografiska och rumslig data som kan användas för inventering och analys gällande trafiksäkerhet. Huvudsyftet med denna uppsats är att föreslå ett arbetsflöde för automatisk klassificering och digitalisering av objekt i ett punktmoln som samlats in av en bilburen laserskanner.   Den nuvarande metoden som används för bearbetning av punktmoln innebär mycket manuellt arbete för användaren vilket är kostnadsineffektivt och tidskrävande på grund av den stora mängd data punktmolnet består av.   Innan arbetsflödet kunde definieras, har olika programvaror granskats för att hitta vilka som kan användas för klassificeringen. Den genomgångna programvaran visade att en kombination av att använda Terrasolid och FME är lämplig för att utföra de åtgärder som föreslås för klassificeringen och digitalisering.   Det föreslagna arbetsflödet för att utföra automatisk klassificering och digitalisering bygger på sex olika steg: Identifiera egenskaper hos objekt av intresse, Filtrera punktmoln, Brusreducering, Identifiera objekt, Digitalisera och Kontroll av resultat. Denna metod har genomförts på två exempel, vägmärken och målade väglinjer. Attribut som har använts för att klassificera objekten innefattar intensitet, färgvärde och spatiala relationer. Resultaten visar att för digitalisering av vägmärken, kunde funktionen identifiera 15 utav 16 skyltar(94%). Vid digitalisering av de målade väglinjerna, visade resultaten framtagna av den automatiska funktionen en genomsnittlig avvikelse i sidled på 3,8 centimeter i jämförelse med det ursprungliga punktmolnet. Avhandlingen visar att de framlagda funktionerna är mindre tidskrävande för användaren, jämfört med den manuella metoden som utförs idag.

<p dir="ltr">Road safety analysis typically relies on the correlation between road surface conditions, lane marking status, or lane width and crash data. Traditionally, this data is surveyed in the field after road construction or car accidents, which is labor-intensive, time-consuming, and hazardous. With the development of mobile mapping systems (MMS) in recent years, the ability to collect lane marking retroreflectivity or lane width information has been greatly improved. By utilizing Light Detection and Ranging (LiDAR) point clouds and RGB images captured by MMS, it is possible to establish lane marking inventory that includes the conditions of pavement markers (such as lane marking retroreflectivity and lane width) for road safety analysis.</p><p dir="ltr">This dissertation aims to develop a comprehensive framework to extract lane markings and report their characteristics using MMS datasets for transportation safety. The proposed approaches include geometric/morphological and deep learning-based approaches based on the LiDAR point clouds acquired by MMS. A normalization strategy is developed to ensure consistent intensity values across laser beams/LiDAR units/MMS for the same objects, thereby enhancing the lane marking extraction. In addition, an image-aided LiDAR approach is proposed to improve the extraction process further. Following the extraction, lane marking classification and characterization, including intensity profile generation and lane width estimation, are conducted to establish comprehensive lane marking inventory.</p><p dir="ltr">To evaluate the proposed strategies, lane marking extraction with and without intensity normalization is also conducted. The results show that the proposed intensity normalization significantly improves the performance of lane marking extraction, regardless of the approach or data used. The geometric approach using normalized intensity achieves F1-scores higher than 90%, outperforming the learning-based models. Furthermore, the intensity derived from two different MMS is compared for performance evaluation, and the agreement of normalized intensity values is within a range of 3.1 to 3.8 (the used MMS provide intensity as an integer number within 0 to 255). Through the normalization, a positive linear relationship between LiDAR normalized intensity and retroreflectivity is found, with the strongest relationship providing an R² of 0.72 and a Pearson's correlation coefficient of 0.85. A comparison of the correlation between original/normalized intensity and retroreflectivity revealed a stronger correlation between original intensity and retroreflectivity. For image-aided LiDAR approach, the image information indeed enhanced the LiDAR-based lane marking extraction approach, as evidenced by the highest F1-score (92.5%) of the image-aided LiDAR approach, outperforming the LiDAR-based (90.3%) and image-based (77.8%) ones. Specifically, the recall increases by 4.0% – from 87.6% (LiDAR-based) to 91.6% (image-aided LiDAR) – surpasses the slight improvement in the precision of 0.2% – from 93.2% (LiDAR-based) to 93.4% (image-aided LiDAR).</p><p dir="ltr">Finally, a Potree-based web portal is developed to visualize the results derived through the proposed lane marking extraction/classification/characterization strategies. This portal includes a function that enables the projection between 2D images and 3D point clouds, as well as tools for displaying intensity profiles and lane width estimates. It is capable of rendering a large dataset of {approximately 4.2 billion LiDAR points} in around ten seconds and allows for the visualization of intensity profiles and lane width estimates. Users can select points of interest in an intensity profile/lane width plot. This selection will result in the corresponding point being showcased in the LiDAR data on the web portal. Furthermore, the LiDAR point can be projected onto the corresponding image.</p><p dir="ltr">The above proposed strategies facilitate the investigation of the relationship between LiDAR intensity and mobile retroreflectivity. To ensure quality control, lane markings derived from geometric and learning-based extraction approaches were compared. These strategies were evaluated using two MMS (equipped with multiple imaging and LiDAR sensors), covering extensive road segments exceeding 400 miles. Furthermore, a reporting mechanism based on multi-modal data from various MMS sensors was implemented to visualize the results derived from the proposed strategies and to serve as a quality control tool. Consequently, the proposed strategies are easily adaptable for different MMS or the regular updating of lane marking inventory.</p>

The need for accurate 3D reconstructions of complex and large environments or structures has risen dramatically in recent years. In this context, devices known as portable mobile mapping systems have lately emerged as fast and accurate reconstruction solutions. While most of the research and commercial works have relied so far on laser scanners, solutions solely based on cameras and photogrammetry are attracting an increasing interest for the minor costs, size and power consumption of cameras. This thesis presents a novel handheld mobile mapping system based on stereo vision and image-based 3D reconstruction techniques. The main novelty of the system is that it leverages Visual Simultaneous Localization And Mapping (V-SLAM) technology to support and control the acquisition of the images. The real-time estimates of the system trajectory and 3D structure of the scene are used not only to enable a live feedback of the mapped area, but also to optimize the saving of the images, provide geometric and radiometric quality measures of the imagery, and robustly control the acquisition parameters of the cameras. To the best of authors’ knowledge, the proposed system is the first handheld mobile mapping system to offer these features during the acquisition of the images, and the results support its advantages in enabling accurate and controlled visual mapping experiences even in complex and challenging scenarios.

<p dir="ltr">Woody debris (WD) is an important element in forest ecosystems. It provides critical habitat for plants, animals, and insects; but it is also a source of fuel contributing to fire propagation and sometimes leads to catastrophic wildfire. Usually, WD inventory is conducted through field surveys using transects and sample plots. Light Detection and Ranging (LiDAR) point clouds are emerging as a valuable source for the development of comprehensive WD detection strategies. Although results from previous LiDAR-based WD detection approaches have been promising, there is still a lack of a general strategy for handling acquired point clouds by different platforms with varying characteristics (e.g., point density) in a complex environment, especially in natural forests. Here, we propose a general morphological WD detection strategy which requires a few intuitive thresholds, making it applicable to multi-platform LiDAR datasets in both plantation and natural forests. The conceptual basis of the strategy is that WD LiDAR points exhibit non-planar characteristics, distinct intensity, and comprise clusters that exceed a minimum size. The developed strategy is tested using leaf-off point clouds acquired by Geiger-mode, uncrewed aerial vehicle (UAV), and backpack LiDAR systems. The developed approach achieved an average recall of 0.83 indicating a low rate of omission errors. Datasets with higher point density (i.e., from UAV and backpack LiDAR) showed better performance. As for the precision evaluation metric, it ranges from 0.40 to 0.85, indicating a higher level of commission errors at the lower range. The commission errors depend on the presence of bushes and undergrowth, with a lower percentage in forest plantations.</p>

No / The industrial heritage for the City of Bradford Metropolitan District is of international significance, with the city formerly being the centre of the world’s worsted trade during the nineteenth century. The intensification of textile production during the industrial revolution resulted in exponential growth of all aspects of the city, the legacy seen in the townscape heritage of the city today. The structures from this period have played a key role in defining the city’s identity. Since the decline of the textile industry the fabric of many of these buildings from the city’s golden age are under threat and at high risk of loss due to weathering, vandalism and fire. Given the varied nature and condition of these structures, a rapid approach has been applied that complements initiatives in train with Bradford Council to regenerate the ‘Top of Town’; that are reflective of Historic England’s ‘Engines of Prosperity’ report into the regeneration of Industrial Heritage; and with the Management of Saltaire World Heritage site. This chapter focuses on the digital documentation of a conservation area which is highly vulnerable, producing a dataset to aid conservation, management, interpretation and promotion of Bradford’s rich heritage.

Mobile Terrestrial LiDAR (MTL) is an active remote sensing technology that uses laser-based ranging and global positioning systems (GPS) to record 3D point location measurements on surfaces within and near transportation corridors, such as along a railroad track or a street. This thesis examines geovisualization for improving user-oriented workflows and also examines geographic object-based image analysis (GEOBIA) for the development of automated feature extraction. A LiDAR sensor-centric perspective during the data acquisition phase is used to organize data for the user and to transform the data into a 2D reference frame for object-oriented image analysis of MTL data. Organizing the display of MTL data relative to the scanner presented new opportunities for visualization techniques and was an effective method for communicating space that was scanned, or not, in an urban scene. It offers new avenues for quality assessment of MTL survey of urban environments by explicitly displaying gaps in data coverage. A number of techniques for navigating and visualizing data from a sensor-perspective are examined. A novel sensor-perspective transformation of MTL data from three to two dimensions enables analysis of MTL data in common GIS and image-processing environments. GEOBIA software (Definiens’ eCognition) is used to construct a procedural feature extraction workflow. The procedures are constructed with semantic classes, data processing rules and functions that drive geometric segmentation and feature recognition. Geometric regularities in urban scenes and knowledge about spatial and semantic relationships are incorporated into the rule set. The results are fluidly integrated back into a GIS environment. Investigation of alternative approaches to handling MTL data such as those carried out in this thesis are essential if this technology is to see widespread use. / Thesis (Master, Geography) -- Queen's University, 2011-05-24 13:10:15.198

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Agradecemos a compreensão. on 2016-05-17T15:00:18Z (GMT) / Submitted by VICTOR BLASECHI null (victorblasechi@yahoo.com.br) on 2016-05-17T15:49:29Z No. of bitstreams: 1 DISSERTACAO_VICTOR_BLASECHIFINAL_R05.pdf: 1986271 bytes, checksum: b7f47f40ba442b7c083b6159620ea982 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-05-19T17:10:23Z (GMT) No. of bitstreams: 1 blasechi_v_me_prud.pdf: 1986271 bytes, checksum: b7f47f40ba442b7c083b6159620ea982 (MD5) / Made available in DSpace on 2016-05-19T17:10:23Z (GMT). No. of bitstreams: 1 blasechi_v_me_prud.pdf: 1986271 bytes, checksum: b7f47f40ba442b7c083b6159620ea982 (MD5) Previous issue date: 2016-03-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os sistemas de mapeamento móvel (SMM) podem ser definidos como um conjunto de sensores instalados sobre uma mesma plataforma com o intuito de obter informação espacial. Estes sensores têm função de imageamento ou orientação. A orientação integrada utilizando a fototriangulação pode ser empregada tanto na extração de informações espaciais quanto para a orientação do SMM. No mapeamento móvel terrestre, o caminhamento fotogramétrico (CF), é um modo especial de levantamento utilizando pares estereoscópicos para determinar as orientações e coordenadas tridimensionais de pontos do terreno. No CF, um mesmo ponto pode ser visto por um par de imagens ou por quantas for possível. Esta característica, entretanto, não garante que erros grosseiros sejam detectados em todas as direções. A introdução de uma terceira câmara que não forme uma geometria coplanar (sobre o plano epipolar) permite uma melhoria na qualidade da determinação da rede fotogramétrica, formada pelos pontos do espaço-objeto e as estações de exposição. Os principais objetivos deste trabalho são mostrar a contribuição da terceira câmara para a qualidade da fototriangulação, encontrar uma situação ótima de trabalho para este arranjo e mostrar que a orientação obtida no processamento sequencial da fototriangulação pode ser utilizada como um sensor de dead-reckoning. Isto é feito através de 9 experimentos, em que são analisadas as características de processamento, geometria e controlabilidade de erros grosseiros. Em todos os experimentos, a determinação da orientação exterior é precisa. Os erros nos pontos de enlace são bem maiores e se propagam na direção do caminhamento. A comparação entre processamento em lote com o sequencial mostra que o processamento em lote pode ser menos oneroso do que o sequencial quando se tem poucas observações, mesmo tendo mais iterações. A controlabilidade é maior no processamento em lote, sendo que a determinação das coordenadas tridimensionais dos pontos de enlace é mais acurada. Maiores janelas de processamento resultam em maior qualidade na orientação, mas não afetam os pontos de enlace. A quantidade de avanços de base não afeta a qualidade. O aumento da distância focal resulta em melhora na estimativa da trajetória no sentido do caminhamento, mas reduz o ângulo de abertura, diminuindo o campo de visão. Uma maior distância focal melhora a determinação das coordenadas tridimensionais dos pontos de enlace proporcionalmente ao aumento da distância focal. Aumentando-se o espaçamento entre as câmaras do arranjo, aumenta-se a qualidade do posicionamento das câmaras no sentido do levantamento, bem como a acurácia das coordenadas dos pontos de enlace, mas torna-se mais difícil a correspondência intra-imagens de feições próximas às câmaras. O distanciamento entre estações de exposição subsequentes não afeta a qualidade da fototriangulação, mas pode dificultar a correspondência de imagens. Na comparação com o arranjo formado por um par estereoscópico, o arranjo triangular permitiu a detecção-localização-tratamento do erro introduzido, enquanto que o par estereoscópico perde convergência já nas primeiras janelas de processamento. Um percurso sinuoso tende a reduzir a acurácia, mas mesmo assim, o programa mostrou conseguir processar toda a sequência. / The Mobile Mapping Systems (MMS) can be defined as a set of sensors embedded on a common platform in order to get spatial information. These sensors are used for imaging or orientation. The integrated orientation using phototriangulation can be employed on both spatial information extracting and MMS orientation. On terrestrial mobile mapping, the photogrammetric bridge (PB) is a special mode of surveying that uses stereopairs to determine the orientation and tridimensional points on terrain. On PB, a point can be viewed by one pair of images or as many as possible images. This characteristic, however, do not ensure that blunders can be detected for all directions. Introducing a third camera having a non-coplanar geometry (based on the epipolar plane) allows a quality improvement of the photogrammetric network determination, formed by the object-space points and exposure stations. The main objectives of this work are showing the third camera contribution for the phototriangulation quality, find an optimal working situation for this set and show that the orientation obtained on the sequential phototriangulation processing can be used as a dead-reckoning sensor. This is done through nine experiments by witch are analyzed processing characteristics, geometry and controllability of blunders. On all experiments, the exterior orientation determination is precise. The tiepoints errors are larger and propagates on the moving direction of the platform. The comparison between batch and sequential processing shows that the batch can be less onerous than sequential when it has few observations, even though it costs more iterations. The controllability is better on the batch processing and the tiepoints tridimensional coordinates determination is more accurate. Bigger processing windows results in more quality on the orientation, but do not affect the tiepoints determination. The dimension of base lift does not affects the quality. A rise of the focal length results on improvement of the trajectory estimation in the movement direction, but reduces the aperture angle, decreasing the field of view. A bigger focal length improves the tiepoints tridimensional coordinates determination proportionally to the rising of focal length. When rising the distance between cameras of the arrange, the positioning quality of the cameras rises in the movement direction as well the tiepoints accuracy, but it turns intra-images matching more difficult for close features. The distance between subsequent exposure stations does not affects the phototriangulations quality, but image matching tends to be more difficult. Comparing with arrange formed by a stereopair, the triangular arrange allowed a detecting-localizationtreatment of an intentionally introduced blunder, while the stereopair lost convergence on the early processing windows. A sinuous trajectory tends to reduce the accuracy, but even so, the program had success on processing the whole sequence.

[pt] Com o crescimento tecnológico temos visto uma popularização crescente de equipamentos de localização por satélite (receptores GPS) e computadores de bolso (PDA) em diversas áreas: nos transportes aéreo, marítimo e terrestre, mapeamento e geoprocessamento, esporte e lazer. Onde podemos ver, como exemplo, praticantes de caminhadas adquirindo seus próprios receptores GPS. No meio militar, esta popularização também crescente, onde as Forças Armadas de diversos países tendem a adquirir cada vez mais equipamentos de posicionamento por satélite (receptores GPS) e testam equipamentos para interação com os mesmos. O foco deste trabalho a integração do receptor GPS e PDA visando sua utilização em operações militares, com intuito de obter respostas rápidas para um emprego mais eficiente e rápido de frações das tropas envolvidas. Este trabalho envolve a geração de arquivos legíveis aos PDA, a comunicação de receptores GPS com estes, bem como a visualização da informação fornecida por estes receptores de forma fácil e rápida. Abrange também uma comparação entre a utilização de mapas em duas diferentes representações raster e vetorial, possibilitando zoom e movimento da imagem em ambos, além da possibilidade de medir distâncias entre pontos do mapa na tela do PDA e inclusão, exclusão e alteração de observações diversas. Verificou-se a grande vantagem da utilização de imagens raster em relação utilização de imagens vetoriais no PDA para esta finalidade, e também algumas fragilidades do uso de PDA comuns em operações militares e com receptores GPS de usos gerais. / [en] With technological development, we have been witnessing a growing popularization of satellite-location equipment (GPS receivers) and pocket computers (PDA) in several areas: air, sea and earth transports, mapping and geoprocessing, sports and entertainment. We can see hikers, for example, acquiring their own GPS receivers. In the military environment, this popularization is also occurring: the Armed Forces in several countries are obtaining increasing numbers of GPS receivers and are testing equipment to interact with them. The purpose of this work is to integrate GPS receivers and PDAs, with the intention of employing them in military operations in order to obtain quick responses for a faster and more efficient use of fractions of involved troops. This work involves the generation of files readable by PDAs, the communication of GPS receivers with PDAs, and an easy and fast visualization of the information provided by the receivers. It also includes a comparison between the use of maps in two different representations, raster and vector, both allowing for zooming and movement of the image, as well as the possibility of measuring distances between points of the map in the PDA screen, and the inclusion, exclusion and alteration of several observations. The great advantage of using raster images instead of vector images in PDAs for this purpose was verified, as well as some disadvantages in the use of PDAs, common in military operations, with general-purpose GPS receivers.

The diploma thesis studies accuracy of cheap GPS devices intended for mobile mapping in the landscape. Methodlogy for testing the accuracy of two GPS devices was established on the base of studied literature and apllied to two different GPS devices. The first device is PDA ASUS A639 connected by Bluetooth with external GPS reciever Navilock BT-338 and the second one is PDA ASUS A639 using its inbuilt GPS chipset. The result of testing is firstly comparison of accuracy of these two GPS devices and secondly the elements, which influnce their accuracy the most. The database of results is large enough to make some general conclusions concerning the accuracy of different GPS devices and their usage in the process of mobile mapping.

The diploma thesis deals with possibilities of tracing the trajectory of mobile mapping systems in order to compare their accuracy. This thesis discusses the individual components of the mobile mapping device that were used in its construction. The thesis contains the results of the experiments that were performed on individual test.