arXiv subjects

Wontak Kim

Publications and source records attributed to Wontak Kim.

3 recordsLinked to original sources

arXiv2026

A semi-analytical geometrical acoustics method for numerical simulation of ultrasound based motion sensing

We present a semi-analytical geometrical acoustics method to numerically simulate ultrasonic signal characteristics pertinent to motion sensing applications in indoor environments. The proposed methodology treats motion sensing from the first-principles in the sense that the expressions for acoustic field from the source, that scattered by the target and then received at the receiver are all derived from a kinematic standpoint incorporating target motion into consideration. A series of examples are presented throughout to demonstrate the effect of source directivity, wall reflections, and motion trajectories on the Doppler signal strength and frequency characteristics observed for motion sensing applications. Finally, we present a comparison of simulated results with experimental results on data acquired with a human target moving in an environment with an ultrasonic source and receiver. We specifically compare the baseband signal characteristics and their corresponding Short-time Fourier Transforms that depict Doppler frequency characteristics and show them to be in good qualitative agreement.

physics.app-ph↗

arXiv2022

Upmixing via style transfer: a variational autoencoder for disentangling spatial images and musical content

In the stereo-to-multichannel upmixing problem for music, one of the main tasks is to set the directionality of the instrument sources in the multichannel rendering results. In this paper, we propose a modified variational autoencoder model that learns a latent space to describe the spatial images in multichannel music. We seek to disentangle the spatial images and music content, so the learned latent variables are invariant to the music. At test time, we use the latent variables to control the panning of sources. We propose two upmixing use cases: transferring the spatial images from one song to another and blind panning based on the generative model. We report objective and subjective evaluation results to empirically show that our model captures spatial images separately from music content and achieves transfer-based interactive panning.

eess.AS↗

arXiv2019

On Acoustic Modeling for Broadband Beamforming

In this work, we describe limitations of the free-field propagation model for designing broadband beamformers for microphone arrays on a rigid surface. Towards this goal, we describe a general framework for quantifying the microphone array performance in a general wave-field by directly solving the acoustic wave equation. The model utilizes Finite-Element-Method (FEM) for evaluating the response of the microphone array surface to background 3D planar and spherical waves. The effectiveness of the framework is established by designing and evaluating a representative broadband beamformer under realistic acoustic conditions.

cs.SD↗