Image processing for ice floe analyses in broken-ice model testing

Zhang, Qin; Skjetne, Roger; Metrikin, Ivan; Løset, Sveinung

doi:10.1016/j.coldregions.2014.12.004

Cited by 13 publications

(4 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These authors made a 'fishbone' pre-sawn ice channel surrounded by large PP plates, similar to ice conditions in refrigerated model test facilities. Zhang et al [19] developed a tool to obtain ice positions through image processing by using the Gradient Vector Flow (GVF) snake method and distance transform. This method allows the separation of the contours of ice pieces that initially seem to be connected.…”

Section: Numerical Modellingsmentioning

confidence: 99%

Methodology Based on Photogrammetry for Testing Ship-Block Resistance in Traditional Towing Tanks: Observations and Benchmark Data

Gutiérrez-Romero

Ruiz-Capel

Esteve-Pérez

et al. 2022

JMSE

View full text Add to dashboard Cite

The real resistance that a ship must face when it is navigating in ice floes is the key factor for knowing the necessary power and the required engine size. The aim of this work is to provide valuable data to help other research in which numerical frameworks will be developed to study ship navigation in broken ice. In this work, we used paraffin wax as an alternative to obtain affordable solutions, avoiding the high cost of ice tests. The experiments were carried out in a traditional basin facility and they consisted of towing tank tests with a ship model using different concentrations of blocks simulated by the use of paraffin wax. Photogrammetry was used as technique to determine the initial position of the ice blocks, which is important as starting data in the current development of numerical simulation code for studying the features of ship resistance in drift ice. These data are available for some ice concentrations in attached files. In addition, a procedure for testing in traditional towing facilities is presented and discussed. The results of the resistance obtained in the experiments in the presence of simulated floes are presented for three concentrations and three model speeds. Some findings may be applicable to ice sailing, under given circumstances.

show abstract

Section: Numerical Modellingsmentioning

confidence: 99%

Methodology Based on Photogrammetry for Testing Ship-Block Resistance in Traditional Towing Tanks: Observations and Benchmark Data

Gutiérrez-Romero

Ruiz-Capel

Esteve-Pérez

et al. 2022

JMSE

View full text Add to dashboard Cite

show abstract

“…As one of our main goals was to evaluate CNNs as sea ice extraction tools, we did no post-processing on the output. There are several post-processing steps developed to improve the output from threshold-based or clustering-based methods that could also be beneficial if applied to our CNN-based pipeline (e.g., [16,17]), especially with obtaining better ice floe boundaries when floes are tied together [38].…”

Section: Model Out-of-sample Performancementioning

confidence: 99%

Fine-Scale Sea Ice Segmentation for High-Resolution Satellite Imagery with Weakly-Supervised CNNs

Gonçalves

Lynch

2021

Remote Sensing

View full text Add to dashboard Cite

Fine-scale sea ice conditions are key to our efforts to understand and model climate change. We propose the first deep learning pipeline to extract fine-scale sea ice layers from high-resolution satellite imagery (Worldview-3). Extracting sea ice from imagery is often challenging due to the potentially complex texture from older ice floes (i.e., floating chunks of sea ice) and surrounding slush ice, making ice floes less distinctive from the surrounding water. We propose a pipeline using a U-Net variant with a Resnet encoder to retrieve ice floe pixel masks from very-high-resolution multispectral satellite imagery. Even with a modest-sized hand-labeled training set and the most basic hyperparameter choices, our CNN-based approach attains an out-of-sample F1 score of 0.698–a nearly 60% improvement when compared to a watershed segmentation baseline. We then supplement our training set with a much larger sample of images weak-labeled by a watershed segmentation algorithm. To ensure watershed derived pack-ice masks were a good representation of the underlying images, we created a synthetic version for each weak-labeled image, where areas outside the mask are replaced by open water scenery. Adding our synthetic image dataset, obtained at minimal effort when compared with hand-labeling, further improves the out-of-sample F1 score to 0.734. Finally, we use an ensemble of four test metrics and evaluated after mosaicing outputs for entire scenes to mimic production setting during model selection, reaching an out-of-sample F1 score of 0.753. Our fully-automated pipeline is capable of detecting, monitoring, and segmenting ice floes at a very fine level of detail, and provides a roadmap for other use-cases where partial results can be obtained with threshold-based methods but a context-robust segmentation pipeline is desired.

show abstract

“…Up to now, the photogrammetry of broken ice in model-scale experiments with the retrieval of the geometric characteristics of single ice objects has been successfully implemented using nadir view cameras [14][15][16]. In these cases, the planar dimensions of thousands of objects floating on the water surface have been retrieved, which allowed researchers to draw conclusions on the floe size distribution after a physical action, i.e., wave ice breakage.…”

Section: Introductionmentioning

confidence: 99%

“…For nadir images, there are still some issues of recognition demanding manual corrections such as the over-segmentation of peculiar-shaped ice floes or the under-segmentation of tightly positioned floes. The recognition of separate modeled ice pieces in an image of the ice tank surface is not an easy task due to fuzzy edges and errors in the recognition of the closing ice floes [14,16,18].…”

Section: Introductionmentioning

confidence: 99%

Broken Ice Photogrammetry in Model-Scale Experiments with Sloped Structure

Zvyagin

Pavlov

Zvyagina

2022

JMSE

View full text Add to dashboard Cite

Testing a physical model of an ice-resistant marine structure in an ice tank is one of the methods used for design validation. For a stationary structure design, not only is the possible global ice load of interest but also the processes of creation and evolution of ice rubble in front of the contacting surface. While the load registering technique in model-scale experiments is very well-developed, the photogrammetric analysis of broken ice morphometry and locomotion is not. The photographs taken to illustrate the breaking process do not usually accompany the information necessary for the photogrammetric reconstruction of the scene. This paper outlines a systematic approach to the photogrammetric analysis of the scenes in model-scale conditions. Using this approach, the broken ice dimensions were measured in seven model-scale experiments for which the model of a sloped marine structure was reconstructed. In these experiments, a 700 mm wide slope with an inclination angle of 53° caused an upward flexural failure of the model’s granular ice. Reference global load histories for these experiments are provided. For the first contact episodes, the successful reconstruction of the broken ice mosaic in the polynya showed the insignificant contribution of compressive failure. In continual ice–structure interaction, the morphometry of the ice blocks visible on the slope of the rubble pile and on the surface of the surrounding ice sheet was retrieved from orthorectified video frames. The results were compared with the after-test nadir drone view of the polynya. The error in estimating the top-side area and the maximum linear dimension of the ice block fell into the interval of 0–10%. The morphometric information of the broken ice floes obtained in ice tank experiments with physical models can be used for the improvement of the mechanical models of ice fracture and failure against inclined offshore ice-resistant structures.

show abstract

Image processing for ice floe analyses in broken-ice model testing

Cited by 13 publications

References 19 publications

Methodology Based on Photogrammetry for Testing Ship-Block Resistance in Traditional Towing Tanks: Observations and Benchmark Data

Methodology Based on Photogrammetry for Testing Ship-Block Resistance in Traditional Towing Tanks: Observations and Benchmark Data

Fine-Scale Sea Ice Segmentation for High-Resolution Satellite Imagery with Weakly-Supervised CNNs

Broken Ice Photogrammetry in Model-Scale Experiments with Sloped Structure

Contact Info

Product

Resources

About