Method and apparatus for determining the position of a moving object, by using visible light communication

• US 7,973,819 B2
• Filed: 07/17/2008
• Issued: 07/05/2011
• Est. Priority Date: 07/31/2007
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Shimada, Shigehito
• Primary Examiner(s): Tran; Sinh
• Assistant Examiner(s): Peterson; Christopher K
• Application Number:
  US12/174,815
• Publication Number:
  US 20090033757A1
• Time in Patent Office: 1,083 Days
• Field of Search: 348/208.14, 348 94- 95, 348148-149, 348113-120, 348135-142, 340988-996, 359/155
• US Class Current: 348/208.14
• CPC Class Codes: G01S 1/7034 Mounting or deployment thereof
• CPC Class Codes: G01S 1/7038 Signal details
• CPC Class Codes: G01S 2201/01 adapted for specific applications or environments
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves
• CPC Class Codes: G08G 1/096716 where the received information does not generate an automatic action on the vehicle control
• CPC Class Codes: G08G 1/096758 where no selection takes place on the transmitted or the received information
• CPC Class Codes: G08G 1/096783 where the origin of the information is a roadside individual element

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.

Claims

1. A system for determining the position of a moving object, comprising:

a transmitting unit which is located at a fixed position and transmits a visible optical signal modulated with position data including height data;

a single-lens photographing unit which is provided on the moving object and photographs the transmitting unit;

a data-acquiring unit which is provided on the moving object and receives the visible optical signal and acquires the position data from the visible optical signal; and

a determining unit which is provided on the moving object and uses video data generated by the single-lens photographing unit, thereby determining the position of the moving object,

wherein the determining unit comprises;

a height-calculating unit which uses synthesized video data prepared by synthesizing first video data representing an image photographed by the single-lens photographing unit when the moving object is at a first position and second video data representing an image photographed by the single-lens photographing unit when the moving object reaches a second position from the first position, thereby calculating a height difference that the fixed position has in a synthesized image represented by the synthesized video data;

a distance-calculating unit which uses the height difference, the data included in the position data and the distance between the first and second positions, thereby calculating a distance between a present position of the moving object and the fixed position; and

a correcting/calculating unit which uses the distance calculated by the distance-calculating unit, a bearing detected by a bearing detector provided on the moving object and coordinates of the fixed position, thereby calculating the present position of the moving object.

2. The system according to claim 1, wherein the transmitting unit is provided in a road-illuminating lamp for illuminating a road on which the moving object such as a vehicle moves and includes:

a storage unit which stores the position data included in the visible optical signal; and

a light-emitting element drive unit which controls and drives a light-emitting element provided in the road-illuminating lamp, causing the light-emitting element to transmit the visible optical signal modulated with the position data stored in the storage unit.

3. The system according to claim 1, wherein the transmitting unit is provided in a facility such as a building and secured to a structure which is able to transmit the visible optical signal.

4. An apparatus to be mounted on a moving object and designed to determine the position of the moving object, the apparatus comprising:

a receiving unit which receives a visible optical signal transmitted from a transmitting unit at a fixed position, the visible optical signal being modulated with position data including height data;

a demodulating unit which demodulates the visible optical signal, thereby restoring the position data;

a single-lens photographing unit which photographs an object located at the fixed position and outputs video data representing an image of the object; and

a determining unit which uses the video data output by the single-lens photographing unit, thereby determining the position of the moving object,

wherein the determining unit comprises;

a height-calculating unit which uses synthesized video data prepared by synthesizing first video data representing an image photographed by the single-lens photographing unit when the moving object is at a first position and second video data representing an image photographed by the single-lens photographing unit when the moving object reaches a second position from the first position, thereby calculating a height difference that the fixed position has in a synthesized image represented by the synthesized video data;

a distance-calculating unit which uses the height difference, the data included in the position data and the distance between the first and second positions, thereby calculating a distance between a present position of the moving object and the fixed position; and

a correcting/calculating unit which uses the distance calculated by the distance-calculating unit, a bearing detected by a bearing detector provided on the moving object and coordinates of the fixed position, thereby calculating the present position of the moving object.

5. The apparatus according to claim 4, wherein the moving object is a vehicle, and the receiving unit includes:

a light-receiving element which receives the visible optical signal transmitted from the transmitting unit provided on a road-illuminating lamp for illuminating a road.

6. A method of determining the present position of a moving object by utilizing a visible optical signal which is transmitted from a transmitting unit located at a fixed position and which is modulated with position data including height data, the method comprising:

photographing the transmitting unit by using a single-lens photographing unit provided on the moving object, thereby generating video data;

receiving the visible optical signal at the moving object, thereby acquiring the position data from the visible optical signal; and

using video data and the position data at the moving object, thereby determining the position of the moving object,

wherein the determining comprises;

using synthesized video data prepared by synthesizing first video data representing an image photographed by the single-lens photographing unit when the moving object is at a first position and second video data representing an image photographed by the single-lens photographing unit when the moving object reaches a second position from the first position, thereby calculating a height difference that the fixed position has in a synthesized image represented by the synthesized video data;

using the height difference, the data included in the position data and the distance between the first and second positions, thereby calculating a distance between a present position of the moving object and the fixed position; and

using the distance calculated by the distance-calculating unit, a bearing detected by a bearing detector provided on the moving object and coordinates of the fixed position, thereby calculating the present position of the moving object.