Browsing by Author "Detchev, Ivan"
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- ItemOpen Access2D-3D Registration for a High-speed Biplanar Videoradiography Imaging System(2022-04) Zhang, Shu; Lichti, Derek; Detchev, Ivan; Ronsky, Janet; Wang, Ruisheng; Armenakis, Costas; Lichti, DerekHigh-Speed Biplanar Videoradiography (HSBV) is an X-ray based imaging system that can derive dynamic bony translations and rotations. The 2D-3D registration process matches a 3D bone model acquired from magnetic resonance imaging (MRI) or computed tomography (CT) scans with the 2D X-ray image pairs. 2D-3D registration is usually conducted in two ways, marker-based and model-based registration. The marker-based method is known for its high registration accuracy thanks to corresponding marker pairs. On the other hand, the model-based method avoids the implantation of radiopaque beads but uses the radiograph’s features, intensities, or gradients to accomplish the data alignment. Two novel marker-based registration methods, the back-projection and the projection methods, were proposed and compared with the state-of-the-art RSA (Roentgen Stereophotogrammetric Analysis) method. A 3D printed bone model with beads was used to validate the proposed methods. The results showed that both methods acquired higher accuracy than the RSA method. In addition, the projection and back-projection techniques can be used for the model-based registration while the RSA method cannot. The projection method was applied to a model-based registration to achieve higher accuracy, providing a 3D reconstruction accuracy of 0.79 mm for both the tibia and femur. By using the non-rigid transformation with a scale factor, this accuracy was successfully increased to 0.56 mm for the tibia and 0.64 mm for the femur. The discrepancies in the 2D-3D registration that led to the non-rigid transformation were validated. It was caused by the offset between the detected edge points in the radiographs and their actual position. A Kalman filter was tested on the marker- and model-based registration results with different random processes and parameters. For marker-based registrations, the standard deviations of the kinematics parameters were improved by 25 – 62% for the translations and 35 – 43% for the rotations. For the model-based registration, these standard deviations were improved by 6 – 38% and 29 – 38%, respectively. While the projection method provided higher accuracy, the back-projection method had the larger capture range for the initialization. An automatic initialization method with 64 starting poses based on the back-projection method was proposed and validated. It successfully eliminated the user intervention in the registration initialization. The improved 2D-3D registration with non-rigid transformation and dynamic estimation allows the determination of accurate 3D kinematic parameters with high efficiency. These kinematic parameters can be used to calculate joint cartilage contact mechanics that provide insight into the mechanical processes and mechanisms of joint degeneration or pathology.
- ItemOpen Access3-D Cadastral Boundary Relationship Classification Algorithms using Conformal Geometric Algebra(2021-04-26) Pullano, Dillon; Barry, Michael; Wang, Xin; O'Keefe, Kyle; Detchev, Ivan; Barry, Michael; Wang, Xin; Rangelova, ElenaAs urban centers continue to grow and develop, there is an increasing need for institutions to be able to digitally model and perform relationship analysis on 3-D cadastral boundary data. 3-D boundary analysis can be performed through visual inspection of survey plan drawings, but this often requires professional expertise such as a land surveyor or lawyer. This study examined the development, testing, and application of methodological processes and algorithms that were designed to classify various geometrical and topological relationships between the boundary components of two 3-D cadastral units to solve cadastral boundary problems. It applied established mathematical theory using Conformal Geometric Algebra objects and operational techniques, in combination with various 3-D point-point distance evaluations and geometric concepts to the classification of relationships between 3-D cadastral boundaries. A literature search suggests that the theory and methodology as it was applied in this study have not been used to classify topological relationships between 3-D cadastral boundaries elsewhere. Six sets of data flow processing algorithms were developed to determine the relationship classifications between boundary component pair sets that exist between two 3-D cadastral units. The classification processes were first validated using seven simulated experimental testing datasets, each consisting of two cube-like units. The classification processes were then applied to a cadastral dataset that was derived from a condominium survey plan registered in Alberta, Canada. This showed how the methods developed here can be applied to solving a practical 3-D cadastral boundary problem example in the land surveying field, specifically towards validating a shared boundary between two adjacent condominium units as is intended on the plan before survey plan registration. Results from the experimental datasets support the methods that were proposed to classify 53 distinct types of topological relationships between 3-D boundary component pair sets. While this type of boundary relationship analysis can be done through visual inspection of survey plans, the methods developed here are more mathematically rigorous. These processes could be leveraged by land surveyors and land administration professionals when analyzing 3-D survey plan boundaries.
- ItemOpen AccessAlternative Dispute Resolution Mechanisms to Define Aboriginal Parcel Boundaries in Canada(2017) Jones, Kent Douglas; Barry, Michael; Bankes, Nigel; Detchev, IvanThe objective of this research was to explore strategic options for alternative boundary dispute resolution (ABDR) mechanisms that improve non-treaty boundary determination for First Nations in Canada by rebalancing the power relationships with government to relieve the comprehensive claims backlog. The comprehensive claims process concerns the negotiation of modern treaties between First Nations and the Canadian government and includes boundary determination. Boundary determination needs to balance the land interests of Aboriginal Peoples and government. This is informed by the seminal case, Tsilhqot’in Nation v. British Columbia, [2014] SCC 44, where the Supreme Court of Canada said that traditional use informed boundary determination and relied on non-treaty boundary determination to grant Aboriginal title within Canada’s cadastre for the first time. A review of the literature found that a Canadian Alternative Boundary Dispute Resolution (ABDR) mechanism may assist boundary determination in comprehensive claims if it is structured to (i) include expert panels, (ii) apply both common law and Indigenous legal principles, and (iii) innovate by accommodating Aboriginal legal boundary principals. A graduated spectrum of diminishing rights was also described as a framework for Aboriginal traditional use lands within ABDR. The method of Barry (1999) that coupled induction with a descriptive narrative method was adapted to this research using twenty-two semi-structured interviews of seven First Nations in Canada and fifteen non-Aboriginal Canadians familiar with non-treaty boundary determination. Responses were coded into themes and ranked using an ordinal scale to support interpretation of the interview data and triangulation between the participants. It was found that a quasi-judicial framework may be established that is only reviewable by superior courts of appeal by developing a novel ABDR mechanism that empanels experts on Aboriginal law and issues who are culturally sensitive to Aboriginal Peoples. It should also utilize land surveyors in the field to walk the boundaries. By induction, it also found that a quasi-judicial ABDR mechanism may be viable within the Surveyor General Branch if this department is moved out of Natural Resources Canada where it could be expected to have greater autonomy and perceived independence by Aboriginal Peoples.
- ItemOpen AccessAn Adaptive Land Tenure Information System Database Design for Conflict and Post-Conflict Situations(2017) Dabboor, Alaa; Barry, Michael; Wang, Xin; Detchev, IvanThe key objective of this study was to design, develop, and test a schema-less graph network Land Tenure Information System (LTIS) database prototype that is integrated with data mining and social network analysis techniques for the purpose of revealing hidden tenure information in the data related to conflict and post-conflict situations. Conventional LTISs are ineffective in conflict and post-conflict situations because they only describe recorded tenure information, and therefore these systems are not reflective of land practices taking place on the ground. In conflict and post-conflict situations, multiple sets of state held and privately held land tenure records may exist. The question then is how can LTISs be better designed to capture and describe tenure information in conflict and post-conflict situations. The study adapts a spiral software development model to develop a Talking Titler Network (TTN) database prototype. Simulated tenure data from two illustrative cases was entered and automatically mined and analysed within the database system. The results show that a schema-less graph network database integrated with data mining and social network analysis techniques can capture and describe complex land tenure information among and between people and tenure objects. In addition, the integrated techniques automatically extract, investigate, and visualise embedded tenure information emerging from these situations. The experimental test results provide important empirical observations to advance the TTN database design and development in order to assist in supporting land tenure dispute resolution for conflict and post-conflict situations. However, further field work needs to be carried out to validate the results.
- ItemOpen AccessAutomated Floor Plan and Building Model Creation for Cultural Heritage Buildings from Laser Scanner Data(2021-06-21) Pexman, Katherine; Lichti, Derek D.; Dawson, Peter; O'Keefe, Kyle; Detchev, IvanThis research project developed and implemented an automated modelling system to create 2D floor plans and 3D building models of heritage sites. Without building plans, it is more difficult for an historic building to receive historic designation and restoration funding. Under current practice, the creation of such physical documentation is expensive and time-consuming. Physical documentation can include as-built architectural plans, elevations, profiles and photographs, whereas historic documentation includes important documents, artefacts, and historic photographs or archives. Important heritage sites whose building plans have been lost or destroyed or become inaccurate through renovations are often left abandoned or not kept up properly because they are unable to receive the necessary support. The current modelling process involves the utilization of CAD software and a trained modeller to digitally draw a 2D floor plan, or a more complex 3D building model, overlain upon the point cloud data collected by a laser scanner. As currently applied, point cloud modelling requires inefficient manual manipulation, editing and rendering of large datasets within a CAD environment to produce floor plans and building models. This research project used statistical methods such as principal components analysis (PCA) and M-estimator sample consensus (MSAC) to automatically detect building features from a point cloud captured through a 3D terrestrial laser scan (TLS) of the building site. Two novel methods were developed in this work to help in the automation of floor plan and building model creation. The first was a novel methodology for the automated separation of storeys within a multi-level, multi-storey building. The second was a novel methodology for the automated detection of doors and windows within a point cloud using a wall-defined search space. These new methods were implemented as components in an end-to-end modelling strategy for the creation of floor plans and building models, the final output of which is written in a CAD-accessible file format. The modelling strategy showed an overall accuracy of 92.75% for the tested datasets, demonstrating the ability of the developed program to accurately produce both 2D floor plans and 3D building models of multi-level building storeys with door and window features. The development of this automated process will allow a non-geomatics expert to create floor plans and/or building models of sites with significantly less manual effort and reduced cost. This will increase the ability of heritage sites to receive historic designation, allowing them to be better preserved over time.
- ItemOpen AccessImage-based Fine-scale Infrastructure Monitoring(2016) Detchev, Ivan; Habib, Ayman; Lichti, Derek; El-Badry, Mamdouh; El-Sheimy, Naser; Sadeghpour, Farnaz; Sohn, GunhoMonitoring the physical health of civil infrastructure systems is an important task that must be performed frequently in order to ensure their serviceability and sustainability. Additionally, laboratory experiments where individual system components are tested on the fine-scale level provide essential information during the structural design process. This type of inspection, i.e., measurements of deflections and/or cracks, has traditionally been performed with instrumentation that requires access to, or contact with, the structural element being tested; performs deformation measurements in only one dimension or direction; and/or provides no permanent visual record. To avoid the downsides of such instrumentation, this dissertation proposes a remote sensing approach based on a photogrammetric system capable of three-dimensional reconstruction. The proposed system is low-cost, consists of off-the-shelf components, and is capable of reconstructing objects or surfaces with homogeneous texture. The scientific contributions of this research work address the drawbacks in currently existing literature. Methods for in-situ multi-camera system calibration and system stability analysis are proposed in addition to methods for deflection/displacement monitoring, and crack detection and characterization in three dimensions. The mathematical model for the system calibration is based on a single or multiple reference camera(s) and built-in relative orientation constraints where the interior orientation and the mounting parameters for all cameras are explicitly estimated. The methods for system stability analysis can be used to comprehensively check for the cumulative impact of any changes in the system parameters. They also provide a quantitative measure of this impact on the reconstruction process in terms of image space units. Deflection/displacement monitoring of dynamic surfaces in three dimensions is achieved with the system by performing an innovative sinusoidal fitting adjustment. The input data for the adjustment comes from either model-based image fitting or full surface fitting procedures. The crack characterization, i.e., estimation of the average crack width, approximate length and overall orientation, is achieved directly in three dimensions by detecting cracks in a region of interest in a truly-rectified photo via image processing techniques. This hybrid approach combines the use of both geometric and radiometric data, and it performs best in a multi-epoch setting.
- ItemOpen AccessAn Investigation of Coordinates as Mathematical Evidence for Cadastral Surveying in Alberta(2021-04-27) Sakatch, Matthew Michael Philip; Rangelova, Elena; Detchev, Ivan; Lichti, Derek; O'Keefe, Kyle; Jacobson, DanThis research delves into the topic of coordinates as legal survey evidence for boundary positions. It is spurred by the recently adopted Hybrid Cadastre project in Alberta, Canada and the evidentiary changes concurrent with this initiative. A review of literature pertaining to how survey evidence in assessed historically under the Hierarchy of Evidence, as well as the implications of modern evidentiary initiatives with coordinates is provided. Hypotheses are formed from this literature review and enlighten the qualitative study design. Key informant interviews apprise of the profession’s perspectives on this form of evidence are assessed using qualitative methods. Informants included practicing land surveyors, academics, members of the public, and government officials. A descriptive narrative approach was applied to the informant’s feedback to generate emergent themes. Informant feedback was assessed against the themes by incorporating an ordinal scale to provide a parameterized data set. Inferences made from this dataset prime the synthesis and theory development. In synthesis, an emergent theory on coordinates as evidence is provided as well as a continuum for assessing coordinate based evidentiary initiatives. When properly framed within the legislative framework and in specific de facto applications coordinates can govern legal survey boundaries and be considered a sui generis form of boundary evidence. An emergent continuum is proposed to provide a metric for assessing future applications of coordinates as evidence in alternate jurisdictions. This continuum is founded in the principles of cadastral management, and ensuring the public's continued faith in the land framework. Conclusions are provided relating to the adoption of coordinates as evidence currently within the land framework and case law. Ultimately future adoption of coordinates as evidence is a topic that requires legislative intervention to provide for widespread adoption and acceptance.
- ItemOpen AccessPractical In Situ Implementation of a Multicamera Multisystem Calibration(2018-02-07) Detchev, Ivan; Habib, Ayman; Mazaheri, Mehdi; Lichti, DerekConsumer-grade cameras are generally low-cost and available off-the-shelf, so having multicamera photogrammetric systems for 3D reconstruction is both financially feasible and practical. Such systems can be deployed in many different types of applications: infrastructure health monitoring, cultural heritage documentation, bio-medicine, as-built surveys, and indoor or outdoor mobile mapping for example. A geometric system calibration is usually necessary before a data acquisition mission in order for the results to have optimal accuracy. A typical system calibration must address the estimation of both the interior and the exterior, or relative, orientation parameters for each camera in the system. This article reviews different ways of performing a calibration of a photogrammetric system consisting of multiple cameras. It then proposes a methodology for the simultaneous estimation of both the interior and the relative orientation parameters which can work in several different types of scenarios including a multicamera multisystem calibration. A rigorous in situ system calibration was successfully implemented and tested. The same algorithm is able to handle the equivalent to a traditional-style bundle adjustment, that is, a network solution without constraints, for a single or multicamera calibrations, and the proposed bundle adjustment with built-in relative orientation constraints for the calibration of a system or multiple systems of cameras.