Investigation of a Hybrid Algorithm for Sea Ice Drift Measurements Using Synthetic Aperture Radar Images

Abstract

Areal matching by phase correlation and feature tracking are two complementary methods used to measure sea ice drift between synthetic aperture radar images. This paper evaluates a new algorithm that combines the two methods. Areal matching is improved by new methods to handle large motions and rotated ice. It is shown that areal rotation can be resolved using a frequency-domain approach. Image segmentation is a prerequisite for feature tracking and achieved by a new method that performs better than Otsu's method for two-component Gaussian mixture distributions. A circular weighted median filter is found to be suitable for the filtering of the motion field. The algorithm is evaluated through a thorough analysis of the response and sensitivity to various algorithm settings. The accuracy of the algorithm varies by up to 50% for one image pair within the studied range of parameter settings, thus indicating the need for a proper initialization of the algorithm.

Evaluating Landfast Sea Ice Ridging near UtqiaġVik Alaska Using TanDEM-X Interferometry

“…When drifting pack ice comes in contact with landfast ice, it can result in cm-scale ice fracturing or large m-scale deformation in terms of rafting and riding events. Sea ice drift is therefore of relevance and can be evaluated using SAR [49] through ice drift algorithms [35,50,51]. Here, we applied an algorithm based on SAR backscatter and specifically areal matching by phase correlation and feature tracking [35].…”

“…Sea ice drift is therefore of relevance and can be evaluated using SAR [49] through ice drift algorithms [35,50,51]. Here, we applied an algorithm based on SAR backscatter and specifically areal matching by phase correlation and feature tracking [35]. This method enables robust identification and tracking of translational as well as rotational motion of the image structures.…”

“…Here, we present a change detection approach based on bistatic X-band InSAR to detect the evolution of ridges. We apply this approach to the landfast sea ice near Utqiaġvik and validate the results using backscatter-intensity features, coastal radar data, and SAR-derived sea ice drift [35]. In this effort, we investigate InSAR as a tool to capture ridging events which can help provide insight into relevant properties and processes within the landfast ice critical to ice stability and use.…”

Open-source sea ice drift algorithm for Sentinel-1 SAR imagery using a combination of feature tracking and pattern matching

“…To also provide drift estimates in areas where areal matching procedures (like cross and phase correlation) fail, Berg and Eriksson (2014) introduced a hybrid algorithm for sea ice drift retrieval from ENVISAT ASAR data using phase correlation and a feature based matching procedure that is activated if the phase correlation value is below a certain threshold.…”

“…We aim to improve the feature-tracking approach by combining it with pattern matching. Unlike Berg and Eriksson (2014), the feature-tracking step is performed initially and serves as a first guess to limit the search area of the pattern-matching step.…”