We present AirCode, a technique that allows the user to tag physically fabricated objects with given information. An AirCode tag consists of a group of carefully designed air pockets placed beneath the object surface. These air pockets are easily produced during the fabrication process of the object, without any additional material or postprocessing. Meanwhile, the air pockets affect only the scattering light transport under the surface, and thus are hard to notice to our naked eyes. But, by using a computational imaging method, the tags become detectable. We present a tool that automates the design of air pockets for the user to encode information. AirCode system also allows the user to retrieve the information from captured images via a robust decoding algorithm. We demonstrate our tagging technique with applications for metadata embedding, robotic grasping, as well as conveying object affordances.

downloads
Paper / Paper (low resolution) / arxiv
Source Code: Github
Youtube / Video (100MB)
Slides: keynote (100MB) / pdf (30MB) / html viewer
Conference Presentation: Youtube
Models: Triangle Drawer / Mug / Statue

external resources
Ellipse Detector
Local and Global Component Separation

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equipment
UR5 Robot
Objet Eden 260VS Printer
Mitsubishi PK20 Projector
PointGrey GrassHopper3 Monochrome Camera
Fujinon lenses: 25mm / 50mm

@inproceedings{Li:2017:aircode,
  title={AirCode: Unobtrusive Physical Tags for Digital Fabrication},
  author={Li, Dingzeyu and Nair, Avinash S. and Nayar, Shree K. and Zheng, Changxi},
  booktitle = {Proceedings of ACM Symposium on User Interface Software \& Technology},
  year={2017},
}