| 1. |
- Berggren, Magnus, et al.
(författare)
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Audio Processing Solution for Video Conference Based Aerobics
- 2010
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Ingår i: 2010 Digest of Technical Papers, International Conference on Consumer Electronics. - Las Vegas : IEEE. - 9781424443147 - 9781424443161 ; , s. 407-408
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Konferensbidrag (refereegranskat)abstract
- In this paper an audio processing solution for video conference based aerobics is presented. The proposed solution leaves the workout music unaltered by separating it from the speech and processing each signal separately. The speech signal processing is also performed at a lower sample rate, which saves computational power. Real time evaluation of the system shows that high quality music as well as a good two-way communication is maintained during the aerobic session.
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| 2. |
- Berggren, Magnus, et al.
(författare)
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Low-complexity network echo cancellation approach for systems equipped with external memory
- 2011
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Ingår i: IEEE Transactions on Audio, Speech, and Language Processing. - : IEEE. - 1558-7916 .- 1558-7924. ; 19:8, s. 2506-2515
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Tidskriftsartikel (refereegranskat)abstract
- Long delays and sparseness characterize impulse responses in telecommunication networks and a vast number of solutions for network echo cancellation have been proposed over the years. In this paper, an approach for detecting dispersive regions of a sparse impulse response and a proportionate normalized least mean square (PNLMS)-based selective updating approach are combined with an adaptive double-talk detector to form a complete solution for echo cancellation. The proposed solution has low computational complexity and is targeted for systems equipped with external memory.
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| 3. |
- Borgh, Markus, 1983-, et al.
(författare)
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A Personal Voice Analyzer and Trainer
- 2010
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Konferensbidrag (refereegranskat)abstract
- This paper presents a personal voice analyzer and trainer that allow the user to perform four daily exercises to improve the voice capacity. The system grades how well the user is performing the exercises by analyzing the duration, the intensity and the pitch of the user’s voice.
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| 4. |
- Borgh, Markus, 1983-, et al.
(författare)
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An improved adaptive gain equalizer for noise reduction with low speech distortion
- 2011
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Ingår i: EURASIP Journal on Audio, Speech, and Music Processing. - : Springer. - 1687-4714 .- 1687-4722. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- In high-quality conferencing systems, it is desired to perform noise reduction with as limited speech distortion as possible. Previous work, based on time varying amplification controlled by signal-to-noise ratio estimation in different frequency subbands, has shown promising results in this regard but can suffer from problems in situations with intense continuous speech. Further, the amount of noise reduction cannot exceed a certain level in order to avoid artifacts. This paper establishes the problems and proposes several improvements. The improved algorithm is evaluated with several different noise characteristics, and the results show that the algorithm provides even less speech distortion, better performance in a multi-speaker environment and improved noise suppression when speech is absent compared with previous work.
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| 5. |
- Lindström, Fredric, et al.
(författare)
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Long-term measurements of sound levels in child day-care centers
- 2010
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Ingår i: 39th International Congress on Noise Control Engineering 2010 (INTER-NOISE 2010). - : Sociedade Portuguesa de Acustica. - 9781617823961 ; , s. 2992-3001
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Konferensbidrag (refereegranskat)abstract
- Over the years numerous measurements of the sound levels in Swedish child care centers have been performed. However, most of these measurements consist of short one day measurements sessions. In this study we have measured the sound levels continuously during the whole day for several months in a row. Stationary sound level meters were used to measure the sound. In the study 6 day-care centers, with about 15 children in each, participated and for each center measurements were done in 4 different rooms, i.e. The sound levels in 24 rooms were measured continuously. Analysis of data show a wide spread between the different rooms and in time, which demonstrate the uncertainty in using single location short time, e.g. one day, measurements to assess the long-term sound levels in child day-care centers. The paper further demonstrates that long-term measurements can be used to identify e.g. differences between rooms, differences over time, etc, and that these differences can evoke questions about the activities generating them.
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| 6. |
- Lindström, Fredric, 1974, et al.
(författare)
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Mean F0 values obtained through standard phrase pronunciation compared with values obtained from the normal work environment: A study on teacher and child voices performed in a pre-school environment
- 2010
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Ingår i: Journal of Voice. - 0892-1997. ; 24:3, s. 319-323
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Tidskriftsartikel (refereegranskat)abstract
- Mean fundamental frequency (F0) values are often used in research on vocal load. In this study, we examine how the mean F0 differs when evaluated through pronouncing a standard phrase as compared to the mean F0 obtained in a real work/play environment. We also examine how the F0 values change throughout the day. The study was performed in a preschool, nine adult female preschool teachers and 11 children participated. The participants wore a digital recorder equipped with an accelerometer, which was attached to the neck. In the study, the participant first pronounced a standard phrase in a controlled environment; thereafter, the voice was recorded in the environment where both children and adults normally reside throughout the day, denoted by the work/play environment. For each participant, the procedure was repeated four times throughout the day. Analyses showed that the F0 values of the children's and adult's voices were significantly higher when recorded in the work/play environment as compared to the controlled environment. The average difference was 36 Hz for adults and 24 Hz for children. Previous studies have shown an increase of F0 over the day for teachers. In this study, an increase between morning and afternoon values was found amounting to 8 Hz for adults and 24 Hz for children. For the child population, this increase was statistically significant. However, the total changes over the day revealed a somewhat more complex scheme, with an increase of F0 in the morning, a decrease during lunch, and finally an increase in the afternoon. This pattern was verified statistically for the joint child-adult population.
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| 7. |
- Lindström, Fredric, 1974, et al.
(författare)
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Observations of the Relationship Between Noise Exposure and Preschool Teacher Voice Usage in Day-Care Center Environments
- 2011
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Ingår i: Journal of Voice. - : Elsevier BV. - 0892-1997 .- 1873-4588. ; 25:2, s. 166-172
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Tidskriftsartikel (refereegranskat)abstract
- Although the relationship between noise exposure and vocal behavior (the Lombard effect) is well established, actual vocal behavior in the workplace is still relatively unexamined. The first purpose of this study was to investigate correlations between noise level and both voice level and voice average fundamental frequency (F-0) for a population of preschool teachers in their normal workplace. The second purpose was to study the vocal behavior of each teacher to investigate whether individual vocal behaviors or certain patterns could be identified. Voice and noise data were obtained for female preschool teachers (n = 13) in their workplace, using wearable measurement equipment. Correlations between noise level and voice level, and between voice level and F-0, were calculated for each participant and ranged from 0.07 to 0.87 for voice level and from 0.11 to 0.78 for F-0. The large spread of the correlation coefficients indicates that the teachers react individually to the noise exposure. For example, some teachers increase their voice-to-noise level ratio when the noise is reduced, whereas others do not.
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| 8. |
- Nygren, M., et al.
(författare)
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Gender Differences in Children's Voice Use in a Day Care Environment
- 2012
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Ingår i: Journal of Voice. - : Elsevier BV. - 0892-1997 .- 1873-4588. ; 26:6
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Tidskriftsartikel (refereegranskat)abstract
- Background. The prevalence of dysphonia is higher in boys than in girls before puberty. This could be because of the differences in boys' and girls' voice use. Previous research on gender differences in prepubescent children's voice parameters has been contradictory. Most studies have focused on examining fundamental frequency. Objectives. The purpose of this study was to investigate voice use in boys and girls in a day care environment based on the voice parameters fundamental frequency (Hz), vocal intensity (dB SPL), and phonation time (%) and to ascertain whether there were any significant gender differences. Study Design. Prospective comparative design. Method. The study was conducted in a day care environment where 30 children (17 boys and 13 girls aged 4-5 years) participated. The participants' voices were measured continuously for 4 hours with a voice accumulator that registered fundamental frequency, vocal intensity level, phonation time, and background noise. Results. Mean (standard deviation) fundamental frequency was 310 (22) and 321 (16) Hz, vocal intensity was 93 (4) and 91 (3) dB SPL, and phonation time was 7.7 (2.0)% and 7.6 (2.5)% for boys and girls, respectively. No differences between genders were statistically significant. Conclusion. The finding of no statistically significant gender differences for measurements of voice parameters in a group of children aged 4-5 years in a day care environment is an important finding that contributes to increased knowledge about young boys' and girls' voice use.
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| 9. |
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| 10. |
- Persson Waye, Kerstin, et al.
(författare)
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Being in a pre-school sound environment - Annoyance and subjective symptoms among personnel and children
- 2010
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Ingår i: 39th International Congress on Noise Control Engineering 2010 (INTER-NOISE 2010). - : Sociedade Portuguesa de Acustica. - 9781617823961 ; , s. 1026-1032
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Konferensbidrag (refereegranskat)abstract
- Pre-school noise may be a serious occupational and public health problem. The equivalent sound levels are high, the exposure time long and the sound environment highly intermittent with maximum levels in the range of 110-115 dB. In order to elucidate how children and personnel experience their pre-school sound environment, a cross sectional study was carried out. Interview data was obtained from 63 children from seven pre-schools and questionnaire data from 187 personnel from 67 pre-schools. The results showed that as many as 59% of the personnel reported being rather, very or extremely annoyed by noise. More than 50% of the children reported loud and angering/screaming sounds often or very often. They coped by avoidance, holding their ears and/or telling the teacher. The study gives clear indications of a loud and often disturbing pre-school sound environment and the health consequences need to be furthered assessed.
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| 11. |
- Schüldt, Christian, et al.
(författare)
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A Delay-Based Double-Talk Detector
- 2012
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Ingår i: IEEE Transactions on Audio, Speech, and Language Processing. - 1558-7916 .- 1558-7924. ; 20:6, s. 1725-1733
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Tidskriftsartikel (refereegranskat)abstract
- When an adaptive filter is used for echo cancellation, it is essential to prevent the filter from diverging in situations when the echo signal is contaminated with near-end disturbance, i.e. during double-talk. This paper presents an extension of a previously proposed double-talk detector for improved performance. It is shown that the computational complexity of the proposed detector is lower than that of the well-used normalized cross correlation (NCC) double-talk detector, at the cost of performance. Further, it is shown that there can be a significant performance difference, in terms of detecting double-talk, between having a fixed echo cancellation filter, which is a common strategy in objective evaluation techniques, and an adaptive filter, which is more close to realistic conditions.
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| 12. |
- Schüldt, Christian, et al.
(författare)
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An Improved Deviation Measure for Two-Path Echo Cancellation
- 2010
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Konferensbidrag (refereegranskat)abstract
- Parallel adaptive filters have been proposed for echo cancellation to solve the dead-lock problem, occurring when the echo is detected as near-end speech after a severe echo-path change; causing the updating of the adaptive filter to halt. To control the parallel filters and monitor their performance, estimates of the filter deviation (i.e. the squared norm of the filter mismatch vector) are typically used. This paper presents a modification of a filter mismatch estimator. The proposed modification requires slightly more computational resources than the original measure, but provides a significantn improvement in terms of robustness during double-talk. This is shown both analytically and through simulations.
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| 13. |
- Schüldt, Christian, et al.
(författare)
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Evaluation of an Improved Deviation Measure for Two-Path Echo Cancellation
- 2010
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Konferensbidrag (refereegranskat)abstract
- The two-path algorithm is a well-known approach for overcoming the dead-lock problem in echo cancellation systems. Typically, a fixed foreground filter is producing the echo cancelled output while a continuously updating background filter adapts to the echo-path. When the background filter is considered to perform better than the foreground filter, the coefficients of the background filter are copied into the foreground filter. To determine which filter is better adjusted to the true echo-path, a filter deviation measure can be used. Recently, a method which introduces a delay in the calculation of the filter deviation measure, yielding a more reliable estimate has been proposed. However, a thorough evaluation of the effect of different delay settings has not yet been performed. Thus, in this paper a number of simulations with different delay parameter settings are carried out to show how this parameter affects the overall performance of the filter deviation measure.
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| 14. |
- Schüldt, Christian, et al.
(författare)
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Robust low-complexity transfer logic for two-path echo cancellation
- 2012
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Konferensbidrag (refereegranskat)abstract
- A well used approach for echo cancellation is the two-path method, where two adaptive filters in parallel are utilized. Typically, one filter is continuously updated, and when this filter is considered better adjusted to the echo-path than the other filter, the coefficients of the better adjusted filter is transferred to the other filter. When this transfer should occur is controlled by the transfer logic. This paper proposes transfer logic that is both more robust and more simple to tune, owing to fewer parameters, than the conventional approach. Extensive simulations show the advantages of the proposed method.
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| 15. |
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