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.
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.
Images can be directional unlike RF.Can simplify or ignore handshake and authentication steps.Useful as NFC for phones without dedicated hardware.
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 movementNew 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.
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.