841 research outputs found
Measurement of Micro-bathymetry with a GOPRO Underwater Stereo Camera Pair
A GO-PRO underwater stereo camera kit has been used to measure the 3D topography (bathymetry) of a patch of seafloor producing a point cloud with a spatial data density of 15 measurements per 3 mm grid square and an standard deviation of less than 1 cm A GO-PRO camera is a fixed focus, 11 megapixel, still-frame (or 1080p high-definition video) camera, whose small form-factor and water-proof housing has made it popular with sports enthusiasts. A stereo camera kit is available providing a waterproof housing (to 61 m / 200 ft) for a pair of cameras. Measures of seafloor micro-bathymetrycapable of resolving seafloor features less than 1 cm in amplitude were possible from the stereoreconstruction. Bathymetric measurements of this scale provide important ground-truth data and boundary condition information for modeling of larger scale processes whose details depend on small-scale variations. Examples include modeling of turbulent water layers, seafloor sediment transfer and acoustic backscatter from bathymetric echo sounders
Development Of A Vision System For Ship Hull Inspection
Penyelidikan ini memperkenalkan strategi pengawalan untuk memperbaiki
prestasi pemeriksaan visual badan kapal dengan menggunakan kenderaan dalam air.
This work introduces a strategy to improve the performance of visual ship hull
inspection using a Remotely-Operated Vehicle (ROV) as its underwater vehicle
platform
Analysis and application of an underwater optical-ranging system
Submitted in partial fulfillment of the requirements for the degree of Ocean Engineer at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1992In order to provide a high-resolution underwater-ranging capability for scientific
measurement, a commercially available optical-ranging system is analyzed for performance
and feasibility. The system employs a structured-lighting technique using a laser-light plane
and single-camera imaging system. The mechanics of determining range with such a system
are presented along with predicted range error. Controlled testing of the system is performed
and range error is empirically determined. The system is employed in a deep-sea application,
and its performance is evaluated. The measurements obtained are used for a scientific
application to determine seafloor roughness for very-high-spatial frequencies (greater than 10
cycles/meter). Use and application recommendations for the system are presented
Development Of A Vision System For Ship Hull Inspection [K4165. Z94 2007 f rb].
Penyelidikan ini memperkenalkan strategi pengawalan untuk memperbaiki prestasi pemeriksaan visual badan kapal dengan menggunakan kenderaan dalam air. Kaedah yang dicadangkan bertujuan untuk membangunkan sebuah sistem yang secara visualnya sentiasa kekal selari pada permukaan badan kapal.
This work introduces a strategy to improve the performance of visual ship hull inspection using a Remotely-Operated Vehicle (ROV) as its underwater vehicle platform. The proposed method is aimed at developing a system that will maintain the camera viewing angle parallel to the ship hull surface
Generación de imagen tridimensional de objetos sumergidos en aguas turbias
This article presents the design and implementation of a novel method to generate 3D coordinates from the projection of a laser line over a solid object and the processing of the images obtained during scanning. The result obtained is a 3D model of an isometric view that provides the possibility of being seen from different perspectives under a virtual environment. The methodology is applied in the capture and reconstruction of 3D images of objects submerged in murky waters.Este artículo presenta el diseño e implementación de un novedoso método para generar coordenadas tridimensionales a partir de la proyección de una línea láser sobre un objeto sólido y el procesamiento de las imágenes obtenidas durante el escaneo. El resultado obtenido es un modelo tridimensional de una vista isométrica que brinda la posibilidad de ser visto desde diferentes perspectivas bajo un ambiente virtual. La metodología es aplicada en la captura y reconstrucción de imágenes tridimensionales de objetos sumergidos en aguas turbias
ANALYSIS OF UNCERTAINTY IN UNDERWATER MULTIVIEW RECONSTRUCTION
Multiview reconstruction, a method for creating 3D models from multiple images from different views, has been a popular topic of research in the eld of computer vision in the last two decades. Increased availability of high-quality cameras led to the development of advanced techniques and algorithms. However, little attention has been paid to multiview reconstruction in underwater conditions. Researchers in a wide variety of elds (e.g. marine biology, archaeology, and geology) could benefit from having 3D models of seafloor and underwater objects. Cameras, designed to operate in air, must be put in protective housings to work underwater. This affects the image formation process. The largest source of underwater image distortion results from refraction of light, which occurs when light rays travel through boundaries between media with different refractive indices. This study addresses methods for accounting for light refraction when using a static rig with multiple cameras. We define a set of procedures to achieve optimal underwater reconstruction results, and we analyze the expected quality of the 3D models\u27 measurements
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