VEHICLE-INSTALLATION INTERSECTION JUDGMENT APPARATUS AND PROGRAM

• US 20140297171A1
• Filed: 03/27/2014
• Published: 10/02/2014
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: DENSO Corporation, Nippon Soken, Inc.
• Original Assignee: DENSO Corporation, Nippon Soken, Inc.
• Inventors: Ogata, Yoshihisa, Yokoyama, Takahisa, Minemura, Akitoshi
• Granted Patent: US 9,390,624 B2
• Time in Patent Office: Days
• US Class Current: 701/301
• CPC Class Codes: B60R 21/34 Protecting non-occupants of a vehicle, e.g. pedestrians B60R19/02 takes precedence
• CPC Class Codes: G01S 13/867 Combination of radar systems with cameras
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes

Abstract

A vehicle-installation intersection judgement apparatus determines whether a target object such as a pedestrian is located ahead and to one side of the vehicle, and if so, judges whether the object is moving laterally to intersect with the advancement of the vehicle. Successive amounts of lateral displacement of the object are periodically derived, each amount is compared with a displacement threshold, a count is made of the number of times that the displacement threshold is exceeded, and the count is compared with a predetermined count threshold. The judgement concerning the target object is made based upon whether the count threshold is attained.

Claims

1. An intersection judgement apparatus installed on a host vehicle, comprising

distance measurement circuitry configured for receiving target object detection information from target object detection means, and for periodically calculating updated values of a relative distance between the host vehicle and a target object based on the target object information, the target object information relating to an object positioned within an external region, the external region located ahead of the host vehicle and to one side of an advancement direction of the host vehicle;

direction angle measurement circuitry configured for periodically calculating updated values of a direction angle of the target object relative to the host vehicle based on the target object detection information,

displacement amount calculation circuitry configured for periodically calculating updated amounts of lateral displacement of the target object based upon respective values of the calculated relative distance and calculated direction angle of the target object, each lateral displacement amount being measured along an intersection direction oriented towards and at right angles to the advancement direction of the host vehicle, and

intersection judgement circuitry configured for applying the periodically calculated lateral displacement amounts in judgement processing, the judgement processing executed for judging whether the target object is becoming successively displaced along the intersection direction;

wherein;

the intersection judgement circuitry executes the judgement processing by utilizing a plurality of threshold condition groups, each threshold condition group comprising at least a corresponding lower displacement threshold and a corresponding count threshold having respectively predetermined values, the plurality of threshold condition groups being assigned respectively different values of the corresponding lower displacement threshold and respectively different values of the corresponding count threshold;

with respect to each of the threshold condition groups, the intersection judgement circuitry counts a number of times that the periodically calculated lateral displacement amounts obtained for a target object exceed the corresponding lower displacement threshold, and judges that the threshold condition group changes from a non-satisfied status to a satisfied status when the counted number exceeds the corresponding count threshold; and

,

the intersection judgement circuitry judges whether the target object is moving laterally towards intersection with the advancement of the host vehicle based upon evaluating respective statuses of the plurality of threshold condition groups.

2. The intersection judgement apparatus as claimed in claim 1 wherein, only when all of the plurality of threshold condition groups become satisfied, the intersection judgement circuitry judges that the target object is moving laterally towards intersection with the advancement of the host vehicle.

3. The intersection judgement apparatus as claimed in claim 1 wherein, when at least one of the plurality of threshold condition groups becomes satisfied, the intersection judgement circuitry judges that the target object is moving laterally towards intersection with the advancement of the host vehicle.

4. The intersection judgement apparatus as claimed in claim 1 wherein within the plurality of threshold condition groups, the lower the value of the count threshold corresponding to a threshold condition group, the higher is made the value of the corresponding lower displacement threshold of that group.

5. The intersection judgement apparatus as claimed in claim 1, wherein the intersection judgement circuitry judges that a threshold condition group is satisfied when the counted number attains the corresponding count threshold within a predetermined count range (M), the count range comprising a predetermined number of consecutive timings at which respective lateral displacement amounts are calculated.

6. The intersection judgement apparatus as claimed in claim 5, wherein an identical count range is applied for each of the plurality of threshold condition groups.

7. The intersection judgement apparatus as claimed in claim 1, wherein the target object detection means comprises

a radar apparatus configured to transmit radar waves within a first external region located ahead of the host vehicle and receive resultant reflected radar waves, and to produce radar information based on the received reflected waves, and

a camera apparatus configured to capture successive images of contents of a second external region located ahead of the host vehicle and to produce image information based on the captured images, said second external region at least partially overlapping said first external region;

wherein the distance measurement circuitry measures the distance of the target object based on the radar information and the direction angle measurement circuitry measures the direction of the target object based on the image information,

and wherein, designating a No. 1 lateral displacement amount as a lateral displacement amount that is calculated based on a distance value derived from the radar information and a direction value derived from the image information, the intersection judgement circuitry evaluates the statuses of the threshold condition groups with respect to successively calculated values of the No. 1 lateral displacement amount.

8. The intersection judgement apparatus as claimed in claim 7, wherein the distance measurement circuitry is further configured to calculate the distance of the target object relative to the host vehicle based upon the image information, and the direction angle measurement circuitry is further configured to calculate the direction of the target object relative to the host vehicle based upon the radar information, and wherein the displacement amount calculation circuitry is configured to:

calculate a first position error region by adding predetermined estimated image measurement error amounts to a first obtained position of the target object, the first obtained position being expressed by values of relative distance and relative direction of the target object respectively derived from the image information;

calculate a second position error region by adding predetermined estimated radar measurement error amounts to a second obtained position for the target object, the second obtained position being expressed by values of relative distance and relative direction of the target object derived from the radar information; and

calculate a No. 1 displacement amount, by employing the image information and the radar information, only under condition that at least some degree of overlap exists between the first position error region and the second position error region.

9. The intersection judgement apparatus as claimed in claim 7, wherein the distance measurement circuitry is further configured to calculate the distance of the target object from the host vehicle based upon the image information, and the direction angle measurement circuitry is further configured to calculate the direction of the target object relative to the host vehicle based upon the radar information;

and wherein the displacement amount calculation circuitry is configured to

calculate a position difference as a distance between a first obtained position of the target object and a second obtained position of the target object, the first obtained position being expressed by values of distance and direction calculated based on the image information, and the second obtained position being expressed by values of distance and direction calculated based on the radar information, and

calculate a No. 1 displacement amount, by employing the image information and the radar information, only under condition that the position difference amount is within a predetermined error range.

10. The intersection judgement apparatus as claimed in claim 7, wherein designating a No. 2 lateral displacement amount as a lateral displacement amount that is calculated based on values of distance and direction of the target object respectively obtained based on the radar information, the intersection judgement circuitry:

evaluates a first plurality of threshold condition groups with respect to successively calculated values of the No. 1 lateral displacement amount and evaluates a second plurality of threshold condition groups with respect to successively calculated values of the No. 2 lateral displacement amount;

and

when it is judged that all of the first plurality of threshold condition groups are satisfied by values of the No. 1 lateral displacement amount while also all of the second plurality of threshold condition groups are satisfied by values of the No. 2 lateral displacement amount, judges that the target object is moving laterally towards intersection with the advancement of the host vehicle.

11. The intersection judgement apparatus as claimed in claim 1, wherein

a value of a displacement limit threshold is predetermined, higher than each of the values of the lower displacement thresholds respectively corresponding to the plurality of threshold condition groups, and

for each of the threshold condition groups, when a displacement amount exceeds the lower displacement threshold corresponding to the threshold condition group and also exceeds the displacement limit threshold, the intersection judgement circuitry omits to increment the count number accordingly.

12. The intersection judgement apparatus as claimed in claim 11, wherein the displacement limit threshold is predetermined in accordance with a type of target object required to be judged.

13. The intersection judgement apparatus as claimed in claim 1, wherein

a lower limit value of speed is predetermined in accordance with a type of target object which is required to be judged,

the intersection judgement circuitry calculates a motion speed of a target object as an average value, and

when the calculated motion speed does not attain the lower limit value of speed, the intersection judgement circuitry judges that the target object will not intersect with the advancement of the host vehicle, irrespective of the statuses of the plurality of threshold condition groups.

14. The intersection judgement apparatus as claimed in claim 1 comprising a computer incorporating a non-volatile storage apparatus having a computer program stored therein, wherein respective functions of the displacement amount calculation circuitry, the intersection judgement circuitry, the distance measurement circuitry and the direction angle measurement circuitry, are implemented by the computer in executing the stored program.

15. An intersection judgement apparatus installed on a host vehicle, comprising

distance measurement circuitry configured for receiving target object detection information from target object detection means, and for periodically calculating updated values of a relative distance between the host vehicle and a target object based on the target object information, the target object information relating to an object positioned within an external region, the external region located ahead of the host vehicle and to one side of an advancement direction of the host vehicle;

direction angle measurement circuitry configured for periodically calculating updated values of a direction angle of the target object relative to the host vehicle based on the target object information,

displacement amount calculation circuitry configured for periodically calculating updated amounts of lateral displacement of the target object based upon respective values of the calculated relative distance and calculated direction angle of the target object, each lateral displacement amount being measured along an intersection direction oriented towards and at right angles to an advancement direction of the host vehicle,

the displacement amount calculation circuitry being configured for operating at each of successive calculation timings to calculate a current position of the target object based on currently measured values of the relative distance and the relative direction and to calculate a corresponding amount of lateral displacement of the target object since the preceding calculation timing, each lateral displacement amount being measured along an intersection direction which is at right angles to the advancement direction of the host vehicle; and

intersection judgement circuitry configured for applying the successively calculated lateral displacement amounts in judgement processing, the judgement processing executed for determining whether the target object is moving to laterally intersect with the advancement of the host vehicle;

wherein

the intersection judgement circuitry executes the judgement processing based upon counting a number of calculation timings for which sequentially calculated lateral displacement amounts exceed a predetermined lower displacement threshold, and judges that the target object is moving to laterally intersect with the advancement of the host vehicle when a result of the count exceeds a predetermined count threshold.

16. The intersection judgement apparatus as claimed in claim 15, wherein the intersection judgement circuitry judges that the target object is moving laterally towards intersection with the advancement of the host vehicle under condition that a result of the count exceeds the count threshold within a predetermined count range, the count range comprising a fixed number of consecutive calculation timings.

17. The intersection judgement apparatus as claimed in claim 15, comprising a computer incorporating a non-volatile storage apparatus having a computer program stored therein, wherein respective functions of the displacement amount calculation circuitry, the intersection judgement circuitry, the distance measurement circuitry and the direction angle measurement circuitry, are implemented by the computer in executing the stored program.