JP2000003499A - Walker detection system and its controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to clearly distinguish a walker from a vehicle or a stopped structure and judge them even when they are a group of many irradiation points. SOLUTION: Respective irradiation points having mutual intervals less than a prescribed value out of plural irradiation points irradiated by a scanning laser radar in the front of a driver's vehicle are grouped (steps S1 to S3), the moving speed of a center of each group is derived from a distance change between the group and the driver's own vehicle (step S4), and a group of which the extended width is less than a normal value and the center moving speed is within a prescribed range out of respective groups is judged as a walker or a walker group (YES in step S5 and step S6). In remaining groups not judged as walkers or walker groups, the timewise change of an almost rectangular area occupied by each group is derived (step S8) and the group of which the timewise change of its area is less than a set value and the center moving speed is within the set range is judged as a walker group (YES in step S9, step S10).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pedestrian detection system for detecting a pedestrian to prevent a pedestrian accident, and a control method thereof.

[0002]

2. Description of the Related Art Conventionally, from the viewpoint of improving the safety of automobiles,
Various sensors have been installed to prevent accidents before they happen. Specifically, an ultrasonic sensor is attached to a place where a driver becomes a blind spot, in particular, to detect obstacles around the vehicle, or a laser radar that detects an inter-vehicle distance to a preceding vehicle while driving is mounted on the vehicle. There is a vehicle mounted on a vehicle so that a warning is issued when the inter-vehicle distance approaches a predetermined value to prevent a rear-end collision.

However, these are road structures and fixed objects,
Vehicles, etc. are to be detected, not pedestrians.
Recently, interest in preventing pedestrian accidents has been particularly increasing, and various systems for detecting pedestrians have been proposed. Specifically, there is one described in "Development of a Pedestrian Recognition Logic Using Laser Radar" on pages 363-366, preprints 961, 1996-5, Academic Lecture Meeting of the Society of Automotive Engineers of Japan.

[0004] This type of pedestrian detection system is configured, for example, as shown in FIG. In FIG. 4, reference numeral 1 denotes a scan laser radar, which comprises a semiconductor laser or the like;
The scan laser radar 1 is driven by a laser controller (not shown), and the laser light from the scan laser radar 1 is reflected by a mirror and projected to the front of the vehicle.

At this time, a stepping motor (not shown) is driven and controlled by a laser controller to rotate the mirror, and a mirror angle sensor detects the rotation angle of the mirror so that the rotation angle becomes constant. The stepping motor is controlled, and the laser beam projected forward by the rotation of the mirror is scanned by a predetermined angle such as 1 ° in a direction perpendicular to the traveling direction of the vehicle.

[0006] The laser beam scanned at a predetermined angle in this manner is applied to an object such as a vehicle or a pedestrian in front of the own vehicle, and is irradiated from the object by a light receiving element (not shown) such as a phototransistor. The reflected light is received, and the distance from the vehicle to the target object is calculated by the control computer described below based on the time and the speed of light from irradiating the laser light at each irradiation point to receiving the reflected light. .

Further, in FIG. 4, reference numeral 2 denotes a vehicle speed sensor for detecting the vehicle speed of the own vehicle, and 3 denotes a driver operation comprising various sensors for detecting various driver operation amounts such as a steering angle, an accelerator opening, and a foot brake depression amount. A detection unit 4 is a vehicle traveling direction detection unit including an azimuth sensor for detecting the traveling direction of the vehicle, an alarm output unit 5 including a buzzer, a lamp, and the like, a control computer 6, a vehicle speed sensor 2, a driver operation detection Based on output signals from the unit 3 and the vehicle traveling direction detecting unit 4, the present situation of the own vehicle such as stop or running is determined, and the laser beam is emitted by the scan laser radar 1 while the own vehicle is stopped or running. The distance to each irradiation point ahead is calculated.

The control computer 6 determines whether or not there is a group of irradiation points having substantially the same distance. If there is such a group of irradiation points, the group is determined to be a pedestrian, and is determined to be a pedestrian. From the distance between the collection of irradiation points and the own vehicle, the speed of the own vehicle, the situation of the own vehicle, etc., determine the risk of collision of the own vehicle with the collection of irradiation points determined as pedestrians,
When it is determined that the danger is high, the alarm output unit 5 is driven to notify the driver of the fact. If necessary, control such as automatic braking is performed so as to avoid a collision.

[0009]

However, in the case of the above-mentioned conventional system, basically, based on the criterion that the size of the object does not change, the irradiation point of which the distance from the own vehicle is almost the same is determined. Since only relatively small gatherings are extracted and judged as pedestrians, for example, in places where large numbers of pedestrians come and go, for example, at intersections in downtown areas in urban areas, a large number of irradiation points are gathered. Can not be judged as a pedestrian,
There is a problem that it can be determined only as a large object.

[0010] An object of the present invention is to make it possible to clearly distinguish a pedestrian from a vehicle or a stationary structure even in a group of a large number of irradiation points.

[0011]

In order to solve the above-mentioned problems, a pedestrian detection system according to the present invention scans an irradiation laser beam of a laser radar at a predetermined angle in a direction orthogonal to a traveling direction of a vehicle and forwardly. Is irradiated with laser light from the laser radar, and the distance from the vehicle to the irradiation point is calculated based on the time until the reflected light from the irradiation point in front is received. In a pedestrian detection system that performs a distance and determines whether the irradiation point corresponds to a pedestrian from a temporal change in the distance to each of the irradiation points, a mutual interval among the irradiation points is equal to or less than a predetermined value. Grouping unit for grouping objects, and a moving speed deriving unit that derives a moving speed of a center of the group from a change in distance between each of the plurality of groups formed by the grouping unit and the own vehicle. And, among the groups formed by the grouping unit, a pedestrian or a pedestrian whose moving speed at the center of the group is less than a predetermined value and whose moving speed at the center derived by the moving speed deriving unit is within a predetermined range. A first pedestrian determination unit that determines a pedestrian group; and a time of a substantially rectangular area occupied by the group among the remaining groups that are not determined to be a pedestrian or a pedestrian group by the first pedestrian determination unit. Pedestrian who determines that the temporal change of the area derived by deriving the temporal change is equal to or less than a set value and the moving speed of the center of the group by the moving speed deriving unit is within the predetermined range as the pedestrian group And a determining unit.

[0012] According to such a configuration, of the irradiation points, irradiation points which are considered to correspond to a pedestrian or a pedestrian group are grouped by the grouping unit, and these are pedestrian candidate groups. Then, the first pedestrian determination unit detects a pedestrian or a pedestrian group from these pedestrian candidate groups based on the spread width and the center moving speed. At this time, from the characteristics of the pedestrian when walking,
By setting the spread width of the group and the moving speed of the center, it becomes possible to extract a group of pedestrians or relatively small pedestrians from the pedestrian candidate groups while distinguishing them from the stationary structures.

On the other hand, the remaining pedestrian candidate groups determined not to be pedestrians or pedestrian groups by the first pedestrian determination unit are determined by the second pedestrian determination unit to be substantially rectangular occupied by the group. Pedestrians or groups of pedestrians are further detected based on the temporal change of the area and the moving speed of the center. Here, the remaining groups that are determined not to be pedestrians or pedestrian groups by the first pedestrian determination unit are, for example, those whose spread width is large and whose moving speed is fast can be also determined as vehicles. If the temporal change of the area is relatively small and the center moving speed is within the range corresponding to the human moving speed, the group is not a vehicle or a stationary structure but a relatively large group of pedestrians Can be determined.

Therefore, even in the case of a group of a large number of irradiation points, it is possible to make a distinction between a pedestrian and a vehicle or a stationary structure for judgment.

In the pedestrian detection system according to the present invention, the predetermined value serving as a reference when the grouping unit groups the irradiation points is about 0.5 m.

In this way, when a plurality of people walk together, it is normal to walk side by side with a distance equal to or less than the shoulder width of the human, so that the distance between the irradiation points is approximately the shoulder width. If these irradiation points are grouped as a group of pedestrian candidates when the distance is about 0.5 m or less (approximately 0.3 to 0.8 m), a group of a plurality of pedestrians walking together can be extracted. Can be.

Further, in the pedestrian detection system according to the present invention, when the first pedestrian determination unit determines that the pedestrian or the pedestrian group, the reference value as a reference of the spread width of the group is 1 m, When the first and second pedestrian determination units determine that a pedestrian or a group of pedestrians, the predetermined range serving as a reference for the moving speed of the center of the group is both 0.
It is characterized by being 5 to 3.0 m / sec.

In this case, since the speed range of 0.5 to 3.0 m / sec almost covers the speed at which a human walks, the spread range of the pedestrian candidates is 1 m or less. By extracting objects that are not large like vehicles and move at about the walking speed of humans,
A group of a plurality of pedestrians walking together can be accurately extracted.

Further, in the control method of the pedestrian detection system according to the present invention, the illuminated points having a mutual interval equal to or less than a predetermined value are grouped, and a plurality of groups to be formed and each of the plurality of groups are formed. The moving speed of the center of the group is derived from the change in distance, and in the first determination step, walking is performed among the groups in which the spreading width is equal to or less than a specified value and the moving speed of the center of the group is within a predetermined range. Among the remaining groups that are not determined to be pedestrians or pedestrian groups in the first determination step, and that in the second determination step, the time of the substantially rectangular area occupied by the group is determined. And that the temporal change in the derived area is equal to or less than a set value and the moving speed of the center of the group is within the predetermined range is determined as a pedestrian group. It is set to.

In this way, even for a group of a large number of irradiation points, a pedestrian can be clearly distinguished from a vehicle or a stationary structure.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. However, FIG. 1 is an operation explanation flowchart, and FIGS. 2 and 3 are operation explanation diagrams. Note that the basic configuration in the present embodiment is almost the same as the conventional one, and thus the duplicated description will be omitted.
Also, the points different from the related art will be mainly described with reference to FIG.

In the present embodiment, the function of the control computer 6 is significantly different from that of the related art. That is, the control computer 6 groups the irradiation points in front of the laser beam from the scanning laser radar 1 whose intervals are equal to or less than a predetermined value, and sets a distance between each of the plurality of groups formed thereby and the vehicle. Derives the moving speed of the center of the group from the change in the distance, and in the first determination step, walks the group in which the spread width is equal to or less than a specified value and the moving speed of the center of the group is within a predetermined range. Among the remaining groups that are not determined to be pedestrians or pedestrian groups in the first determination step, and that in the second determination step the temporal area of the substantially rectangular area occupied by the group is determined. The change is derived, and the one where the temporal change of the derived area is equal to or less than the set value and the moving speed of the center of the group is within a predetermined range is determined as the pedestrian group. It has become the jar.

As described above, the grouping process of each irradiation point corresponds to a grouping unit, the process of deriving the moving speed of the center of each group corresponds to the moving speed deriving unit, and the spread width of each group is defined. The process of determining a pedestrian or a group of pedestrians whose moving speed is equal to or less than a value and whose center is within a predetermined range corresponds to a first pedestrian determination unit, and the remaining group occupies a substantially rectangular shape. The process of judging a pedestrian group that has a temporal change in the area of not more than a set value and a moving speed at the center thereof within a predetermined range corresponds to a second pedestrian determination unit.

At this time, when the area change of the group is derived by the second pedestrian determination unit of the control computer 6, the position of each irradiation point of the group is determined by, for example, the X and Y coordinate axes whose origin is the vehicle position. Expressed as a position in a two-dimensional coordinate system (see FIGS. 2 and 3), the width of the group in the X-axis direction is derived from the minimum and maximum irradiation points of the X coordinate,
Similarly, the width of the group in the Y-axis direction is derived from the minimum and maximum irradiation points of the Y coordinate, and the derived X-axis,
The area of the rectangle determined by the width in the Y-axis direction is calculated, and its temporal change is calculated.

Here, the control computer 6 sets a predetermined value, which is a reference when the irradiation points are grouped, to 0.
It is 3 to 0.8 m. In addition, when the control computer 6 determines a pedestrian or a group of pedestrians as a reference value of a spread width of a group when the determined value is 1 m, a reference value of a moving speed of a center of the group when determining a pedestrian or a group of pedestrians is set. Is set to 0.5 to 3.0 m / sec.

In this case, when a plurality of persons walk together, it is usual to walk side by side at intervals of about the shoulder width of the person (about 0.5 m) or less. If the irradiation points are grouped as a group of pedestrian candidates when the interval is equal to or less than a predetermined value in the range of 0.3 to 0.8 m, which is about the width of the shoulder, a group of pedestrians walking together with a plurality of pedestrians Can be extracted.

Furthermore, since the speed range of 0.5 to 3.0 m / sec almost covers the speed at which a person walks, among those grouped as pedestrian candidates, the spread width is 1 m or less. By extracting an object that is not large and moves at about the walking speed of a human, such as a vehicle, it is possible to accurately extract a group of pedestrians who walk together with a plurality.

That is, considering the case where a group of pedestrians approaches the own vehicle, as shown in FIGS. 2 (a) and 2 (b), the irradiation points in the group are largely dispersed. It approaches as a lump. Therefore, when the group is approximated by a rectangle, there is almost no change in area with time. Here, the temporal change in the area is a change in the area approximated by a rectangle of the group obtained each time the scanning laser radar 1 scans. FIGS. 2A and 2B show the state of the specific group at different times.

On the other hand, considering the case where the vehicle approaches the own vehicle, first, as shown in FIG. 3A, only irradiation point data corresponding to the reflection of the laser beam from the front of the vehicle can be obtained. The groups of these irradiation points form almost straight lines and have almost no area. Then, as the vehicle approaches the vehicle, as shown in FIG. 3B, irradiation point data corresponding to the reflection of the laser beam from the side surface of the vehicle can be obtained. Will form a rectangle, so that the area of the rectangle increases in a very short time, for example, increases by more than 20% each time the scanning laser radar 1 scans.

Further, in the case of the stop structure, since the area of the stop structure does not change with time even if the spread width is large, it can be easily distinguished from a pedestrian or a car.

The group that is not extracted by the first pedestrian determination unit of the control computer 6 is formed by a group of a very large number of pedestrians or an irradiation point on a vehicle such as an automobile or a stationary structure. Group. Also, according to the determination conditions of the first and second pedestrian determination units as described above, if at least two irradiation points are obtained from one person, not a plurality of pedestrians, 1 It is possible to extract human pedestrians.

Next, the procedure of pedestrian detection will be described with reference to the flowchart of FIG.

As shown in FIG. 1, first, the scanning laser radar 1 is driven and a laser beam to be scanned is irradiated in front of the own vehicle (step S1), and the laser beam is directed to an obstacle such as a pedestrian or a car in front. The distance from the own vehicle to each irradiation point is calculated (step S2).

Based on the distance to each of the irradiation points, the interval between the irradiation points is set to a predetermined value (here,
Those within the range of 0.3 to 0.8 m) are grouped as pedestrian candidates (step S3), and the change in distance between each of the plurality of groups thus formed and the own vehicle is used as a pedestrian candidate. The moving speed V of the center of the group is derived (step S4).

Subsequently, of the grouped groups, as a first determination step, the spread width W is equal to or less than a specified value (here, 1 m) and the moving speed V of the center of the group is within a predetermined range. (Here, 0.5 to 3.0 m / sec)
Is determined (step S5).
If the result of this determination is YES, the group is determined to be a pedestrian or a pedestrian group composed of a relatively small group (step S6), and taking into account the current situation of stopping or running the own vehicle, The risk of collision of the own vehicle with a pedestrian or a group of pedestrians is determined, and when it is determined that the risk is high, the alarm output unit 5 is driven to notify the driver (step S7). ).

On the other hand, the result of the determination in step S5 is NO, that is, of the remaining groups that were not determined to be pedestrians or pedestrian groups in the first determination step, a substantially rectangular shape occupied by the group is determined as a second determination step. Is derived (step S8), the derived temporal change δ of the area is equal to or less than a set value (in this case, 20%), and the moving speed V of the center of the group is within a predetermined range. (Here, 0.5 to 3.0 m / sec) is determined (step S9).

If the result of the determination in step S8 is Y
If it is ES, it is determined that the group is a pedestrian group composed of a relatively large group (step S10), and thereafter, the process proceeds to step S7 described above. If the determination result in step S8 is NO, the group remains. The group is determined to be a vehicle other than a pedestrian or a stop structure (step S
11) Then, the process returns to the above-described step S1 together with the process of the above-described step S7.

Therefore, according to the above-described embodiment, it is possible to extract a pedestrian or a group of pedestrians from the pedestrian's walking characteristics among those grouped as pedestrian candidates. , A pedestrian and a vehicle or a stationary structure can be clearly distinguished and detected.

Further, a pedestrian group consisting of a single pedestrian or a small group can be extracted in the first determination step, and a pedestrian group consisting of a large group can be extracted in the next second determination step even if the pedestrian is not determined to be a pedestrian here. Group can be extracted,
In particular, even in a place where a large number of irradiation points can be gathered, such as a downtown area in an urban area, it is possible to reliably distinguish a pedestrian from a vehicle or a stop structure.

In the above-described embodiment, the case has been described in which the alarm output unit 5 notifies the driver when it is determined that a pedestrian or a group of pedestrians exists in front of the own vehicle. In order to avoid a collision between the detected pedestrian or a group of pedestrians and the own vehicle, the control computer 6 controls to forcibly apply braking when the own vehicle is running. Of course, while the vehicle is stopped, the vehicle may not be started until the pedestrian or the group of pedestrians passes by.

The present invention is not limited to the above-described embodiment, and various changes other than those described above can be made without departing from the gist of the present invention.

[0042]

As described above, according to the first and fourth aspects of the present invention, the spread width of the group and the moving speed of the center are set in consideration of the pedestrian's walking characteristics. Thus, after extracting a group as a pedestrian candidate from among the grouped groups, it becomes possible to further extract a pedestrian or only a pedestrian group from the remaining groups.

Therefore, even if it is a group of many irradiation points, a pedestrian and a vehicle or a stationary structure can be clearly distinguished and detected, and a pedestrian accident can be prevented.

According to the second aspect of the present invention, when a plurality of people walk together, it is usual to walk side by side at intervals equal to or less than the shoulder width of the human. When the distance between the irradiation points is about 0.5 m or less, which is substantially equal to the shoulder width, if these irradiation points are grouped as a pedestrian candidate group, a group of a plurality of pedestrians walking together can be extracted. .

According to the third aspect of the present invention,
Since the speed range of 0.5 to 3.0 m / sec almost covers the speed at which a person walks, among those grouped as pedestrian candidates, the spread width is 1 m or less, and is large like a vehicle. By extracting objects that move at about the same walking speed as a human, it is possible to accurately extract a group of a plurality of pedestrians walking together.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining the operation of an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of one embodiment.

FIG. 3 is an operation explanatory diagram of one embodiment.

FIG. 4 is a block diagram of a pedestrian detection system as a background of the present invention.

[Explanation of symbols]

1 scan laser radar 6 control computer (grouping unit, moving speed derivation unit, first and second pedestrian determination units)

Claims (4)

[Claims] 1. A laser beam emitted by a laser radar is scanned forward by a predetermined angle in a direction orthogonal to the traveling direction of the vehicle at a predetermined angle, and the laser beam is emitted forward by the laser radar to receive reflected light from a forward irradiation point. The distance from the vehicle to the irradiation point is calculated based on the time until the irradiation point is measured, and the distance to the plurality of irradiation points is measured. In a pedestrian detection system that determines whether or not to correspond to a pedestrian, a grouping unit that groups the irradiation points having a mutual interval equal to or less than a predetermined value, and a plurality of groups formed by the grouping unit A moving speed deriving unit that derives a moving speed of the center of the group from a change in distance between each of the groups and the own vehicle; and, among the groups formed by the grouping unit, a spread width is equal to or less than a specified value. And a first pedestrian determination unit that determines that the moving speed of the center of the group derived by the moving speed deriving unit within a predetermined range is a pedestrian or a group of pedestrians; Of the remaining groups that are not determined to be pedestrians or pedestrian groups by the section, the temporal change in the area of the substantially rectangular area occupied by the group is derived and the temporal change in the derived area is equal to or less than a set value and the moving speed is derived. A pedestrian detection system comprising: a second pedestrian determination unit that determines a group of pedestrians whose moving speed of the center of the group within the predetermined range is within the predetermined range. 2. The pedestrian detection system according to claim 1, wherein the predetermined value serving as a reference when the grouping unit groups the irradiation points is about 0.5 m. 3. The first pedestrian and the second pedestrian according to claim 1, wherein when the first pedestrian determination unit determines that the pedestrian or the pedestrian group, the reference value of the spread width of the group is 1 m. The predetermined range serving as a reference of the moving speed of the center of the group when the determination unit determines that the group is a pedestrian or a group of pedestrians is both 0.5 to 3.0 m / sec. 2. A pedestrian detection system according to claim 1. 4. A laser beam emitted by the laser radar is scanned forward by a predetermined angle in a direction orthogonal to the traveling direction of the vehicle while the laser beam is emitted forward by the laser radar, and reflected light from a forward irradiation point is received. The distance from the vehicle to the irradiation point is calculated based on the time until the irradiation point is measured, and the distance to the plurality of irradiation points is measured. In the control method of the pedestrian detection system for determining whether or not to correspond to the pedestrian, among the irradiating points, those having a mutual interval of less than or equal to a predetermined value are grouped, and a plurality of groups to be formed and the own vehicle The moving speed of the center of the group is derived from the distance change of the group. In the first determination step, the group whose spread width is equal to or less than a specified value and whose moving speed of the center of the group is within a predetermined range is determined. In the second determination step, among the remaining groups that are not determined to be pedestrians or pedestrian groups in the first determination step, the area of the substantially rectangular area occupied by the group is determined. A pedestrian detection system which derives a temporal change, and determines that the temporal change of the derived area is equal to or less than a set value and the moving speed of the center of the group is within the predetermined range as a pedestrian group. Control method.