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Full-Text Articles in Mechanical Engineering
Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz
Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz
Christopher N. Roman
Practical autonomous robotic vehicles require dependable methods for accurately identifying course or roadway boundaries. The authors have developed a method to reliably extract the boundary line using simple dynamic thresholding, noise filtering, and blob removal. This article describes their efforts to apply this procedure in developing an autonomous vehicle.
Preliminary Model Tests For The Design Of A Gliding Deep Water Elevator, Christopher Roman, T. Gregory, E. Martin, A. Sanguinetti, J. Drummond
Preliminary Model Tests For The Design Of A Gliding Deep Water Elevator, Christopher Roman, T. Gregory, E. Martin, A. Sanguinetti, J. Drummond
Christopher N. Roman
This paper presents progress on the design of a "smart elevator" to be used in conjunction with deep sea ROV operations. Deep sea elevators are gravity driven untethered platforms used to deliver and or return items from the sea floor. Elevators are used when items are too large or heavy to be handled by the ROV, or when the turn around time to recover and redeploy the ROV system for sample removal is prohibitive. Unfortunately, efficiency is complicated by the precision with which elevators can be landed at a specific location on the bottom and recovered on the surface because …
Design Of A Gas Tight Water Sampler For Auv Operations, Christopher Roman, R. Camilli
Design Of A Gas Tight Water Sampler For Auv Operations, Christopher Roman, R. Camilli
Christopher N. Roman
This paper presents the design and preliminary test results for a small gas tight water sampler intended to work on scientific AUVs. In recent years AUVs have developed into reliable platforms capable of carrying a wide variety of environmental sensors for in-situ chemical measurements. Physical sample collection however remains difficult, due to the combination of space, power and complexity constraints inherent in working with autonomous platforms. The AUV sampler is a small (12 cm times 85 cm) cylindrical package designed to collect eight 20 ml gas tight volumes of water, with each sample maintained at high pressure to depths of …
Consistency Based Error Evaluation For Deep Sea Bathymetric Mapping With Robotic Vehicles, Christopher Roman, Hanumant Singh
Consistency Based Error Evaluation For Deep Sea Bathymetric Mapping With Robotic Vehicles, Christopher Roman, Hanumant Singh
Christopher N. Roman
This paper presents a method to evaluate the mapping error present in point cloud terrain maps created using robotic vehicles and range sensors. This work focuses on mapping environments where no a priori ground truth is available and self consistency is the only available check against false artifacts and errors. The proposed error measure is based on a disparity measurement between common sections of the environment that have been imaged multiple times. This disparity measure highlights inconsistency in the terrain map by showing regions where multiple overlapping point clouds do not fit together well. This error measure provides the map …
Improved Vehicle Based Multibeam Bathymetry Using Sub-Maps And Slam, Christopher Roman, Hanumant Singh
Improved Vehicle Based Multibeam Bathymetry Using Sub-Maps And Slam, Christopher Roman, Hanumant Singh
Christopher N. Roman
This paper presents an algorithm to improve sub-sea acoustic multibeam bottom mapping based on the simultaneous mapping and localization (SLAM) methodology. Multibeam bathymetry from underwater water vehicles can yield valuable large scale terrain maps of the sea door, but the overall accuracy of these maps is typically limited by the accuracy of the vehicle position estimates. The solution presented here uses small bathymetric patches created over short time scales in a sub-mapping context. These patches are registered with respect to one another and assembled in a single coordinate frame to produce a more accurate terrain estimate and provide improved renavigation …
Micro-Bathymetric Mapping Using Acoustic Range Images, Christopher Roman, Hanumant Singh
Micro-Bathymetric Mapping Using Acoustic Range Images, Christopher Roman, Hanumant Singh
Christopher N. Roman
This work focuses on the creation of high resolution micro-bathymetric maps using a high frequency pencil beam sonar. These maps typically cover areas of 10's to 100's of square meters. Data is collected using a sonar mounted to an underwater vehicle that can be positioned at discrete locations on the sea floor or flown in a survey pattern above the bottom. Specifically, we are focused on improving the accuracy of these terrain maps by merging sonar pings taken from multiple vantage points over the same location. This requires the adaption of data registration techniques to handle errors related to the …
Optical And Acoustic Habitat Characterization With The Seabed Auv, Hanumant Singh, Ryan Eustice, Oscar Pizarro, Christopher Roman
Optical And Acoustic Habitat Characterization With The Seabed Auv, Hanumant Singh, Ryan Eustice, Oscar Pizarro, Christopher Roman
Christopher N. Roman
The Seabed AUV is an Autonomous Underwater Vehicle (AUV) built to serve as a readily available and operationally simple tool for high resolution imaging. It is a hover-capable vehicle that performs optical sensing with a 12 bit 1280/spl times/1024 CCD camera and acoustic high resolution mapping using an MST 300 kHz sidescan and a 675 kHz pencil beam bathymetric sonar. The AUV has been designed for operations from small vessels with minimal support equipment. It has an operational depth of 2000 meters and at 1 m/s can run for up to 10 hours. In this paper we report on the …
Estimation Of Error In Large Area Underwater Photomosaics Using Vehicle Navigation Data, C. Roman, H. Singh
Estimation Of Error In Large Area Underwater Photomosaics Using Vehicle Navigation Data, C. Roman, H. Singh
Christopher N. Roman
Creating geometrically accurate photomosaics of underwater sites using images collected from an AUV or ROV is a difficult task due to dimensional errors which grow as a function of 3D image distortion and the mosaicking process. Although photomosiacs are accurate locally their utility for accurately representing a large survey area is jeopardized by this error growth. Evaluating the error in a mosaic is the first step in creating globally accurate photomosaics of an unstructured environment with bounded error. Using vehicle navigation data and sensor offsets it is possible to estimate the error present in large area photomosaics independent of the …
A New Autonomous Underwater Vehicle For Imaging Research, C. Roman, O. Pizarro, R. Eustice, H. Singh
A New Autonomous Underwater Vehicle For Imaging Research, C. Roman, O. Pizarro, R. Eustice, H. Singh
Christopher N. Roman
Currently, unmanned underwater vehicles either tend to be cumbersome and complex to run, or operationally simple, but not quite suitable platforms for deep water imaging. This paper presents an alternative design in the form of a new low cost and easier to use autonomous underwater vehicle (AUV) for imaging research. The objective of the vehicle is to serve as a readily available and operationally simple tool that allows rapid testing of imaging algorithms in areas such as photomosaicking, 3D image reconstruction from a single camera, image based navigation, and multi-sensor fusion of bathymetry and optical data. These are all current …
Advances In Fusion Of High Resolution Underwater Optical And Acoustic Data, H. Singh, C. Roman, L. Whitcomb, D. Yoerger
Advances In Fusion Of High Resolution Underwater Optical And Acoustic Data, H. Singh, C. Roman, L. Whitcomb, D. Yoerger
Christopher N. Roman
We report efforts to merge data from the complementary modalities of optical and acoustic sensing for obtaining more accurate representations of the seafloor. We show that the principal obstacles to merging the acoustic and optical imaging modalities are the distortions inherent to each modality. The construction of geometrically accurate photomosaics is dominated by incremental errors arising as individual images are scaled and warped to form the photomosaic. For microbathymetric mapping, principal errors arise from sensor position and orientation calibration parameters that affect our ability to construct maps from sonar data that are commensurate with sensor and navigation resolution. We show …
Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz
Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz
Graduate School of Oceanography Faculty Publications
Practical autonomous robotic vehicles require dependable methods for accurately identifying course or roadway boundaries. The authors have developed a method to reliably extract the boundary line using simple dynamic thresholding, noise filtering, and blob removal. This article describes their efforts to apply this procedure in developing an autonomous vehicle.