Image Processing for the Analysis of an Evolving Broken-Ice Field in Model Testing

2012 ◽  
Author(s):  
Qin Zhang ◽  
Solange van der Werff ◽  
Ivan Metrikin ◽  
Sveinung Løset ◽  
Roger Skjetne
Keyword(s):  
Image Processing ◽  
Water Area ◽  
Test Results ◽  
Detection Algorithms ◽  
Ice Concentration ◽  
Broken Ice ◽  
Ice Field ◽  
Ice Floes ◽  
Processing Techniques ◽  
Ice Forces

Dynamic positioning (DP) experiments in model ice were carried out in the ice tank at the Hamburg Ship Model Basin (HSVA) in the summer of 2011. In these experiments the behavior of two different ships in a broken-ice field were studied. One of the main parameters characterizing a broken-ice field is the ice concentration, defined as the fraction of the total water area covered by ice. In this paper, image processing techniques are applied to derive the ice concentration in the model basin. Several points in time are analyzed in order to describe the evolution of the ice field. The applied techniques include methods for identifying individual ice floes and calculating the ice concentration in the vicinity of the model ship. Ice floe boundaries are then obtained, and the ice floe size distribution and shape factor may further be extracted from the images. The image processing methods applied in this work are object extraction and edge detection algorithms, which are further customized to ice identification. The obtained results can be used for relating the ice field characteristics to the model test results, such as the vessel’s displacements and the corresponding ice forces.

Interaction of Ice Floes With Columns of a Semi-Submersible Platform

1983 ◽  
Vol 105 (4) ◽  
pp. 460-463
Author(s):  
P. G. Noble ◽  
D. Singh
Keyword(s):  
Maximum Load ◽  
Test Results ◽  
Ice Load ◽  
Physical Model Tests ◽  
Ice Concentration ◽  
Drilling Unit ◽  
Ice Loads ◽  
Ice Field ◽  
Preliminary Research ◽  
Ice Floes

A preliminary research project has been carried out to determine the effect of small ice floes on a semi-submersible drilling unit. Physical model tests have been conducted with two main objectives: first, to determine the ability of the columns to prevent ice from passing between them (arching) and thus minimizing the chance of riser damage, and second, to determine the total ice load on the semi-submersible during interaction with ice field concentrations. Three models were used, representing one half of a four, six or eight-legged semi-submersible platform. The dimensions and spacing of the columns were such that the heave and pitch responses were kept constant. The tests were conducted at a model scale of 1:30 using synthetic ice. Test results showed the maximum load measured on a four-legged semi-submersible model, at 100 percent ice floe concentration, was on the order of half of that measured on six or eight-legged semi-submersible models. Also the ice loads on a four-legged semi-submersible model at lower ice floe concentration were substantially less than those for six or eight-legged semi-submersible models. The total ice load on semi-submersible models is found to be a function of ice floe concentration. Up to about 75 percent ice concentration, ice loads varied linearly. Beyond that, the loads increased exponentially for all semi-submersible models.

Laboratory Testing of a Flexible Boom for Ice Management

1993 ◽  
Vol 115 (3) ◽  
pp. 149-153 ◽  
Author(s):  
S. Lo̸set ◽  
G. W. Timco
Keyword(s):  
Oil Spills ◽  
The Arctic ◽  
Small Scale ◽  
Test Results ◽  
Offshore Structure ◽  
Video Cameras ◽  
Ice Concentration ◽  
Broken Ice ◽  
Ice Field ◽  
Force Components

Combatting oil spills in the Arctic is a major challenge. Drilling or producing oil or gas in the marginal ice zone (MIZ) may allow booms to be deployed upstream of an offshore structure to clear the water of ice, thereby enabling conventional oil spill countermeasures to be used. Such a boom would be kept in place by two ice-going service vessels or by moored buoys. SINTEF NHL and NRC have performed a number of small-scale tests with a flexible boom in the NRC ice basin in Ottawa. The purpose of the tests was to measure the effectiveness of using a flexible boom for collecting ice, and to determine the loads associated with collecting the ice. In the tests, various boom configurations were towed against a broken ice field consisting of ice pieces typically 50–100 mm across and 30 mm thick. The ice concentration was usually 10/10, but it was reduced to 8/10 and 5/10 for two tests. The boom was towed at speeds of 20 and 50 mm-s−1. Both the width of the boom and the slackness of the boom were varied over reasonable ranges. Two six-component dynamometers were used to support the boom. Thus, the force components on each end of the boom were measured. Further, two video cameras were used to record the effectiveness of each boom configuration. In this paper, the full results of this test program are presented and the application of the test results to the full-scale situation are discussed. The tests show that, under certain conditions, the use of boom is feasible for ice management in oil-contaminated water.

Research on the Influences of Broken Ice Parameters on Maneuverable Forces of Ice-Going Ship Oblique Sailing

2021 ◽  
Author(s):  
Shenyu Xuan ◽  
Chengsheng Zhan ◽  
Zuyuan Liu ◽  
Binfeng He ◽  
Qiaosheng Zhao ◽  
...  
Keyword(s):  
Time History ◽  
Test Results ◽  
Ship Maneuvering ◽  
Average Value ◽  
Ocean Science ◽  
Broken Ice ◽  
Ice Conditions ◽  
Ice Field ◽  
Ice Resistance ◽  
Good Agreement

Abstract The broken ice is one of the most common ice conditions for ice-going ships, and the research of ship maneuvering movement in broken ice field can improve sailing safety. In this paper, the discrete element method (DEM) was adopted to study the maneuverable forces, including resistance and transverse force, of ice-going ship oblique sailing in broken ice fields. First, the Araon model tests data of Korea Institute of Ocean Science & Technology (KIOST) was used to verify the ice resistance of direct sailing under different ice sizes and model speeds, and the numerical results are in good agreement with the test results. Second, the influences of broken ice parameters (including concentration, thickness, and shape) on ship-ice interaction and maneuverable forces distribution were researched. The maneuverable forces on the ice-going ships are mainly from the ship-ice interaction. The time history curves of maneuverable forces were analyzed from the average value of maneuverable forces, the average value of peak maneuverable forces, and the number of peaks. Besides, the parameters of broken ice have a heavy influence on the movement of broken ice around the hull, such as accumulating and sliding. The analysis of the broken ice movement contributes to understanding the influences of broken ice parameters on ice-going ships.

Guidance Model Representing an Ice Field for Path-Planning in Ice Management

2020 ◽  
Author(s):  
Jon Bjørnø ◽  
Mathias Marley ◽  
Roger Skjetne
Keyword(s):  
Path Planning ◽  
Breaking Effect ◽  
B Splines ◽  
Planning Algorithm ◽  
Broken Ice ◽  
Ice Field ◽  
Ice Floes ◽  
Path Planning Algorithm ◽  
Guidance Information ◽  
Guidance Model

Abstract In the work presented in this paper, the problem on how to represent a simplified ice field in a guidance model, enabling path and maneuver planning for IM operation, has been studied. The use of B-splines and other basis functions are considered to represent relevant guidance information over the 2D drifting ice field. A weight value is computed and updated at locations that represents broken ice (visited by an icebreaker) versus unbroken ice. The guidance model will ensure that there is a continuous representation of the state of the ice field during the operations. The drifting behavior of the ice field is incorporated into the guidance model. The model will be updated with new (solid) ice that is formed at the beginning of the ice field, and it will continuously be updated in the path where the icebreaker moves. To simulate the maneuvers of the icebreaker, a dynamic model is used, and the ice breaking effect where the ice field is continuously broken into smaller ice floes is included in the model. This representation of an ice field can be used in a path-planning algorithm to determine the icebreaker path in a moving ice environment in order to reduce the ice field into small enough ice floes and reduce the load on the protected structure.

Identity Concealment When Uploading Pictures of Patients in a Tele-Medicine System

2019 ◽  
Vol 10 (2) ◽  
pp. 44-62
Author(s):  
Judith Jumig Azcarraga ◽  
John Zachary Raduban ◽  
Ma. Christine Gendrano ◽  
Arnulfo P. Azcarraga
Keyword(s):  
Image Processing ◽  
Patient Information ◽  
Medical Records ◽  
Exact Distribution ◽  
Eye Detection ◽  
Unauthorized Access ◽  
Image Processing Techniques ◽  
Detection Algorithms ◽  
Identity Concealment ◽  
Processing Techniques

Tele-medicine systems run the risk of unauthorized access to medical records, and there is greater possibility for the unlawful sharing of sensitive patient information, including children, and possibly showing their private parts. Aside from violating their right to privacy, such practices discourage patients from subjecting themselves to tele-medicine. The authors thus present an automatic identity concealment system for pictures, the way it is designed in the GetBetter tele-medicine system developed under a WHO/TDR grant. Based on open-source face- and eye-detection algorithms, identity concealment is executed by blurring the eye region of a detected face using pixel shuffling. This method is shown to be not only effective in concealing the identity of the patient, but also in preserving the exact distribution of pixel values in the image. This is useful when subsequent image processing techniques are employed, such as when identifying the type of lesions based on images of the skin.

Discrete Element Modelling of Pack Ice Interaction With Floating Structures

2015 ◽  
Author(s):  
Jie Dai ◽  
Heather Peng
Keyword(s):  
Discrete Element ◽  
Wave Force ◽  
Interaction Force ◽  
Discrete Element Modelling ◽  
Empirical Formulas ◽  
Pack Ice ◽  
Broken Ice ◽  
Ice Conditions ◽  
Ice Field ◽  
Ice Floes

This paper presents a two-dimensional numerical model for ship-ice interaction simulatiion using the discrete element method (DEM). The simulation was conducted for a broken ice field with hundreds of circular ice floes and various combinations of ice conditions. A viscous-elastic ice rheology was adopted to model the dynamic behavior of each individual ice floe. Both ship-ice and ice-ice contacts were considered in the interaction force. Environment forces, including wind force and wave force, were calculated by empirical formulas. An algorithm was developed to log each contact and solve motions of individual ice floe and the ship. The resistance of ship advancing in ice was predicted and compared with model test results.

Peculiarities of Multi-Legged Platform Operation in Ice Condition

2014 ◽  
Author(s):  
Evgeny Karulin ◽  
Marina Karulina
Keyword(s):  
Mutual Influence ◽  
Experimental Studies ◽  
Vertical Axis ◽  
Research Centre ◽  
Interaction Processes ◽  
Ice Drift ◽  
Ice Concentration ◽  
Broken Ice ◽  
Ice Conditions ◽  
Ice Floes

A usage of multi-legged structures in ice conditions involves some peculiarities that should be taken into account both while designing the platform and while planning technological operations nearby it. In 2010–2013 a range of theoretical and experimental studies were performed at the Krylov State Research Centre, St. Petersburg, Russia. The work aimed to investigate main peculiarities of multi-legged structure interaction with ice, such as 1). mutual influence on ice action on each leg, 2) jamming of the inner space between legs and blocking the space between the front legs with ice floes, and 3) arisen yaw moments about the platform vertical axis due to unsymmetrical ice action on the legs. Three series of model tests with various multi-legged structures models were carried out in the Ice Basin. The presented in the paper main results show effect of key parameters on the interaction processes and on the ice action. During the tests the following parameters were varying: distance between the legs, ice drift speed and direction, broken ice concentration and the ice pieces size. Also, the paper contains results of numerical simulations of some tested scenarios in broken ice conditions. The numerical model is based on discrete element method, and it enables to extend a range of the investigations.

Digital Image Processing for Sea Ice Observations in Support to Arctic DP Operations

2012 ◽  
Author(s):  
Qin Zhang ◽  
Roger Skjetne ◽  
Sveinung Løset ◽  
Aleksey Marchenko
Keyword(s):  
Image Processing ◽  
Sea Ice ◽  
Unmanned Aerial Vehicles ◽  
Remotely Sensed Data ◽  
Sensor Platforms ◽  
Ice Concentration ◽  
Image Processing Algorithms ◽  
Processing Algorithms ◽  
Support Estimation ◽  
Ice Forces

Various types of remotely sensed data and imaging technology will aid the development of sea ice observation to support estimation of ice forces that are critical to Dynamic Positioning (DP) operations in Arctic waters. The use of cameras as sensors on mobile sensor platforms such as unmanned aerial vehicles in Arctic DP operations will be explored for measurements of ice statistics and ice properties. Several image processing algorithms are adopted to analyze ice concentration, ice floe boundaries, and ice types. The resulting image processing methods for ice observation, including a discussion of possibilities, limitations, and further improvements, are presented in this paper.

Identity Concealment When Uploading Pictures of Patients in a Tele-Medicine System

2021 ◽  
pp. 591-611
Author(s):  
Judith Jumig Azcarraga ◽  
John Zachary Raduban ◽  
Ma. Christine Gendrano ◽  
Arnulfo P. Azcarraga
Keyword(s):  
Image Processing ◽  
Open Source ◽  
Patient Information ◽  
Exact Distribution ◽  
Eye Detection ◽  
Unauthorized Access ◽  
Image Processing Techniques ◽  
Detection Algorithms ◽  
Identity Concealment ◽  
Processing Techniques

Tele-medicine systems run the risk of unauthorized access to medical records, and there is greater possibility for the unlawful sharing of sensitive patient information, including children, and possibly showing their private parts. Aside from violating their right to privacy, such practices discourage patients from subjecting themselves to tele-medicine. The authors thus present an automatic identity concealment system for pictures, the way it is designed in the GetBetter tele-medicine system developed under a WHO/TDR grant. Based on open-source face- and eye-detection algorithms, identity concealment is executed by blurring the eye region of a detected face using pixel shuffling. This method is shown to be not only effective in concealing the identity of the patient, but also in preserving the exact distribution of pixel values in the image. This is useful when subsequent image processing techniques are employed, such as when identifying the type of lesions based on images of the skin.

scholarly journals Perbandingan Metode Sobel, Prewitt, Robert dan Canny pada Deteksi Tepi Objek Bergerak

2020 ◽  
Vol 12 (2) ◽  
pp. 112-120
Author(s):  
Wahyu Supriyatin
Keyword(s):  
Image Processing ◽  
Computer Vision ◽  
Edge Detection ◽  
Moving Object ◽  
Video Object ◽  
Test Results ◽  
Detection Algorithms ◽  
Canny Algorithm

Computer vision is one of field of image processing. To be able to recognize a shape, it requires the initial stages in image processing, namely as edge detection. The object used in tracking in computer vision is a moving object (video). Edge detection is used to recognize edges of objects and reduce existing noise. Edge detection algorithms used for this research are using Sobel, Prewitt, Robert and Canny. Tests were carried out on three videos taken from the Matlab library. Testing is done using Simulik Matlab tools. The edge and overlay test results show that the Prewitt algorithm has better edge detection results compared to other algorithms. The Prewitt algorithm produces edges whose level of accuracy is smoother and clearer like the original object. The Canny algorithm failed to produce an edge on the video object. The Sobel and Robert algorithm can detect edges, but it is not clear as Prewitt does, because there are some missing edges.

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