Transcript [Drew Carpenter](slides)

COBRA
COlor Barcode stReaming for smArtphones
-Drew Carpenter
VLC-Visual Light
Comunication
• Widely used in the form of barcodes.
• Research has been done with inexpensive
leds and photo sensors.
• Current LCD/Camera implementations
are costly and cumbersome.
• Newer 2D barcodes use colors to improve
data density.
COBRA
• Improves data rate with 2D color
barcodes.
• Uses a sending and receiving device.
• Transmits data by showing a series of
Color Blocks at a rate of 30fps.
Why?
• Images can be directional unlike RF.
• Can simplify or ignore handshake and
authentication steps.
• Useful as NFC for phones without
dedicated hardware.
Challenges
• Low density phone screens and cameras
cause the colors to blur.
• Movement of the phones can increase
blur.
• Small block sizes can be detrimental to
overall data rate.
• Processing power is limited on phones
and algorithms must be fast and optimal.
Mitigation - Deblur
• Block sizes are
•
based on phones
movement
New frames are
shown at half the
capture rate,
approximately 15
fps.
Mitigation - Speed
•
•
•
Corners are located based off previous frame.
Multiple images are captured of the same barcode.
Blocks are arranged together on the senders phone to
increase the number of adjacent colors.
Future Work
• Two way communications with front
facing cameras.
• ECC included to mitigate noise.
• Optimize colors for LED and LCD
screens.
• Utilize two way communication to
synchronize camera and screen refreshes.
Questions?