When you think of “time-lapse video,” what typically comes to mind is a camera fixed on a tripod, capturing images at set intervals. But what if you could achieve the same effect simply by taking out your phone and snapping a picture every time you pass a certain tree on your way to work? No tripod necessary.
A research group at Cornell University has developed groundbreaking software that allows anyone with a camera-equipped mobile phone to capture subtle changes over time—such as those at a construction site or the changing seasons—and turn them into a panoramic time-lapse video.
Innovative Research at Cornell
Abe Davis, an assistant professor of computer science in the Cornell Ann S. Bowers College of Computing and Information Science, is the senior author of “Pocket Time-Lapse,” a paper his research group will present at the Association for Computing Machinery’s SIGGRAPH 2025 conference in Vancouver, British Columbia, from August 10-14.
Eric Chen, a 2024 graduate now pursuing a doctorate at the Massachusetts Institute of Technology, is the lead author of the paper. Other contributors include Žiga Kovačič, class of 2026, and Madhav Aggarwal, M.S. 2024.
The Genesis of Pocket Time-Lapse
Davis arrived at Cornell in the summer of 2020, during the early days of the pandemic, when lockdowns made setting up a traditional lab with conventional equipment impossible. Instead, he started taking pictures.
“Even under lockdown, we could still go outdoors,” Davis said. “So I started thinking a lot about how to support fieldwork—applications where people need to collect data outside, in uncontrolled settings.”
To explore that interest, Davis began snapping cellphone pictures “from places that I happened to visit every day.” Over several years, he amassed more than 50,000 images from various spots around Ithaca, capturing scenes from outside his apartment window, the bus stop, and the parking garage overlooking construction of the new Bowers CIS building. From these pictures, the researchers built time-lapse videos.
Technical Breakthroughs
Davis initiated this work with Ruyu Yan, a 2023 graduate now a doctoral student at Princeton University, and later recruited Chen. Chen helped develop new techniques to align and visualize the growing dataset, correcting for slight inconsistencies in how pictures were taken. Their technique is believed to be the first to handle registration for thousands of panoramic images into a single, consistent time-lapse video.
“We had to figure out a new trick for doing this alignment that takes advantage of the fact that we have so much data over such a long period of time that sees so many different conditions,” Chen explained. “We link together high-quality alignments from photos that aren’t necessarily in sequential order, so we can connect a daytime photo with one taken at night by inserting a picture taken during twilight on a different day.”
Innovative Techniques
Another key innovation, a reconstruction method they call “time splatting,” involves matching the position of the sun and local GPS coordinates, along with local weather data for each photography session, to inform the positioning of shadows in the video.
“From that,” Chen noted, “we’re able to do things like re-light a photo from sunrise to sunset, or change where the shadows are, or maybe change the lighting from daytime to nighttime.”
Potential Applications and Future Prospects
Davis envisions Pocket Time-Lapse being applicable in a range of areas, including field sciences, construction, and healthcare monitoring. It also offers a novel way to view one’s environment.
“This tool gives you a different way to look at the world,” he said. “Most of the data for this project comes from places I see every day, but there are so many little details I never noticed until I saw them in a time-lapse. It’s like a different window into what’s around you.”
Support for this work came from the National Science Foundation Graduate Research Fellowship Program, a NSF Faculty Early Career Development Grant, and Meta.
The development of Pocket Time-Lapse represents a significant leap forward in making time-lapse video creation accessible to the general public, potentially transforming how we document and perceive changes in our surroundings.
