US 8,942,570 B2 · Data detection for visible light communications using conventional camera sensor

Abstract

The invention relates to a detection system for determining data embedded into the light output of a light source in a form of a repeating sequence of N symbols. The detection system includes a camera and a processing unit. The camera is configured to acquire a series of images of the scene via specific open/closure patterns of the shutter. The processing unit is configured to process the acquired series of images to determine the repeating sequence of N symbols. By carefully triggering when a shutter of the camera is open to capture the different symbols of the encoded light within each frame time of a camera, a conventional camera with a relatively long frame time may be employed. Therefore, the techniques presented herein are suitable for detecting the invisible “high frequency” coded light while using less expensive cameras as those used in the prior art.

Claims16

Dependent claims

A detection system for determining a repeating first sequence of N symbols included in a first code, wherein the first code is embedded into a light output of a first light source of an illumination system, the detection system comprising:

a camera configured to acquire a series of images of a scene, wherein:
each acquired image includes a plurality of pixels, each pixel representing an intensity of a total light output of the illumination system at a different physical position within the scene and the total light output of the illumination system comprises the light output of the first light source in at least one physical position within the scene,
the series comprises at least N different images, and
each image of the at least N different images is acquired with a total exposure time comprising one or more exposure instances at different temporal positions within the repeating first sequence of N symbols, wherein, for each image, the total exposure time is less than the frame time of the camera;
and
a processing unit configured to process the acquired series of images to determine the repeating first sequence of N symbols.

3 more elements

A method for determining a repeating first sequence of N symbols included in a first code, wherein the first code is embedded into a light output of a first light source of an illumination system, the method comprising:

acquiring a series of images of a scene, wherein:
each acquired image includes a plurality of pixels, each pixel representing an intensity of a total light output of the illumination system at a different physical position within the scene and the total light output of the illumination system comprises the light output of the first light source in at least one physical position within the scene,
the series comprises at least N different images, and
each image of the at least N different images is acquired with a total exposure time comprising one or more exposure instances at different temporal positions within the repeating first sequence of N symbols, wherein, for each image, the total exposure time is less than the frame time of the camera;
and
processing the acquired series of images to determine the repeating first sequence of N symbols.

3 more elements

A non-transitory computer readable medium comprising a computer readable program for determining a repeating first sequence of N symbols included in a first code, wherein the first code is embedded into a light output of a first light source of an illumination system, wherein the computer readable program, when executed on a computer, causes the computer to perform the steps comprising:

acquiring a series of images of a scene, wherein:
each acquired image includes a plurality of pixels, each pixel representing an intensity of a total light output of the illumination system at a different physical position within the scene and the total light output of the illumination system comprises the light output of the first light source in at least one physical position within the scene,
the series comprises at least N different images, and
each image of the at least N different images is acquired with a total exposure time comprising one or more exposure instances at different temporal positions within the repeating first sequence of N symbols, wherein, for each image, the total exposure time is less than the frame time of the camera;
and
processing the acquired series of images to determine the repeating first sequence of N symbols.

3 more elements

Dependencies are inferred from the claim text.

Data detection for visible light communications using conventional camera sensor

Life of this patent

Data detection for visible light communications using conventional camera sensor

Life of this patent

Abstract

Claims16