HU Yingying, LANG Wenhui, ZHANG Pan, et al. Monitoring sea ice motion by combining projection transformation and phase correlation[J]. Journal of Remote Sensing, 2016, 20(4): 579-589. DOI: 10.11834/jrs.20165259.
Monitoring sea ice motion by combining projection transformation and phase correlation
The Bohai Sea is located in the sea area of China with the highest latitude. This region is an important economic development zone in China. However
sea ice and its drift often block shipping vessels
destroy offshore structures
and limit development of the marine industry. Thus
sea ice monitoring techniques must be developed. Phase correlation based on polar transformation is extensively applied to image registration and sea ice tracking because of its robustness; however
this method results in various forms of noise and is insensitive to illumination changes. In addition
this approach can capture the translational and rotational motions of sea ice. Nevertheless
polar coordinate transformation and its subsequent operation extract amplitude information alone and ignore phase characteristics
which determine the position of each frequency. Consequently
errors in the matching results significantly increased. Moreover
traditional phase correlation involves several Fourier transformation and inverse transformation
which may increase computational burden and reduce tracking efficiency.By considering the limitations of sea ice tracking through phase correlation
this paper presents another approach for phase correlation based on projection transformation by combining the unique characteristics of sea ice in the Bohai Sea based on GOCI to track and monitor sea ice motion.First
sea ice samples with identified; stable characteristics were quantitatively selected and projected into the one-dimensional space to minimize the function of rotational components. The characteristics of individual images and the relationship among them were fully considered. This step is crucial for setting appropriate correlation values to discriminate good angles from mixed ones. Next
the measured errors generated from the two methods were compared and analyzed based on the manual tracking results. The translation components can be determined from differences among the phase representatives of the cross power spectral function and extended to the sub-pixel level. Outliers should be excluded during the entire process by using correlation coefficients
visual inspection
and two-way matching. Finally
the derived sea ice motion in the Bohai Sea was analyzed with insitu data and historical records.Results show that the maximum/average of root-mean-square error between the rotation angles via the proposed method and manual measurements is 0.59/0.50
whereas that between the traditional technique and manual values is 1.41/0.94. The running speed increased by50.6%. In terms of translation
the sea ice motion field agrees well with insitu data and historical records of the Bohai Sea.Recent developments in local research on sea ice motion usually ignore the rotational condition. This paper presents a method that combines phase correlation and projection transformation based on GOCI to simultaneously track and monitor sea ice rotation and translation in the Bohai Sea. Projection transformation replaces the polar coordinates
thereby improving the matching errors generated from the traditional method. Sea ice translation is derived from phase information in terms of image feature windows. This method can efficiently track sea ice motion.