Least-asymmetric signal extension for two-band paraunitary FIR filter banks

An algorithm for least-asymmetric signal extension for two-band paraunitary FIR filter banks is derived. The development of the algorithm is governed by the symmetric signal extension method for perfect reconstruction filter banks with even-length linear-phase filters. The approach yields an equality-constrained least-squares problem which is solved efficiently. The computational load is evaluated and simulation results for comparison of least-asymmetric and circular signal extension are presented

Fast full search block matching based on combined SAD and MSE measures

A new fast block matching algorithm is presented. The sum of absolute differences (SAD) and the mean square error (MSE) are used to find a suitable motion vector. A lower bound for both error measures is exploited to reduce the number of search positions and therefore the computational requirements. The error measures for the remaining search positions are calculated simultaneously so that the computational load for these calculations only slightly increases. The algorithm is compared to a fast full search block matching algorithm based on the same concept but only using the SAD or the MSE as the matching criterion. It is shown that the algorithm using both error measures combines the advantages of both algorithms using only the SAD or the MSE

Automated ice-sheet snowmelt detection using microwave radiometer measurements

Monitoring ice-sheet snowmelt is fundamental to understanding global climate change. A simple and automated snowmelt detection process is critical to the establishment of an ice-sheet snowmelt monitoring system. However, different ice-sheet snowmelt detection methods are based on a variety of thresholding schemes using different melt signals for dry and wet snow; these complicate the regular operation of an ice-sheet snowmelt monitoring. We propose an automated melt signal detection method developed using melt signals derived from the cross-gradient polarization ratio snowmelt detection method over Greenland and the wavelet transformation-based snowmelt detection method over Antarctica. Initial results indicate that the proposed method not only increases computational efficiency, practicability and operability but is also more accurate