Steven M. Schimmel

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Previous studies have shown that infant-directed speech ('motherese') exhibits overemphasized acoustic properties which may facilitate the acquisition of phonetic categories by infant learners. It has been suggested that the use of infant-directed data for training automatic speech recognition systems might also enhance the automatic learning and(More)
Modulation filtering, which has been previously described as several related approaches to achieve modification of speech temporal dynamics, is shown to be less effective than intended. In particular, past Hilbert envelope approaches generate distortion which spreads across frequency sub-bands and modulation rejection is far from the amount intended. The(More)
We explore the use of the modulation frequency domain for single channel speaker separation. We discuss features of the modulation spectrogram of speech signals that suggest that multiple speakers are highly separable in this space. In a preliminary experiment, we separate a target speaker from an interfering speaker by manually masking out modulation(More)
Modulation filtering is a technique for filtering slowly-varying envelopes of frequency subbands of a signal, without affecting the signal's phase and fine-structure. Coherent modulation filtering is a promising subtype of such techniques where subband envelopes are determined through demodulation of the subband signal with a coherently detected subband(More)
This study evaluated the maximal attainable performance of speech enhancement strategies based on coherent modulation filtering. An optimal adaptive coherent modulation filtering algorithm was designed to enhance known signals from a target talker in two-talker babble noise. The algorithm was evaluated in a closed-set, speech-recognition-in-noise task. The(More)
PURPOSE Calculation of the time-integrated activity coefficient (residence time) is a crucial step in dosimetry for molecular radiotherapy. However, available software is deficient in that it is either not tailored for the use in molecular radiotherapy and/or does not include all required estimation methods. The aim of this work was therefore the(More)
The aim of this project is to remove the motion related artifacts of the current watermarking algorithm, known as the 'dirty window problem'. It was observed that part of the dirty window problem originated from watermark artifacts in still images. Therefore, two possible improvements of the current algorithm are suggested that will lower the visibility of(More)