Paul Kraeutner - Academia.edu (original) (raw)
Papers by Paul Kraeutner
Scientific Reports, 2020
While considered analogous to physical practice, the nature of imagery-based skill acquisition—sp... more While considered analogous to physical practice, the nature of imagery-based skill acquisition—specifically whether or not both effector independent and dependent encoding occurs through motor imagery—is not well understood. Here, motor imagery-based training was applied prior to or after physical practice-based training to probe the nature of imagery-based skill acquisition. Three groups of participants (N = 38) engaged in 10 days of training of a dart throwing task: 5 days of motor imagery prior to physical practice (MIP-PP), motor imagery following physical practice (PP-MIP), or physical practice only (PP-PP). Performance-related outcomes were assessed throughout. Brain activity was measured at three time points using fMRI (pre/mid/post-training; MIP-PP and PP-MIP groups). In contrast with physical practice, motor imagery led to changes in global versus specific aspects of the movement. Following 10 days of training, performance was greater when motor imagery preceded physical pr...
FLATDAN is a program that implements a Farfield Line Array Time Domain beamformer for processing ... more FLATDAN is a program that implements a Farfield Line Array Time Domain beamformer for processing large amounts of acoustic data. Upsampling is used to increase the time delay resolution beyond that of the input sampling frequency. However, decimation after the beamforming operation ensures that the output data rate per beam is the same as the input data rate per sensor.
OCEANS 2006, 2006
Increasing usage of the Autonomous Underwater Vehicles (AUVs) in ocean applications has generated... more Increasing usage of the Autonomous Underwater Vehicles (AUVs) in ocean applications has generated some new opportunities as well challenges for acoustic sensor system design. Particularly for small AUVs, the integrated sonar systems must be low power, compact size, and in some applications, expendable. In this paper, we first discuss a novel design concept which applies the Computed Angle-of-Arrival Transient Imaging (CAATI) technology for forward looking imaging. We then introduce an example CAATI-based system and present first results of field testing for the developed prototype. As a result of this effort, a 3D obstacle avoidance sonar is now available with ~10 watts of power consumption fitting into a payload of 7.5" in diameter by 6" in length
The Journal of the Acoustical Society of America, 1988
The underwater acoustic noise spectrum during rainfall has been measured in a coastal ocean envir... more The underwater acoustic noise spectrum during rainfall has been measured in a coastal ocean environment for a wide range of sea states and rainfall intensities. The relationship between spectral noise level and rain rate was examined and a power law function fitted to data at 5, 8, 15, 20, and 30 kHz. Finally, a family of curves representing the acoustic noise spectrum for sea states 12, 1, 2, 3, 4, and 5 and rain conditions of 1.0, 3.0, 5.0, and 7.0 mm/h was derived. Results indicate a domination of the acoustic noise spectra by rain-generating mechanisms at frequencies in the band 7–25 kHz and sea states less than 4. Furthermore, the smearing of the rain-generated spectral peak near 15 kHz strongly supports the postulation of a strong dependence of rain-generated acoustic noise on sea surface conditions. [Work supported by DSS Unsolicited Proposals Program, IOS, and DND.]
Proceedings of OCEANS 93 OCEANS-93, 1993
Apart from water, the most important component in an experimental underwater acoustics program is... more Apart from water, the most important component in an experimental underwater acoustics program is a versatile sonar system for transmitting, receiving, and recording acoustic waveforms. At the Underwater Research Lab (URL) at Simon Fraser University a simple yet fully coherent sonar workstation has been developed by making use of ZBM compatible personal computer (PC) technology, commercially available digital signal processing (DSP) hardware, and a small amount of custom electronics. The resulting sonar operates at carrier frequencies between 25 kHz and 500 kHz and can incorporate a variety of sonar signal processing tasks in real or pseudo-real time, yet, required a total investment of less than $5000. This paper discusses the design and performance of the URL coherent sonar.
Oceans '97. MTS/IEEE Conference Proceedings
Page 1. PRlNCIPAL COMPONENTS ARRAY PROCESSING FOR SWATH ACOUSTIC MAPPING Paul H. Kraeutner and Jo... more Page 1. PRlNCIPAL COMPONENTS ARRAY PROCESSING FOR SWATH ACOUSTIC MAPPING Paul H. Kraeutner and John S. Bird Underwater Research Lab School of Engineering Science Simon Fraser University Bumaby ...
'Challenges of Our Changing Global Environment'. Conference Proceedings. OCEANS '95 MTS/IEEE
Swath bathymetry sidescan sonar obtains bathymetry information from seafloor returns by measuring... more Swath bathymetry sidescan sonar obtains bathymetry information from seafloor returns by measuring the phase difference as a function of time between two closely-spaced, vertically separated sidescan transducers. In general, over a slowly varying seafloor, results compare favourably with depth measurements taken from larger more costly multibeam sounders and therefore the popularity of swath bathymetry has been increasing. However, susceptibility to spurious and nonstationary differential phase errors, known as 'glint', has slowed overall acceptance and prevented the development of robust bathymetric processing algorithms. The purpose of this paper is to investigate, in a deterministic sense, the mechanism by which glint is produced. The authors begin by introducing a z transform method for deterministic analysis of discrete scattering problems and then apply it to the differential phase measurements of swath bathymetry sidescan systems. A simple two point scattering model is then used to demonstrate the potential for significant angle of arrival errors in a typical swath bathymetry sidescan system.
In this paper, we review an acoustic method for measuring both average ocean current speed and so... more In this paper, we review an acoustic method for measuring both average ocean current speed and sound speed along an acoustic path. The method requires two or more stations on the sea floor, synchronized through a connecting underwater electric cable, that can transmit and receive an acoustic signal and The method is based on reciprocal acoustic transmissions to determine time of flight in both the forward and reverse directions. A specific implementation of this method is proposed. We also consider a novel method for monitoring ocean current perturbations through acoustic phase measurements. In simplest form, a continuous sinusoidal signal is transmitted from one station to a second station. Any variations in ocean current speed will introduce a phase shift in the received signal proportional to the time derivative of the current speed. This effect has been demonstrated through ultrasonic in-air experiments. Finally, the two methods are combined into a single system that continuously measures small-scale ocean current velocity changes.
Oceans '99. MTS/IEEE. Riding the Crest into the 21st Century. Conference and Exhibition. Conference Proceedings (IEEE Cat. No.99CH37008)
This paper presents a new swath bathymetric sidescan sonar concept that extends the single angle-... more This paper presents a new swath bathymetric sidescan sonar concept that extends the single angle-of-arrival measurement technique used in interferometric sidescan to multiple angles-of-arrival. The new sonar concept utilizes a small array of vertically stacked sidescan transducer elements and affords high resolution 3D imaging and mapping of underwater geometries difficult to address using simple interferometry. The focus of the paper
OCEANS 2007, 2007
This paper proposes a new distance measuring system to monitor tectonic plate motions. The method... more This paper proposes a new distance measuring system to monitor tectonic plate motions. The method is based on estimation of phase shift between two acoustic signals. The measurement error of plate displacement is determined by the phase estimation error. Phase estimation is performed with a conventional quadrature phase estimator in this paper. Simulation results show that under ideal conditions, the root-mean-square (RMS) error of the displacement estimation is within 1 millimetre when the signal-to-noise ratio (SNR) equals OdB. This error can be further reduced if we use a longer transmission pulse. Measurement errors caused by environmental factors such as ocean currents are also addressed. Reciprocal transmission is suggested to reduce this effect.
Oceans '99. MTS/IEEE. Riding the Crest into the 21st Century. Conference and Exhibition. Conference Proceedings (IEEE Cat. No.99CH37008)
This paper describes a small-aperture sonar and processing technique that provides vertical profi... more This paper describes a small-aperture sonar and processing technique that provides vertical profile information with a single ping without the large arrays of acoustic elements required for beamforming. The small acoustic aperture makes the sonar suitable for small vehicles and towfish. The sonar uses angle of arrival estimates, derived from a small number of acoustic elements, for determining the lay of the land in front of the transducer. Unlike two-element interferometric sonars, this sonar's performance does not suffer from the presence of multiple time-coincident targets because multiple angles can be estimated. Examples of lookahead profiles derived from simulated and experimental data are given for different target geometries and propagation conditions. The results are compared with those that would be obtained using two-element interferometry. Potential applications of the sonar and processing technique, and direction of future research are discussed.
Oceans '02 MTS/IEEE
The recent extension of Swath Bathymetry Sidescan (SBS) sonar to Multiangle Swath Bathymetry Side... more The recent extension of Swath Bathymetry Sidescan (SBS) sonar to Multiangle Swath Bathymetry Sidescan (MSBS) has rekindled the argument that existing performance limits (spatial resolution, swath width and accuracy) of seafloor and water column acoustic mapping/imaging may still be improved upon. While beamformed systems continue to improve in achievable angular resolution, these systems also continue to encounter difficulties in achieving
OCEANS Conference, 2001
The Cramer-Rao bound is employed to establish a lower bound on the estimation accuracy of bottom ... more The Cramer-Rao bound is employed to establish a lower bound on the estimation accuracy of bottom detection and angle estimation methods for swath bathymetry. The angle estimation bound is converted to a distance along an arc at the given range and then compared to the range estimation accuracy obtained for bottom detection methods. It is determined that for bottom detection
IEEE Transactions on Instrumentation and Measurement, 1996
An important tool for experimental underwater acoustics research is a versatile sonar system for ... more An important tool for experimental underwater acoustics research is a versatile sonar system for transmitting, receiving, anti recording acoustic waveforms. In this paper the design, implementation and performance of a variable-frequency (25 kHz to 500 kHz) coherent sonar are presented. The significance of the design lies in its simplicity and versatility. These attributes are a result of a sampling technique that provides quadrature samples of the complex envelope of a bandpass signal without analog demodulation using a single A/D converter. Implementation of the design is accomplished using an ISA bus personal computer (PC), a commercially available digital signal processing (DSP) board, and a small amount of custom electronics. Performance of the sonar, in terms of magnitude and phase errors, is determined from wideband noise characterization, a linear-system model, and transmit/receive measurements
Scientific Reports, 2020
While considered analogous to physical practice, the nature of imagery-based skill acquisition—sp... more While considered analogous to physical practice, the nature of imagery-based skill acquisition—specifically whether or not both effector independent and dependent encoding occurs through motor imagery—is not well understood. Here, motor imagery-based training was applied prior to or after physical practice-based training to probe the nature of imagery-based skill acquisition. Three groups of participants (N = 38) engaged in 10 days of training of a dart throwing task: 5 days of motor imagery prior to physical practice (MIP-PP), motor imagery following physical practice (PP-MIP), or physical practice only (PP-PP). Performance-related outcomes were assessed throughout. Brain activity was measured at three time points using fMRI (pre/mid/post-training; MIP-PP and PP-MIP groups). In contrast with physical practice, motor imagery led to changes in global versus specific aspects of the movement. Following 10 days of training, performance was greater when motor imagery preceded physical pr...
FLATDAN is a program that implements a Farfield Line Array Time Domain beamformer for processing ... more FLATDAN is a program that implements a Farfield Line Array Time Domain beamformer for processing large amounts of acoustic data. Upsampling is used to increase the time delay resolution beyond that of the input sampling frequency. However, decimation after the beamforming operation ensures that the output data rate per beam is the same as the input data rate per sensor.
OCEANS 2006, 2006
Increasing usage of the Autonomous Underwater Vehicles (AUVs) in ocean applications has generated... more Increasing usage of the Autonomous Underwater Vehicles (AUVs) in ocean applications has generated some new opportunities as well challenges for acoustic sensor system design. Particularly for small AUVs, the integrated sonar systems must be low power, compact size, and in some applications, expendable. In this paper, we first discuss a novel design concept which applies the Computed Angle-of-Arrival Transient Imaging (CAATI) technology for forward looking imaging. We then introduce an example CAATI-based system and present first results of field testing for the developed prototype. As a result of this effort, a 3D obstacle avoidance sonar is now available with ~10 watts of power consumption fitting into a payload of 7.5" in diameter by 6" in length
The Journal of the Acoustical Society of America, 1988
The underwater acoustic noise spectrum during rainfall has been measured in a coastal ocean envir... more The underwater acoustic noise spectrum during rainfall has been measured in a coastal ocean environment for a wide range of sea states and rainfall intensities. The relationship between spectral noise level and rain rate was examined and a power law function fitted to data at 5, 8, 15, 20, and 30 kHz. Finally, a family of curves representing the acoustic noise spectrum for sea states 12, 1, 2, 3, 4, and 5 and rain conditions of 1.0, 3.0, 5.0, and 7.0 mm/h was derived. Results indicate a domination of the acoustic noise spectra by rain-generating mechanisms at frequencies in the band 7–25 kHz and sea states less than 4. Furthermore, the smearing of the rain-generated spectral peak near 15 kHz strongly supports the postulation of a strong dependence of rain-generated acoustic noise on sea surface conditions. [Work supported by DSS Unsolicited Proposals Program, IOS, and DND.]
Proceedings of OCEANS 93 OCEANS-93, 1993
Apart from water, the most important component in an experimental underwater acoustics program is... more Apart from water, the most important component in an experimental underwater acoustics program is a versatile sonar system for transmitting, receiving, and recording acoustic waveforms. At the Underwater Research Lab (URL) at Simon Fraser University a simple yet fully coherent sonar workstation has been developed by making use of ZBM compatible personal computer (PC) technology, commercially available digital signal processing (DSP) hardware, and a small amount of custom electronics. The resulting sonar operates at carrier frequencies between 25 kHz and 500 kHz and can incorporate a variety of sonar signal processing tasks in real or pseudo-real time, yet, required a total investment of less than $5000. This paper discusses the design and performance of the URL coherent sonar.
Oceans '97. MTS/IEEE Conference Proceedings
Page 1. PRlNCIPAL COMPONENTS ARRAY PROCESSING FOR SWATH ACOUSTIC MAPPING Paul H. Kraeutner and Jo... more Page 1. PRlNCIPAL COMPONENTS ARRAY PROCESSING FOR SWATH ACOUSTIC MAPPING Paul H. Kraeutner and John S. Bird Underwater Research Lab School of Engineering Science Simon Fraser University Bumaby ...
'Challenges of Our Changing Global Environment'. Conference Proceedings. OCEANS '95 MTS/IEEE
Swath bathymetry sidescan sonar obtains bathymetry information from seafloor returns by measuring... more Swath bathymetry sidescan sonar obtains bathymetry information from seafloor returns by measuring the phase difference as a function of time between two closely-spaced, vertically separated sidescan transducers. In general, over a slowly varying seafloor, results compare favourably with depth measurements taken from larger more costly multibeam sounders and therefore the popularity of swath bathymetry has been increasing. However, susceptibility to spurious and nonstationary differential phase errors, known as 'glint', has slowed overall acceptance and prevented the development of robust bathymetric processing algorithms. The purpose of this paper is to investigate, in a deterministic sense, the mechanism by which glint is produced. The authors begin by introducing a z transform method for deterministic analysis of discrete scattering problems and then apply it to the differential phase measurements of swath bathymetry sidescan systems. A simple two point scattering model is then used to demonstrate the potential for significant angle of arrival errors in a typical swath bathymetry sidescan system.
In this paper, we review an acoustic method for measuring both average ocean current speed and so... more In this paper, we review an acoustic method for measuring both average ocean current speed and sound speed along an acoustic path. The method requires two or more stations on the sea floor, synchronized through a connecting underwater electric cable, that can transmit and receive an acoustic signal and The method is based on reciprocal acoustic transmissions to determine time of flight in both the forward and reverse directions. A specific implementation of this method is proposed. We also consider a novel method for monitoring ocean current perturbations through acoustic phase measurements. In simplest form, a continuous sinusoidal signal is transmitted from one station to a second station. Any variations in ocean current speed will introduce a phase shift in the received signal proportional to the time derivative of the current speed. This effect has been demonstrated through ultrasonic in-air experiments. Finally, the two methods are combined into a single system that continuously measures small-scale ocean current velocity changes.
Oceans '99. MTS/IEEE. Riding the Crest into the 21st Century. Conference and Exhibition. Conference Proceedings (IEEE Cat. No.99CH37008)
This paper presents a new swath bathymetric sidescan sonar concept that extends the single angle-... more This paper presents a new swath bathymetric sidescan sonar concept that extends the single angle-of-arrival measurement technique used in interferometric sidescan to multiple angles-of-arrival. The new sonar concept utilizes a small array of vertically stacked sidescan transducer elements and affords high resolution 3D imaging and mapping of underwater geometries difficult to address using simple interferometry. The focus of the paper
OCEANS 2007, 2007
This paper proposes a new distance measuring system to monitor tectonic plate motions. The method... more This paper proposes a new distance measuring system to monitor tectonic plate motions. The method is based on estimation of phase shift between two acoustic signals. The measurement error of plate displacement is determined by the phase estimation error. Phase estimation is performed with a conventional quadrature phase estimator in this paper. Simulation results show that under ideal conditions, the root-mean-square (RMS) error of the displacement estimation is within 1 millimetre when the signal-to-noise ratio (SNR) equals OdB. This error can be further reduced if we use a longer transmission pulse. Measurement errors caused by environmental factors such as ocean currents are also addressed. Reciprocal transmission is suggested to reduce this effect.
Oceans '99. MTS/IEEE. Riding the Crest into the 21st Century. Conference and Exhibition. Conference Proceedings (IEEE Cat. No.99CH37008)
This paper describes a small-aperture sonar and processing technique that provides vertical profi... more This paper describes a small-aperture sonar and processing technique that provides vertical profile information with a single ping without the large arrays of acoustic elements required for beamforming. The small acoustic aperture makes the sonar suitable for small vehicles and towfish. The sonar uses angle of arrival estimates, derived from a small number of acoustic elements, for determining the lay of the land in front of the transducer. Unlike two-element interferometric sonars, this sonar's performance does not suffer from the presence of multiple time-coincident targets because multiple angles can be estimated. Examples of lookahead profiles derived from simulated and experimental data are given for different target geometries and propagation conditions. The results are compared with those that would be obtained using two-element interferometry. Potential applications of the sonar and processing technique, and direction of future research are discussed.
Oceans '02 MTS/IEEE
The recent extension of Swath Bathymetry Sidescan (SBS) sonar to Multiangle Swath Bathymetry Side... more The recent extension of Swath Bathymetry Sidescan (SBS) sonar to Multiangle Swath Bathymetry Sidescan (MSBS) has rekindled the argument that existing performance limits (spatial resolution, swath width and accuracy) of seafloor and water column acoustic mapping/imaging may still be improved upon. While beamformed systems continue to improve in achievable angular resolution, these systems also continue to encounter difficulties in achieving
OCEANS Conference, 2001
The Cramer-Rao bound is employed to establish a lower bound on the estimation accuracy of bottom ... more The Cramer-Rao bound is employed to establish a lower bound on the estimation accuracy of bottom detection and angle estimation methods for swath bathymetry. The angle estimation bound is converted to a distance along an arc at the given range and then compared to the range estimation accuracy obtained for bottom detection methods. It is determined that for bottom detection
IEEE Transactions on Instrumentation and Measurement, 1996
An important tool for experimental underwater acoustics research is a versatile sonar system for ... more An important tool for experimental underwater acoustics research is a versatile sonar system for transmitting, receiving, anti recording acoustic waveforms. In this paper the design, implementation and performance of a variable-frequency (25 kHz to 500 kHz) coherent sonar are presented. The significance of the design lies in its simplicity and versatility. These attributes are a result of a sampling technique that provides quadrature samples of the complex envelope of a bandpass signal without analog demodulation using a single A/D converter. Implementation of the design is accomplished using an ISA bus personal computer (PC), a commercially available digital signal processing (DSP) board, and a small amount of custom electronics. Performance of the sonar, in terms of magnitude and phase errors, is determined from wideband noise characterization, a linear-system model, and transmit/receive measurements