Binaural Speech Enhancement Using STOI-Optimal Masks

STOI-optimal masking has been previously proposed and developed for single-channel speech enhancement. In this paper, we consider the extension to the task of binaural speech enhancement in which spatial information is known to be important to speech understanding and therefore should be preserved by the enhancement processing. Masks are estimated for each of the binaural channels individually and a `better-ear listening' mask is computed by choosing the maximum of the two masks. The estimated mask is used to supply probability information about the speech presence in each time-frequency bin to an Optimally-modified Log Spectral Amplitude (OM-LSA) enhancer. We show that using the proposed method for binaural signals with a directional noise not only improves the SNR of the noisy signal but also preserves the binaural cues and intelligibility.Comment: Accepted at IWAENC 202

Graph neural networks for sound source localization on distributed microphone networks

Distributed Microphone Arrays (DMAs) present many challenges with respect to centralized microphone arrays. An important requirement of applications on these arrays is handling a variable number of input channels. We consider the use of Graph Neural Networks (GNNs) as a solution to this challenge. We present a localization method using the Relation Network GNN, which we show shares many similarities to classical signal processing algorithms for Sound Source Localization (SSL). We apply our method for the task of SSL and validate it experimentally using an unseen number of microphones. We test different feature extractors and show that our approach significantly outperforms classical baselines.Comment: Presented as a poster at ICASSP 202

"Random" gentamicin concentrations do not predict trough levels in neonates receiving once daily fixed dose regimens

BACKGROUND: Monitoring plasma gentamicin concentrations in neonates 24 hours after a once daily dose (4 mg/kg) often necessitates additional blood sampling. In adults a nomogram has been developed enabling evaluation of gentamicin doses by sampling concentrations with other blood tests, 4 – 16 hours after administration. We attempted to develop a similar nomogram for neonates. METHODS: In addition to standard 24 hour sampling to monitor trough concentrations, one additional "random" gentamicin concentration was measured in each of 50 neonates <4 days of age (median gestation 33 weeks [28–41]), when other blood samples were clinically necessary, 4 – 20 hours after gentamicin administration. 24 hour concentrations of >1 mg/L were considered high, and an indication to extend the dosing interval. RESULTS: Highest correlation (r(2 )= 0.51) of plasma gentamicin concentration against time (4 to 20 hours) was with logarithmic regression. A line drawn 0.5 mg/L below the true regression line resulted in all babies with 24 hr gentamicin concentrations >1 mg/L having the additional "random" test result above that line, i.e. 100% sensitivity for 24 hour concentrations>1 mg/L, though only 58% specificity. Having created the nomogram, 39 further babies (median gestation 34 weeks [28–41]), were studied and results tested against the nomogram. In this validation group, sensitivity of the nomogram for 24 hr concentrations >1 mg/L was 92%; specificity 14%, positive predictive value 66%, and negative predictive value 50%. Prematurity (≤ 37 weeks) was a more sensitive (94%) and specific (61%) indicator of high 24-hour concentrations. 62 (87%) of 71 preterm babies had high 24-hour concentrations. CONCLUSION: It was not possible to construct a nomogram to predict gentamicin concentrations at 24 hours in neonates with a variety of gestational ages. Dosage tailored to gestation with monitoring of trough concentrations remains management of choice