ROAD CONFIGURATION ESTIMATION APPARATUS, COMPUTER PROGRAM, AND ROAD CONFIGURATION ESTIMATION METHOD

• US 20110295548A1
• Filed: 02/03/2011
• Published: 12/01/2011
• Est. Priority Date: 05/26/2010
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Obata, Yasushi, Kameda, Hiroshi, TAKABAYASHI, Yuki, Matsuzaki, Takashi
• Granted Patent: US 8,606,539 B2
• Time in Patent Office: Days
• US Class Current: 702/142
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 7/2955 Means for determining the position of the radar coordinate system for evaluating the position data of the target in another coordinate system G01S7/24 takes precedence; sighting devices adapted for indirect laying of fire F41G3/16; inertial navigation G01C21/16
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road

Abstract

There is provided a road configuration estimation apparatus that precludes influences of erroneous detection of an object and erroneous still determination and estimates a road configuration.

A radar (peripheral object observation device) 110 repeatedly observes a relative position of an object relative to the moving object, which is located in the vicinity of a moving object. A stationary object identification unit (stationary object determination unit) 130 determines whether or not the object the relative positions of which have been observed by the radar 110 is still. A road approximate curve temporary computation unit (object correlation unit) 140 determines a plurality of the relative positions of an identical object observed by the radar 110 from among the relative positions observed by the radar 110. A road approximate curve main computation unit (approximate curve computation unit) 160 computes an approximate curve that approximates the configuration of a road on which the moving object is located, based on a result of the determination by the stationary object identification unit 130 and a result of the determination by the road approximate curve computation unit 140.

Claims

1. A road configuration estimation apparatus comprising:

a relative position acquisition unit, for obtaining a result of an observation by the peripheral object observation device that repeatedly observes an object located in the vicinity of a moving object to measure a relative position of the object relative to the moving object;

a stationary object determination unit, for determining whether or not the object observed by the peripheral object observation device is still, based on the result of the observation obtained by the relative position acquisition unit;

an object correlation unit, for determining a set of relative positions measured by observing an identical object by the peripheral object observation device, from among a plurality of the relative positions measured by the peripheral object observation device, based on a plurality of the results of the observations obtained by the relative position acquisition unit; and

an approximate curve computation unit, for computing an approximate curve that approximates a configuration of a road on which the moving object is located, based on a result of the determination by the stationary object determination unit and a result of the determination by the object correlation unit.

2. The road configuration estimation apparatus according to claim 1, wherein

the approximate curve computation unit estimates a coefficient of a predetermined function representing the approximate curve, using a tracking filter that treats the coefficient of the function representing the approximate curve as a state, and treats the relative position measured by the peripheral object observation device by observing an object determined to be still by the stationary object determination unit from among the result of the observation obtained by the relative position acquisition unit as a measurement.

3. The road configuration estimation apparatus according to claim 2, wherein

when a distance between the approximate curve and the relative position measured by the peripheral object observation device is shorter than a predetermined threshold value, the approximate curve computation unit performs an updating process of the tracking filter, using the relative position as the measurement.

4. The road configuration estimation apparatus according to claim 2, further comprising:

an initial value computation unit, for approximating a trajectory of a plurality of the relative positions belonging to the set determined by the object correlation unit to be the relative positions measured by observing an identical object by the peripheral object observation device, using the predetermined function representing the approximate curve, and for computing the coefficient of the function that approximates the trajectory of the plurality of the relative positions; and

wherein

the approximate curve computation unit sets the coefficient computed by the initial value computation unit to an initial value of an estimation value of the state for the tracking filter.

5. The road configuration estimation apparatus according to claim 4, wherein

the initial value computation unit computes a coefficient of the function that approximates a trajectory of a plurality of the relative positions, based on the plurality of the relative positions belonging to the set determined by the object correlation unit to be the relative positions measured by observing an identical object by the peripheral object observation device, the number of the relative positions belonging the set being larger than a predetermined threshold value.

6. The road configuration estimation apparatus according to claim 4, wherein

the initial value computation unit computes a coefficient of the function that approximates a trajectory of a plurality of the relative positions, based on the plurality of the relative positions belonging to the set determined by the object correlation unit to be the relative positions measured by observing an identical object by the peripheral object observation device, a distance between at least one relative position belonging to the set and the moving object being shorter than a predetermined value.

7. The road configuration estimation apparatus according to claim 1, further comprising:

a reliability level computation unit, for computing a reliability level of the approximate curve computed by the approximate curve computation unit; and

wherein

the approximate curve computation unit discards the computed approximate curve when the reliability level computed by the reliability level computation unit is lower than a predetermined threshold value.

8. The road configuration estimation apparatus according to claim 1, wherein

the approximate curve computation unit computes a plurality of approximate curves;

and

the road configuration estimation apparatus further comprises;

a reliability level computation unit, for computing a reliability level of each of the plurality of approximate curves computed by the approximate curve computation unit; and

an approximate curve selection unit, for selecting one of the plurality of approximate curves for adoption, from among the plurality of approximate curves computed by the approximate curve computation unit, based on the reliability level computed by the reliability level computation unit.

9. The road configuration estimation apparatus according to claim 7, wherein

the reliability level computation unit computes a dispersion of distances between the moving object and each of the relative positions used for computation of the approximate curve by the approximate curve computation unit, and increases the reliability level as the computed dispersion increases.

10. The road configuration estimation apparatus according to claim 1, further comprising:

a moving speed acquisition unit, for obtaining a result of an observation by a moving speed observation device that observes a moving speed of the moving object;

an angular velocity acquisition unit, for obtaining a result of an observation by an angular velocity observation device that observes an angular velocity of the moving object;

a curvature computation unit, for computing a quotient resulting from division of the angular velocity of the moving object by the moving speed of the moving object as a curvature of a trajectory of the moving object, based on the result of the observation obtained by the moving speed acquisition unit and the result of the observation obtained by the angular velocity acquisition unit;

a curvature constant curve computation unit, for computing a curvature constant curve with a constant curvature as an approximate curve that approximates the configuration of the road on which the moving object is located, based on the curvature computed by the curvature computation unit; and

an approximate curve selection unit, for selecting one of the approximate curve computed by the approximate curve computation unit and the curvature constant curve computed by the curvature constant curve computation unit and for adopting the selected approximate curve as the approximate curve that approximates the configuration of the road on which the moving object is located.

11. The road configuration estimation apparatus according to claim 10, wherein

the approximate curve selection unit determines a road configuration type of the road on which the moving object is located, from among road configuration types that are classified into at least four types of a straight road, a road before a curved road, a curved road, and a curved road exit, and selects the curvature constant curve computed by the curvature constant curve computation unit as the approximate curve that approximates the configuration of the road on which the moving object is located when the determined road configuration type is the curved road.

12. The road configuration estimation apparatus according to claim 1, further comprising:

a moving speed acquisition unit, for obtaining a result of an observation by a moving speed observation device that observes a moving speed of the moving object;

an angular velocity acquisition unit, for obtaining a result of an observation by an angular velocity observation device that observes an angular velocity of the moving object;

a curvature computation unit, for computing a quotient resulting from division of the angular velocity of the moving object by the moving speed of the moving object as a curvature of a trajectory of the moving object, based on the result of the observation obtained by the moving speed acquisition unit and the result of the observation obtained by the angular velocity acquisition unit;

a curvature constant curve computation unit, for computing a curvature constant curve with a constant curvature as an approximate curve that approximates the configuration of the road on which the moving object is located, based on the curvature computed by the curvature computation unit; and

an approximate curve integration unit, for computing a weight for the approximate curve computed by the approximate curve computation unit and a weight for the curvature constant curve computed by the curvature constant curve computation unit, and for integrating the approximate curve computed by the approximate curve computation unit and the curvature constant curve computed by the curvature constant curve computation unit, based on the computed weights, to compute an approximate curve that approximates the configuration of the road on which the moving object is located.

13. The road configuration estimation apparatus according to claim 12, wherein

the approximate curve integration unit determines a road configuration type of the road on which the moving object is located, from among road configuration types that are classified into at least four types of a straight road, a road before a curved road, a curved road, and a curved road exit, and increases the weight of the curvature constant curve computed by the curvature constant curve computation unit when the determined road configuration type is the curved road.

14. The road configuration estimation apparatus according to claim 1, further comprising:

an ahead moving object tracking unit, for tracking an object moving ahead of the moving object in substantially a same direction as the moving object, based on the result of the observation obtained by the relative position acquisition unit;

an approximate curve crossing determination unit, for determining, when the approximate curve computation unit computes a plurality of approximate curves, whether or not at least two of the plurality of approximate curves mutually cross; and

an approximate curve initialization unit, for determining, when the approximate curve crossing determination unit determines that two of the plurality of approximate curves mutually cross, whether or not each of the approximate curves determined to mutually cross by the approximate curve crossing determination unit is correct, based on a positional relationship between the object tracked by the ahead moving object tracking unit and each of the approximate curves, and for initializing the approximate curve determined not to be correct.

15. A computer readable storage medium having stored therein a computer program, for causing a computer that executes the computer program to be functioned as the road configuration estimation apparatus according to claim 1.

16. A road configuration estimation method of estimating a configuration of a road on which a moving object is located, the method comprising:

obtaining a result of an observation by a peripheral object observation device that repeatedly observes an object located in the vicinity of a moving object to measure a relative position of the object relative to the moving object;

determining whether or not the object observed by the peripheral object observation device is still, based on the obtained result of the observation;

determining a set of a plurality of relative positions measured by observing an identical object by the peripheral object observation device, from among the relative positions measured by the peripheral object observation device, based on the obtained result of the observation; and

computing an approximate curve that approximates a configuration of a road on which the moving object is located, based on a result of the determination of stillness of the object and a result of the determination of the set of the relative positions.