Journal articles: 'HRTF measurement'

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Li, Song, and Jürgen Peissig. "Measurement of Head-Related Transfer Functions: A Review." Applied Sciences 10, no. 14 (July 21, 2020): 5014. http://dx.doi.org/10.3390/app10145014.

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A head-related transfer function (HRTF) describes an acoustic transfer function between a point sound source in the free-field and a defined position in the listener’s ear canal, and plays an essential role in creating immersive virtual acoustic environments (VAEs) reproduced over headphones or loudspeakers. HRTFs are highly individual, and depend on directions and distances (near-field HRTFs). However, the measurement of high-density HRTF datasets is usually time-consuming, especially for human subjects. Over the years, various novel measurement setups and methods have been proposed for the fast acquisition of individual HRTFs while maintaining high measurement accuracy. This review paper provides an overview of various HRTF measurement systems and some insights into trends in individual HRTF measurements.

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Braren, Hark Simon, and Janina Fels. "Towards Child-Appropriate Virtual Acoustic Environments: A Database of High-Resolution HRTF Measurements and 3D-Scans of Children." International Journal of Environmental Research and Public Health 19, no. 1 (December 29, 2021): 324. http://dx.doi.org/10.3390/ijerph19010324.

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Head-related transfer functions (HRTFs) play a significant role in modern acoustic experiment designs in the auralization of 3-dimensional virtual acoustic environments. This technique enables us to create close to real-life situations including room-acoustic effects, background noise and multiple sources in a controlled laboratory environment. While adult HRTF databases are widely available to the research community, datasets of children are not. To fill this gap, children aged 5–10 years old were recruited among 1st and 2nd year primary school children in Aachen, Germany. Their HRTFs were measured in the hemi-anechoic chamber with a 5-degree × 5-degree resolution. Special care was taken to reduce artifacts from motion during the measurements by means of fast measurement routines. To complement the HRTF measurements with the anthropometric data needed for individualization methods, a high-resolution 3D-scan of the head and upper torso of each participant was recorded. The HRTF measurement took around 3 min. The children’s head movement during that time was larger compared to adult participants in comparable experiments but was generally kept within 5 degrees of rotary and 1 cm of translatory motion. Adult participants only exhibit this range of motion in longer duration measurements. A comparison of the HRTF measurements to the KEMAR artificial head shows that it is not representative of an average child HRTF. Difference can be seen in both the spectrum and in the interaural time delay (ITD) with differences of 70 μs on average and a maximum difference of 138 μs. For both spectrum and ITD, the KEMAR more closely resembles the 95th percentile of range of children’s data. This warrants a closer look at using child specific HRTFs in the binaural presentation of virtual acoustic environments in the future.

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Kohnen, Michael, Florian Denk, Josep Llorca-Bofi, Birger Kollmeier, and Michael Vorländer. "Cross-site investigation on head-related and headphone transfer functions: variabilities in relation to loudness balancing." Acta Acustica 5 (2021): 58. http://dx.doi.org/10.1051/aacus/2021051.

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Headphone transfer function (HpTF) and head-related transfer function (HRTF) measurements are crucial in acoustic science and in binaural virtual acoustic applications. Yet, their measurement set-up, procedure or post-processing is different for nearly every lab, especially for the HRTF measurements. To compare findings between different labs, these measurement deviations have to be quantified alongside with their influence on perceptual aspects. In the scope of a cross-site investigation on loudness balancing between headphone and loudspeaker listening, a set of HpTFs with three different headphones (open, closed, insert earphones) and HRTF close to the eardrum were measured in 14 participants travelling to two different measurement sites at Aachen and Oldenburg. Though set-ups for measuring the HRTF are very different between sites, the gathered HRTFs are quite consistent across them. For the measured HpTFs, across sites the open headphones consistently yield a slightly lower variability in the range from 70 to 5000 Hz than the closed one while the insert earphones exhibit much higher variabilities and a limited range of reproducible results. The difference in loudness balancing across labs could well be predicted by site-specific systematic differences in HpTFs with the exception of 1 kHz narrowband stimulus. This clearly indicates the limits in comparability of HpTFs and loudness balancing across labs and the importance of using headphones with high repeatability like the open ones used in this investigation.

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Yao, Shu-Nung, and Li Jen Chen. "HRTF Adjustments with Audio Quality Assessments." Archives of Acoustics 38, no. 1 (March 1, 2013): 55–62. http://dx.doi.org/10.2478/aoa-2013-0007.

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Abstract There are an increasing number of binaural systems embedded with head-related transfer functions (HRTFs), so listeners can experience virtual environments via conventional stereo loudspeakers or head- phones. As HRTFs vary from person to person, it is difficult to select appropriated HRTFs from already existing databases for users. Once the HRTFs in a binaural audio device hardly match the real ones of the users, poor localization happens especially on the cone of confusion. The most accurate way to obtain personalized HRTFs might be doing practical measurements. It is, however, expensive and time consuming. Modifying non-individualized HRTFs may be an effort-saving way, though the modifications are always accompanied by undesired audio distortion. This paper proposes a flexible HRTF adjustment system for users to define their own HRTFs. Also, the system can keep sounds from suffering intolerable distortion based on an objective measurement tool for evaluating the quality of processed audio.

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Aoki, Shigeaki, Michael Cohen, and Nobuo Koizumi. "Design and Control of Shared Conferencing Environments for Audio Telecommunication Using Individually Measured HRTFs." Presence: Teleoperators and Virtual Environments 3, no. 1 (January 1994): 60–72. http://dx.doi.org/10.1162/pres.1994.3.1.60.

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A technique is presented for dynamically invoking a set of head-related transfer functions (HRTFs) and scaling gain, driven by a dynamic map in a graphic window. With such an interface, users may configure a virtual conferencing environment, manipulating virtual positions of teleconferees. The design of a personal headphone teleconferencing prototype is proposed, integrating spatialized sound presentation with individualized HRTF measurement using a bifunctional transducer. According to judgment tests, the use of individualized HRTFs instead of dummy-head HRTFs can reduce front-back sound image confusion.

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Andreopoulou, Areti, Durand R. Begault, and Brian F. G. Katz. "Inter-Laboratory Round Robin HRTF Measurement Comparison." IEEE Journal of Selected Topics in Signal Processing 9, no. 5 (August 2015): 895–906. http://dx.doi.org/10.1109/jstsp.2015.2400417.

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Armstrong, Cal, Lewis Thresh, Damian Murphy, and Gavin Kearney. "A Perceptual Evaluation of Individual and Non-Individual HRTFs: A Case Study of the SADIE II Database." Applied Sciences 8, no. 11 (October 23, 2018): 2029. http://dx.doi.org/10.3390/app8112029.

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As binaural audio continues to permeate immersive technologies, it is vital to develop a detailed understanding of the perceptual relevance of HRTFs. Previous research has explored the benefit of individual HRTFs with respect to localisation. However, localisation is only one metric with which it is possible to rate spatial audio. This paper evaluates the perceived timbral and spatial characteristics of both individual and non-individual HRTFs and compares the results to overall preference. To that end, the measurement and evaluation of a high-resolution multi-environment binaural Impulse Response database is presented for 20 subjects, including the KU100 and KEMAR binaural mannequins. Post-processing techniques, including low frequency compensation and diffuse field equalisation are discussed in relation to the 8802 unique HRTFs measured for each mannequin and 2818/2114 HRTFs measured for each human. Listening test results indicate that particular HRTF sets are preferred more generally by subjects over their own individual measurements.

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Lee, Yun-Jae, Young-Jin Park, and Youn-Sik Park. "Newly Designed HRTF Measurement System and its Analysis." Journal of Institute of Control, Robotics and Systems 16, no. 2 (February 1, 2010): 202–5. http://dx.doi.org/10.5302/j.icros.2010.16.2.202.

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Sumner, Eric M., Morris Riedel, and Rúnar Unnþórsson. "Design and manufacture of synthetic pinnæ for studying head-related transfer functions." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A220—A221. http://dx.doi.org/10.1121/10.0011115.

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The study of head-related transfer functions (HRTFs) is hampered by an inability to isolate the effects of individual anthropometric properties in an experimental setting. The authors propose to address this issue by studying the HRTFs of synthetic pinnæ which are designed to specification. The design, manufacture, and measurement of these synthetic pinnæ are detailed: A mold for each pinna is printed with a finite-deposition 3D printer and then cast in silicone with appropriate acoustic properties. These castings are then installed on a KEMAR mannequin whose HRTF is measured in an anechoic chamber. Additionally, comparative results are presented between commercially produced pinnæ inserts and copies produced via the proposed method.

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Ben-Hur, Zamir, David L. Alon, Boaz Rafaely, and Ravish Mehra. "Localization and externalization in binaural reproduction with sparse HRTF measurement grids." Journal of the Acoustical Society of America 143, no. 3 (March 2018): 1830. http://dx.doi.org/10.1121/1.5036007.

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Bai, Mingsian R., and Teng-Chieh Tsao. "Numerical Modeling of Head-Related Transfer Functions Using the Boundary Source Representation." Journal of Vibration and Acoustics 128, no. 5 (April 4, 2006): 594–603. http://dx.doi.org/10.1115/1.2203337.

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A technique based on the virtual source representation is presented for modeling head-related transfer functions (HRTFs). This method is motivated by the theory of simple layer potential and the principle of wave superposition. Using the virtual source representation, the HRTFs for a human head with pinnae are calculated with a minimal amount of computation. In the process, a special regularization scheme is required to calculate the equivalent strengths of virtual sources. To justify the proposed method, tests were carried out to compare the virtual source method with the boundary element method (BEM) and a direct HRTF measurement. The HRTFs obtained using the virtual source method agrees reasonably well in terms of frequency response, directional response, and impulse response with the other methods. From the numerical perspectives, the virtual source method obviates the singularity problem as commonly encountered in the BEM, and is less computationally demanding than the BEM in terms of computational time and memory storage. Subjective experiments are also conducted using the calculated and the measured HRTFs. The results reveal that the spatial characteristics of sound localization are satisfactorily reproduced as a human listener would naturally perceive by using the virtual source HRTFs.

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Kang, Kyeong Ok, Dong‐Gyu Kang, Min‐Soo Hahn, Mun‐Jae Jho, and Dae‐Kwon Jeong. "Construction of a HATS and its HRTF measurement for 3‐D sound." Journal of the Acoustical Society of America 103, no. 5 (May 1998): 2988. http://dx.doi.org/10.1121/1.421690.

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Ben-Hur, Zamir, David L. Alon, Boaz Rafaely, and Ravish Mehra. "Perceived stability and localizability in binaural reproduction with sparse HRTF measurement grids." Journal of the Acoustical Society of America 143, no. 3 (March 2018): 1824. http://dx.doi.org/10.1121/1.5035993.

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Ewers, Megan, Sam Kincaid, and Marco Beltman. "Head related transfer function measurements of common PPE." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 4 (August 1, 2021): 2430–41. http://dx.doi.org/10.3397/in-2021-2134.

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Due to COVID 19, personal protective equipment (PPE) is now used in everyday life. Such PPE affects communication and perception. This paper provides an overview of the impact of PPE on Head Related Transfer Functions (HRTF's). Spatial acoustic effects of common PPE on human hearing can be documented to improve and inform field worker safety and communication. After a general description of the measurement process and required tools, we focus on a few methods which contribute significantly to the accuracy and analysis of PPE-based HRTF data. The dedicated setup allows measuring a full 360 degree map in automated fashion. It includes a special ring setup with 25 speakers, and a precise turn table that is used to adjust the angle of the device under test with respect to the ring. Binaural measurements were performed on a set of common PPE items on a Head And Torso Simulator (HATS) system, including hard hats, safety glasses, hearing protection, and various face masks. An overview of the data is presented.

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Jiang, Ziran, Jinqiu Sang, Chengshi Zheng, Andong Li, and Xiaodong Li. "Modeling individual head-related transfer functions from sparse measurements using a convolutional neural network." Journal of the Acoustical Society of America 153, no. 1 (January 2023): 248–59. http://dx.doi.org/10.1121/10.0016854.

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Individual head-related transfer functions (HRTFs) are usually measured with high spatial resolution or modeled with anthropometric parameters. This study proposed an HRTF individualization method using only spatially sparse measurements using a convolutional neural network (CNN). The HRTFs were represented by two-dimensional images, in which the horizontal and vertical ordinates indicated direction and frequency, respectively. The CNN was trained by using the HRTF images measured at specific sparse directions as input and using the corresponding images with a high spatial resolution as output in a prior HRTF database. The HRTFs of a new subject can be recovered by the trained CNN with the sparsely measured HRTFs. Objective experiments showed that, when using 23 directions to recover individual HRTFs at 1250 directions, the spectral distortion (SD) is around 4.4 dB; when using 105 directions, the SD reduced to around 3.8 dB. Subjective experiments showed that the individualized HRTFs recovered from 105 directions had smaller discrimination proportion than the baseline method and were perceptually undistinguishable in many directions. This method combines the spectral and spatial characteristics of HRTF for individualization, which has potential for improving virtual reality experience.

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Tsui, Benjamin, William A. P. Smith, and Gavin Kearney. "Low-Order Spherical Harmonic HRTF Restoration Using a Neural Network Approach." Applied Sciences 10, no. 17 (August 20, 2020): 5764. http://dx.doi.org/10.3390/app10175764.

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Spherical harmonic (SH) interpolation is a commonly used method to spatially up-sample sparse head related transfer function (HRTF) datasets to denser HRTF datasets. However, depending on the number of sparse HRTF measurements and SH order, this process can introduce distortions into high frequency representations of the HRTFs. This paper investigates whether it is possible to restore some of the distorted high frequency HRTF components using machine learning algorithms. A combination of convolutional auto-encoder (CAE) and denoising auto-encoder (DAE) models is proposed to restore the high frequency distortion in SH-interpolated HRTFs. Results were evaluated using both perceptual spectral difference (PSD) and localisation prediction models, both of which demonstrated significant improvement after the restoration process.

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Ramos, Oscar Alberto, and Fabián Carlos Tommasini. "Magnitude Modelling of HRTF Using Principal Component Analysis Applied to Complex Values." Archives of Acoustics 39, no. 4 (March 1, 2015): 477–82. http://dx.doi.org/10.2478/aoa-2014-0051.

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Abstract Principal components analysis (PCA) is frequently used for modelling the magnitude of the head-related transfer functions (HRTFs). Assuming that the HRTFs are minimum phase systems, the phase is obtained from the Hilbert transform of the log-magnitude. In recent years, the PCA applied to HRTFs is also used to model individual HRTFs relating the PCA weights with anthropometric measurements of the head, torso and pinnae. The HRTF log-magnitude is the most used format of input data to the PCA, but it has been shown that if the input data is HRTF linear magnitude, the cumulative variance converges faster, and the mean square error (MSE) is smaller. This study demonstrates that PCA applied directly on HRTF complex values is even better than the two formats mentioned above, that is, the MSE is the smallest and the cumulative variance converges faster after the 8th principal component. Different objective experiments around all the median plane put in evidence the differences which, although small, seem to be perceptually detectable. To elucidate this point, psychoacoustic discrimination tests are done between measured and reconstructed HRTFs from the three types of input data mentioned, in the median plane between -45°. and +9°.

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Yao, Shu-Nung, Tim Collins, and Chaoyun Liang. "Head-Related Transfer Function Selection Using Neural Networks." Archives of Acoustics 42, no. 3 (September 26, 2017): 365–73. http://dx.doi.org/10.1515/aoa-2017-0038.

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AbstractIn binaural audio systems, for an optimal virtual acoustic space a set of head-related transfer functions (HRTFs) should be used that closely matches the listener’s ones. This study aims to select the most appropriate HRTF dataset from a large database for users without the need for extensive listening tests. Currently, there is no way to reliably reduce the number of datasets to a smaller, more manageable number without risking discarding potentially good matches. A neural network that estimates the appropriateness of HRTF datasets based on input vectors of anthropometric measurements is proposed. The shapes and sizes of listeners’ heads and pinnas were measured using digital photography; the measured anthropometric parameters form the feature vectors used by the neural network. A graphical user interface (GUI) was developed for participants to listen to music transformed using different HRTFs and to evaluate the fitness of each HRTF dataset. The listening scores recorded were the target outputs used to train the neural networks. The aim was to learn a mapping between anthropometric parameters and listener’s perception scores. Experimental validations were performed on 30 subjects. It is demonstrated that the proposed system produces a much more reliable HRTF selection than previously used methods.

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Spagnol, Simone, Michele Geronazzo, Davide Rocchesso, and Federico Avanzini. "Synthetic individual binaural audio delivery by pinna image processing." International Journal of Pervasive Computing and Communications 10, no. 3 (August 26, 2014): 239–54. http://dx.doi.org/10.1108/ijpcc-06-2014-0035.

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Purpose – The purpose of this paper is to present a system for customized binaural audio delivery based on the extraction of relevant features from a 2-D representation of the listener’s pinna. Design/methodology/approach – The most significant pinna contours are extracted by means of multi-flash imaging, and they provide values for the parameters of a structural head-related transfer function (HRTF) model. The HRTF model spatializes a given sound file according to the listener’s head orientation, tracked by sensor-equipped headphones, with respect to the virtual sound source. Findings – A preliminary localization test shows that the model is able to statically render the elevation of a virtual sound source better than non-individual HRTFs. Research limitations/implications – Results encourage a deeper analysis of the psychoacoustic impact that the individualized HRTF model has on perceived elevation of virtual sound sources. Practical implications – The model has low complexity and is suitable for implementation on mobile devices. The resulting hardware/software package will hopefully allow an easy and low-tech fruition of custom spatial audio to any user. Originality/value – The authors show that custom binaural audio can be successfully deployed without the need of cumbersome subjective measurements.

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Gardner, William G., and Keith D. Martin. "HRTF measurements of a KEMAR." Journal of the Acoustical Society of America 97, no. 6 (June 1995): 3907–8. http://dx.doi.org/10.1121/1.412407.

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Zhao, Manlin, Zhichao Sheng, and Yong Fang. "Magnitude Modeling of Personalized HRTF Based on Ear Images and Anthropometric Measurements." Applied Sciences 12, no. 16 (August 15, 2022): 8155. http://dx.doi.org/10.3390/app12168155.

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In this paper, we propose a global personalized head-related transfer function (HRTF) method based on anthropometric measurements and ear images. The model consists of two sub-networks. The first is the VGG-Ear Model, which extracts features from the ear images. The second sub-network uses anthropometric measurements, ear features, and frequency information to predict the spherical harmonic (SH) coefficients. Finally, the personalized HRTF is obtained through inverse spherical harmonic transform (SHT) reconstruction. With only one training, the HRTF in all directions can be obtained, which greatly reduces the parameters and training cost of the model. To objectively evaluate the proposed method, we calculate the spectral distance (SD) between the predicted HRTF and the actual HRTF. The results show that the SD provided by this method is 5.31 dB, which is better than the average HRTF of 7.61 dB. In particular, the SD value is only increased by 0.09 dB compared to directly using the pinna measurements.

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Lee, Geon, and Hong Kim. "Personalized HRTF Modeling Based on Deep Neural Network Using Anthropometric Measurements and Images of the Ear." Applied Sciences 8, no. 11 (November 7, 2018): 2180. http://dx.doi.org/10.3390/app8112180.

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This paper proposes a personalized head-related transfer function (HRTF) estimation method based on deep neural networks by using anthropometric measurements and ear images. The proposed method consists of three sub-networks for representing personalized features and estimating the HRTF. As input features for neural networks, the anthropometric measurements regarding the head and torso are used for a feedforward deep neural network (DNN), and the ear images are used for a convolutional neural network (CNN). After that, the outputs of these two sub-networks are merged into another DNN for estimation of the personalized HRTF. To evaluate the performance of the proposed method, objective and subjective evaluations are conducted. For the objective evaluation, the root mean square error (RMSE) and the log spectral distance (LSD) between the reference HRTF and the estimated one are measured. Consequently, the proposed method provides the RMSE of −18.40 dB and LSD of 4.47 dB, which are lower by 0.02 dB and higher by 0.85 dB than the DNN-based method using anthropometric data without pinna measurements, respectively. Next, a sound localization test is performed for the subjective evaluation. As a result, it is shown that the proposed method can localize sound sources with higher accuracy of around 11% and 6% than the average HRTF method and DNN-based method, respectively. In addition, the reductions of the front/back confusion rate by 12.5% and 2.5% are achieved by the proposed method, compared to the average HRTF method and DNN-based method, respectively.

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HIRAHARA, Tatsuya, Makoto OTANI, and Iwaki TOSHIMA. "Issues on HRTF Measurements and Binaural Reproduction." IEICE ESS Fundamentals Review 2, no. 4 (2009): 4_68–4_85. http://dx.doi.org/10.1587/essfr.2.4_68.

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Abbasi, Mustafa Z., Preston S. Wilson, and Ofodike A. Ezekoye. "Head-related transfer function measurements in a compartment fire." Journal of the Acoustical Society of America 151, no. 3 (March 2022): 1730–40. http://dx.doi.org/10.1121/10.0009597.

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The Personal Alert Safety System (PASS) is an alarm signal device carried by firefighters to help rescuers locate and extricate downed firefighters. A fire creates temperature gradients and inhomogeneous time-varying temperature, density, and flow fields that modify the acoustic properties of a room. To understand the effect of the fire on an alarm signal, experimental measurements of head-related transfer functions (HRTF) in a room with fire are presented in time and frequency domains. The results show that low-frequency (<1000 Hz) modes in the HRTF increase in frequency and higher-frequency modal structure weakens and becomes unstable in time. In the time domain, the time difference of arrival between the ears changes and becomes unstable over time. Both of these effects could impact alarm signal detection and localization. The receive level of narrowband tones is presented that shows that the fire makes the receive level of a source vary by > 10 dB. All of these effects could impact the detection and localization of the PASS alarm and have life safety consequences.

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Richter, Jan-Gerrit, and Janina Fels. "On the influence of continuous subject rotation during HRTF measurements." Journal of the Acoustical Society of America 141, no. 5 (May 2017): 3986. http://dx.doi.org/10.1121/1.4989115.

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Papet, L., N. Grimault, N. Boyer, and N. Mathevon. "Influence of head morphology and natural postures on sound localization cues in crocodilians." Royal Society Open Science 6, no. 7 (July 2019): 190423. http://dx.doi.org/10.1098/rsos.190423.

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As top predators, crocodilians have an acute sense of hearing that is useful for their social life and for probing their environment in hunting situations. Although previous studies suggest that crocodilians are able to localize the position of a sound source, how they do this remains largely unknown. In this study, we measured the potential monaural sound localization cues (head-related transfer functions; HRTFs) on alive animals and skulls in two situations, both mimicking natural positions: basking on the land and cruising at the interface between air and water. Binaural cues were also estimated by measuring the interaural level differences (ILDs) and the interaural time differences (ITDs). In both conditions, HRTF measurements show large spectral variations (greater than 10 dB) for high frequencies, depending on the azimuthal angle. These localization cues are influenced by head size and by the internal coupling of the ears. ITDs give reliable information regarding sound-source position for low frequencies, while ILDs are more suitable for frequencies higher than 1.5 kHz. Our results support the hypothesis that crocodilian head morphology is adapted to acquire reliable localization cues from sound sources when outside the water, but also when only a small part of their head is above the air–water interface.

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Liu, Xuejie, Hao Song, and Xiaoli Zhong. "A Hybrid Algorithm for Predicting Median-Plane Head-Related Transfer Functions from Anthropometric Measurements." Applied Sciences 9, no. 11 (June 5, 2019): 2323. http://dx.doi.org/10.3390/app9112323.

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Since head-related transfer functions (HRTFs) represent the interactions between sounds and physiological structures of listeners, anthropometric parameters represent a straightforward way to customize (or predict) individualized HRTFs. This paper proposes a hybrid algorithm for predicting median-plane individualized HRTFs using anthropometric parameters. The proposed hybrid algorithm consists of three parts: decomposition of HRTFs; selection of key anthropometric parameters; and establishing a prediction formula. Firstly, an independent component analysis (ICA) is applied to median-plane HRTFs from multiple subjects to obtain independent components and subject-dependent weight coefficients. Then, a factor analysis is used to select key anthropometric parameters relevant to HRTFs. Finally, a regression formula that connects ICA weight coefficients to key anthropometric parameters is established by a multiple linear regression. Further, the effectiveness of the proposed hybrid algorithm is verified by an objective evaluation via spectral distortion and a subjective localization experiment. The results show that, when compared with generic Knowles Electronics Manikin for Acoustic Research (KEMAR) HRTFs, the spectral characteristics of the predicted HRTFs are closer to those of the individualized HRTFs. Moreover, the predicted HRTFs can alleviate front–back and up–down confusion and improve the accuracy of localization for most subjects.

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Yu, Guang-Zheng, Bo-Sun Xie, and Dan Rao. "Directivity of Spherical Polyhedron Sound Source Used in Near-Field HRTF Measurements." Chinese Physics Letters 27, no. 12 (December 2010): 124302. http://dx.doi.org/10.1088/0256-307x/27/12/124302.

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Ito, T., K. Omura, and H. Ito. "BABHY – A New Strategy of Hydrofracturing for Deep Stress Measurements." Scientific Drilling SpecialIssue (November 1, 2007): 113–16. http://dx.doi.org/10.5194/sd-specialissue-113-2007.

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Park, Jeong-Hui, Myong-Won Seo, Hyun Chul Jung, Jong-Kook Song, and Jung-Min Lee. "Association between Health-Related Physical Fitness and Respiratory Diseases in Adolescents: An Age- and Gender-Matched Study." International Journal of Environmental Research and Public Health 18, no. 12 (June 21, 2021): 6655. http://dx.doi.org/10.3390/ijerph18126655.

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The current study examined the differences in health-related physical fitness (HRPF), physical activity (PA), and sedentary behavior (SB) between adolescents with and without ongoing respiratory diseases (RD). This study’s participants were from 12 to 15 years old (7th–10th grade) in South Korea. Adolescents with RD were selected through RD-related questions (i.e., asthma, rhinitis, sinusitis, and bronchitis) (n = 139); in contrast, adolescents without RD, randomly selected from the general group, responded to any health problem-related questions as “No” (n = 139). HRPF was measured based on the FITNESSGRAM and EURO FIT test batteries and the measurements of HRPF included cardiovascular endurance, muscular strength, muscular endurance, flexibility, and body composition. All statistical analyses were conducted by SPSS 25.0, and the independent t-test was used to compare the HRPF and PA between the two groups. Moreover, the measured HRPF was compared with a series of analyses of three-way ANOVAs (age × gender × group). Adolescents with RD had a positive association with less participation in PA (p < 0.05; RD: 3081.81 ± 4793.37; general: 2073.64 ± 3123.47) and with more time spent on SB (above 12 h per week: RD group (38.85%) and general group (33.09%)). Furthermore, adolescents in the RD group showed significant effects on all components of HRPF (p < 0.05). Our study confirmed that HRPF is an essential predictor of adolescents’ health outcomes, especially for those with RD. We suggest that increased HRPF can be an effective treatment for respiratory diseases in adolescents, and health practitioners should pay more attention to helping adolescents with RD to gain or maintain high HRPF.

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Kano, Y., J. Mori, R. Fujio, T. Yanagidani, S. Nakao, H. Ito, O. Matsubayashi, and K. F. Ma. "Precise Temperature Measurements and Earthquake Heat Associated with the 1999 Chi-Chi, Taiwan Earthquake." Scientific Drilling SpecialIssue (November 1, 2007): 94–96. http://dx.doi.org/10.5194/sd-specialissue-94-2007.

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Mayo, Paul G., Andrew D. Brown, and Matthew J. Goupell. "A creeping-wave elliptic-head model that explains non-monotonic envelope interaural time differences." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A163. http://dx.doi.org/10.1121/10.0010983.

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Interaural time and level differences (ITDs and ILDs) created by interactions of impinging sound with the head facilitate horizontal-plane sound localization. ILDs are known to be non-monotonic functions of azimuth, resulting in predictable mislocalization of tonal sources at some frequencies, while ITDs are typically construed as monotonic functions of azimuth. However, recent measurements using a binaural mannequin revealed envelope ITDs (ENV-ITDs) that were non-monotonic functions of azimuth, with the extent of nonmonotonicity dependent on carrier frequency. This study proposes that delayed sound traveling around the back of the head causes this phenomenon. ENV-ITDs created by a time-dependent model of incident sound waves propagating around the front and back of an elliptical head were compared to ENV-ITDs computed using publicly available HRTF libraries for a broadband speech excitation signal. Results from the model align with data from the HRTF libraries, with nonmonotonicities in the ENV-ITD-azimuth functions occurring at nearly identical azimuths and frequencies. These data suggest the veracity of this phenomenon and may have implications for spatial hearing abilities. They also suggest that time-independent models of ITDs that only consider frequency and incident angle, such as spherical head or circular arc length models, could be updated to include such time dependence.

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MACFARLANE, P. W. "Measurement of QT dispersion." Heart 80, no. 5 (November 1, 1998): 421–23. http://dx.doi.org/10.1136/hrt.80.5.421.

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Chen, Hui-Ling, Po-Fu Lee, Yun-Chi Chang, Fu-Shu Hsu, Ching-Yu Tseng, Xin-Yu Hsieh, and Chien-Chang Ho. "The Association between Physical Fitness Performance and Subjective Happiness among Taiwanese Adults." International Journal of Environmental Research and Public Health 17, no. 11 (May 26, 2020): 3774. http://dx.doi.org/10.3390/ijerph17113774.

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The purpose of the present study was to determine the association between health-related physical fitness (HRPF) performance and perceived happiness status among adults in Taiwan. A cross-sectional study was conducted, and data derived from the National Physical Fitness Survey in Taiwan 2014–2015 were reviewed. The participants included 27,930 men and 30,885 women, aged 23 to 64 years. Each participant completed a standardized, structured questionnaire and underwent anthropometric variable and HRPF measurements. The happiness outcome of an individual was obtained using the questionnaire, and the results were stratified into happy (very happy, quite happy, and fair) and unhappy (unhappy and not at all happy) groups for perceived happiness status. HRPF measurements were evaluated using cardiorespiratory endurance (3 min step test), muscle strength and endurance (1 min sit-up test), flexibility (sit-and-reach test), and body composition (body mass index (BMI) and waist-to-hip ratio). To determine the existence of a dose–response relationship between HRPF component levels and happiness status, four quartiles of HRPF components were analyzed using multiple logistic regression models. Multiple logistic regression results indicated that with the worst performance level of HRPF components as a baseline, significant associations were observed for the sit-and-reach test (third level: OR = 1.24, 95% CI: 1.02–1.49) and BMI (second level: OR = 0.78, 95% CI: 0.64–0.95) among men. For women, significant associations were observed for the 1 min sit-up test (second level: OR = 1.28, 95% CI: 1.03–1.60; third level: OR = 1.32, 95% CI: 1.04–1.67; fourth (the best) level: OR = 1.48, 95% CI: 1.12–1.95) and BMI (third level: OR = 0.73, 95% CI: 0.58–0.92). The current study suggested that higher values in flexibility and body composition, happiness-related factors, potentially improve the occurrence of happiness among men. Moreover, this positive effect of higher values of muscle strength, endurance, and BMI was observed for the occurrence of happiness in women. However, the relevant mechanism underlying this phenomenon must be further explored.

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Lopez-Hilfiker, F. D., C. Mohr, M. Ehn, F. Rubach, E. Kleist, J. Wildt, Th F. Mentel, et al. "A novel method for online analysis of gas and particle composition: description and evaluation of a Filter Inlet for Gases and AEROsols (FIGAERO)." Atmospheric Measurement Techniques 7, no. 4 (April 15, 2014): 983–1001. http://dx.doi.org/10.5194/amt-7-983-2014.

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Abstract. We describe a novel inlet that allows measurement of both gas and particle molecular composition when coupled to mass spectrometric, chromatographic, or optical sensors: the Filter Inlet for Gases and AEROsols (FIGAERO). The design goals for the FIGAERO are to allow unperturbed observation of ambient air while simultaneously analyzing gases and collecting particulate matter on a Teflon® (hereafter Teflon) filter via an entirely separate sampling port. The filter is analyzed periodically by the same sensor on hourly or faster timescales using temperature-programmed thermal desorption. We assess the performance of the FIGAERO by coupling it to a high-resolution time-of-flight chemical-ionization mass spectrometer (HRToF-CIMS) in laboratory chamber studies of α-pinene oxidation and field measurements at a boreal forest location. Low instrument backgrounds give detection limits of ppt or lower for compounds in the gas-phase and in the picogram m−3 range for particle phase compounds. The FIGAERO-HRToF-CIMS provides molecular information about both gases and particle composition on the 1 Hz and hourly timescales, respectively for hundreds of compounds. The FIGAERO thermal desorptions are highly reproducible (better than 10%), allowing a calibrated assessment of the effective volatility of desorbing compounds and the role of thermal decomposition during the desorption process. We show that the often multi-modal desorption thermograms arising from secondary organic aerosol (SOA) provide additional insights into molecular composition and/or particle morphology, and exhibit changes with changes in SOA formation or aging pathways.

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Lopez-Hilfiker, F. D., C. Mohr, M. Ehn, F. Rubach, E. Kleist, J. Wildt, T. F. Mentel, et al. "A novel method for on-line analysis of gas and particle composition: description and evaluation of a Filter Inlet for Gases and AEROsols (FIGAERO)." Atmospheric Measurement Techniques Discussions 6, no. 5 (October 30, 2013): 9347–95. http://dx.doi.org/10.5194/amtd-6-9347-2013.

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Abstract. We describe a novel inlet that allows measurement of both gas and particle molecular composition when coupled to mass spectrometric, chromatographic, or optical sensors: the Filter Inlet for Gas and AEROsol (FIGAERO). The design goals for the FIGAERO are to allow unperturbed observation of ambient air while simultaneously analyzing gases and collecting particulate matter on a Teflon filter via an entirely separate sampling port. The filter is analyzed periodically by the same sensor on hourly or faster timescales using temperature-programmed thermal desorption. We assess the performance of the FIGAERO by coupling it to a high-resolution time-of-flight chemical-ionization mass spectrometer (HRToF-CIMS) in laboratory chamber studies of α-pinene oxidation and field measurements at a boreal forest location. Low instrument backgrounds give detection limits of ppt or lower for compounds in the gas-phase and in the pg m−3 range for particle phase compounds. The FIGAERO-HRToF-CIMS provides molecular information about both gases and particle composition on the 1 Hz and hourly timescales, respectively for hundreds of compounds. The FIGAERO thermal desorptions are highly reproducible (better than 10%), allowing a calibrated assessment of the effective volatility of desorbing compounds and the role of thermal decomposition during the desorption process. We show that the often multi-modal desorption thermograms arising from secondary organic aerosol (SOA) provide additional insights into molecular composition and/or particle morphology, and exhibit changes with changes in SOA formation or aging pathways.

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Begault, Durand R., and Elizabeth M. Wenzel. "Headphone Localization of Speech." Human Factors: The Journal of the Human Factors and Ergonomics Society 35, no. 2 (June 1993): 361–76. http://dx.doi.org/10.1177/001872089303500210.

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Three-dimensional acoustic display systems have recently been developed that synthesize virtual sound sources over headphones based on filtering by headrelated transfer functions (HRTFs), the direction-dependent spectral changes caused primarily by the pinnae. In this study 11 inexperienced subjects judged the apparent spatial location of headphone-presented speech stimuli filtered with nonindividualized HRTFs. About half of the subjects "pulled" their judgments toward either the median or the lateral-vertical planes, and estimates were almost always elevated. Individual differences were pronounced for the distance judgments; 15% to 46% of stimuli were heard inside the head, with the shortest estimates near the median plane. The results suggest that most listeners can obtain useful azimuth information from speech stimuli filtered by nonindividualized HRTFs. Measurements of localization error and reversal rates are comparable with a previous study that used broadband noise stimuli.

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He, Jianjun, Rishabh Ranjan, Woon-Seng Gan, Nitesh Kumar Chaudhary, Nguyen Duy Hai, and Rishabh Gupta. "Fast Continuous Measurement of HRTFs with Unconstrained Head Movements for 3D Audio." Journal of the Audio Engineering Society 66, no. 11 (November 16, 2018): 884–900. http://dx.doi.org/10.17743/jaes.2018.0050.

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Shukla, Shruti. "A Bradford multiplexing method for protein estimation in fermented foods: Soy sauces." Bangladesh Journal of Pharmacology 11, no. 1 (December 16, 2015): 24. http://dx.doi.org/10.3329/bjp.v11i1.25796.

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Proteins for foods, in addition to providing nutrition, should also possess specific functional properties that facilitate processing and serve as the basis of product performance. Soy protein is a major component of the diet of food and is increasingly important in the human diet. Hence, here in the present article, we are focusing a rapid and easy method for quantitative determination of total protein content with multiplex samples in any food products such as soy sauce or other traditional fermented foods. We described a bioassay procedure (Bradford method) for the evaluation of total protein content in foods. This method involves measurement of the protein efficiency ratio under standardized conditions. The experiment will provide researchers a scientific way to determine pretentious quality of variety of foods and/or health supplements. VIDEO CLIPS<a href="https://www.youtube.com/v/xVzg0rq4VxE">Requirement and sample preparation method:</a> 3 min 26 sec<a href="https://www.youtube.com/v/6plwYgGGFuE">Assay procedure:</a> 6 min 4 sec<a href="https://www.youtube.com/v/bV2tGWLh4ug">Measurement of absorbance using an ELISA microtiter plate reader:</a>5 min 1 sec

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Sofieva, Viktoria F., Francis Dalaudier, Alain Hauchecorne, and Valery Kan. "High-resolution temperature profiles retrieved from bichromatic stellar scintillation measurements by GOMOS/Envisat." Atmospheric Measurement Techniques 12, no. 1 (January 28, 2019): 585–98. http://dx.doi.org/10.5194/amt-12-585-2019.

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Abstract. In this paper, we describe the inversion algorithm for retrievals of high vertical resolution temperature profiles (HRTPs) using bichromatic stellar scintillation measurements in the occultation geometry. This retrieval algorithm has been improved with respect to nominal ESA processing and applied to the measurements by Global Ozone Monitoring by Occultation of Stars (GOMOS) operated on board Envisat in 2002–2012. The retrieval method exploits the chromatic refraction in the Earth's atmosphere. The bichromatic scintillations allow the determination of the refractive angle, which is proportional to the time delay between the photometer signals. The paper discusses the basic principle and detailed inversion algorithm for reconstruction of high-resolution density, pressure and temperature profiles in the stratosphere from scintillation measurements. The HRTPs are retrieved with a very good vertical resolution of ∼200 m and high precision (random uncertainty) of ∼1–3 K for altitudes of 15–32 km and with a global coverage. The best accuracy is achieved for in-orbital-plane occultations, and the precision weakly depends on star brightness. The whole GOMOS dataset has been processed with the improved HRTP inversion algorithm using the FMI's scientific processor; and the dataset (HRTP FSP v1) is in open access. The validation of small-scale fluctuations in the retrieved HRTPs is performed via comparison of vertical wavenumber spectra of temperature fluctuations in HRTPs and in collocated radiosonde data. We found that the spectral features of temperature fluctuations are very similar in HRTPs and collocated radiosonde temperature profiles. HRTPs can be assimilated into atmospheric models, used in studies of stratospheric clouds and used for the analysis of internal gravity waves' activity. As an example of geophysical applications, gravity wave potential energy has been estimated using the HRTP dataset. The obtained spatiotemporal distributions of gravity wave energy are in good agreement with the previous analyses using other measurements.

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Lindström, L., U. M. Wilkenshoff, H. Larsson, and B. Wranne. "Echocardiographic assessment of arrhythmogenic right ventricular cardiomyopathy." Heart 86, no. 1 (July 1, 2001): 31–38. http://dx.doi.org/10.1136/hrt.86.1.31.

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OBJECTIVETo evaluate new echocardiographic modes in the diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC).DESIGNProspective observational study.SETTINGUniversity Hospital.SUBJECTS15 patients with ARVC and a control group of 25 healthy subjects.METHODSTransthoracic echocardiography included cross sectional measurements of the right ventricular outflow tract, right ventricular inflow tract, and right ventricular body. Wall motion was analysed subjectively. M mode and pulsed tissue Doppler techniques were used for quantitative measurement of tricuspid annular motion at the lateral, septal, posterior, and anterior positions. Doppler assessment of tricuspid flow and systemic venous flow was also performed.RESULTSAssessed by M mode, the total amplitude of the tricuspid annular motion was significantly decreased in the lateral, septal, and posterior positions in the patients compared with the controls. The tissue Doppler velocity pattern showed decreased early diastolic peak annular (EA) velocity and an accompanying decrease in early (EA) to late diastolic (AA) velocity ratio in all positions; the systolic annular velocity was significantly decreased only in the lateral position. Four patients had normal right ventricular dimensions and three were judged to have normal right ventricular wall motion. The patient group had also a significantly decreased tricuspid flow E:A ratio.CONCLUSIONSTricuspid annular measurements are valuable, easy to obtain, and allow quantitative assessment of right ventricular function. ARVC patients showed an abnormal velocity pattern that may be an early but non-specific sign of the disease. Normal right ventricular dimensions do not exclude ARVC, and subjective detection of early changes in wall motion may be difficult.

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Häcker, Anna-Luisa, Barbara Reiner, Renate Oberhoffer, Alfred Hager, Peter Ewert, and Jan Müller. "Functional outcomes in children with anatomically repaired transposition of the great arteries with regard to congenital ventricular septal defect and coronary pattern." Archives of Disease in Childhood 104, no. 9 (May 11, 2019): 851–56. http://dx.doi.org/10.1136/archdischild-2018-316444.

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ObjectiveDespite decreasing mortality, functional impairments in children with transposition of the great arteries (TGA) are still a concern. This study analyses health-related physical fitness (HRPF), arterial stiffness and health-related quality of life (HRQoL) in children with anatomically repaired TGA regarding congenital ventricular septal defect (VSD) and coronary patterns.Patients and methods68 children with anatomically repaired TGA with or without VSD (12.9±3.7 years, 19.1% female) were investigated between August 2014 and October 2017. HRPF was assessed by five tests of the FITNESSGRAM, arterial stiffness was measured by oscillometric measurement using Mobil-O-Graph and HRQoL was analysed with a self-report questionnaire (KINDL-R). All test results were compared with a healthy reference cohort (n=2116, 49.1% female) adjusted for sex and age.ResultsChildren with anatomically repaired TGA had significantly worse HRPF (z-score: −0.58±0.81, p<0.001), increased pulse wave velocity (TGA: 4.9±0.3 m/s vs healthy: 4.8±0.3 m/s, p=0.028) and central systolic blood pressure (TGA: 105.9±5.8 mm Hg vs healthy: 103.3±5.7 mm Hg, p=0.001). No difference was found for HRQoL between the two groups (total HRQoL score: TGA: 76.5±10.2 vs healthy: 75.2±10.1, p=0.315). Neither the coronary pattern nor a congenital VSD resulted in significant differences in all functional outcomes.ConclusionChildren with anatomically repaired TGA exhibit impaired HRPF and increased arterial stiffness whereas their HRQoL is normal. The underlying coronary pattern seems to have no influence on the functional outcome, nor does an accompanied congenital VSD.

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Zhang, Y., H. Ihlen, E. Myhre, K. Levorstad, and S. Nitter-Hauge. "Measurement of mitral regurgitation by Doppler echocardiography." Heart 54, no. 4 (October 1, 1985): 384–91. http://dx.doi.org/10.1136/hrt.54.4.384.

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Zhang, Y., S. Nitter-Hauge, H. Ihlen, K. Rootwelt, and E. Myhre. "Measurement of aortic regurgitation by Doppler echocardiography." Heart 55, no. 1 (January 1, 1986): 32–38. http://dx.doi.org/10.1136/hrt.55.1.32.

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Murray, A., N. B. McLaughlin, J. P. Bourke, J. C. Doig, S. S. Furniss, and R. W. Campbell. "Errors in manual measurement of QT intervals." Heart 71, no. 4 (April 1, 1994): 386–90. http://dx.doi.org/10.1136/hrt.71.4.386.

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Pijls, N. H. J., and B. De Bruyne. "Coronary pressure measurement and fractional flow reserve." Heart 80, no. 6 (December 1, 1998): 539–42. http://dx.doi.org/10.1136/hrt.80.6.539.

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Foale, R., P. Nihoyannopoulos, W. McKenna, A. Kleinebenne, A. Nadazdin, E. Rowland, G. Smith, and A. Klienebenne. "Echocardiographic measurement of the normal adult right ventricle." Heart 56, no. 1 (July 1, 1986): 33–44. http://dx.doi.org/10.1136/hrt.56.1.33.

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TREASURE, T. "The measurement of health related quality of life." Heart 81, no. 4 (April 1, 1999): 331–32. http://dx.doi.org/10.1136/hrt.81.4.331.

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Richter, Jan-Gerrit, and Janina Fels. "Evaluation of Localization Accuracy of Static Sources Using HRTFs from a Fast Measurement System." Acta Acustica united with Acustica 102, no. 4 (July 1, 2016): 763–71. http://dx.doi.org/10.3813/aaa.918992.

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POULLIS, M. "Coronary pressure measurements: catheter induced errors." Heart 82, no. 5 (November 1, 1999): 644–45. http://dx.doi.org/10.1136/hrt.82.5.644a.

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Journal articles on the topic 'HRTF measurement'

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