Search results for "Structure from Motion"
showing 10 items of 44 documents
Investigating snowcover volumes and icings dynamics in the moraine of an Arctic catchment using UAV/ photogrammetry and LiDAR
2016
International audience; Means for assessing the contribution of the terminal moraine into the water budget of an Arctic glacier is investigated: on the one hand the terminal moraine represents a significant fraction (22%)of the catchment area of the glacier under investigation – Austre Lovenbreen, in the Brøgger peninsula, Spitsbergen – and on the other hand icings formation (or aufeis) each winter illustrates the contribution of subglacial water flow. While over the glacier, with a smooth surface readily interpolated, the winter and summer mass balances are assessed with only a few sparsely distributed stakes, such an approach is not valid with the rough topography of the glacier moraine: …
High-resolution UAV imagery for field olive (Olea europaea L.) phenotyping
2021
Remote sensing techniques based on images acquired from unmanned aerial vehicles (UAVs) could represent an effective tool to speed up the data acquisition process in phenotyping trials and, consequently, to reduce the time and cost of the field work. In this study, we assessed the ability of a UAV equipped with RGB-NIR cameras in highlighting differences in geometrical and spectral canopy characteristics between eight olive cultivars planted at different planting distances in a hedgerow olive orchard. The relationships between measured and estimated canopy height, projected canopy area and canopy volume were linear regardless of the different cultivars and planting distances (RMSE of 0.12 m…
Image-based 3D reconstruction using traditional and UAV datasets for analysis of road pavement distress
2018
Abstract On local and urban networks, the enduring issue of scarce resources for Maintenance, Rehabilitation, and Reconstruction strategies (MR&R) has led, in many cases, to using unadjusted or poor techniques for road pavement distress detection and analysis, yielding ineffective or even counterproductive results. Therefore, it is necessary to have tools that can carry out quick, reliable and low-cost assessment surveys. This paper aims at validating the use of innovative and low-cost technologies for road pavement analysis, assessing their potentialities for improving the automation and reliability of distress detection. A Structure from Motion (SfM) technique is analyzed at different alt…
Extrinsic calibration of heterogeneous cameras by line images
2014
International audience; The extrinsic calibration refers to determining the relative pose of cameras. Most of the approaches for cameras with non-overlapping fields of view (FOV) are based on mirror reflection, object tracking or rigidity constraint of stereo systems whereas cameras with overlapping FOV can be calibrated using structure from motion solutions. We propose an extrinsic calibration method within structure from motion framework for cameras with overlapping FOV and its extension to cameras with partially non-overlapping FOV. Recently, omnidirectional vision has become a popular topic in computer vision as an omnidirectional camera can cover large FOV in one image. Combining the g…
Biologically Inspired Vision Architectures: a Software/Hardware Perspective
2007
Even tough the field of computer vision has seen huge improvement in the last few decades, computer vision systems still lack, in most cases, the efficiency of biological vision systems. In fact biological vision systems routinely accomplish complex visual tasks such as object recognition, obstacle avoidance, and target tracking, which continue to challenge artificial systems. The study of biological vision system remains a strong cue for the design of devices exhibiting intelligent behaviour in visually sensed environments but current artificial systems are vastly different from biological ones for various reasons. First of all, biologically inspired vision architectures, which are continu…
Using dense stereo matching techniques in survey
2013
In recent years there has been an enormous increase in the dissemination of modelling techniques known as dense stereo matching (DSM) or image-based modelling (IBM) using free, low cost, open source software, especially applications involving the survey of cultural heritage (architecture, archaeology, and town planning). The algorithms used by these software programmes process photographic datasets and provide a 3D model of the scene in question. During complex survey and 3D restitution procedures, these techniques save time (processing) and money: these advantages Can he useful to any professional. This is why it is important to identify the real potential and limits of these software prog…
Three-dimensional rigid motion estimation using genetic algorithms from an image sequence in an active stereo vision system
2004
This paper proposes a method for estimating the three-dimensional (3D) rigid motion parameters from an image sequence of a moving object. The 3D surface measurement is achieved using an active stereovision system composed of a camera and a light projector, which illuminates the objects to be analyzed by a pyramid-shaped laser beam. By associating the laser rays with the spots in the two-dimensional image, the 3D points corresponding to these spots are reconstructed. Each image of the sequence provides a set of 3D points, which is modeled by a B-spline surface. Therefore, estimating the 3D motion between two images of the sequence boils down to matching two B-spline surfaces. We consider the…
Assessing Seagrass Restoration Actions through a Micro-Bathymetry Survey Approach (Italy, Mediterranean Sea)
2022
Underwater photogrammetry provides a means of generating high-resolution products such as dense point clouds, 3D models, and orthomosaics with centimetric scale resolutions. Underwater photogrammetric models can be used to monitor the growth and expansion of benthic communities, including the assessment of the conservation status of seagrass beds and their change over time (time lapse micro-bathymetry) with OBIA classifications (Object-Based Image Analysis). However, one of the most complex aspects of underwater photogrammetry is the accuracy of the 3D models for both the horizontal and vertical components used to estimate the surfaces and volumes of biomass. In this study, a photogrammetry…
Low Cost Handheld 3D Scanning for Architectural Elements Acquisition
2016
3D scanning has gone a long way since its first appearance in cultural heritage digitization and modeling. In the recent years some new low cost, fast, accurate emerging technologies are flooding the market. Envisioning the massive use of these cheap and easy to use devices in the next years, it is crucial to explore the possible fields of application and to test their effectiveness in terms of easiness of 3D data collection, processing, mesh resolution and metric accuracy against the size and features of the objects. In this study we focus the attention on one emerging technology, the Structure Sensor device, in order to verify a 3D pipeline acquisition on an architectural element and its …
Il Portico meridionale della Cattedrale di Palermo: sperimentazioni di rilievo attraverso l’utilizzo di tecniche Structure from Motion
2014
Structure from Motion (SfM) techniques constitute a very fertile field of investigation within the research of the surveying sector and that of the representation of architecture. They allow us to reach higher levels of reliability and accuracy, both metric and graphical, extremely quickly and with lower costs than other methods, including the laser scanner. In this study, we report the results of some experiments carried out on the southern Portico entrance of the Cathedral of Palermo through the use of the SfM techniques later validated by comparison with the point cloud obtained from laser scanning.