A Constrained Optimal Hear-Through Filter Design Approach for Earphones

Signal characteristics can be altered when sound from environment transmits through earphones to the ear canal. A hear-through filter is usually implemented in an earphone to create a more natural hearing experience. Hear-through filter is also important in augmented reality audio applications. In this paper, a constrained optimal hear-through filter design approach is proposed, where the hear-through filter is designed using a formulation similar to that for a constrained active noise control filter design. One advantage of such a filter design approach is that, compared with the commonly used direct plant response inversion method, the leakage sound around and through earphone will be attenuated in the proposed method, so that the comb-filtering effect is alleviated. Another advantage of the proposed method is that multiple practical constraints can be applied conveniently by formulating a constrained optimization problem and it can be solved efficiently. The proposed design approach can specify the desired delays of reproduced sound in each earphone channel, if a spatial sound impression is desired. The designed hear-through filter can be directly implemented in an active noise control system framework so that the requirement for additional electronic hardware and software components can be minimal for an active noise control earphone

Augmenting TV Viewing using Acoustically Transparent Auditory Headsets

This paper explores how acoustically transparent auditory headsets can improve TV viewing by intermixing headset and TV audio, facilitating personal, private auditory enhancements and augmentations of TV content whilst minimizing occlusion of the sounds of reality. We evaluate the impact of synchronously mirroring select audio channels from the 5.1 mix (dialogue, environmental sounds, and the full mix), and selectively augmenting TV viewing with additional speech (e.g. Audio Description, Directors Commentary, and Alternate Language). For TV content, auditory headsets enable better spatialization and more immersive, enjoyable viewing; the intermixing of TV and headset audio creates unique listening experiences; and private augmentations offer new ways to (re)watch content with others. Finally, we reflect on how these headsets might facilitate more immersive augmented TV viewing experiences within reach of consumers

Developing interactions in augmented materiality: an enhancement method based on RGB-D segmentation

Knowledge and understanding of how Augmented Reality develops the illusion of an alternative reality that needs to be critically considered with philosophical and technical points of view. Researchers have been investigating exploring different techniques to generate enhanced experiences for the users. In this article, the technological reality scenarios embodied within several Augmented Reality techniques are explored and a classification scheme is proposed in detail. Additionally, for the purposes of enhancing the cohesion of augmented visual content to the actuality, an Augmented Reality software based on a segmentation using RGB-D camera system that handles the occlusion problem will also be explained and an enhancement method will be discussed

Current Use and Future Perspectives of Spatial Audio Technologies in Electronic Travel Aids

Electronic travel aids (ETAs) have been in focus since technology allowed designing relatively small, light, and mobile devices for assisting the visually impaired. Since visually impaired persons rely on spatial audio cues as their primary sense of orientation, providing an accurate virtual auditory representation of the environment is essential. This paper gives an overview of the current state of spatial audio technologies that can be incorporated in ETAs, with a focus on user requirements. Most currently available ETAs either fail to address user requirements or underestimate the potential of spatial sound itself, which may explain, among other reasons, why no single ETA has gained a widespread acceptance in the blind community. We believe there is ample space for applying the technologies presented in this paper, with the aim of progressively bridging the gap between accessibility and accuracy of spatial audio in ETAs.This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement no. 643636.Peer Reviewe

Adaptiiviset läpikuuluvuuskuulokkeet

Hear-through equalization can be used to make a headset acoustically transparent, i.e.~to produce sound perception that is similar to perception without the headset. The headset must have microphones outside the earpieces to capture the ambient sounds, which is then reproduced with the headset transducers after the equalization. The reproduced signal is called the hear-through signal. Equalization is needed, since the headset affects the acoustics of the outer ear. \\ In addition to the external microphones, the headset used in this study has additional internal microphones. Together these microphones can be used to estimate the attenuation of the headset online and to detect poor fit. Since the poor fit causes leaks and decreased attenuation, the combined effect of the leaked sound and the hear-through signal changes, when compared to proper fit situation. Therefore, the isolation estimate is used to control the hear-through equalization in order to produce better acoustical transparency. Furthermore, the proposed adaptive hear-through algorithm includes manual controls for the equalizers and the volume of the hear-through signal. \\ The proposed algorithm is found to transform the used headset acoustically transparent. The equalization controls improve the performance of the headset, when the fit is poor or when the volume of the hear-through signal is adjusted, by reducing the comb-filtering effect due to the summation of the leaked sound and the hear-through signal inside the ear canal. The behavior of the proposed algorithm can be demonstrated with an implemented Matlab simulator.Läpikuuluvuusekvalisoinnilla voidaan saavuttaa akustinen läpinäkyvyys kuulokkeita käytettäessä, eli tuottaa samankaltainen ääniaistimus kuin mikä havaittaisiin ilman kuulokkeita. Käytetyissä kuulokkeissa tulee olla mikrofonit kuulokkeen ulkopinnalla, joiden avulla voidaan tallentaa ympäröiviä ääniä. Mikrofonisignaalit ekvalisoidaan, jolloin niistä tulee läpikuuluvuussignaalit, ja toistetaan kuulokkeista. Ekvalisointi on tarpeellista, sillä kuulokkeet muuttavat ulkokorvan akustiikka ja siten myös äänihavaintoa. \\ Tässä diplomityössä käytetyssä prototyyppikuulokeparissa on edellä mainittujen mikrofonien lisäksi myös toiset, korvakäytävän sisälle asettuvat mikrofonit. Yhdessä näiden kahden mikrofonin avulla voidaan määrittää reaaliaikainen estimaatti kuulokkeen vaimennukselle ja tunnistaa huono istuvuus. Koska huonosti asetettu kuuloke vuotaa enemmän ääntä korvakäytävän sisään kuin kunnolla asetettu, kuulokkeen äänen ja vuotavan äänen yhteisvaikutus muuttuu. Tästä syystä vaimennusestimaattia käytetään läpikuuluvuusekvalisoinnin säätöön, jotta akustinen läpinäkyvyys ei kärsisi. Lisäksi esitellyssä algoritmissa on manuaaliset säädöt ekvalisaattoreille ja läpikuuluvuussignaalin voimakkuudelle.\\ Esitetyn algoritmin havaitaan tuottavan akustinen läpinäkyvyys, kun sitä käytetään prototyyppikuulokkeiden kanssa. Ekvalisointisäädöt parantavat kuulokkeiden toimintaa istuvuuden ollessa huono tai säädettäessä läpikuuluvuussignaalin voimakkuutta, koska ne vähentävät kampasuodatusefektiä, joka voi aiheutua vuotavan äänen ja läpikuuluvuussignaalin summautuessa. Esitellyn algoritmin toimintaa voidaan havainnollistaa toteutetulla Matlab-simulaattorilla

Methods and applications of mobile audio augmented reality

In augmented reality, virtual objects are presented as if they were a part of the real world. In mobile audio augmented reality, sounds presented with headphones are perceived as if they originated from the surrounding environment. This thesis investigates potential applications of mobile audio augmented reality and different methods that are needed in these applications. The two main topics studied are distance presentation and spatial audio guidance. Reverberation is known to be an important factor affecting the perceived distance of sound sources. Here, a practical method for modifying the perceived distance of virtual sound sources is investigated, where the temporal envelopes of binaural room impulse responses (BRIRs) are modified. In a listening test, speech sources were presented using these modified BRIRs. The results show that the perceived distance is controlled most effectively by modifying an early-to-late energy ratio with the first 50–100 ms of the BRIR included in the early energy. Presenting large distances in an audio augmented reality environment is difficult, since people underestimate the distances of distant sound sources and very distant sound sources cannot even be heard. In a user study, the presentation of points of interest (POIs) outdoors using auditory distance cues was compared with a voice saying the distance in meters. The results suggest that distances should be given in meters if fairly accurate distance estimates are needed without prior training. With training, however, the user study participants were able to estimate the distances of the POIs fairly accurately based on the provided auditory distance cues, performing the task faster than when the distances were presented in meters. In addition to the presentation of POIs, another type of spatial audio guidance is investigated: using spatialized music to guide pedestrians and cyclists to their destination. Two forms of guidance, route and beacon guidance, were tested in different environments. The user studies showed that music guidance is a pleasant and effective aid for navigation. Both route and beacon guidance were effective methods, but suitable for different environments and circumstances. This thesis also investigates a mobile teleconferencing scenario, where participants can move freely from one location to another. With hear-through headphones, co-located participants can hear each other naturally. To avoid transmitting the speech of the participants to other participants in the same room – as this would be perceived as an echo – acoustic co-location detection is applied. In a user study, utilization of acoustic co-location detection was shown to improve the clarity of communication. Together, the studies presented in this thesis provide methods and guidelines for the development of mobile audio augmented reality applications

Creación de experiencias de realidad aumentada realistas por usuarios finales

Programa de Doctorado en Ciencia y Tecnología Informática por la Universidad Carlos III de MadridPresidente: Juan Manuel Dodero Beardo.- Secretario: Andrea Bellucci.- Vocal: Camino Fernández Llama