Danlin Huang
Augmented Soma with Intelligence

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EchoVision


2024
by Botao Amber Hu, Jiabao Li, Danlin Huang, Jianan Johanna Liu, Xiaobo Aaron Hu, Yilan Tao




Key Words


Bat’s Echolocation  Augmented Reality  Handheld Mixed Reality Mask  Ecocentric design Eco-Phenomenology


Concept


EchoVision is an immersive art installation that allows participants to experience the world of bats using sound visualization and mixed reality technology. With a custom-designed, bat-shaped headset from the open-source HoloKit project, users can simulate echolocation, the natural navigation system bats use in the dark. They do this by using their voices and interpreting the returned echoes with the mixed-reality visualization.

The exhibit adjusts visual feedback based on the pitch and tone of the user's voice, offering a dynamic and interactive depiction of how bats perceive their environment. This installation combines scientific learning with empathetic engagement, encouraging an ecocentric design perspective and understanding between species. EchoVision educates and inspires a deeper appreciation for the unique ways non-human creatures interact with their ecosystems.




"What Is it Like to Be a Bat?"


In "What Is it Like to Be a Bat?" Thomas Nagel explores the unique, subjective experience of consciousness, using bats as a primary example due to their use of echolocation, a sensory perception vastly different from human experiences. He argues that understanding what it is like to be another creature is inherently limited by our inability to fully grasp their subjective experiences. This concept directly relates to EchoVision that allows participants to simulate the echolocation of bats using sound visualization and mixed reality technology. By adjusting visual feedback based on the user's voice, EchoVision bridges the gap between human and bat perception, offering a deeper, empathetic understanding of non-human sensory worlds and emphasizing the profound differences in how various species interact with their environments.

Photo credit: Merlin Tuttle's Bat Conservation (https://www.merlintuttle.org/)


Misconception of Bats


People often harbor misconceptions about bats, viewing them as dangerous, dirty, or associated with negative superstitions. Common myths include the belief that bats are blind, that they commonly get tangled in human hair, or that they are primarily carriers of diseases (especially during the COVID-19 pandemic). These misconceptions contribute to a general fear and misunderstanding of bats, overshadowing their ecological importance and unique biological features.

Bats are ecologically vital, providing essential benefits such as pest control by consuming large quantities of insects, pollination of numerous plants, and seed dispersal that aids in forest regeneration. Their guano enriches soil fertility, contributing to nutrient cycling. These roles help maintain ecosystem balance and biodiversity.

EchoVision aims to challenge and transform these misconceptions by providing participants with an immersive, empathetic experience of the world through a bat's perspective. By simulating echolocation using sound visualization and mixed reality technology, EchoVision allows users to understand how bats navigate and perceive their environment with remarkable precision. This interactive experience highlights the sophistication and elegance of bat echolocation, fostering a greater appreciation for their role in ecosystems, such as pest control and pollination.

Through EchoVision, participants can see bats not as menacing creatures but as fascinating and integral parts of the natural world. The installation encourages scientific learning and empathetic engagement, promoting an ecocentric design perspective that values the diverse ways non-human creatures interact with their surroundings. By offering a new perspective, EchoVision helps dispel myths, reduces unfounded fears, and inspires a deeper connection to and respect for bats and their vital ecological contributions.


Echolocation


Bat echolocation is a sophisticated biological process that allows bats to navigate and hunt in the dark by emitting high-frequency sound waves and listening to the echoes that bounce back from objects in their environment. When a bat emits a sound, it travels through the air and reflects off surfaces, returning to the bat as an echo. By analyzing the time delay and changes in the frequency of the returning echoes, bats can determine the distance, size, shape, and texture of objects, as well as the speed and direction of moving prey.

In "An Immense World," Ed Yong describes how bats' echolocation abilities are finely tuned and highly specialized. He explains that bats can emit sounds at frequencies higher than the human ear can detect, often using calls that range from 20 to 200 kHz. The bat's brain processes these echoes with remarkable speed and accuracy, allowing it to create a detailed auditory map of its surroundings. This process is so efficient that bats can detect tiny insects in complete darkness and avoid obstacles with precision. Yong also highlights the diversity among bat species in their echolocation strategies, noting that different bats have evolved various adaptations to suit their ecological niches. Some bats have highly directional calls for pinpointing prey, while others use more omnidirectional calls to navigate cluttered environments like dense forests. These adaptations demonstrate the incredible versatility and effectiveness of echolocation as a sensory tool for survival.

In addition to bats, several other animals use echolocation to navigate and hunt, including dolphins, porpoises, whales (such as sperm and beluga whales), certain species of shrews, and swiftlets. One notable human who uses echolocation is Daniel Kish. Blind since infancy, Kish developed the ability to navigate his surroundings by making clicking sounds with his tongue and interpreting the echoes that bounce back from objects around him. This technique, known as human echolocation, allows him to "see" the world through sound, enabling him to walk, ride a bike, and engage in various activities independently. Kish has also founded the organization World Access for the Blind to teach echolocation to other visually impaired individuals.



Mask Design


2min Rapid Draft


The bat-shaped mask encases the HoloKit, an smartphone-basedopen-source optical see-through stereoscopic mixed reality headset[Hu et al. 2024]. It attaches to the HoloKit’s headpad via Velcro,with the original headband removed. The iPhone is mounted inthe HoloKit, and the mask design carefully avoids obstructing theiPhone’s camera and LiDAR sensor. This enables 3D environmentsensing while keeping the headset’s optical see-through area unob-structed for audience viewing.

Our mask design draws inspiration from four distinct bat species,including two native to Austin—the Pallid bat and the Brazilian free-tailed bat (Figure 3). We employed a low-poly aesthetic to simplifythe bats’ intricate forms while accentuating their key features. Thecolor palettes were meticulously chosen to reflect the natural furcolors of these bat species. Each mask was crafted using Rhinofor 3D modeling, followed by resin 3D printing and detailed hand-painting.The mask uniquely features claw-like handheld handles designedto mimic bat legs. This design allows it to hang upside down frompoles, ropes, or branches, replicating the natural resting postureof bats. 

The handles provide an ergonomic way for users to holdthe entire mask, preventing discomfort from headset weight andenabling easy passing to the next user. These detachable handles notonly facilitate easy storage and replacement but also offer intuitiveaffordances for audience interaction and manipulation.




Design drawings of bat-shaped masks. Mask designs inspired by four batspecies, two native to Austin. 
Image courtesy: Merlin Tuttle’s Bat Conservation.






Production process



XR Effect Display

LiDAR sensors and bat echolocation share fundamental similaritiesin detecting and mapping surroundings through signal reflection. LiDAR produces high-resolution 3D models, while bats formmental maps for navigation and hunting in darkness. Both methodsoffer high accuracy in object detection and positioning.EchoVision leverages this similarity, visualizing sound wavesto mimic bat echolocation. 


Mixed reality first-person views of EchoVision visualizations: (a) and (b) Echolocation effects in actual bat-inhabitedcaves; (c) Sound wave interactions within a crowd; (d) Sound propagation along a corridor with passersby.


It illustrates sound propaga-tion in a LiDAR-reconstructed environment, artistically simulatingecholocation and bridging human technology with natural pro-cesses. The visual effects are influenced by the voice volume ofthe user’s real-time voice input, the pitch of the voice, and the 3Dcontour of the surrounding environment:Sound Propagation and Brightness. Visualized sound waves prop-agate forward, with louder voices creating wider angles and brighterlines. This encourages users to experiment with volume levels.Pitch and Wave Thickness. Higher pitches are represented byfiner, farther-traveling lines, demonstrating how pitch amplifiessound reach. Users are motivated to try different pitch levels.Particle Effects. 

Particles burst upon wave collision with surfaces,providing visual cues of sound reflection in the environment.Human Body Recognition. Golden-colored waves and additionalparticles appear when sound waves interact with human bodies.This feature highlights human body forms and encourages users to vocalize towards nearby individuals, enhancing social interactivityand creating engaging social dynamics.



Download App


EchoVision on Apple Store for iOS
EchoVision on Apple Store for visionOS


Pop-up in-the-wild Exhibition

EchoVision premiered at the Congress Avenue Bridge in Austin,Texas—home to the world’s largest urban bat colony, comprisingapproximately 1.5 million Brazilian free-tailed bats. Our pop-upexhibition, which drew over 200 participants, unfolded beneaththis remarkable "bat bridge" in collaboration with renowned batconservationist Merlin Tuttle, celebrated for his pivotal role inpreserving Austin’s bridge-dwelling bat population.

The event progressed through three engaging phases:
• Participants gathered to hear Merlin Tuttle’s captivatingnarratives about bats and conservation efforts.
• Participants experienced EchoVision firsthand, allowing themto glimpse the world through a bat’s unique sensory per-spective. The handheld devices were passed from person toperson, creating a self-propagating experience.
• As dusk descended, participants witnessed the awe-inspiringspectacle of countless bats emerging from their daytime roostto hunt insects beneath the bridge.

This multifaceted event seamlessly merged ecologicaleducation, natural wonder, sensory experience, and cutting-edgetechnology. The social, interactive nature of the pop-up exhibitionoffered participants an immersive introduction to bats’ perceptualumwelt, bridging ecological knowledge with embodied experienceand fostering a collective eco-phenomenological understanding ofbat ecology.










Publications


Botao Amber Hu, Jiabao Li*, Danlin Huang, Jianan Johanna Liu, Xiaobo Aaron Hu, and Yilan Elan Tao. 2024. "Becoming Bat with EchoVision: Experiencing More-than-human Perception through Mixed Reality". In Proceeding of SIGGRAPH Asia 2024 (SA '24). Art Paper. [→]

Botao Amber Hu, Jiabao Li*, Danlin Huang, Jianan Johanna Liu, Xiaobo Aaron Hu, and Yilan Elan Tao. 2024. "EchoVision: Experiencing Bat Echolocation via Mixed Reality". In Proceeding of SIGGRAPH Asia 2024 (SA '24). Extended Reality. [→]

Jiabao Li, Matt McCorkle, and Botao Amber Hu. 2024. "Becoming Bat". In Proceedings of the Halfway to the Future Symposium 2024 (HTTF '24). Pictorial. [→]

Botao Amber Hu*, Jiabao Li*, Danlin Huang, Jianan Johanna Liu, Xiaobo Aaron Hu, and Yilan Elan Tao. 2024. "EchoVision". 2024 IEEE VIS Arts Program (VISAP). Art Exhibition. [To appear]

Botao Amber Hu*, Jiabao Li*, Danlin Huang, Jianan Johanna Liu, Xiaobo Aaron Hu, and Yilan Elan Tao. 2024. "EchoVision: A Handheld Mixed Reality Mask for Experiencing Bat Echolocation". In Adjunct Proceedings of the 2024 ACM International Joint Conference on Pervasive and Ubiquitous Computing & the 2024 ACM International Symposium on Wearable Computing (UbiComp/ISWC '24 Adjunct). Design Exhibition.[→]


Exhibitions


SIGGRAPH Asia. 2024. XR. "EchoVision". Tokyo, Japan

West Bund Art Festival. 2024. "EchoVision". Shanghai, China.

TANK Art Festival. 2024. "EchoVision". Shanghai, China.

International Symposium on Wearable Computers (Ubicomp-ISWC), Design Exhibition. 2024. "EchoVision". Melbourne, Australia.

Vancouver International Film Festival. 2024. "Nocturnal Fugue". Vancouver, Canada.

Ars Electronica. 2024. "Nocturnal Fugue - Becoming Bat with EchoVision". Linz, Austria. [→].

Sheffield DocFest. 2024. "Nocturnal Fugue". Sheffield, UK. [→].

Omotesando interactivité. 2024. "Nocturnal Fugue". Tokyo, Japan. [→]

Host: Fusebox Program, The Contemporary Austin. "Nocturnal Fugue". Austin, US. [→]