CODED LIGHT

摘要

A coded light signal is embedded into visible light emitted from the light source, to be received by a rolling-shutter camera which captures frames (16) by exposing a plurality of lines (18, 24) of each frame in sequence, the camera having an exposure time with each line being exposed for the exposure time. The coded light signal is formatted according to a format whereby the coded light signal comprises at least one message and the message is repeated multiple times with a timing such that, when samples of the coded light signal are obtained from a substantially smaller number of lines (24) than exposed by the camera in each frame and the message is longer than this number of lines, a different part of the message is seen by the camera in each of a plurality of different ones said frames.

主权项

1. A device comprising:
a driver for controlling a light source based on a controller output to embed a coded light signal into visible light emitted from the light source, for reception by a rolling-shutter camera which captures frames by exposing a plurality of lines of each frame in sequence, the camera having an exposure time being the time for which each line is exposed; and a controller configured to generate the controller output to generate the coded light signal according to a format whereby the coded light signal comprises at least one message and the message is repeated multiple times with a timing such that, when samples of the coded light signal are obtained from a substantially smaller number of said lines than exposed by the camera in each frame and the message is longer than said number of lines, a different part of the message is seen by the camera in each of a plurality of different ones of said frames;wherein:
the message is of a duration longer than one frame; and the message comprises one or more packets comprising different data content, wherein each of the packets of the message is followed by an inter-packet idle period, and wherein the repetitions of the message are separated by an inter-message idle period different than the inter-packet idle period.