Research Projects

Abstract: Screen-to-camera visible light communication links are fundamentally limited by inter-symbol interference, in which the camera receives multiple overlapping symbols in a single capture exposure. By determining interference constraints, we are able to decode symbols with multi-bit depth across all three color channels. We present Styrofoam, a coding scheme which optimally satisfies the constraints by inserting blank frames into the transmission pattern. The coding scheme improves upon the state-of-the-art in camera-based visible-light communication by: (1) ensuring a decode with at least half-exposure of colored multi-bit symbols, (2) limiting decode latency to two transmission frames, and (3) transmitting 0.4 bytes per grid block at the slowest camera's frame rate. In doing so, we outperform peer unsynchronized VLC transmission schemes by 2.9x. Our implementation on smartphone displays and cameras achieves 69.1 kbps.

Paper Links:

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Citation:

R. LiKamWa, D. Ramirez, and J. Holloway. Styrofoam: A tightly packed coding scheme for camera-based visible light communication. In Proceedings of the 1st ACM MobiCom Workshop on Visible Light Communication Systems, VLCS '14, pages 27-32, New York, NY, USA, 2014. ACM.

[+] BibTex Citation

@inproceedings{likamwa2014styrofoam,
author = {LiKamWa, Robert and Ramirez, David and Holloway, Jason},
title = {Styrofoam: A Tightly Packed Coding Scheme for Camera-based Visible Light Communication},
booktitle = {Proceedings of the 1st ACM MobiCom Workshop on Visible Light Communication Systems},
series = {VLCS '14},
year = {2014},
pages = {27--32},
publisher = {ACM},
address = {New York, NY, USA},
}

Slides

Download the presenation accompaning this project as a PowerPoint slideshow (10.5 MB) or PDF (1.3 MB).

Poster

Download the poster (48" x 36") presented at Mobicom: PDF (713 kB)