Dynamic prediction of traffic congestion by tracing feature-space trajectory of sparse floating-car data

• US 7,542,844 B2
• Filed: 08/18/2008
• Issued: 06/02/2009
• Est. Priority Date: 09/11/2007
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kumagai, Masatoshi, Hiruta, Tomoaki, Okude, Mariko, Tanikoshi, Koichiro
• Primary Examiner(s): Black; Thomas G
• Assistant Examiner(s): Chen; Shelley
• Application Number:
  US12/193,565
• Publication Number:
  US 20090070025A1
• Time in Patent Office: 288 Days
• Field of Search: 701117-119
• US Class Current: 701/117
• CPC Class Codes: G08G 1/0112 from the vehicle, e.g. floating car data [FCD]
• CPC Class Codes: G08G 1/0116 from roadside infrastructure, e.g. beacons
• CPC Class Codes: G08G 1/0129 for creating historical data or processing based on historical data
• CPC Class Codes: G08G 1/0141 for traffic information dissemination

Abstract

A traffic situation is predicted based on the correlation in the traffic situation between road sections. A base vector generation unit generates the base vectors constituting a feature space representing the correlation between a plurality of links by making a principal component analysis for the necessary time in the past recorded in a necessary time database. A projection point trajectory generation unit records a projection point trajectory of projecting the necessary time in the past recorded in the necessary time database to the feature space in a projection point database. A feature space projection unit projects the necessary time at present to the feature space, and a neighboring projection point retrieval unit retrieves a past projection point in the neighborhood of the concerned projection point from the projection point database, and a projection point trajectory trace unit traces the trajectory of past projection points starting from the retrieved neighboring projection point for a prediction target time width, and an inverse projection unit inversely projects the end point of the concerned trajectory to calculate the predicted value of the necessary time.

Claims

1. A traffic situation prediction apparatus for predicting a traffic situation, said apparatus having a base generation unit for generating the bases by making a principal component analysis for the necessary time of a plurality of road sections in the past, comprising:

a feature space projection unit for projecting the necessary time of the plurality of road sections at present to a feature space having said bases as the axes to obtain a current projection point;

a neighboring projection point retrieval unit for retrieving a projection point in the neighborhood of said current projection point based on a projection point trajectory that is a sequence of projection points of projecting the necessary time of said plurality of road sections in the past with said bases;

a projection point trajectory trace unit for tracing said projection point trajectory starting from the projection point in the neighborhood of said current projection point for a time width between the present time and the prediction target time to obtain the projection point; and

an inverse projection unit for inversely projecting the projection point traced by said projection point trajectory trace unit to calculate the predicted value of the necessary time of said plurality of road sections.

2. The traffic situation prediction apparatus according to claim 1, further comprising a projection point trajectory generation unit for generating said projection point trajectory by projecting the necessary time of said plurality of road sections in the past.

3. The traffic situation prediction apparatus according to claim 1, further comprising a gravitational center operation unit for calculating a representative projection point by making a gravitational center operation for the plurality of projection points, wherein said neighboring projection point retrieval unit retrieves the plurality of projection points in the neighborhood of said current projection point, said projection point trajectory trace unit traces said projection point trajectory starting from the plurality of projection points retrieved by said neighboring projection point retrieval unit to obtain the plurality of projection points, said gravitational center operation unit calculates the representative projection point from said plurality of projection points, and said inverse projection unit inversely projects said representative projection point to calculate the predicted value of the necessary time of said plurality of road sections.

4. A traffic situation prediction method for predicting a traffic situation using the bases generated by a principal component analysis for the necessary time of a plurality of road sections in the past, comprising:

projecting the necessary time of said plurality of road sections at present to a feature space having said bases as the axes to obtain a current projection point;

retrieving a projection point nearest to said current projection point from a projection point trajectory that is a sequence of projection points for the necessary time of said plurality of road sections in the past to have a neighboring projection point;

tracing said projection point trajectory starting from said neighboring projection point for a time width between the present time and the prediction target time to obtain the projection point; and

inversely projecting said projection point with said bases to calculate the predicted value of the necessary time of said plurality of road sections.

5. The traffic situation prediction method according to claim 4, further comprising generating said projection point trajectory by projecting the necessary time of said plurality of road sections in the past to said feature space.

6. A traffic situation prediction method for predicting a traffic situation, comprising:

generating the bases by a principal component analysis for the necessary time of a plurality of road sections in the past;

projecting the necessary time of said plurality of road sections at present to a feature space having said bases as the axes to obtain a current projection point;

retrieving a plurality of projection points in the neighborhood of said current projection point from a projection point trajectory that is a sequence of projection points of projecting the necessary time of said plurality of road sections in the past with said bases to have the neighboring projection points;

tracing said projection point trajectory starting from said neighboring projection points for a time width between the present time and the prediction target time to obtain a plurality of projection points;

defining the gravitational center of said plurality of projection points as a representative projection point; and

inversely projecting the representative projection point with said bases to calculate the predicted value of the necessary time of said plurality of road sections.