Title: Improved real-time method for noise reduction of directional Doppler audio signals

Authors: Erdenedalai Naranchimeg; Byambasuren Bat-Erdene; Seung-Moo Han

Addresses: Laboratory of Medical System, Department of Biomedical Engineering, University of Kyung Hee, 446-701, Republic of Korea ' Laboratory of Medical System, Department of Biomedical Engineering, University of Kyung Hee, 446-701, Republic of Korea ' Laboratory of Medical System, Department of Biomedical Engineering, University of Kyung Hee, 446-701, Republic of Korea

Abstract: A noise reduction filter for Doppler audio signals is one important part of Transcranial Doppler ultrasound system. Several studies have been carried out for low-pass filter with fixed value for Doppler audio signals; however, most of these studies lacked complex research works and few studies analyzed the relationship of both parts of spectrum signal processing and audio signal processing. To solve the above-mentioned concern, this research is focused on the algorithms of de-noising and enveloping of spectrum signal processing part and improved new real-time method, which reduces the noise using low-pass filter with a variable threshold value based on maximum frequency of spectrum signals. The noise of Doppler audio signals was reduced efficiently by using this algorithm.

Keywords: biomedical engineering; Doppler audio signals; directional audio separation; noise reduction; transcranial Doppler ultrasound; spectrum signal processing; blood flow velocity; brain blood vessels; cerebrovascular disease; intracranial arteries.

DOI: 10.1504/IJBET.2012.049367

International Journal of Biomedical Engineering and Technology, 2012 Vol.10 No.2, pp.174 - 184

Received: 08 May 2021
Accepted: 12 May 2021

Published online: 01 Oct 2012 *

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