Building Online Communities: Pupil Labs and the Future of Open Source Eye Tracking

In the realm of eye tracking technology, one open source project stands out: Pupil Labs. Founded in 2013 by Will Patera and Moritz Kassner, Pupil Labs has pioneered accessible, open source tools for mobile eye tracking research and applications. Their journey from a master‘s thesis to a thriving online community offers valuable lessons for any developer interested in the potential of open source software and hardware.

The Origins of Pupil Labs

Pupil Labs began as Patera and Kassner‘s master‘s thesis at MIT. Seeking to study how people visually navigate architectural spaces, they quickly encountered a problem. As Kassner explains:

"Current eye tracking gear was far too expensive and closed off to be practical for our research. A single eye tracker could cost over $40,000, and you were completely dependent on the vendor‘s software. We knew there had to be a better way."

Drawing on their backgrounds in interaction design and computer science, they set out to build an open source, mobile eye tracking system from the ground up. The core components included:

• 3D printed eye tracking glasses with integrated cameras and sensors
• Open source software for capturing and visualizing eye tracking data
• Detailed documentation enabling others to build and modify the system

After graduating, Patera and Kassner released their eye tracking software, aptly named Pupil Capture, along with build guides for the hardware. The response was immediate. Researchers around the world began constructing their own Pupil eye trackers and contributing back to the codebase.

The Rise of the Pupil Community

As Pupil adoption grew, a vibrant online community coalesced around the open source platform. Researchers collaborated on everything from troubleshooting hardware builds to brainstorming new eye tracking visualizations and analysis techniques.

Key to the community‘s growth was Pupil Labs‘ commitment to open source principles and active nurturing of the ecosystem. As Patera describes:

"From the beginning, we knew we wanted Pupil to be more than just our project. By open sourcing the code and designs, we aimed to empower a community to take eye tracking in innovative new directions. Whenever someone posted an issue or question, we tried to respond promptly and supportively. Over time, something wonderful happened – the community began answering each other‘s questions and contributing substantial improvements to the platform."

Pupil Labs formalized their community channels, setting up:

• Open source repositories on GitHub
• Detailed documentation and build guides
• An active Gitter chat channel
• Public community forum

These channels evolved into the nerve center of the Pupil community. On Gitter, new eye tracking researchers could get help setting up their first DIY Pupil rigs while veteran users compared techniques and brainstormed collaborations. The discussion forum became a hub for showcasing novel Pupil use cases, from eye-tracking-guided robot assistants to gaze-based video games.

As the community grew, so did its impact. Here are a few key statistics:

• 10,000+ active Pupil Capture users
• 500+ contributors to the open source codebase
• 150+ academic papers published using Pupil eye trackers
• 20ms latency from eye movement to visualization output

The Interdisciplinary Impact of Eye Tracking

One of the most exciting aspects of the Pupil community is the sheer diversity of applications. The following chart breaks down Pupil usage across different research domains:

Domain	% of Pupil Community
Psychology & Neuroscience	35%
Human-Computer Interaction & UX	30%
Virtual & Augmented Reality	15%
Education & Learning Sciences	10%
Assistive Technology & Accessibility	5%
Other (Art, Gaming, Robotics, etc)	5%

This interdisciplinary mixes creates a uniquely vibrant knowledge ecosystem. On any given day, the Pupil forums might feature:

• A cognitive scientist sharing data on how students allocate visual attention during online lectures
• A VR developer demonstrating a novel gaze-based interaction mechanic
• UX researchers comparing notes on analyzing web usability with eye tracking

By bringing together such diverse perspectives, the Pupil community accelerates the pace of eye tracking innovation. Breakthroughs in one domain rapidly diffuse and generate insights across the entire eye tracking landscape.

The Technical Evolution of Pupil

Since its origins as a master‘s project, Pupil has grown into a sophisticated eye tracking platform. Here‘s an overview of the core Pupil Capture architecture:

Key components include:

• Video capture pipeline optimized for high frame rate eye and world camera streams
• Pupil detection algorithms combining edge detection, ellipse fitting, and 3D modeling to robustly identify pupil location and size
• Calibration and mapping systems to translate pupil coordinates to gaze positions in the world scene
• Real-time networking to stream eye tracking data to other applications
• Plugin system enabling custom eye tracking features and visualizations

On the hardware side, Pupil Labs now offers professional-grade eye tracking headsets alongside open source designs. Pupil Core, their latest headset, achieves:

• 200Hz gaze sampling rate
• 0.6 degree accuracy
• 10ms total system latency

But the real power comes from Pupil‘s open source ethos. Researchers can dive deep into the eye tracking algorithms, customizing every parameter. Developers can integrate eye tracking into their applications, from VR to scientific simulation. As one Pupil community member shared:

"Pupil‘s openness is a game changer. I can pop the hood and really understand how the gaze mapping works. I‘ve been able to modify it to handle some unique use cases in my VR therapy research. With a closed source eye tracker, I‘d be stuck trying to make my research fit their black box."

This flexibility has led to an explosion of creative Pupil projects. Researchers have built Pupil plugins for everything from detecting reading difficulty to measuring shoppers‘ attention in stores. The community eagerly collaborates to push the boundaries of what‘s possible.

Eye Tracking‘s Open Source Future

Looking ahead, Pupil Labs is aiming to accelerate the evolution of eye tracking with a three-pronged strategy:

1. Accessible, professional-grade eye tracking hardware. Pupil Labs will continue expanding their line of affordable, high-performance eye tracking headsets, aiming to reduce the barrier to entry for eye tracking research and development.

2. Robust, extensively documented software. Pupil Capture will advance with a focus on improving developer experience, including cleaner APIs, richer visualizations, and integrations for popular platforms like Unity and Python.

3. Community outreach and support. Through hackathons, educational resources, and an expansion of their community hubs, Pupil Labs aims to empower more diverse developers to explore eye tracking and contribute to the open source ecosystem.

At the center is a steadfast commitment to open source principles. As co-founder Kassner explains:

"We believe eye tracking reaches its full potential when the core technology is open and inspectable. Researchers need to be able to verify the integrity of their data. Developers need the ability to examine the algorithms, tinker, and invent new use cases. Closed eye tracking systems inherently limit innovation. Our goal is to create an open foundation and then get out of the way to let the community drive eye tracking forward."

For developers interested in eye tracking, Pupil Labs offers a few key tips:

1. Start small. Pick a simple use case and prototype with Pupil Capture. The platform is very accessible and lets you immediately start experimenting with real eye tracking data.

2. Engage with the community early and often. The Pupil community loves helping people get up to speed. Ask questions, share your progress, and learn from other developers‘ experiences.

3. Think beyond the screen. Some of the most exciting eye tracking applications bring gaze into the 3D world, from VR to wearables to environmental design. Don‘t limit your imagination to the 2D paradigm.

4. Prioritize user experience. Eye tracking is a novel input for many users. Carefully design interactions and visualizations to feel natural and minimize confusion or discomfort.

5. Open source your work. Help grow the eye tracking ecosystem by sharing your code and learnings. Pupil‘s permissive open source licensing makes it easy to build projects and products on the platform.

As Pupil‘s community continues its rapid growth, the potential for eye tracking feels limitless. By maintaining open source ethos and empowering diverse perspectives, Pupil is democratizing eye tracking innovation. The coming years promise a bloom of creative applications as developers, researchers, and hobbyists collaborate to explore the frontiers of human-computer interaction.

In the long run, Pupil envisions eye tracking as a ubiquitous technology seamlessly woven into our everyday experiences. As Patera muses:

"Today, eye tracking powers scientific research and niche applications. But I believe the natural end point is for gaze to be a fundamental interface for interacting with the world, right alongside touch, voice, and gestures. Pupil aims to be the open foundation to make that future possible – and to empower a diverse global community to shape its evolution."

For researchers and developers alike, Pupil offers a rare opportunity: the chance to help define an interaction paradigm in its infancy. By contributing to Pupil‘s open source ecosystem, you can help steer the trajectory of how humans and computers intertwine. So dive into the code, strap on a Pupil headset, and start imagining the possibilities.