Application of Variational Mode Decomposition and Whale Optimization Algorithm to Laser Ultrasonic Signal Denoising

Abstract

Laser ultrasound signal echoes are easily drowned out by the surrounding environmental noise in industrial field applications, and it is worthwhile to study methods of retaining the weak ultrasound signal during signal processing. To address this problem, this paper proposes to adopt the parameters optimized by the whale optimization algorithm to the variational mode decomposition (VMD) of laser ultrasound signals. The optimized parameters can avoid the frequency mixing and incomplete noise separation caused by the choice of artificial VMD parameters. The Hausdorff distance is applied in the process of reconstructing the signal to help accurately select the relevant modes and improve the signal-to-noise ratio. Simulation and experimental results show that the proposed method is feasible and effective compared with the other three available denoising methods.

Microscale Chiral Rectennas for Energy Harvesting

“…Getting rid of this module opens the path to dramatically reduce the rectenna size, a critical constraint in emerging applications that must operate with low powers while keeping reduced dimensions, such as skin‐wearable sensors. [ 43 ] Furthermore, the elimination of frequency matching issues between the two modules renders matching circuits unnecessary enabling a broader operational frequency range.…”