Tytuł: Subsea wellhead spud-in marking and as-built position estimation method based on ultra-short baseline acoustic positioning

Autor/Autorzy: Arkadiusz Tomczak, Grzegorz Stępień, Tomasz Abramowski, Artur Bejger

Miejsce publikacji: MEASUREMENT

Rok: 2022

Słowa kluczowe: subsea offshore assets positioning, position estimation, subsea navigation, seafloor mapping

Abstrakt: Positioning seabed objects in ultra-deep waters is critical in the mapping, exploration, and industrial exploitation of oceans. This paper presents research on a subsea wellhead positioning process for the marking of seabed positions and its subsequent as-built verification. The results indicate that the ultra-short baseline (USBL) acoustic technique can provide static positioning accuracy and precision comparable to those of a long-baseline method (LBL) and significantly reduces the time and cost of the offshore project. The new approach was tested at different stages of the process. First, an innovative offset transformation method, which increases the precision of alignments, was proposed, followed by a step-by-step procedure for determining the positions of marker buoys on the seabed based on spin tests and cardinal heading calibration. Finally, the M-estimation method, which has not yet been applied in subsea engineering, was implemented and proved to be a suitable alternative to the ordinary least squares method.

Adres strony internetowej (link) do pełnego tekstu publikacji: https://www.sciencedirect.com/science/article/pii/S0263224122004134

DOI: 10.1016/j.measurement.2022.111155

Tytuł: Seabed Modelling by Means of Airborne Laser Bathymetry Data and Imbalanced Learning for Offshore Mapping

Autor/Autorzy: Tomasz Kogut, Arkadiusz Tomczak, Adam Słowik, Tomasz Oberski

Miejsce publikacji: SENSORS

Rok: 2022

Słowa kluczowe: classification, airborne laser bathymetry, imbalanced learning, oversampling, SMOTE

Abstrakt: An important problem associated with the aerial mapping of the seabed is the precise classification of point clouds characterizing the water surface, bottom, and bottom objects. This study aimed to improve the accuracy of classification by addressing the asymmetric amount of data representing these three groups. A total of 53 Synthetic Minority Oversampling Technique (SMOTE) algorithms were adjusted and evaluated to balance the amount of data. The prepared data set was used to train the Multi-Layer Perceptron (MLP) neural network used for classifying the point cloud. Data balancing contributed to significantly increasing the accuracy of classification. The best overall classification accuracy achieved varied from 95.8% to 97.0%, depending on the oversampling algorithm used, and was significantly better than the classification accuracy obtained for unbalanced data and data with downsampling (89.6% and 93.5%, respectively). Some of the algorithms allow for 10% increased detection of points on the objects compared to unbalanced data or data with simple downsampling. The results suggest that the use of selected oversampling algorithms can aid in improving the point cloud classification and making the airborne laser bathymetry technique more appropriate for seabed mapping.

Adres strony internetowej (link) do pełnego tekstu publikacji: https://www.mdpi.com/1424-8220/22/9/3121

DOI: 10.3390/s22093121

Tytuł: Applicability of Machine Learning for Vessel Dimension Survey with a Minimum Number of Common Points

Autor/Autorzy: Ilona Garczyńska, Arkadiusz Tomczak, Grzegorz Stępień, Lech Kasyk, Wojciech Ślączka, Tomasz Kogut

Miejsce publikacji: Applied Sciences-Basel

Rok: 2022

Słowa kluczowe: dimensional control, three-dimensional coordinates transformations, off-shore surveying, marine geodesy, artificial neural networks, applied engineering

Abstrakt: This paper presents the challenges encountered in the dimensional control of ships, platforms, and offshore units. This novel approach utilizes machine learning (MLP—Multilayer Perceptron Neural Network) for three-dimensional (3D) spatial coordinate transformations when only three common points are known. The proposed method was verified based on laboratory and field data. The main issue was to provide a sufficient number of valid training points. The oversampling method was used to meet this criterion. The achieved results indicate equal or better accuracy when the points were located inside the adjustment points array. In the case where the points lay outside this array, no improvement in the accuracy of the transformation was observed. The neural approach restores the transformation symmetry, and in some cases, such as the study of deformation of engineering objects, breaks the symmetry rather than restoring it.

Adres strony internetowej (link) do pełnego tekstu publikacji: https://www.mdpi.com/2076-3417/12/7/3453

DOI: 10.3390/app12073453

Tytuł: Method of Improving Incomplete Spatial-Temporal Data in Inland Navigation, on the Basis of Industrial Camera Images – West Oder River Case Study

Autor/Autorzy: Grzegorz Stępień, Artur Kujawski, Arkadiusz Tomczak, Roman Hałaburda, Kamil Borczyk

Miejsce publikacji: Transport and Telecommunication Journal

Rok: 2022
 

Słowa kluczowe: freight transport, image processing, inland navigation, geodesy, industrial camera

Abstrakt: Main aim of the paper is to use a single non-metric camera to support the determination of the position of. Authors propose to use the existing infrastructure of CCTV cameras mounted on bridges and wharves to determine the position of inland waterway vessels. Image from cameras giving the pixel coordinates of moving object is transformed to the geodetic data domain using a modified projective transformation method. Novel approach is to use of Sequential Projection Transformation (SPT) which additionally uses virtual reference points. The transformation coefficients calculated using the virtual points are used to determine the position of the vessels and are also simultaneously used to calibrate the industrial camera. The method has been verified under real conditions, and the results obtained are average 30% more accurate compared to the traditionally used projective transformation using a small number of real points.
 

Adres strony internetowej (link) do pełnego tekstu publikacji: https://sciendo.com/pl/article/10.2478/ttj-2022-0005

DOI: 10.2478/ttj-2022-0005

Tytuł: Application of Unmanned Aerial Vehicles and Image Processing Techniques in Monitoring Underwater Coastal Protection Measures

Autor/Autorzy: Jakub Śledziewski, Paweł Terefenko, Andrzej Giza, Paweł Forczmański, Andrzej Łysko, Witold Maćków, Grzegorz Stępień, Arkadiusz Tomczak, Apoloniusz Kurylczyk

Miejsce publikacji: Remote Sensing

Rok: 2022

Słowa kluczowe: image processing, object detection, Unmanned Aerial Vehicle (UAV), coastal monitoring, underwater reef

Abstrakt: A prerequisite for solving issues associated with surf zone variability, which affect human activity in coastal zones, is an accurate estimation of the effects of coastal protection methods. Therefore, performing frequent monitoring activities, especially when applying new nature-friendly coastal defense methods, is a major challenge. In this manuscript, we propose a pipeline for performing low-cost monitoring using RGB images, accessed by an unmanned aerial vehicle (UAV) and a four-level analysis architecture of an underwater object detection methodology. First, several color-based pre-processing activities were applied. Second, contrast-limited adaptive histogram equalization and the Hough transform methodology were used to automatically detect the underwater, circle-shaped elements of a hybrid coastal defense construction. An alternative pipeline was used to detect holes in the circle-shaped elements with an adaptive thresholding method; this pipeline was subsequently applied to the normalized images. Finally, the concatenation of the results from both the methods and the validation processes were performed. The results indicate that our automated monitoring tool works for RGB images captured by a low-cost consumer UAV. The experimental results showed that our pipeline achieved an average error of four pixels in the test set.

Adres strony internetowej (link) do pełnego tekstu publikacji: https://www.mdpi.com/2072-4292/14/3/458

DOI: 10.3390/rs14030458

Tytuł: Identification of Gate Turn-off Thyristor Switching Patterns Using Acoustic Emission Sensors

Autor/Autorzy: Maciej Kozak, Artur Bejger, Arkadiusz Tomczak
 

Miejsce 
publikacji: SENSORS

Rok: 2020

Słowa 
kluczowe: acoustic emission, sensor, transducer, gate turn-off thyristor, power electronics

Abstrakt: Modern seagoing ships are often equipped with converters which utilize semiconductor power electronics devices like thyristors or power transistors. Most of them are used in driving applications such as powerful main propulsion plants, auxiliary podded drives and thrusters. When it comes to main propulsion drives the power gets seriously high, thus the need for use of medium voltage power electronics devices arises. As it turns out, power electronic parts are the most susceptible to faults or failures in the whole electric drive system. These devices require efficient cooling, so manufacturers design housings in a way that best dissipates heat from the inside of the chips to the metal housing. This results in susceptibility to damage due to the heterogeneity of combined materials and the difference in temperature expansion of elements inside the power device. Currently used methods of prediction of damage and wear of semiconductor elements are limited to measurements of electrical quantities generated by devices during operation and not quite effective in case of early-stage damage to semiconductor layers. The article presents an introduction and preliminary tests of a method utilizing an acoustic emission sensor which can be used in detecting early stage damages of the gate turn-off thyristor. Theoretical considerations and chosen experimental results of initial measurements of acoustic emission signals of the medium voltage gate turn-off thyristor are presented https://www.mdpi.com/1424-8220/21/1/70
 

Adres strony internetowej (link) do pełnego tekstu 
publikacji: https://www.mdpi.com/1424-8220/21/1/70

DOI: 10.3390/s21010070

Tytuł: Dimensioning Method of Floating Offshore Objects by Means of Quasi-Similarity Transformation with Reduced Tolerance Errors

Autor/Autorzy: Grzegorz Stępień, Arkadiusz Tomczak, Martin Loosaar, Tomasz Ziębka

Miejsce
publikacji: SENSORS

Rok: 2020

Słowa
kluczowe: similarity transformation, affine transformation, rotation matrix, offshore surveying, dimensional control, orthogonal coordinate system, close range photogrammetry, total station

Abstrakt: The human activities in the offshore oil and gas, renewable energy and construction industry require reliable data acquired by different types of hydrographic sensors: DGNSS (Differential Global Navigation Satellite System) positioning, attitude sensors, multibeam sonars, lidars or total stations installed on the offshore vessel, drones or platforms. Each component or sensor that produces information, unique to its position, will have a point that is considered as the reference point of that sensor. The accurate measurement of the offsets is vital to establish the mathematical relation between sensor and vessel common reference point in order to achieve sufficient accuracy of the survey data. If possible, the vessel will be put on a hard stand so that it can be very accurately measured using the standard land survey technique. However, due to the complex environment and sensors being mobilized when the vessel is in service, this may not be possible, and the offsets will have to be measured in sea dynamic conditions by means of a total station from a floating platform. This article presents the method of transformation by similarity with elements of affine transformation, called Q-ST (Quasi-Similarity Transformation). The Q-ST has been designed for measurements on such unstable substrates when it is not possible to level the total station (when the number of adjustment points is small (4–6 points)). Such situation occurs, among others, when measuring before the offshore duties or during the jack up or semi-submersible rig move. The presented calculation model is characterized by zero deviations at the adjustment points (at four common points). The transformation concerns the conversion of points between two orthogonal and inclined reference frames. The method enables the independent calculation of the scale factor, rotation matrix and system translation. Scaling is performed first in real space, and then both systems are shifted to the centroid, which is the center of gravity. The center of gravity is determined for the fit points that meet the criterion of stability of the orthogonal transformation. Then, the rotation matrix is computed, and a translation is performed from the computational (centroid) to real space. In the applied approach, the transformation parameters, scaling, rotation and translation, are determined independently, and the least squares method is applied independently at each stage of the calculations. The method has been verified in laboratory conditions as well as in real conditions. The results were compared to other known methods of coordinate transformation. The proposed approach is a development of the idea of transformation by similarity based on centroids.

Adres strony internetowej (link) do pełnego tekstu
publikacji: https://www.mdpi.com/1424-8220/20/22/6497

DOI: 10.3390/s20226497

Tytuł: Analysis of the Dynamic Height Distribution at the Estuary of the Odra River Based on Gravimetric Measurements Acquired with the Use of a Light Survey Boat—A Case Study

Autor/Autorzy: Krzysztof Pyrchla, Arkadiusz Tomczak, Grzegorz Zaniewicz, Jerzy Pyrchla, Paulina Kowalska
 

Miejsce publikacji: SENSORS

Rok: 2020

Słowa 
kluczowe: gravity anomalies and earth structure, gravimetric river survey, Fourier analysis, numerical modelling, time-series analysis

Abstrakt: This article presents possible applications of a dynamic gravity meter (MGS-6, Micro-g LaCoste) for determining the dynamic height along the Odra River, in northwest Poland. The gravity measurement campaign described in this article was conducted on a small, hybrid-powered survey vessel (overall length: 9.5 m). We discuss a method for processing the results of gravimetric measurements performed on a mobile platform affected by strong external disturbances. Because measurement noise in most cases consists of signals caused by non-ideal observation conditions, careful attempts were made to analyze and eliminate the noise. Two different data processing strategies were implemented, one for a 20 Hz gravity data stream and another for a 1 Hz data stream. A comparison of the achieved results is presented. A height reference level, consistent for the entire estuary, is critical for the construction of a safe waterway system, including 3D navigation with the dynamic estimation of under-keel clearance on the Odra and other Polish rivers. The campaign was conducted in an area where the accuracy of measurements (levelling and gravimetric) is of key importance for shipping safety. The shores in the presented area of interest are swampy, so watercraft-based measurements are preferred. The method described in the article can be successfully applied to measurements in all near-zero-depth areas.
 

Adres strony internetowej (link) do pełnego tekstu 
publikacji: https://www.mdpi.com/1424-8220/20/21/6044

DOI: 10.3390/s20216044

Tytuł: Application of Total Free Station Method (TFS) for Offshore Surveying in Oblique Coordinate System

Autor/Autorzy: Grzegorz Stępień, Arkadiusz Tomczak, Tomasz Ziębka

Miejsce
publikacji: E3S Web of Conferences

Rok: 2018

Słowa kluczowe: deformations of engineering objects, unstable area, geological monitoring, geodesy engineering

Abstrakt: The location of reference points in deformation studies of engineering objects is often associated with low reliability of the obtained measurement results. This concerns the lack of proper diagnosis of the geological structure of the area. The reliability of deformation measurements is also low when we obtain data that only characterize the effects and not the cause-and-effects. The authors reviewed the influence of geological conditions on the formation of deformations of some engineering objects. The reference points were located in the immediate vicinity of the facilities, without taking into account the geological structure of the areas where the facilities were located. The proposed test method is based on a three-segment control and measurement system. An example of such considerations is the engineering facilities on the Grodzka and Ostrów Grabowski Island in the Szczecin area. The basic issue is to locate geologically stable areas in the vicinity of monitored engineering objects on the basis of geological substrate assessment and to analyse archival materials concerning periodical measurements of class 1 and 2 levelling lines in the Szczecin area. Reference points are located, which constitute the first segment of the control and measurement system. Subsequent segments of the system are organized with reference to the points of the first segment. This method provides reliable data on deformations of engineering objects.

Adres strony internetowej (link) do pełnego tekstu
publikacji: https://www.e3s-conferences.org/articles/e3sconf/abs/2018/46/e3sconf_cpsys18_00008/e3sconf_cpsys18_00008.html

DOI: 10.1051/e3sconf/20187100018