P. Van Hengel

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Papers by P. Van Hengel

Verbal aggression detection in complex social environments

2007 IEEE Conference on Advanced Video and Signal Based Surveillance, 2007

The paper presents a knowledge-based system designed to detect evidence of aggression by means of... more The paper presents a knowledge-based system designed to detect evidence of aggression by means of audio analysis. The detection is based on the way sounds are analyzed and how they attract attention in the human auditory system. The performance achieved is comparable to human performance in complex social environments. The SIgard system has been deployed in a number of different real-life situations and was tested extensively in the inner city of Groningen. Experienced police observers have annotated ~1400 recordings with various degrees of shouting, which were used for optimization. All essential events and a small number of nonessential aggressive events were detected. The system produces only a few false alarms (non-shouts) per microphone per year and misses no incidents. This makes it the first successful detection system for a non-trivial target in an unconstrained environment.

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Evidence for the distortion product frequency place as a source of distortion product otoacoustic emission (DPOAE) fine structure in humans. I. Fine structure and higher-order DPOAE as a function of the frequency ratio f2/f1

The Journal of the Acoustical Society of America, 1999

Critical experiments were performed in order to validate the two-source hypothesis of distortion ... more Critical experiments were performed in order to validate the two-source hypothesis of distortion product otoacoustic emissions (DPOAE) generation. Measurements of the spectral fine structure of DPOAE in response to stimulation with two sinusoids have been performed with normal-hearing subjects. The dependence of fine-structure patterns on the frequency ratio f2/f1 was investigated by changing f1 or f2 only (fixed f2 or fixed f1 paradigm, respectively), and by changing both primaries at a fixed ratio and looking at different order DPOAE. When f2/f1 is varied in the fixed ratio paradigm, the patterns of 2 f1-f2 fine structure vary considerably more if plotted as a function of f2 than as a function of fDP. Different order distortion products located at the same characteristic place on the basilar membrane (BM) show similar patterns for both, the fixed-f2 and fDP paradigms. Fluctuations in DPOAE level up to 20 dB can be observed. In contrast, the results from a fixed-fDP paradigm do not show any fine structure but only an overall dependence of DP level on the frequency ratio, with a maximum for 2f1-f2 at f2/f1 close to 1.2. Similar stimulus configurations used in the experiments have also been used for computer simulations of DPOAE in a nonlinear and active model of the cochlea. Experimental results and model simulations give strong evidence for a two-source model of DPOAE generation: The first source is the initial nonlinear interaction of the primaries close to the f2 place. The second source is caused by coherent reflection from a re-emission site at the characteristic place of the distortion product frequency. The spectral fine structure of DPOAE observed in the ear canal reflects the interaction of both these sources.

Audio event detection for in-home care

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An Adaptive Background Model for Real-World Auditory Event Detection

by Gineke Holt, Dirkjan Krijnders, and P. Van Hengel

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Aircraft sound level measurements in residential areas using sound source separation

Measuring the contribution of a particular sound source to the am bient sound level at an arbitra... more Measuring the contribution of a particular sound source to the am bient sound level at an arbitrary location is impossible without some form of sound sour ce separation. This made it difficult, if not impossible, to design automated systems that measure the contribution of a target sound to the ambient sound level. This paper introduces sound source separation technology that

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An Improved Cochlea Model with a General User Interface

by P. Van Hengel and J. Kruseman

Biophysics of the Cochlea, 2003

ABSTRACT We have developed a flexible 1D cochlea model to test hypotheses and data against physic... more ABSTRACT We have developed a flexible 1D cochlea model to test hypotheses and data against physical and mathematical constraints. The model is flexible in the sense that several linear and nonlinear model characteristics can be selected, and different boundary conditions can be tested. The software model runs at a reasonable speed at a modern PC. As an example, we will show the results of the model in comparison with the systematic study of the phase behavior (group delay) of distortion product otoacoustic emissions (DPOAEs) in the guinea pig (S. Schneider, V. Prijs and R. Schoonhoven, [9]). We also will demonstrate the effects of some common non-physical boundary conditions. Finally, we briefly indicate that this model of the auditory periphery provides a superior front end for an ASR (automatic speech recognition)-system.

Three-dimensional Fourier Transformation Constructive Interference in Steady State Magnetic Resonance Imaging of the Inner Ear in Patients with Unilateral and Bilateral Meni??re's Disease

Otology & Neurotology, 2002

In this study, three-dimensional Fourier transformation constructive interference in steady state... more In this study, three-dimensional Fourier transformation constructive interference in steady state (3DFT-CISS) magnetic resonance imaging was used to quantify the distance between the vertical part of the posterior semicircular canal and the posterior fossa as a measure of the endolymphatic sac and duct in patients with Menière&#39;s disease. Differences in this distance between affected and unaffected ears, as well as differences between unilaterally and bilaterally affected patients, were studied and compared with a control group. Also, possible correlations between the measured distance and the duration and severity of symptoms, patient age, and average hearing loss were investigated in the group of patients with Menière&#39;s disease. Retrospective clinical study. Tertiary referral center (University Hospital) as part of a large, diagnostic research project on Menière&#39;s disease. Of the 111 patients with Menière&#39;s disease initially included, 90 patients underwent 3DFT-CISS MRI. Eighty-six of these patients were analyzed in this MRI study. Fifty-six patients had unilateral Menière&#39;s disease, and 30 patients had bilateral Menière&#39;s disease (116 affected and 56 unaffected ears). Sixty-two ears in patients without Menière&#39;s disease were studied as controls. The distance between the vertical part of the posterior semicircular canal and the posterior fossa was determined by 3DFT-CISS MRI. Contiguous axial 3DFT-CISS MRI slices of 0.7 to 1.0 mm were made by a radiologist according to a strict protocol. Measurements of the distance between the vertical part of the posterior semicircular canal and the posterior fossa were taken by two professionals-a radiologist and an otolaryngologist-using a ruler and the original scan. A significantly smaller distance (2.9 mm) between the vertical part of the posterior semicircular canal and the posterior fossa as visualized on MRI scans was found in the ears of patients with Menière&#39;s disease than in the ears of patients in the control group (3.8 mm, p &lt; 0.001). In both uni- and bilaterally affected patients (n = 56 and n = 30, respectively), no significant difference between ears was found (p = 0.44 and p = 0.19, respectively). In bilaterally affected patients, however, this distance (3.2 mm) was significantly greater than the distance in unilaterally affected patients (2.7 mm, p = 0.004). There was no relationship between the MRI-visualized distance between the vertical part of the posterior semicircular canal and the posterior fossa and the duration of disease, average hearing loss, or severity of symptoms in uni- and bilaterally affected patients. The difference in MRI-visualized distances between the vertical part of the posterior semicircular canal and the posterior fossa of uni- and bilaterally affected patients strongly suggests that unilateral and bilateral hearing loss are two different entities in patients with Menière&#39;s disease. The size of the endolymphatic sac seems not to be the only factor in the pathogenesis of Menière&#39;s disease. That the MRI-visualized distance between the vertical part of the posterior semicircular canal and the posterior fossa does not have any relationship to the duration of the disease or to patient age indicates that this distance is a congenital feature.

Spatial periodicity in the cochlea: The result of interaction of spontaneous emissions?

The Journal of the Acoustical Society of America, 1996

In this study the results of simulations with a nonlinear macromechanical model of the human coch... more In this study the results of simulations with a nonlinear macromechanical model of the human cochlea are presented. In this model it is possible to investigate the interactions between large numbers of spontaneous emissions. The focus of this study is on the effect of a local maximum in emission strength on its direct surroundings. The suppression that such an emitter causes depends on the distance between suppressor and suppressee in a strongly nonmonotonic manner. This nonmonotonicity leads to natural minimal distances between emission frequencies, without additional assumptions about the mechanics of the cochlea. The origin of this nonmonotonicity in the suppression lies in reflection of the generated energy at the stapes. The fact that these minimum distances correspond to distances observed between measured SOAE frequencies in adults, but not in newborns, suggests that the nonmonotonicity may play a role in the development of the cochlea in the early years of childhood.

The Lower Saxony research network design of environments for ageing : towards interdisciplinary research on information and communication technologies in ageing societies

Informatics for Health and Social Care, 2010

Worldwide, ageing societies are bringing challenges for independent living and healthcare. Health... more Worldwide, ageing societies are bringing challenges for independent living and healthcare. Healthenabling technologies for pervasive healthcare and sensor-enhanced health information systems offer new opportunities for care. In order to identify, implement and assess such new information and communication technologies (ICT) the 'Lower Saxony Research Network Design of Environments for Ageing' (GAL) has been launched in 2008 as interdisciplinary research project. In this publication, we inform about the goals and structure of GAL, including first outcomes, as well as to discuss the potentials and possible barriers of such highly interdisciplinary research projects in the field of healthenabling technologies for pervasive healthcare. Although GAL's high interdisciplinarity at the beginning slowed down the speed of research progress, we can now work on problems, which can hardly be solved by one or few disciplines alone. Interdisciplinary research projects on ICT in ageing societies are needed and recommended.

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Pure-tone and speech audiometry in patients with Meniere's disease

Clinical Otolaryngology and Allied Sciences, 2001

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A Comparison of Spectro-Temporal Representations of Audio Signals

by P. Van Hengel and Dirkjan Krijnders

Audio, Speech, and Language Processing, IEEE/ACM Transactions on, 2014

ABSTRACT This article compares methods for the conversion of timeseries into a spectro-temporal r... more ABSTRACT This article compares methods for the conversion of timeseries into a spectro-temporal representation. These methods are designed based on a resemblance with the auditory processing of sound in the mammalian inner ear, or on mathematical principles related to, for example, Fourier analysis. This study provides a comparison between several of these methods. Two tests were devised for this comparison: one based on susceptibility to noise and one on the expression of spectrotemporal detail. These two aspects were considered of importance for real world applications. While some methods produced good results on one of the two tests, others produced good results on both. Overall the transmission line model using an impedance function suggested by Zweig [1] provided the best results, though not significantly. Also a larger computational load may hinder application in some domains. The gammatone filterbank and straightforward spectrogram provide good alternatives with less computational load. The introduction of nonlinearity was shown to deteriorate performance on both tests, in both the filterbank and in the transmission line model.

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