A system clock reference is transmitted to user devices over a short range communication channel and used to calculated a clock offset. The clock offset is stored together with a user identifier in a server memory, from which the clock offset can be retrieved when receiving the user identifier together with a video stream of video frames tagged with respective timestamps. The timestamps are converted into capture times according to a system clock using the retrieved clock offsets. Video streams from multiple user devices thereby have video frames timestamped using a same clock reference and can be time aligned.

A system clock reference is transmitted to user devices over a short range communication channel and used to calculated a clock offset. The clock offset is stored together with a user identifier in a server memory, from which the clock offset can be retrieved when receiving the user identifier together with a video stream of video frames tagged with respective timestamps. The timestamps are converted into capture times according to a system clock using the retrieved clock offsets. Video streams from multiple user devices thereby have video frames timestamped using a same clock reference and can be time aligned.

A mobile terminal is a communication device that communicates using visible light, and includes: a plurality of light emitters, each of which is disposed along the front surface of the mobile terminal and transmits a visible light signal; and a plurality of light receivers, each of which is disposed along the front surface and receives a visible light signal. The plurality of light emitters are disposed on the left side of all of the plurality of light receivers, and the plurality of first light receivers are disposed on the right side of all of the plurality of light emitters.

A mobile terminal is a communication device that communicates using visible light, and includes: a plurality of light emitters, each of which is disposed along the front surface of the mobile terminal and transmits a visible light signal; and a plurality of light receivers, each of which is disposed along the front surface and receives a visible light signal. The plurality of light emitters are disposed on the left side of all of the plurality of light receivers, and the plurality of first light receivers are disposed on the right side of all of the plurality of light emitters.

In accordance with increasing communication demand, means for efficiently providing mass downstream communication at a low cost are desired. Accordingly, a communication system providing supplemental downlink as well as multicast communication comprising a display control device for causing a display unit to display a video, and a communication terminal having an image capturing unit for directly capturing the video displayed by the display unit or capturing a video projected or reflected on a wall surface or the like is provided, wherein the display control device includes a video acquiring unit, a region identification unit, a video generating unit, and a display control unit, and the communication terminal includes a region identification unit, a decoding unit, and a mechanism for communicating a control signal for supplemental downlink by the above-described optical communication using means other than optical communication (means such as WiFi, mobile data communication or the like).

A light transmitting device that includes a light transmitter that transmits a spatial light signal including a communication signal, and a light transmission control unit that adds a dummy signal having a same brightness as a ghost image of the communication signal to the spatial light signal and controls the light transmitter in such a way that the dummy signal is displayed at a position of the ghost image.

A light transmitting device that includes a light transmitter that transmits a spatial light signal including a communication signal, and a light transmission control unit that adds a dummy signal having a same brightness as a ghost image of the communication signal to the spatial light signal and controls the light transmitter in such a way that the dummy signal is displayed at a position of the ghost image.

A method and apparatus of a device that transmits a message using a light pattern is described. In an exemplary embodiment, the device receives an indication to transmit a message using the light pattern. In addition, the device activates a flash on the device. The device further encodes the message into instructions for transmitting the light pattern. The device additionally transmits the message using the flash according to the instructions for the light pattern.

A method and apparatus of a device that transmits a message using a light pattern is described. In an exemplary embodiment, the device receives an indication to transmit a message using the light pattern. In addition, the device activates a flash on the device. The device further encodes the message into instructions for transmitting the light pattern. The device additionally transmits the message using the flash according to the instructions for the light pattern.

A display device and a driving method are provided. The display device includes a display panel and a control IC. The display panel includes a plurality of light-emitting elements. The control IC is configured to control the plurality of light-emitting elements to be turned on at a first frequency so as to display display-related data, and control at least two light-emitting elements of the plurality of light-emitting elements to be turned on and off at a second frequency greater than the first frequency so as to transmit visible light data.