Vehicle-installation intersection judgment apparatus and program

Patent metadata

Field	Value
Publication number	US-9390624-B2
Application number	US-201414227371-A
Country	US
Kind code	B2
Filing date	Mar 27, 2014
Priority date	Mar 29, 2013
Publication date	Jul 12, 2016
Grant date	Jul 12, 2016

Abstract

A vehicle-installation intersection judgment 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 judgment concerning the target object is made based upon whether the count threshold is attained.

First claim

What is claimed is:

1. An intersection judgement apparatus incorporated in a PCS (pre-crash system) of a host vehicle for assisting the PCS to calculate a TTC (time to collision) with a target object, the intersection judgement apparatus 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 located ahead of the host vehicle and to one side of a longitudinal motion 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 a lateral direction which is at right angles to longitudinal motion direction of the host vehicle, and
intersection judgement circuitry configured for applying the periodically calculated lateral displacement amounts in judgement processing for judging whether the target object is moving substantially continuously along the lateral direction;
wherein:
the intersection judgement circuitry is configured to:
execute the judgement processing based on utilizing a plurality of threshold condition groups, each threshold condition group comprising a combination of a corresponding lower displacement threshold and a corresponding count threshold having respectively predetermined values, the corresponding lower displacement thresholds of the threshold condition groups being respectively different and the corresponding count thresholds of the threshold condition groups being respectively different;
apply each of the threshold condition groups in an operation of counting a number of times that sequential ones of the lateral displacement amounts exceed the corresponding lower displacement threshold of the threshold condition group, and make a determination that the threshold condition group changes from a non-satisfied status to a satisfied status when the counted number attains the corresponding count threshold of the threshold condition group; and,
judge whether the target object is moving laterally towards intersection with the longitudinal motion direction of the host vehicle, based upon evaluating the respective statuses of the plurality of threshold condition groups, with results of the judgement being supplied to the PCS for use in calculating the time to collision with the target object.

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 longitudinal motion direction 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 the respective count threshold values assigned to the threshold condition groups vary in inverse proportion to the respective displacement threshold values assigned to the threshold condition groups.

5. The intersection judgement apparatus as claimed in claim 1 , wherein for each of the threshold condition groups, the intersection judgement circuitry judges that the 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, a No. 1 lateral displacement amount 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 sequentially 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 the 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 angle 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

Assignees

• Denso Corp
• Nippon Soken

Inventors

• Minemura Akitoshi
• Ogata Yoshihisa
• Yokoyama Takahisa

Classifications

• G08G1/166 Primary

  for active traffic, e.g. moving vehicles, pedestrians, bikes · CPC title

• G01S13/867

  Combination of radar systems with cameras · CPC title

• B60R21/34

  Protecting non-occupants of a vehicle, e.g. pedestrians {(B60R19/02 takes precedence)} · CPC title

• G01S13/931

  of land vehicles · CPC title

• G01C21/265

  constructional aspects of navigation devices, e.g. housings, mountings, displays (G01C21/3688 takes precedence) · CPC title