# A Review on Head-Related Transfer Function Generation for Spatial Audio
## 7 Technological Integration and Evaluation
### Consumer Technology Integration  
The work by [PERSON] [215] discusses the increasing integration of consumer technology, such as smartphones and VR headsets, into the process of capturing and utilising personalised HRTFs. They present a novel approach that integrates consumer technology, such as the iPhone's FaceID feature, to capture 3D meshes of a user's head. This method demonstrates the feasibility of using consumer-grade devices to generate personalised HRTFs. The study details the process of extracting head-related features from these 3D scans and discusses the accuracy and practicality of such an approach compared to traditional methods with specialised equipment. The ability to capture and fine-tune HRTFs using readily available consumer devices has democratised access to high-quality spatial audio experiences. Figure 10: Interpolation of gain \(g\) and phase delay \(\tau\) for the left ear at 1500 Hz. The first row represents the sparse lab data, while the second shows the result of the interpolation [66]. In the realm of commercial products, Apple's AirPods Pro and AirPods Max have been pivotal in integrating personalised HRTFs. Their dynamic head-tracking feature adjusts spatial audio in real-time, providing a highly immersive experience for music, movies, and VR content. The system uses machine learning to analyze users' unique auditory profiles, thereby delivering a personalised listening experience. Dolby's Dolby Atmos also integrates HRTF-based spatial audio technologies to create life-like 3D sound environments across media platforms, setting the standard for immersive audio in both consumer and professional markets. The EarFish project, developed by the Active Perception Lab at the University of Antwerp, offers an accessible and affordable HRTF measurement kit that simplifies the personalisation process of spatial audio experiences. By utilising minimal and cost-effective equipment, such as compact microphones and user-friendly software, the EarFish system enables individuals to capture their personal HRTF measurements without the need for expensive hardware or extensive technical expertise. This democratisation of HRTF measurement empowers non-experts to benefit from accurate sound localisation and enhanced immersion in applications like virtual reality, gaming, and immersive media. Additionally, EarFish plays a crucial role in research settings by providing an affordable tool for collecting HRTF data from a larger and more diverse pool of participants, thereby facilitating studies on spatial hearing and audio perception. By reducing the cost and complexity associated with HRTF personalisation, the EarFish project contributes significantly to advancing spatial audio technologies and promoting the wider adoption of individualised audio experiences in both research and consumer applications. The work by [PERSON] et al. [216] introduces a practical solution for individualised HRTFs in VR environments, specifically for playing 360-degree video content with Ambisonics spatial audio on head-mounted displays (HMDs). Compatible with both desktop and portable platforms, their system integrates personalised HRTFs through a straightforward, open-source approach. This flexibility enhances spatial audio immersion in HMDs without extensive equipment, demonstrating the potential of individualised HRTFs in consumer VR applications and making advanced spatial audio more accessible in virtual environments. [PERSON] et al. [217] compared six tools for implementing spatial audio experiences in Extended Reality (XR) applications, emphasising the compatibility of these tools with HRTFs and the WebXR Device API. They highlight the challenges of integrating spatial audio into immersive experiences and the lack of standardised frameworks for delivering consistent audio performance. This study is critical for understanding how consumer-facing XR applications can benefit from HRTF personalisation and integration.