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- Image Sensor Communication -



+ Feature of visible light image sensor communication

The visible light image sensor communication is a technology that does a Visible Light Communication by using the image sensor used for the camera etc. though it is general that the receiving part of a Visible Light Communication usually uses the device such as photodiodes.

The visible light image sensor communication has the following features;

- Multi receiving channels
- The position of the transmitter can be specified.
- There are neither interference nor friction by the spatial separation.
- The long distance communication can be possible.
- The device is expensive.
- Speed-up is difficult.


+ Pixel = communication channel



The image sensor is a group of a large amount of photodiode (pixel). It will have one million receiving channels in the image sensor of one million pixels if it thinks one pixel to be one receiving channel.

As each receiving channel has the location information corresponding to the pixel, it can specify the position of the transmission place when receiving.

Moreover, there are neither interference nor friction if it is possible to separate in each pixel even if other sources of light exist nearby.




The photograph above is an image in the experiment that Casio Computer did.

Temperature information is sent from multi thermometers set up on the wall by a Visible Light Communication in this experiment. Using image sensor, multi temperature information and its positions can be received at the same time. Moreover, the communication is normally done if there is a strong source of light such as the illumination light nearby.


+ The communication distance relies on a lens efficiency.



It is possible to receive information if it shows light of the transmission of a message department more than 1 dot in the image sensor communication. Though the size of the appearance of the source of light becomes small, it can read the information from a far-off transmitter by using telephoto lenses.



The photograph above is an image in the experiment that Casio Computer did.

It was confirmed that a camera with image sensor receiver could receive information normally, when it was set in the place that was 1km away from a transmitter with the 10W LED panel of 35cm every direction by this experiment.


+ Background of image sensor communication

The current image sensor device is expensive to use it as a general communication device, and it is the present conditions that the devices of the high frame rate suitable for communication do not spread too much.

However, a mobile telephone and a PDA spreading widely get most camera functions now. It seems that the problem of the cost is broken off if machinery with a camera increases as it is.

In addition, the camera of the high frame rate is released for the consumer, and the performance of the device becomes high efficiency, too.

Using visible light communication, it is hoped that it clears the use domain of unprecedented new communication by using image sensor as a communication device.


Material offered by CASIO Computer Co., LTD.

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