Catalog of lunar mission data

Several series of spacecraft were developed, designed, built and launched to determine different characteristics of the lunar surface and environment for a manned landing. Both unmanned and manned spacecrafts, spacecraft equipment and lunar missions are documented

Treatment of control data in lunar phototriangulation

In lunar phototriangulation, there is a complete lack of accurate ground control points. The accuracy analysis of the results of lunar phototriangulation must, therefore, be completely dependent on statistical procedure. It was the objective of this investigation to examine the validity of the commonly used statistical procedures, and to develop both mathematical techniques and computer softwares for evaluating (1) the accuracy of lunar phototriangulation; (2) the contribution of the different types of photo support data on the accuracy of lunar phototriangulation; (3) accuracy of absolute orientation as a function of the accuracy and distribution of both the ground and model points; and (4) the relative slope accuracy between any triangulated pass points

Map-Based Localization for Unmanned Aerial Vehicle Navigation

Unmanned Aerial Vehicles (UAVs) require precise pose estimation when navigating in indoor and GNSS-denied / GNSS-degraded outdoor environments. The possibility of crashing in these environments is high, as spaces are confined, with many moving obstacles. There are many solutions for localization in GNSS-denied environments, and many different technologies are used. Common solutions involve setting up or using existing infrastructure, such as beacons, Wi-Fi, or surveyed targets. These solutions were avoided because the cost should be proportional to the number of users, not the coverage area. Heavy and expensive sensors, for example a high-end IMU, were also avoided. Given these requirements, a camera-based localization solution was selected for the sensor pose estimation. Several camera-based localization approaches were investigated. Map-based localization methods were shown to be the most efficient because they close loops using a pre-existing map, thus the amount of data and the amount of time spent collecting data are reduced as there is no need to re-observe the same areas multiple times. This dissertation proposes a solution to address the task of fully localizing a monocular camera onboard a UAV with respect to a known environment (i.e., it is assumed that a 3D model of the environment is available) for the purpose of navigation for UAVs in structured environments. Incremental map-based localization involves tracking a map through an image sequence. When the map is a 3D model, this task is referred to as model-based tracking. A by-product of the tracker is the relative 3D pose (position and orientation) between the camera and the object being tracked. State-of-the-art solutions advocate that tracking geometry is more robust than tracking image texture because edges are more invariant to changes in object appearance and lighting. However, model-based trackers have been limited to tracking small simple objects in small environments. An assessment was performed in tracking larger, more complex building models, in larger environments. A state-of-the art model-based tracker called ViSP (Visual Servoing Platform) was applied in tracking outdoor and indoor buildings using a UAVs low-cost camera. The assessment revealed weaknesses at large scales. Specifically, ViSP failed when tracking was lost, and needed to be manually re-initialized. Failure occurred when there was a lack of model features in the cameras field of view, and because of rapid camera motion. Experiments revealed that ViSP achieved positional accuracies similar to single point positioning solutions obtained from single-frequency (L1) GPS observations standard deviations around 10 metres. These errors were considered to be large, considering the geometric accuracy of the 3D model used in the experiments was 10 to 40 cm. The first contribution of this dissertation proposes to increase the performance of the localization system by combining ViSP with map-building incremental localization, also referred to as simultaneous localization and mapping (SLAM). Experimental results in both indoor and outdoor environments show sub-metre positional accuracies were achieved, while reducing the number of tracking losses throughout the image sequence. It is shown that by integrating model-based tracking with SLAM, not only does SLAM improve model tracking performance, but the model-based tracker alleviates the computational expense of SLAMs loop closing procedure to improve runtime performance. Experiments also revealed that ViSP was unable to handle occlusions when a complete 3D building model was used, resulting in large errors in its pose estimates. The second contribution of this dissertation is a novel map-based incremental localization algorithm that improves tracking performance, and increases pose estimation accuracies from ViSP. The novelty of this algorithm is the implementation of an efficient matching process that identifies corresponding linear features from the UAVs RGB image data and a large, complex, and untextured 3D model. The proposed model-based tracker improved positional accuracies from 10 m (obtained with ViSP) to 46 cm in outdoor environments, and improved from an unattainable result using VISP to 2 cm positional accuracies in large indoor environments. The main disadvantage of any incremental algorithm is that it requires the camera pose of the first frame. Initialization is often a manual process. The third contribution of this dissertation is a map-based absolute localization algorithm that automatically estimates the camera pose when no prior pose information is available. The method benefits from vertical line matching to accomplish a registration procedure of the reference model views with a set of initial input images via geometric hashing. Results demonstrate that sub-metre positional accuracies were achieved and a proposed enhancement of conventional geometric hashing produced more correct matches - 75% of the correct matches were identified, compared to 11%. Further the number of incorrect matches was reduced by 80%

Architectural Digital Photogrammetry

This study is to exploit texturing techniques of a common modelling software in the way of creating virtual models of an exist architectures using oriented panoramas. In this research, The panoramic image-based interactive modelling is introduced as assembly point of photography, topography, photogrammetry and modelling techniques. It is an interactive system for generating photorealistic, textured 3D models of architectural structures and urban scenes. The technique is suitable for the architectural survey because it is not a «point by point» survey, and it exploit the geometrical constraints in the architecture to simplify modelling. Many factors are presented to be critical features that affect the modelling quality and accuracy, such as the way and the position in shooting the photos, stitching the multi-image panorama photos, the orientation, texturing techniques and so on. During the last few years, many Image-based modelling programmes have been released. Whereas, in this research, the photo modelling programs was not in use, it meant to face the fundamentals of the photogrammetry and to go beyond the limitations of such software by avoiding the automatism. In addition, it meant to exploit the potent commands of a program as 3DsMax to obtain the final representation of the Architecture. Such representation can be used in different fields (from detailed architectural survey to an architectural representation in cinema and video games), considering the accuracy and the quality which they are vary too. After the theoretical studies of this technique, it was applied in four applications to different types of close range surveys. This practice allowed to comprehend the practical problems in the whole process (from photographing all the way to modelling) and to propose the methods in the ways to improve it and to avoid any complications. It was compared with the laser scanning to study the accuracy of this technique. Thus, it is realized that not only the accuracy of this technique is linked to the size of the surveyed object, but also the size changes the way in which the survey to be approached. Since the 3D modelling program is not dedicated to be used for the image-based modelling, texturing problems was faced. It was analyzed in: how the program can behave with the Bitmap, how to project it, how it could be an interactive projection, and what are the limitations

Close-range photogrammetry enables documentation of environment-induced deformation of architectural heritage

Deformation, damage and permanent loss of heritage assets due to various physical and environmental factors has always been a major problem. As the availability of funds for conservation and restoration is limited, the digital documentation of heritage objects and monitoring of environment-induced deformations are increasingly important for cultural heritage preservation. Our study elucidates developments in the digital image capturing and processing for recording architectural heritage objects focusing on the digital camera calibration, close-range imaging, and photogrammetric modelling of complex structures using image matching techniques. A particular consideration in this paper is given to the ortho-photographic image compiling and accuracy assessment procedure. The practicality of the methodology is demonstrated by applying photogrammetric system PhotoMod for documentation of decorative elements in Uzutrakis manor, a national heritage site in Trakai, Lithuania

Close-range photogrammetry enables documentation of environment-induced deformation of architectural heritage

Deformation, damage and permanent loss of heritage assets due to various physical and environmental factors has always been a major problem. As the availability of funds for conservation and restoration is limited, the digital documentation of heritage objects and monitoring of environment-induced deformations are increasingly important for cultural heritage preservation. Our study elucidates developments in the digital image capturing and processing for recording architectural heritage objects focusing on the digital camera calibration, close-range imaging, and photogrammetric modelling of complex structures using image matching techniques. A particular consideration in this paper is given to the ortho-photographic image compiling and accuracy assessment procedure. The practicality of the methodology is demonstrated by applying photogrammetric system PhotoMod for documentation of decorative elements in Uzutrakis manor, a national heritage site in Trakai, Lithuania

VIRTUAL TOURS FOR SMART CITIES: A COMPARATIVE PHOTOGRAMMETRIC APPROACH FOR LOCATING HOT-SPOTS IN SPHERICAL PANORAMAS

The paper aims to investigate the possibilities of using the panorama-based VR to survey data related to that set of activities for planning and management of urban areas, belonging to the Smart Cities strategies. The core of our workflow is to facilitate the visualization of the data produced by the infrastructures of the Smart Cities. A graphical interface based on spherical panoramas, instead of complex three-dimensional could help the user/citizen of the city to better know the operation related to control units spread in the urban area. From a methodological point of view three different kind of spherical panorama acquisition has been tested and compared in order to identify a semi-automatic procedure for locating homologous points on two or more spherical images starting from a point cloud obtained from the same images. The points thus identified allow to quickly identify the same hot-spot on multiple images simultaneously. The comparison shows how all three systems have proved to be useful for the purposes of the research but only one has proved to be reliable from a geometric point of view to identify the locators useful for the construction of the virtual tour

Navigating Immersive and Interactive VR Environments With Connected 360° Panoramas

Emerging research is expanding the idea of using 360-degree spherical panoramas of real-world environments for use in 360 VR experiences beyond video and image viewing. However, most of these experiences are strictly guided, with few opportunities for interaction or exploration. There is a desire to develop experiences with cohesive virtual environments created with 360 VR that allow for choice in navigation, versus scripted experiences with limited interaction. Unlike standard VR with the freedom of synthetic graphics, there are challenges in designing appropriate user interfaces (UIs) for 360 VR navigation within the limitations of fixed assets. To tackle this gap, we designed RealNodes, a software system that presents an interactive and explorable 360 VR environment. We also developed four visual guidance UIs for 360 VR navigation. The results of a pilot study showed that choice of UI had a significant effect on task completion times, showing one of our methods, Arrow, was best. Arrow also exhibited positive but non-significant trends in average measures with preference, user engagement, and simulator-sickness. RealNodes, the UI designs, and the pilot study results contribute preliminary information that inspire future investigation of how to design effective explorable scenarios in 360 VR and visual guidance metaphors for navigation in applications using 360 VR environments