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Papers by Michał Bujacz

Research paper thumbnail of A Prototype Mobility and Navigation Tele-Assistance System for Visually Disabled

Advances in Soft Computing, 2009

The paper presents initial research on the system for remote guidance of the blind. The concept i... more The paper presents initial research on the system for remote guidance of the blind. The concept is based on the idea that a blind pedestrian can be aided by spoken instructions from an operator who receives a video stream from a camera and GPS readouts from a sensor carried by a visually impaired user. An early prototype utilizing two laptop PCs and a wireless internet connection is used in indoor orientation and mobility trials, which aim to measure the potential usefulness of the system and discover possible problems with user-operator communication or device design. A second prototype is also constructed using a smaller subnotebook Flybook computer, a GPS sensor and GSM modem with HSDPA technology, and tested in outdoor environments. Test results show a quantitative performance increase when travelling with a remote guide: 15-50% speed increase and halved times of navigational tasks in indoor trials, as well as a significant decrease in the number of missteps and accidental obstacle collisions in outdoor trials. A large part of the success is the supportive feedback from the blind testers, who point out the engendered feeling of safety when assisted.

Research paper thumbnail of Remote mobility and navigation aid for the visually disabled

Outdoor tests of a system for remote guidance of the blind are reported in the paper. The main id... more Outdoor tests of a system for remote guidance of the blind are reported in the paper. The main idea of the system is to transmit a video stream from a camera carried by a visually impaired user to a remote assistant that navigates the blind by short spoken instructions. The communication link is established over the GSM network within the High-Speed Downlink Packet Access (HSDPA) communication protocol. Mobility trials of the system were carried out with a mobile prototype and three blind volunteers in the university campus. The aim of the study was to test the overall tele-assistance concept including: communication link efficiency and reliability, influence on mobility and safety, and the improvement of operator-user interaction. Tests, albeit performed on a small group of volunteers, clearly show an objective performance increase when traveling with the remote guide. This is evident primarily in increased travel speeds and decreased occurrences of missteps and collisions.

Research paper thumbnail of Dead reckoning navigation: supplementing pedestrian GPS with an accelerometer-based pedometer and an electronic compass

The article presents a prototype wearable device that corrects inaccurate GPS readouts during ped... more The article presents a prototype wearable device that corrects inaccurate GPS readouts during pedestrian travel. The electronic circuit consists of a microcontroller, an accelerometer and a digital compass. The accelerometer readouts are filtered to detect the steps of the pedestrian and are also used to estimate the stride length. The digital compass provides the direction of motion. When the GPS parameters warn of a high dilution of precision, the location of the pedestrian is corrected by data provided by the accelerometer and the digital compass.

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

Advances in Sound Localization, 2011

Research paper thumbnail of A Prototype Mobility and Navigation Tele-Assistance System for Visually Disabled

Advances in Soft Computing, 2009

The paper presents initial research on the system for remote guidance of the blind. The concept i... more The paper presents initial research on the system for remote guidance of the blind. The concept is based on the idea that a blind pedestrian can be aided by spoken instructions from an operator who receives a video stream from a camera and GPS readouts from a sensor carried by a visually impaired user. An early prototype utilizing two laptop PCs and a wireless internet connection is used in indoor orientation and mobility trials, which aim to measure the potential usefulness of the system and discover possible problems with user-operator communication or device design. A second prototype is also constructed using a smaller subnotebook Flybook computer, a GPS sensor and GSM modem with HSDPA technology, and tested in outdoor environments. Test results show a quantitative performance increase when travelling with a remote guide: 15-50% speed increase and halved times of navigational tasks in indoor trials, as well as a significant decrease in the number of missteps and accidental obstacle collisions in outdoor trials. A large part of the success is the supportive feedback from the blind testers, who point out the engendered feeling of safety when assisted.

Research paper thumbnail of 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.

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

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.

Research paper thumbnail of <title>Synthesizing a 3D auditory scene for use in an electronic travel aid for the blind</title>

A system for auditory presentation of 3D scenes to the blind is presented, with the focus of the ... more A system for auditory presentation of 3D scenes to the blind is presented, with the focus of the paper on the synthesis of sound codes suitable to carry important scene information. First, a short review of existing electronic travel aids for the blind (ETAs) is provided. Second, the project of the wearable ETA device, currently under development at the Technical University of Lodz, is outlined, along with the system modules: 3D scene reconstruction, object (obstacle) selection, synthesis of the sound code and the application of head related transfer functions (HRTFs) for generating spatialized sound. The importance of psychoacoustics, especially Bregman's theory of sound streams, is analyzed and proposed methods of sound code synthesis are presented, along with the software used for their verification.

Contributions by Michał Bujacz

Research paper thumbnail of Sound of Vision - Spatial Audio Output and Sonification Approaches

The paper summarizes a number of audio-related studies conducted by the Sound of Vision consortiu... more The paper summarizes a number of audio-related studies conducted by the Sound of Vision consortium, which focuses on the construction of a new prototype electronic travel aid for the blind. Different solutions for spatial audio were compared by testing sound localization accuracy in a number of setups, comparing plain stereo panning with generic and individual HRTFs, as well as testing different types of stereo headphones vs custom designed quadrophonic proximaural headphones. A number of proposed sonification approaches were tested by sighted and blind volunteers for accuracy and efficiency in representing simple virtual environments.

Research paper thumbnail of Model-based obstacle sonification for the navigation of visually impaired persons

Proceedings of the 19th International Conference on Digital Audio Effects (DAFx-16), 2016

This paper proposes a sonification model for encoding visual 3D information into sounds, inspired... more This paper proposes a sonification model for encoding visual 3D information into sounds, inspired by the impact properties of the objects encountered during blind navigation. The proposed model is compared against two sonification models developed for orientation and mobility, chosen based on their common technical requirements. An extensive validation of the proposed model is reported; five legally blind and five normally sighted participants evaluated the proposed model as compared to the two competitive models on a simplified experimental navigation scenario. The evaluation addressed not only the accuracy of the responses in terms of psychophysical measurements but also the cognitive load and emotional stress of the participants by means of biophysiological signals and evaluation questionnaires. Results show that the proposed impact sound model adequately conveys the relevant information to the participants with low cognitive load, following a short training session.

Research paper thumbnail of A Prototype Mobility and Navigation Tele-Assistance System for Visually Disabled

Advances in Soft Computing, 2009

The paper presents initial research on the system for remote guidance of the blind. The concept i... more The paper presents initial research on the system for remote guidance of the blind. The concept is based on the idea that a blind pedestrian can be aided by spoken instructions from an operator who receives a video stream from a camera and GPS readouts from a sensor carried by a visually impaired user. An early prototype utilizing two laptop PCs and a wireless internet connection is used in indoor orientation and mobility trials, which aim to measure the potential usefulness of the system and discover possible problems with user-operator communication or device design. A second prototype is also constructed using a smaller subnotebook Flybook computer, a GPS sensor and GSM modem with HSDPA technology, and tested in outdoor environments. Test results show a quantitative performance increase when travelling with a remote guide: 15-50% speed increase and halved times of navigational tasks in indoor trials, as well as a significant decrease in the number of missteps and accidental obstacle collisions in outdoor trials. A large part of the success is the supportive feedback from the blind testers, who point out the engendered feeling of safety when assisted.

Research paper thumbnail of Remote mobility and navigation aid for the visually disabled

Outdoor tests of a system for remote guidance of the blind are reported in the paper. The main id... more Outdoor tests of a system for remote guidance of the blind are reported in the paper. The main idea of the system is to transmit a video stream from a camera carried by a visually impaired user to a remote assistant that navigates the blind by short spoken instructions. The communication link is established over the GSM network within the High-Speed Downlink Packet Access (HSDPA) communication protocol. Mobility trials of the system were carried out with a mobile prototype and three blind volunteers in the university campus. The aim of the study was to test the overall tele-assistance concept including: communication link efficiency and reliability, influence on mobility and safety, and the improvement of operator-user interaction. Tests, albeit performed on a small group of volunteers, clearly show an objective performance increase when traveling with the remote guide. This is evident primarily in increased travel speeds and decreased occurrences of missteps and collisions.

Research paper thumbnail of Dead reckoning navigation: supplementing pedestrian GPS with an accelerometer-based pedometer and an electronic compass

The article presents a prototype wearable device that corrects inaccurate GPS readouts during ped... more The article presents a prototype wearable device that corrects inaccurate GPS readouts during pedestrian travel. The electronic circuit consists of a microcontroller, an accelerometer and a digital compass. The accelerometer readouts are filtered to detect the steps of the pedestrian and are also used to estimate the stride length. The digital compass provides the direction of motion. When the GPS parameters warn of a high dilution of precision, the location of the pedestrian is corrected by data provided by the accelerometer and the digital compass.

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

Advances in Sound Localization, 2011

Research paper thumbnail of A Prototype Mobility and Navigation Tele-Assistance System for Visually Disabled

Advances in Soft Computing, 2009

The paper presents initial research on the system for remote guidance of the blind. The concept i... more The paper presents initial research on the system for remote guidance of the blind. The concept is based on the idea that a blind pedestrian can be aided by spoken instructions from an operator who receives a video stream from a camera and GPS readouts from a sensor carried by a visually impaired user. An early prototype utilizing two laptop PCs and a wireless internet connection is used in indoor orientation and mobility trials, which aim to measure the potential usefulness of the system and discover possible problems with user-operator communication or device design. A second prototype is also constructed using a smaller subnotebook Flybook computer, a GPS sensor and GSM modem with HSDPA technology, and tested in outdoor environments. Test results show a quantitative performance increase when travelling with a remote guide: 15-50% speed increase and halved times of navigational tasks in indoor trials, as well as a significant decrease in the number of missteps and accidental obstacle collisions in outdoor trials. A large part of the success is the supportive feedback from the blind testers, who point out the engendered feeling of safety when assisted.

Research paper thumbnail of 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.

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

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.

Research paper thumbnail of <title>Synthesizing a 3D auditory scene for use in an electronic travel aid for the blind</title>

A system for auditory presentation of 3D scenes to the blind is presented, with the focus of the ... more A system for auditory presentation of 3D scenes to the blind is presented, with the focus of the paper on the synthesis of sound codes suitable to carry important scene information. First, a short review of existing electronic travel aids for the blind (ETAs) is provided. Second, the project of the wearable ETA device, currently under development at the Technical University of Lodz, is outlined, along with the system modules: 3D scene reconstruction, object (obstacle) selection, synthesis of the sound code and the application of head related transfer functions (HRTFs) for generating spatialized sound. The importance of psychoacoustics, especially Bregman's theory of sound streams, is analyzed and proposed methods of sound code synthesis are presented, along with the software used for their verification.

Research paper thumbnail of Sound of Vision - Spatial Audio Output and Sonification Approaches

The paper summarizes a number of audio-related studies conducted by the Sound of Vision consortiu... more The paper summarizes a number of audio-related studies conducted by the Sound of Vision consortium, which focuses on the construction of a new prototype electronic travel aid for the blind. Different solutions for spatial audio were compared by testing sound localization accuracy in a number of setups, comparing plain stereo panning with generic and individual HRTFs, as well as testing different types of stereo headphones vs custom designed quadrophonic proximaural headphones. A number of proposed sonification approaches were tested by sighted and blind volunteers for accuracy and efficiency in representing simple virtual environments.

Research paper thumbnail of Model-based obstacle sonification for the navigation of visually impaired persons

Proceedings of the 19th International Conference on Digital Audio Effects (DAFx-16), 2016

This paper proposes a sonification model for encoding visual 3D information into sounds, inspired... more This paper proposes a sonification model for encoding visual 3D information into sounds, inspired by the impact properties of the objects encountered during blind navigation. The proposed model is compared against two sonification models developed for orientation and mobility, chosen based on their common technical requirements. An extensive validation of the proposed model is reported; five legally blind and five normally sighted participants evaluated the proposed model as compared to the two competitive models on a simplified experimental navigation scenario. The evaluation addressed not only the accuracy of the responses in terms of psychophysical measurements but also the cognitive load and emotional stress of the participants by means of biophysiological signals and evaluation questionnaires. Results show that the proposed impact sound model adequately conveys the relevant information to the participants with low cognitive load, following a short training session.