Image Description using Radial Associated Laguerre Moments

This study proposes a new set of moment functions for describing gray-level and color images based on the associated Laguerre polynomials, which are orthogonal over the whole right-half plane. Moreover, the mathematical frameworks of radial associated Laguerre moments (RALMs) and associated rotation invariants are introduced. The proposed radial Laguerre invariants retain the basic form of disc-based moments, such as Zernike moments (ZMs), pseudo-Zernike moments (PZMs), Fourier-Mellin moments (OFMMs), and so on. Therefore, the rotation invariants of RALMs can be easily obtained. In addition, the study extends the proposed moments and invariants defined in a gray-level image to a color image using the algebra of quaternion to avoid losing some significant color information. Finally, the paper verifies the feature description capacities of the proposed moment function in terms of image reconstruction and invariant pattern recognition accuracy. Experimental results confirmed that the associated Laguerre moments (ALMs) perform better than orthogonal OFMMs in both noise-free and noisy conditions

Wideband Inverse Matrix For Radiated Two-Stage MIMO Measurements

Multiple-input and multiple-output (MIMO) technology is one of the significant components in the growing fifth-generation (5G) communication systems. The 5G system has expanded its frequency range and widened the bandwidth to achieve higher throughput rates and more stable wireless qualities, which brings new challenges to the over-the-air (OTA) MIMO evaluations. The wide bandwidth introduces systematic uncertainties into the MIMO measurement because of the increased amplitude and phase variation issues under different frequencies in the wideband signals, and it could lead to invalid MIMO throughput measurement results when severe. The effect on antenna isolation resulting from amplitude and phase variation in wideband MIMO measurements are analyzed based on the RTS MIMO measurement method. A wideband inverse matrix algorithm is introduced to solve this issue and improve the wideband MIMO antenna isolation. The proposed method can be used in both MPAC and RTS chambers, which paves the way for decreasing the OTA measurement uncertainties on both 5G sub-6GHz wideband MIMO and millimeter-wave MIMO evaluations