... sum of surface spherical harmonics (SSHs) up to degree 17. A Gaussian quadrature method is us... more ... sum of surface spherical harmonics (SSHs) up to degree 17. A Gaussian quadrature method is used to pick out a set of experimentally efficient measurement directions. Anechoic impulse responses are measured for these directions between a source loudspeaker and the ...
This paper describes how Large Deformation Diffeomorphic Metric Mapping (LDDMM) can be coupled wi... more This paper describes how Large Deformation Diffeomorphic Metric Mapping (LDDMM) can be coupled with a Fast Multipole (FM) Boundary Element Method (BEM) to investigate the relationship between morphological changes in the head, torso, and outer ears and their acoustic filtering (described by Head Related Transfer Functions, HRTFs). The LDDMM technique provides the ability to study and implement morphological changes in ear, head and torso shapes. The FM-BEM technique provides numerical simulations of the acoustic properties of an individual's head, torso, and outer ears. This paper describes the first application of LDDMM to the study of the relationship between a listener's morphology and a listener's HRTFs. To demonstrate some of the new capabilities provided by the coupling of these powerful tools, we examine the classical question of what it means to ``listen through another individual's outer ears.'' This work utilizes the data provided by the Sydney York Morphological and Acoustic Recordings of Ears (SYMARE) database.
... degrees from the University of York, Department of Physics, York, UK, in 1985 and ... His res... more ... degrees from the University of York, Department of Physics, York, UK, in 1985 and ... His research interests include computational electromagnetics, particularly as applied to radio-frequency and microwave ... If your company or school subscribes to the AES Journal then you can ...
This paper presents a subjective assessment of the plausibility of a non-individualised dynamic b... more This paper presents a subjective assessment of the plausibility of a non-individualised dynamic binaural sound system, created using a dataset of binaural room impulse responses measured with a dummy head microphone. A signal detection theory analysis was carried out on the results, to assess the sensory difference between the simulation and reality. The design and objective validation of the system is also presented. A small but meaningful sensory difference was observed between real and binaurally simulated loudspeaker sounds.
Coded gestures are physical movements to which precise meanings have been attached. Their use wit... more Coded gestures are physical movements to which precise meanings have been attached. Their use with an electronic pointing device potentially increases the power of the pointer by allowing several distinct control functions to be incorporated. The formation of a coded gesture is invariably subject to distortions which make its automatic recognition difficult. After particular consideration of three techniques, a dynamic programming algorithm was developed and was used in the design of a real-time gesture recognizer that allows mouse-driven software to be operated purely by means of an electronic pointer. The decision was taken to implement the gesture recognizer using a widely available, obsolescent microcomputer in order to keep down costs. Despite the inevitable technical compromises in this approach, results of preliminary trials using 10 normal subjects show an average gesture recognition rate of 98.3% and a gesture confusion rate of only 0.4%.
ABSTRACT Demands for increasing numbers of channels in modern surround sound systems can lead to ... more ABSTRACT Demands for increasing numbers of channels in modern surround sound systems can lead to poor coding gains when using current channel-based codecs. Spatialisation is performed prior to encoding and the transmission rate of the coded bitstream is often proportional to the number of channels. Pre-spatialisation also restricts the types of spatial manipulation that may subsequently be applied at the decoder. In this paper we present a novel coding method, based on the continuity illusion, which permits the transmission of individual sound sources within a bandwidth that is independent of their number. Further, spatialisation of the source can be performed in the decoder, allowing the listener some freedom in the choice of spatialisation method. The spatialisation method highlighted in this paper is binaural 3D sound using headphones.
3D audio is concerned with the artificial construction and playback of realistic and stable sound... more 3D audio is concerned with the artificial construction and playback of realistic and stable sound images within a Virtual Auditory Space and has been shown to be useful within the context of the human computer interface. This paper examines some of the issues informing current research in 3D audio and personalised, binaural sound, highlighting potential problems and discussing solutions and
ABSTRACT A major obstacle in point-of-regard monitoring for human-computer interaction has been t... more ABSTRACT A major obstacle in point-of-regard monitoring for human-computer interaction has been the contaminating effect of head movement. A novel solution to this problem has been simulated. A multilayer perceptron converts the distorted pattern of four infrared sources, reflected in the cornea of the user, into an estimate for the point-of-regard. Using an idealised model of the eye the simulation combined vertical, horizontal, pitch and yaw head movements with eye excursions typical of individuals seated in front of a computer display. Results show that the method is capable of dramatically reducing the effects of small head movements. Under these viewing conditions the error in the point-of-regard estimate exhibited a standard deviation of under 0.5 mm. It is concluded that such a scheme could form an attractive solution to the long-standing problem of head movement artefact.
Medical & Biological Engineering & Computing, 1988
ABSTRACT For some disabled people pointing provides a more convenient means of communication and ... more ABSTRACT For some disabled people pointing provides a more convenient means of communication and control than the use of switches. The quadriplegic who retains good control of head movement can be provided with a number of input alternatives, but no existing system meets all the requirements of a general-purpose electronic pointing device. Consequently the Oxford Optical Pointer has been developed. The principle by which it converts relative direction into analogue electrical signals is described and its application as a head-mounted device for controlling an electric wheelchair is presented.
The Journal of the Acoustical Society of America, 2006
ABSTRACT A novel coding technique suitable for the transmission of binaural audio signals with co... more ABSTRACT A novel coding technique suitable for the transmission of binaural audio signals with concurrent multiple sound sources is proposed in this paper. Existing algorithms typically suffer from audible artefacts, poor localization, or excessive bandwidth. Especially with conventional intrasource coding methods, bandwidth is dependent on the number of sources and becomes greater as the number of sources increases. The proposed binaural transformation (BX) encoder synthesizes binaural signals using generic HRTFs and transmits them to the decoder along with side information. The bandwidth of the side information is independent of the number of sources. Using locally stored HRTFs matching those of the listener, the decoder turns the generic binaural signals into personalized ones. We present two types of BX codec: type A and type B. Psychoacoustic experiments based on Recommendation ITU‐R BS.1116‐1 were used to compare signals processed by these codecs with the corresponding unprocessed signals. For a variety of source materials (speech, vocals, guitars, and percussion) we show that high mean opinion scores are achievable using the type A codec when its parameters are set appropriately.
The Journal of the Acoustical Society of America, 2006
ABSTRACT The binaural transformation codec synthesizes generic binaural audio signals and generat... more ABSTRACT The binaural transformation codec synthesizes generic binaural audio signals and generates accompanying side information. In the decoder the side information is used to personalize the generic signal. The performance of the basic codec is described in another paper; this paper describes the estimated effect on quality of incorporating limited head tracking. Generic HRTFs were used to spatialize two concurrent sound sources spatialized at ±30 or ±80 deg. The generic binaural signal was personalized in the BX decoder and at the same time the individual sound sources were rotated. These induced rotations are equivalent to compensating for head yaw rotations of −80, −40, −20, −10, and −5 deg, and for head pitch rotations of 22.5, 45, and 90 deg. Listening tests based on Recommendation ITU‐R BS.1116‐1 were used to evaluate the processed sounds. The tests were conducted using speech, vocals, guitars, and percussion source materials. It was found that the quality of the processed sound tended to degrade as the head yaw rotation increased. However, except for the head yaw condition −80 deg, the quality of the processed sound remained greater than 4.0 on the mean opinion scale. No deterioration of the processed sound was observed for the applied pitch rotations.
The Journal of the Acoustical Society of America, 1998
... sum of surface spherical harmonics (SSHs) up to degree 17. A Gaussian quadrature method is us... more ... sum of surface spherical harmonics (SSHs) up to degree 17. A Gaussian quadrature method is used to pick out a set of experimentally efficient measurement directions. Anechoic impulse responses are measured for these directions between a source loudspeaker and the ...
ABSTRACT This paper introduces the process for creating the Sydney York Morphological and Acousti... more ABSTRACT This paper introduces the process for creating the Sydney York Morphological and Acoustic Recordings of Ears (SYMARE) database. The SYMARE database supports research exploring the relationship between the morphology of human outer ears and their acoustic filtering properties - a relationship that is viewed by many as holding the key to human spatial hearing and the future of 3D personal audio. The SYMARE database is comprised of acoustically measured head-related impulse responses for 60 listeners, multiple high- resolution surface mesh models (upper torso, head and ears) for these listeners obtained from magnetic resonance imaging (MRI) data, and the corresponding simulated HRIR data for these listeners generated using the Fast Multipole Boundary Element Method (FM-BEM). In this work, we compare acoustically measured HRIR data for ten listeners with the listeners’ corresponding simulated HRIR data generated using the FM- BEM.
... sum of surface spherical harmonics (SSHs) up to degree 17. A Gaussian quadrature method is us... more ... sum of surface spherical harmonics (SSHs) up to degree 17. A Gaussian quadrature method is used to pick out a set of experimentally efficient measurement directions. Anechoic impulse responses are measured for these directions between a source loudspeaker and the ...
This paper describes how Large Deformation Diffeomorphic Metric Mapping (LDDMM) can be coupled wi... more This paper describes how Large Deformation Diffeomorphic Metric Mapping (LDDMM) can be coupled with a Fast Multipole (FM) Boundary Element Method (BEM) to investigate the relationship between morphological changes in the head, torso, and outer ears and their acoustic filtering (described by Head Related Transfer Functions, HRTFs). The LDDMM technique provides the ability to study and implement morphological changes in ear, head and torso shapes. The FM-BEM technique provides numerical simulations of the acoustic properties of an individual's head, torso, and outer ears. This paper describes the first application of LDDMM to the study of the relationship between a listener's morphology and a listener's HRTFs. To demonstrate some of the new capabilities provided by the coupling of these powerful tools, we examine the classical question of what it means to ``listen through another individual's outer ears.'' This work utilizes the data provided by the Sydney York Morphological and Acoustic Recordings of Ears (SYMARE) database.
... degrees from the University of York, Department of Physics, York, UK, in 1985 and ... His res... more ... degrees from the University of York, Department of Physics, York, UK, in 1985 and ... His research interests include computational electromagnetics, particularly as applied to radio-frequency and microwave ... If your company or school subscribes to the AES Journal then you can ...
This paper presents a subjective assessment of the plausibility of a non-individualised dynamic b... more This paper presents a subjective assessment of the plausibility of a non-individualised dynamic binaural sound system, created using a dataset of binaural room impulse responses measured with a dummy head microphone. A signal detection theory analysis was carried out on the results, to assess the sensory difference between the simulation and reality. The design and objective validation of the system is also presented. A small but meaningful sensory difference was observed between real and binaurally simulated loudspeaker sounds.
Coded gestures are physical movements to which precise meanings have been attached. Their use wit... more Coded gestures are physical movements to which precise meanings have been attached. Their use with an electronic pointing device potentially increases the power of the pointer by allowing several distinct control functions to be incorporated. The formation of a coded gesture is invariably subject to distortions which make its automatic recognition difficult. After particular consideration of three techniques, a dynamic programming algorithm was developed and was used in the design of a real-time gesture recognizer that allows mouse-driven software to be operated purely by means of an electronic pointer. The decision was taken to implement the gesture recognizer using a widely available, obsolescent microcomputer in order to keep down costs. Despite the inevitable technical compromises in this approach, results of preliminary trials using 10 normal subjects show an average gesture recognition rate of 98.3% and a gesture confusion rate of only 0.4%.
ABSTRACT Demands for increasing numbers of channels in modern surround sound systems can lead to ... more ABSTRACT Demands for increasing numbers of channels in modern surround sound systems can lead to poor coding gains when using current channel-based codecs. Spatialisation is performed prior to encoding and the transmission rate of the coded bitstream is often proportional to the number of channels. Pre-spatialisation also restricts the types of spatial manipulation that may subsequently be applied at the decoder. In this paper we present a novel coding method, based on the continuity illusion, which permits the transmission of individual sound sources within a bandwidth that is independent of their number. Further, spatialisation of the source can be performed in the decoder, allowing the listener some freedom in the choice of spatialisation method. The spatialisation method highlighted in this paper is binaural 3D sound using headphones.
3D audio is concerned with the artificial construction and playback of realistic and stable sound... more 3D audio is concerned with the artificial construction and playback of realistic and stable sound images within a Virtual Auditory Space and has been shown to be useful within the context of the human computer interface. This paper examines some of the issues informing current research in 3D audio and personalised, binaural sound, highlighting potential problems and discussing solutions and
ABSTRACT A major obstacle in point-of-regard monitoring for human-computer interaction has been t... more ABSTRACT A major obstacle in point-of-regard monitoring for human-computer interaction has been the contaminating effect of head movement. A novel solution to this problem has been simulated. A multilayer perceptron converts the distorted pattern of four infrared sources, reflected in the cornea of the user, into an estimate for the point-of-regard. Using an idealised model of the eye the simulation combined vertical, horizontal, pitch and yaw head movements with eye excursions typical of individuals seated in front of a computer display. Results show that the method is capable of dramatically reducing the effects of small head movements. Under these viewing conditions the error in the point-of-regard estimate exhibited a standard deviation of under 0.5 mm. It is concluded that such a scheme could form an attractive solution to the long-standing problem of head movement artefact.
Medical & Biological Engineering & Computing, 1988
ABSTRACT For some disabled people pointing provides a more convenient means of communication and ... more ABSTRACT For some disabled people pointing provides a more convenient means of communication and control than the use of switches. The quadriplegic who retains good control of head movement can be provided with a number of input alternatives, but no existing system meets all the requirements of a general-purpose electronic pointing device. Consequently the Oxford Optical Pointer has been developed. The principle by which it converts relative direction into analogue electrical signals is described and its application as a head-mounted device for controlling an electric wheelchair is presented.
The Journal of the Acoustical Society of America, 2006
ABSTRACT A novel coding technique suitable for the transmission of binaural audio signals with co... more ABSTRACT A novel coding technique suitable for the transmission of binaural audio signals with concurrent multiple sound sources is proposed in this paper. Existing algorithms typically suffer from audible artefacts, poor localization, or excessive bandwidth. Especially with conventional intrasource coding methods, bandwidth is dependent on the number of sources and becomes greater as the number of sources increases. The proposed binaural transformation (BX) encoder synthesizes binaural signals using generic HRTFs and transmits them to the decoder along with side information. The bandwidth of the side information is independent of the number of sources. Using locally stored HRTFs matching those of the listener, the decoder turns the generic binaural signals into personalized ones. We present two types of BX codec: type A and type B. Psychoacoustic experiments based on Recommendation ITU‐R BS.1116‐1 were used to compare signals processed by these codecs with the corresponding unprocessed signals. For a variety of source materials (speech, vocals, guitars, and percussion) we show that high mean opinion scores are achievable using the type A codec when its parameters are set appropriately.
The Journal of the Acoustical Society of America, 2006
ABSTRACT The binaural transformation codec synthesizes generic binaural audio signals and generat... more ABSTRACT The binaural transformation codec synthesizes generic binaural audio signals and generates accompanying side information. In the decoder the side information is used to personalize the generic signal. The performance of the basic codec is described in another paper; this paper describes the estimated effect on quality of incorporating limited head tracking. Generic HRTFs were used to spatialize two concurrent sound sources spatialized at ±30 or ±80 deg. The generic binaural signal was personalized in the BX decoder and at the same time the individual sound sources were rotated. These induced rotations are equivalent to compensating for head yaw rotations of −80, −40, −20, −10, and −5 deg, and for head pitch rotations of 22.5, 45, and 90 deg. Listening tests based on Recommendation ITU‐R BS.1116‐1 were used to evaluate the processed sounds. The tests were conducted using speech, vocals, guitars, and percussion source materials. It was found that the quality of the processed sound tended to degrade as the head yaw rotation increased. However, except for the head yaw condition −80 deg, the quality of the processed sound remained greater than 4.0 on the mean opinion scale. No deterioration of the processed sound was observed for the applied pitch rotations.
The Journal of the Acoustical Society of America, 1998
... sum of surface spherical harmonics (SSHs) up to degree 17. A Gaussian quadrature method is us... more ... sum of surface spherical harmonics (SSHs) up to degree 17. A Gaussian quadrature method is used to pick out a set of experimentally efficient measurement directions. Anechoic impulse responses are measured for these directions between a source loudspeaker and the ...
ABSTRACT This paper introduces the process for creating the Sydney York Morphological and Acousti... more ABSTRACT This paper introduces the process for creating the Sydney York Morphological and Acoustic Recordings of Ears (SYMARE) database. The SYMARE database supports research exploring the relationship between the morphology of human outer ears and their acoustic filtering properties - a relationship that is viewed by many as holding the key to human spatial hearing and the future of 3D personal audio. The SYMARE database is comprised of acoustically measured head-related impulse responses for 60 listeners, multiple high- resolution surface mesh models (upper torso, head and ears) for these listeners obtained from magnetic resonance imaging (MRI) data, and the corresponding simulated HRIR data for these listeners generated using the Fast Multipole Boundary Element Method (FM-BEM). In this work, we compare acoustically measured HRIR data for ten listeners with the listeners’ corresponding simulated HRIR data generated using the FM- BEM.
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