Michal Pec

Principal Component Analysis for Head-Related Transfer Function Low-Order Filter Design

The Principal Component Analysis (PCA) is a technique that allows for dimensionality reduction in... more The Principal Component Analysis (PCA) is a technique that allows for dimensionality reduction in a data set. In this communication, PCA was applied to HRTF data to extract the frequency components that are most important for precise sound localization in both azimuth and elevation. This is a new approach to use PCA for low-order HRTF modelling. In the proposed method, analysis is performed for large overlapping sectors instead of the entire HRTF set. The reported method allows for reduction of HRTF filter order without decreasing virtual sound source localization accuracy.

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A Novel Approach to Global Positioning System Accuracy Assessment, Verified on LiDAR Alignment of One Million Kilometers at a Continent Scale, as a Foundation for Autonomous DRIVING Safety Analysis

Sensors, 2021

This paper concerns a new methodology for accuracy assessment of GPS (Global Positioning System) ... more This paper concerns a new methodology for accuracy assessment of GPS (Global Positioning System) verified experimentally with LiDAR (Light Detection and Ranging) data alignment at continent scale for autonomous driving safety analysis. Accuracy of an autonomous driving vehicle positioning within a lane on the road is one of the key safety considerations and the main focus of this paper. The accuracy of GPS positioning is checked by comparing it with mobile mapping tracks in the recorded high-definition source. The aim of the comparison is to see if the GPS positioning remains accurate up to the dimensions of the lane where the vehicle is driving. The goal is to align all the available LiDAR car trajectories to confirm the of accuracy of GNSS + INS (Global Navigation Satellite System + Inertial Navigation System). For this reason, the use of LiDAR metric measurements for data alignment implemented using SLAM (Simultaneous Localization and Mapping) was investigated, assuring no system...

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Individual HRTF measurements for accurate obstacle sonification in an electronic travel aid for the blind

2008 International Conference on Signals and Electronic Systems, 2008

The article presents a study of virtual sound source localization errors with the use of personal... more The article presents a study of virtual sound source localization errors with the use of personalized head related transfer functions (HRTFs) in light of design of an electronic travel aid for the blind. The proposed device for aiding visually disabled individuals in independent mobility requires presentation of spatial sounds, which lead to the need to construct a system for efficient individual HRTF measurement. Measurements were performed for 15 sighted and blind individuals. Verification trials limited to the frontal hemisphere have shown that the localization of virtual sound sources can be performed with accuracy reaching average errors of 6.36º in azimuth and 9.47º in elevation.

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Sonification of 3D Scenes in an Electronic Travel Aid for the Blind

Advances in Sound Localization, 2011

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Low-Order Modeling of Head Related Transfer Functions Based on Spectral Smoothing and Principal Component Analysis

The presented paper discusses methods of reducing the order of HRTF filters. Two alternative meth... more The presented paper discusses methods of reducing the order of HRTF filters. Two alternative methods of HRTF preprocessing were proposed: wavelet based approximation of HRTF magnitude spectrum and dimensionality reduction by means of Principal Component Analysis. Frequency components of HRTFs were weighted according to the non-linear frequency resolution of human hearing via transformation to the bark scale. The preprocessed HRTFs were modeled with either recursive or non-recursive filters in linear and non-linear frequency domains.

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A Novel Approach to Global Positioning System Accuracy Assessment, Verified on LiDAR Alignment of One Million Kilometers at a Continent Scale, as a Foundation for Autonomous DRIVING Safety Analysis

Sensors

This paper concerns a new methodology for accuracy assessment of GPS (Global Positioning System) ... more This paper concerns a new methodology for accuracy assessment of GPS (Global Positioning System) verified experimentally with LiDAR (Light Detection and Ranging) data alignment at continent scale for autonomous driving safety analysis. Accuracy of an autonomous driving vehicle positioning within a lane on the road is one of the key safety considerations and the main focus of this paper. The accuracy of GPS positioning is checked by comparing it with mobile mapping tracks in the recorded high-definition source. The aim of the comparison is to see if the GPS positioning remains accurate up to the dimensions of the lane where the vehicle is driving. The goal is to align all the available LiDAR car trajectories to confirm the of accuracy of GNSS + INS (Global Navigation Satellite System + Inertial Navigation System). For this reason, the use of LiDAR metric measurements for data alignment implemented using SLAM (Simultaneous Localization and Mapping) was investigated, assuring no system...

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Low-order modelling of head related transfer functions based on spectral smoothing and principal component analysis

Proceedings of Spie the International Society For Optical Engineering, Jun 1, 2009

ABSTRACT The article presents wavelet-based spectral smoothing and Principal Component Analysis a... more ABSTRACT The article presents wavelet-based spectral smoothing and Principal Component Analysis as a pre-processing step for Head Related Transfer Function (HRTF) filter design. Spectral smoothing of HRTF by means of Stationary Wavelet Transform discards low-value peaks and notches in HRTF which can be treated as noise. The Principal Component Analysis applied to the HRTF data extracts most important frequency components responsible for sound source localization in azimuth and elevation. These methods used in combination are used to reduce the order of filters that are applied in 3D audio rendering system.

Measurement System for Personalized Head-Related Transfer Functions and Its Verification by Virtual Source Localization Trials with Visually Impaired and Sighted Individuals

Journal of the Audio Engineering Society, Oct 14, 2010

Creating personalized head-related impulse responses is critically important for visually impaire... more

InTech 2010

Low-order modeling of head-related transfer functions using balanced model truncation

IEEE Signal Processing Letters, 2000

We propose a novel technique for the design of low-order infinite impulse response (IIR) filter m... more We propose a novel technique for the design of low-order infinite impulse response (IIR) filter models of head-related transfer functions (HRTFs) that uses balanced model truncation. We design tenth-order IIR filters, suitable for efficient real-time implementation, from preprocessed HRTF impulse responses that are of significantly superior quality to current IIR models derived with the Prony and Yule-Walker methods

Personalized head related transfer function measurement and verification through sound localization resolution

… of the 15th European Signal Processing …, 2007

Filtering of sounds through head related transfer functions (HRTFs) is a common method for obtain... more

Head related transfer functions measurement and processing for the purpose of creating a spatial sound environment

Proceedings of SPIE - The International Society for Optical Engineering

The use of Head Related Transfer Functions (HRTFs) in audio processing is a popular method of obt... more The use of Head Related Transfer Functions (HRTFs) in audio processing is a popular method of obtaining spatialized sound. HRTFs describe disturbances caused in the sound wave by the human body, especially by head and the ear pinnae. Since these shapes are unique, HRTFs differ greatly from person to person. For this reason measurement of personalized HRTFs is justified. Measured HRTFs also need further processing to be utilized in a system producing spatialized sound. This paper describes a system designed for efficient collecting of Head Related Transfer Functions as well as the measurement, interpolation and verification procedures.

Individual HRTF measurements for accurate obstacle sonification in an electronic travel aid for the blind

by Andrzej Materka, Michal Pec, and Paweł Strumiłło

2008 International Conference on Signals and Electronic Systems, 2008

Abstract - The article presents a study of virtual sound source localization errors with the use ... more

<title>Head related transfer functions measurement and processing for the purpose of creating a spatial sound environment</title>

by Paweł Strumiłło, Michał Bujacz, and Michal Pec

The use of Head Related Transfer Functions (HRTFs) in audio processing is a popular method of obt... more The use of Head Related Transfer Functions (HRTFs) in audio processing is a popular method of obtaining spatialized sound. HRTFs describe disturbances caused in the sound wave by the human body, especially by head and the ear pinnae. Since these shapes are unique, HRTFs differ greatly from person to person. For this reason measurement of personalized HRTFs is justified. Measured HRTFs also need further processing to be utilized in a system producing spatialized sound. This paper describes a system designed for efficient collecting of Head Related Transfer Functions as well as the measurement, interpolation and verification procedures.

Sonification of 3D Scenes in an Electronic Travel Aid for the Blind

by Michal Pec, Pawel Strumillo, and Piotr Skulimowski

Advances in Sound Localization, 2011

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