Directional Equalization of Sparse Head-Related Transfer Function Sets for Spatial Upsampling

Pörschmann, Christoph; Arend, Johannes M.; Brinkmann, Fabian

doi:10.1109/taslp.2019.2908057

Cited by 22 publications

(29 citation statements)

References 34 publications

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“…Recently, several pre-processing methods have been developed with the aim of reducing the effective SH order of the HRTF: for example, by time-alignment [27,30], using directional equalization [47], using minimum-phase representation [28], or by ear-alignment [29,48]. All these methods are based on manipulating the linear-phase component of the HRTF, which was shown to be the main contributor to the high-order nature of the HRTF [27].…”

Section: Basic Vs Ear-aligned Hrtf Representationsmentioning

confidence: 99%

Binaural Reproduction Based on Bilateral Ambisonics

Ben-Hur¹,

Alon²,

Berebi³

et al. 2022

Advances in Fundamental and Applied Research on Spatial Audio

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Binaural reproduction of high-quality spatial sound has gained considerable interest with the recent technology developments in virtual and augmented reality. The reproduction of binaural signals in the Spherical-Harmonics (SH) domain using Ambisonics is now a well-established methodology, with flexible binaural processing realized using SH representations of the sound-field and the Head-Related Transfer Function (HRTF). However, in most practical cases, the binaural reproduction is order-limited, which introduces truncation errors that have a detrimental effect on the perception of the reproduced signals, mainly due to the truncation of the HRTF. Recently, it has been shown that manipulating the HRTF phase component, by ear-alignment, significantly reduces its effective SH order while preserving its phase information, which may be beneficial for alleviating the above detrimental effect. Incorporating the ear-aligned HRTF into the binaural reproduction process has been suggested by using Bilateral Ambisonics, which is an Ambisonics representation of the sound-field formulated at the two ears. While this method imposes challenges on acquiring the sound-field, and specifically, on applying head-rotations, it leads to a significant reduction in errors caused by the limited-order reproduction, which yields a substantial improvement in the perceived binaural reproduction quality even with first order SH.

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Section: Basic Vs Ear-aligned Hrtf Representationsmentioning

confidence: 99%

Binaural Reproduction Based on Bilateral Ambisonics

Ben-Hur¹,

Alon²,

Berebi³

et al. 2022

Advances in Fundamental and Applied Research on Spatial Audio

View full text Add to dashboard Cite

show abstract

“…Several recent studies suggested methods to pre-process the HRTF in the context of SH interpolation of HRTFs. For example, by time-alignment [22], [24], using minimum-phase representation [37], using directional equalization [38], or by ear-alignment [31], [39]. All these methods are based on manipulating the linear-phase component of the HRTF, which makes a major contribution to the high-order nature of the HRTF [22].…”

Section: Proposed Bilateral Ambisonics Reproductionmentioning

confidence: 99%

Binaural Reproduction Based on Bilateral Ambisonics and Ear-Aligned HRTFs

Ben-Hur

Alon

Mehra

et al. 2021

IEEE/ACM Trans. Audio Speech Lang. Process.

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Reproduction of high quality spatial sound has gained considerable importance with the recent technology developments in the fields of virtual and augmented reality. Recently, the reproduction of binaural signals in the Spherical-Harmonics (SH) domain has been proposed. This is performed by using SH representations of the sound-field and the Head-Related Transfer Function (HRTF). These processes offer the flexibility to control the reproduced binaural signals, by manipulating the sound-field or the HRTFs using algorithms that operate directly in the SH domain. However, in most practical cases, the binaural reproduction is order-limited, which introduces truncation error that has a detrimental effect on the perception of the reproduced signals, mainly due to the truncation of the HRTF. A recent study showed that pre-processing of the HRTF by ear-alignment reduces its effective SH order, which may be beneficial for alleviating the above effect. In this paper, a method to incorporate the pre-processed ear-aligned HRTF into the binaural reproduction process is presented. The method uses Ambisonics representation of the sound-field formulated at the two ears, and is denoted here as Bilateral Ambisonics. The proposed method leads to a significant reduction in errors due to the limited-order reproduction, which yields a substantial improvement in perceived binaural reproduction quality even with SH as low as first order.

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“…Since HRTFs are typically measured or simulated offline, it is safe to assume that they can be provided with high spatial resolution. In fact, high-quality, densely sampled generic HRTFs are already publicly available [13] and there is a good amount of ongoing research on the production of individual HRTFs of similar quality (a review was provided by Guezenoc and Seguier [14]) and on the spatial upsampling of sparse HRTFs [15,16]. Therefore, in practice, it is common to encounter situations where a binaural rendering must be obtained by pairing a low-order Ambisonics signal to a spatially dense HRTF.…”

Section: Introduction 1binaural Rendering and Ambisonicsmentioning

confidence: 99%

Assessing HRTF preprocessing methods for Ambisonics rendering through perceptual models

2022

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Binaural rendering of Ambisonics signals is a common way to reproduce spatial audio content. Processing Ambisonics signals at low spatial orders is desirable in order to reduce complexity, although it may degrade the perceived quality, in part due to the mismatch that occurs when a low-order Ambisonics signal is paired with a spatially dense head-related transfer function (HRTF). In order to alleviate this issue, the HRTF may be preprocessed so its spatial order is reduced. Several preprocessing methods have been proposed, but they have not been thoroughly compared yet. In this study, nine HRTF preprocessing methods were used to render anechoic binaural signals from Ambisonics representations of orders 1 to 44, and these were compared through perceptual hearing models in terms of localisation performance, externalisation and speech reception. This assessment was supported by numerical analyses of HRTF interpolation errors, interaural differences, perceptually-relevant spectral differences, and loudness stability. Models predicted that the binaural renderings’ accuracy increased with spatial order, as expected. A notable effect of the preprocessing method was observed: whereas all methods performed similarly at the highest spatial orders, some were considerably better at lower orders. A newly proposed method, BiMagLS, displayed the best performance overall and is recommended for the rendering of bilateral Ambisonics signals. The results, which were in line with previous literature, indirectly validate the perceptual models’ ability to predict listeners’ responses in a consistent and explicable manner.

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Directional Equalization of Sparse Head-Related Transfer Function Sets for Spatial Upsampling

Cited by 22 publications

References 34 publications

Binaural Reproduction Based on Bilateral Ambisonics

Binaural Reproduction Based on Bilateral Ambisonics

Binaural Reproduction Based on Bilateral Ambisonics and Ear-Aligned HRTFs

Assessing HRTF preprocessing methods for Ambisonics rendering through perceptual models

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