Vehicle-use communication apparatus for receiving information transmitted by modulated light from signal lamp of traffic signal apparatus

• US 20080187318A1
• Filed: 02/05/2008
• Published: 08/07/2008
• Est. Priority Date: 02/06/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Osanai, Satoshi
• Granted Patent: US 7,764,194 B2
• Time in Patent Office: Days
• US Class Current: 398/129
• CPC Class Codes: H04B 10/1141 One-way transmission
• CPC Class Codes: H04B 10/116 Visible light communication

Abstract

A communication apparatus of a first vehicle receives information conveyed by modulated light emitted by a signal lamp of a traffic light apparatus or by the tail lamp of a preceding vehicle, and can relay the information to a second (following) vehicle, by modulated light emitted from a tail lamp of the first vehicle. If the first vehicle is concurrently receiving modulated light from both a signal lamp of a traffic light apparatus and a tail lamp of a preceding vehicle, only the information transmitted from the signal lamp is relayed to the second vehicle.

Claims

1. A vehicle-use communication apparatus installed in a vehicle, said vehicle operating within a traffic communication system wherein a signal lamp of a traffic light apparatus emits light which is modulated with a signal conveying specific information, wherein said vehicle-use communication apparatus is responsive to receiving said modulated light for transmitting said specific information to a following vehicle;

said vehicle-use communication apparatus comprising

a photo-receptive device for receiving said modulated light emitted from said signal lamp and light which is emitted from a tail lamp of a preceding vehicle and is modulated with a signal conveying information, and producing an electrical signal in accordance with said received light,

demodulator circuitry for demodulating said electrical signal,

notification means for notifying a driver of said vehicle of received information that is obtained by demodulating said electrical signal, and

light emission control circuitry configured to modulate light emitted from a tail lamp of said vehicle in accordance with said received information, for thereby transmitting said received information to a following vehicle;

wherein said vehicle-use communication apparatus comprises;

discrimination circuitry configured to distinguish between reception of said modulated light emitted from said signal lamp and reception of said modulated light emitted from said tail lamp of a preceding vehicle; and

,

control circuitry configured to control said notification means and said light emission control circuitry in accordance with results obtained by said discrimination circuitry, said control being applied whereby when modulated light is received by said photo-receptive device both from said signal lamp of a traffic light apparatus and from said tail lamp of a preceding vehicle, only information conveyed by said modulated light from said signal lamp is notified to said vehicle driver and transmitted to said following vehicle.

2. A vehicle-use communication apparatus according to claim 1, wherein:

said photo-receptive device comprises a camera apparatus for deriving image data expressing a captured image of an exterior region that is within a field of view of said camera apparatus, said camera apparatus being installed on said vehicle in a condition whereby said signal lamp of said traffic light apparatus and said tail lamp of a preceding vehicle can enter said field of view; and

said discrimination circuitry is configured to analyze said image data, and judge whether said signal lamp of a traffic light apparatus or said tail lamp of a preceding vehicle is represented by said captured image, with said judgement performed based on results of said image data analysis.

3. A vehicle-use communication apparatus according to claim 1, wherein:

said signal which modulates light emitted by said signal lamp of a traffic light apparatus further conveys a transmission source code indicative that said signal is transmitted from a traffic light apparatus and said signal which modulates light emitted by said tail lamp of a preceding vehicle further conveys a transmission source code indicative that said signal is transmitted from a vehicle tail lamp; and

said discrimination circuitry is configured to judge whether said received modulated light is emitted from a signal lamp of a traffic light apparatus or from a tail lamp of a preceding vehicle, with said judgement being based on said transmission source code conveyed by said received modulated light.

4. A vehicle-use communication apparatus according to claim 1, wherein said signal which modulates light emitted by said signal lamp of a traffic light apparatus conveys information indicative of a signaling condition of said traffic light apparatus.

5. A vehicle-use communication apparatus according to claim 1, wherein said signal which modulates light emitted by said signal lamp of a traffic light apparatus conveys position information indicative of a location of said traffic light apparatus, and said vehicle-use communication apparatus comprises:

a position detection apparatus configured to derive position information indicative of a current location of said vehicle of said vehicle-use communication apparatus; and

circuitry configured to calculate a distance between said traffic light apparatus and said vehicle, based on said position information from said traffic light apparatus and said position information from said position detection apparatus, and to detect a condition whereby said distance exceeds a predetermined value;

wherein said light emission control circuitry is configured to respond to detection of said condition by inhibiting said transmission of received information by modulation of light from said tail lamp of said vehicle.

6. A vehicle-use communication apparatus according to claim 1, wherein said signal which modulates light emitted by said signal lamp of a traffic light apparatus conveys timing information indicative of a time point of transmission of said signal, and said vehicle-use communication apparatus comprises:

means for determining a current time; and

circuitry configured to calculate a time duration that has elapsed from between said time point of transmission of said signal by said traffic light apparatus and said current time, and to detect a condition whereby said time duration exceeds a predetermined value;

wherein said light emission control circuitry is configured to respond to said detection of said condition by inhibiting said transmission of received information by modulation of light from said tail lamp of said vehicle.

7. A vehicle-use communication apparatus according to claim 1, wherein said control circuitry comprises timer means responsive to detection of modulate light emitted by said signal lamp for initiating a waiting interval of predetermined duration and wherein when modulated light is received from a tail lamp of a preceding vehicle during said waiting interval, said control circuitry inhibits notification of information conveyed by said modulated light to said vehicle driver and inhibits transmitting of said information to a following vehicle.