Increasing spatial resolution of sea ice motion estimation
Estimation of sea ice motion at a fine scale is essential for climate modeling and naval operations in polar regions. This study proposes an approach for increasing the spatial resolution of the motion estimated from passive microwave satellite images. A hierarchical pattern matching approach, based on normalized cross-correlation and phase correlation, is applied to calculate sea ice drifts between Advanced Microwave Scanning Radiometer 2 (AMSR2) pairs of images captured at different time. Contrary to the widely used approach of embedding oversampling within the pattern matching framework that increases the resolution of the minimum detectable drift, in this study a nearest-neighbor interpolation upscaling is applied directly to the images. This additionally increases the density of the estimated motion vectors. Experiments demonstrate that the proposed method can lead to motion vector field with increased resolution by up to eight times, while outperforming the original images. Image upscaling by four times also outperforms corresponding previous examples with embedded oversampling.