Abstract: According to one embodiment, there is provided a visible-light communications system in which bidirectional visible-light communication is performed between a visible-light communications device and a mobile terminal. The device has one light source. The mobile terminal has a retroflection unit. The mobile terminal further has first and second optical filters. The first optical filter extracts a visible light beam modulated with the data transmitted from the visible-light communications device. The second optical filter extracts a visible light beam that will be used as a retroflection light beam that is not modulated.

Abstract: According to one embodiment, a visible-light communication apparatus includes an image input unit, a calculation unit, a preamble detection unit, a bit train detection unit, and a reception unit. The image input unit is configured to input image data generated by photographing a source of visible light carrying data. The calculation unit is configured to generate, from the image data, luminance data about an image at a designated position. The preamble detection unit is configured to detect a preamble at the head of the data, on the basis of the luminance data. The bit train detection unit is configured to detect the data bit train from the image data, in accordance with the preamble. The reception unit is configured to reproduce the data from the data bit train.

Abstract: Disclosed herein is a visible-light communication system according to one embodiment of the invention. The system comprises two apparatus. One apparatus emits a visible light beam on which is superimposed transmission data. From the void data represented by the visible light beam, the other apparatus generates a retroflected light beam, superimposes transmission data on the retroflected light beam, and applies the retroflected light beam to the apparatus. On receiving the retroflected light beam, the apparatus identifies the transmission data coming from the other apparatus, on the basis of the identification data superimposed on the retroflected light beam.

Abstract: An apparatus for determining the present position of a vehicle, by utilizing a visible-light communication system. The apparatus uses a visible-light communication beacon and video data representing an image photographed by one camera. The beacon emits a visible optical signal, thus transmitting position data. The visible-light communication beacon comprises a road-illuminating lamp and a visible-light communication apparatus, both secured to a lamp post. The vehicle has the camera and a vehicle position determination apparatus. The vehicle position determination apparatus demodulates the visible optical signal, there restoring the position data, and calculates the present position of the vehicle from the position data.

Abstract: According to one embodiment, a visible-light communication apparatus includes an image input unit, a calculation unit, a preamble detection unit, a bit train detection unit, and a reception unit. The image input unit is configured to input image data generated by photographing a source of visible light carrying data. The calculation unit is configured to generate, from the image data, luminance data about an image at a designated position. The preamble detection unit is configured to detect a preamble at the head of the data, on the basis of the luminance data. The bit train detection unit is configured to detect the data bit train from the image data, in accordance with the preamble. The reception unit is configured to reproduce the data from the data bit train.

Abstract: According to one embodiment, there is provided a visible-light communications system in which bidirectional visible-light communication is performed between a visible-light communications device and a mobile terminal. The device has one light source. The mobile terminal has a retroflection unit. The mobile terminal further has first and second optical filters. The first optical filter extracts a visible light beam modulated with the data transmitted from the visible-light communications device. The second optical filter extracts a visible light beam that will be used as a retroflection light beam that is not modulated.

Abstract: Disclosed herein is a visible-light communication system according to one embodiment of the invention. The system comprises two apparatus. One apparatus emits a visible light beam on which is superimposed transmission data. From the void data represented by the visible light beam, the other apparatus generates a retroflected light beam, superimposes transmission data on the retroflected light beam, and applies the retroflected light beam to the apparatus. On receiving the retroflected light beam, the apparatus identifies the transmission data coming from the other apparatus, on the basis of the identification data superimposed on the retroflected light beam.

Abstract: An apparatus for determining the present position of a vehicle, by utilizing a visible-light communication system. The apparatus uses a visible-light communication beacon and video data representing an image photographed by one camera. The beacon emits a visible optical signal, thus transmitting position data. The visible-light communication beacon comprises a road-illuminating lamp and a visible-light communication apparatus, both secured to a lamp post. The vehicle has the camera and a vehicle position determination apparatus. The vehicle position determination apparatus demodulates the visible optical signal, there restoring the position data, and calculates the present position of the vehicle from the position data.