LiDAR sensors have the advantage of being able to generate high-resolution imaging quickly during both day and night; however, their performance is severely limited in adverse weather conditions such as snow, rain, and dense fog. Consequently, many researchers are actively working to overcome these limitations by applying sensor fusion with radar and optical cameras to LiDAR. While studies on the denoising of point clouds acquired by LiDAR in adverse weather have been conducted recently, the results are still insufficient for application to autonomous vehicles because of speed and accuracy performance limitations. Therefore, we propose a new intensity-based filter that differs from the existing distance-based filter, which limits the speed. The proposed method showed overwhelming performance advantages in terms of both speed and accuracy by removing only snow particles while leaving important environmental features. The intensity criteria for snow removal were derived based on an analysis of the properties of laser light and snow particles. INDEX TERMS snow noise removal, desnowing, autonomous vehicle, LiDAR point cloud filtering

Nonlinear LC lattices have shown promise for highpower high-frequency signal generation. Here we offer the first detailed study of the frequency response of these lattices, as well as a method designed to find input excitation frequencies that result in intense harmonic generation. The crux of the method is to locate regions in frequency space where the spectral norm of the lattice response matrix is large. When the fundamental excitation frequency (or one of its multiples) is located in these regions, the lattice harmonic response is intensified. These findings are supported by extensive numerical simulations and experimental measurements. We deal chiefly with a first-order dependency of capacitance (C) on voltage (V); however, it is also shown that lattices with higher order C-V dependencies achieve proportionally higher harmonic generation. Simulations using a 0.13-m CMOS process indicate harmonic generation at 400 GHz (three times the cutoff frequency of the fastest active device in this process), suggesting potential applications of this lattice topology in terahertz range devices.

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