Papers by Panos Hatziantoniou
Journal of the Audio Engineering Society, 2021
Scientific Reports, 2021
This work presents a novel laser-based optoacoustic transducer capable of reproducing controlled ... more This work presents a novel laser-based optoacoustic transducer capable of reproducing controlled and continuous sound of arbitrary complexity in the air or on solid targets. Light-to-sound transduction is achieved via laser-induced breakdown, leading to the formation of plasma acoustic sources in any desired spatial location. The acoustic signal is encoded into pulse streams via a discrete-time audio modulation and is reproduced by fast consecutive excitation of the target medium with appropriately modulated laser pulses. This results in the signal being directly reconstructed at the desired location of the target medium without the need for a receiver or demodulation device. In this work, the principles and evaluation results of such a novel laser-sound prototype system are presented. The performance of the prototype is evaluated by systematic experimental measurements of audio test signals, from which the basic acoustical response is derived. Moreover, a generic computational mode...
Proceedings of the Audio Mostly 2015 on Interaction With Sound, 2015
The characteristics and implementation of a complete software bundle consisting of a room acousti... more The characteristics and implementation of a complete software bundle consisting of a room acoustics measurement tool, an application for the calculation of the room correction filters and a plugin for real time audio filtering is described. Via this plug-in a non-experienced user should be able to follow the documentation, measure the impulse response of his listening room, calculate the appropriate stereo inverse filters and utilize them in order to equalize the audio input in real time. The proposed room equalization solution was evaluated in terms of subjective and objective performance.
H Διδακτορική Διατριβή μελετά το πρόβλημα της ψηφιακής ισοστάθμισης,σκοπεύοντας στην ανάπτυξη απο... more H Διδακτορική Διατριβή μελετά το πρόβλημα της ψηφιακής ισοστάθμισης,σκοπεύοντας στην ανάπτυξη αποτελεσματικών μεθόδων εξάλειψης των ηχητικών παραμορφώσεων, που εισάγονται κατά την ηχητική αναπαραγωγή εξαιτίας της απόκρισης, είτε των ηχείων (ανηχωική ισοστάθμιση), είτε των χώρων ακρόασης (εξάλειψη αντήχησης). Αναπτύσσονται πρωτότυπες μέθοδοι που αφενός εξασφαλίζουν ακριβείς μετρήσεις των ανηχωικών ηλεκτρακουστικών αποκρίσεων μέσα σε μη ανηχωικούς χώρους, αφετέρου πετυχαίνουν κατάλληλη εξομάλυνση των πολύπλοκων αποκρίσεων των ακουστικών συστημάτων για χρήση στην ψηφιακή ισοστάθμιση αλλά και για χρήση σε άλλες εφαρμογές της ακουστικής χώρων που απαιτούν ανάλυση συγκεκριμένων ιδιοτήτων αυτών των συστημάτων. Η συστηματική μελέτη της μεθόδου εξάλειψης αντήχησης που βασίζεται στην ιδανική αντιστροφή των αποκρίσεων χώρων οδηγεί στο πρωτότυπο συμπέρασμα ότι τα ακουστά οφέλη από την εφαρμογή της μεθόδου σε πραγματικό χρόνο είναι σημαντικά υποδεέστερα από τα αναμενόμενα που προκύπτουν από τα α...
1999 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings. ICASSP99 (Cat. No.99CH36258), 1999
Acta Acustica united with Acustica, 2013
Extensive results are presented for acoustic and meteorological measurements at the ancient open ... more Extensive results are presented for acoustic and meteorological measurements at the ancient open theatre of Epidaurus. The analysis of the results, illustrates most aspects of the theatre'sa coustic properties, indicating the pattern and mechanism for the early reflections, the spectral response of the theatre, aspects of time-frequency response interaction and aspects of the spatial impression. The results also verify predictions of earlier acoustic models for this theatre and indicate no significant effects from environmental factors such as temperature, humidity and wind variations across the theatre. Measurements with the theatre partially full with audience shown o change with respect to speech intelligibility.The results restate the renowned exceptional acoustic characteristics of the theatre for speech, for all listener positions.
Formal subjective tests of real-time room dereverberation using Complex Smoothing were conducted ... more Formal subjective tests of real-time room dereverberation using Complex Smoothing were conducted to assess the robustness and the validity of the method under real sound reproduction conditions. For comparison, anechoic, inverse loudspeaker real-time filtering ...
Digital equalisation of room acoustics based on inverse filtering of measured response functions,... more Digital equalisation of room acoustics based on inverse filtering of measured response functions, introduces a number of theoretical and practical challenges. To overcome such problems, inverse filtering based on modified measured responses is proposed, derived via their complex Transfer Function smoothing, so that the processed responses are more perceptually compliant, of lower order and less position-sensitive than the original functions. Aim of this study is to evaluate via objective and subjective tests conducted for different-sized rooms and real-time reproduction, the use of such smoothed room responses for the derivation of appropriate room equalisation filters, which can improve the perceived and measured quality of audio reproduction in any reverberant environment.
The obvious advantages of digital audio technology have up to now being manifested mainly in medi... more The obvious advantages of digital audio technology have up to now being manifested mainly in media storage and processing sub-components, witch are parts of a more elaborate audio / acoustic analog reproduction chain. It is envisaged that the remaining components such as cables, amplifiers and transducers will soon be also implemented in digital form, potentially leading to networked, integrated and highly optimized solutions. The paper examines theoretical and implementation aspects related to each of the modules that could constitute such an all-digital audio / acoustic transducer, namely: (a) the digital wireless receiver, via the Bluetooth and IEEE 802.11 protocols, (b) audio decoding and format adaptation (c) DSP for acoustic compensation, based on measured results for smoothed response equalization, (d) digital amplification, and, (e) all-digital transduction.
Significant measurable audible distortions are generated during real-time room acoustics dereverb... more Significant measurable audible distortions are generated during real-time room acoustics dereverberation, which are far greater in magnitude than those expected from identical simulated (off-line) dereverberation experiments. Long inverse filters worsen this effect. Possible mechanisms for such discrepancy between simulated and real-time tests are examined. It is also shown that dereverberation based on complex smoothing is immune to such errors.
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Papers by Panos Hatziantoniou