JPS6279385A - Object detector - Google Patents

Abstract

PURPOSE:To detect the existence of an object in small zones regardless of the non- coincidence between set small zones in a detection area and an object monitoring area, by judging on the existence of the object based on the results of detection by a directional (e.g. bidirectional) detection area with a petal-like section. CONSTITUTION:An object behind a vehicle is detected with a sonar or the like in a directional detection area with a petal-like section. This detection are is divided into small zones, for example, eight in the number, and when an object exists in the direction of detection, detection bit D0-D7 turns to 1 in the zone corresponding to the distance by a computer processing receiving an ultrasonic wave. On the other hand, an objective monitoring area is divided into small zones, square, for instance, and the left and right parts of the small zone (i) or the like of the monitoring area are detected by the detection area, bidirectional as shown by (a) and (b) or the like. With such an arrangement, based on the combination of the detection results, the existence of the object in the small zone (i) or the like is detected. This enables the detection of an object in a small zone of the monitoring area accurately regardless of non-coincidence between the set small zones of the detection area and the object monitoring area.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to an object detection device, and more specifically, it divides a space to be monitored into a large number of small sections, and accurately detects the presence or absence of an object in the small sections. The present invention relates to an object detection device for detecting objects.

"Problems to be solved by the Invention" The present invention will be explained using a car bank sonar as a typical example of this type of object detection device.

For example, the back sonar for automobiles is disclosed in Japanese Patent Application Laid-Open No. 57-8437.
This device is disclosed in Japanese Patent No. 7, and detects the presence or absence of obstacles behind a vehicle using ultrasonic waves.

Incidentally, the ultrasonic sensor of such a bank sonar has a sensing area having a directional petal-shaped cross section, as shown in FIG. 4, for example. That is, the width of the detection NI region changes with unique characteristics depending on the distance from the ultrasonic sensor.

On the other hand, the display section of the back sonar shows the monitoring space behind the car A in small sections 41, 2, 3, 3, 4, 5, 4, 5, 4, 5, 4, 5, 4, 4, 5, 4, 4, 5, 4, 5, 4, 5, 4, 5, 4, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 2...
..., and for each small section l (II LED
There is an LED matrix 20 as shown in FIG. Each LED is displayed by blinking in response to the presence or absence of an obstacle in each small section.

Of course, the LED matrix 20 is merely an example, and there are not only such display units, but there are many displays that use the basic method of dividing the monitoring space into small sections and displaying the presence or absence of obstacles for each small section. Department is hiring.

By the way, the monitoring space is divided into squares and rectangles to make it easier for humans to understand.

It is usually divided into simple shapes like a fan.

However, as mentioned above, since the detection area of the ultrasonic sensor has a unique shape, it does not match the shape of the subdivision, and at a certain distance, the detection area of the ultrasonic sensor spans two or more subdivisions. The disadvantage arises that at a certain distance, the detection area of the ultrasonic sensor only covers part of one subdivision.

In other words, even if you intend to detect the presence or absence of an obstacle in one small section, you may be aware of an obstacle in an adjacent small section, or you may not be able to detect an obstacle even if there is an obstacle in that small section.
This may cause problems such as:

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an object detection device capable of resolving the above-mentioned disadvantages caused by the difference between the easily understandable and simple shape of the small section and the unique shape of the detection area of the sensor means. That is.

"Structure of the Invention" The object detection device of the present invention has a directional sensing area with a petal-shaped cross section, detects the relationship between the distance and the presence or absence of an object within the sensing area, and detects the relationship between the distance and the presence or absence of an object within the sensing area. sensor means capable of taking a detection direction; direction/distance selection means for selecting one or more combinations of directions and distances such that the detection area falls within a small section set within a monitoring space; and the direction/distance selection means. A configuration characterized by comprising a determining means for determining that an object is present within the small section if the presence of an object is detected in at least one combination of direction and distance selected by the means. It is.

"Example" The present invention will be described in more detail below based on the example shown in the drawings. Here, FIG. 1 is a block diagram of the configuration of an example of a scanning sonar for an automobile, which is an embodiment of the object detection device of the present invention, and FIG. 2 is a perspective view of a portion of the vehicle equipped with the scanning sonar shown in FIG. 1. , Figure 3 is a conceptual diagram showing the relationship between sonar detection directions and small sections of monitoring space,
Figure 4 is a characteristic diagram of the sonar detection area, and Figure 5 (al (
bl (cl (dl) is an explanatory diagram for determining the presence or absence of obstacles in small sections A1, C, and II. Note that the present invention is not limited to the embodiments shown in the figures.

As shown in FIG. 1, a scanning sonar 1 for an automobile is configured such that a computer 2 drives a stepping motor 4 via a driver 3 to rotate an ultrasonic unit 5.

The ultrasonic unit 5 includes a transmitting sensor 5. and receiving sensor 51
．． are located adjacent to each other.

The 40 kHz carrier wave generated by the fundamental wave generation circuit 6 becomes a pulse wave by the computer 2 opening the AND gate 7 in a 300 μs pulse shape, and is inputted to the transmission sensor 5a via the amplifier circuit 8 and the output circuit 9. . As a result, ultrasonic waves are transmitted in a pulsed manner from the transmitting sensor 5□.

The ultrasonic waves emitted in a pulsed manner are reflected externally and the reflected waves are detected by the receiving sensor 5L and sent to the amplifier circuit 1.
0. Filter 11. Detection circuit 12, programmable gain amplifier 13. Programmable peak hold circuit 14
and is input to the computer 2 as a digital value via the A/D converter 15.

The reason for using the programmable gain amplifier 13 is
This is because the further away the obstacle is, the greater the attenuation of the ultrasonic waves, making it difficult to detect, so to compensate for this, the gain is increased as time passes.

The computer 2 determines that if a reflected wave is detected within a predetermined time from when the AND gate 7 is opened and the pulsed ultrasonic wave is emitted, there is an obstacle at a distance proportional to the elapsed time until the reflected wave is detected. If no obstacle is detected even after a period of time, it is basically determined that there is no obstacle. Further, the computer 2 determines the rotational position of the ultrasonic unit 5, that is, the detection direction, from the rotation angle of the stepping motor 4.

In this way, the computer 2 can determine the presence or absence of an obstacle and its position (direction, distance).

After determining the presence or absence of an obstacle and its position (direction, distance), the computer 2 determines the presence or absence of an obstacle and its position (direction, distance).
2. The presence or absence of an obstacle is determined for each of . Details of this determination will be described later.

The determination result for each subdivision is sent to the LED matrix 2 via a decoder 16.17 and a driver 18.19.
It is displayed by blinking the LED corresponding to 0.

FIG. 2 shows the ultrasonic unit 5 and rotary table 24 installed at the left end of the rear bumper B of the automobile A.

By rotating the rotary table 24 by the motor 4,
The ultrasonic unit 5 sets its search direction to FIG.
(b), (C1... Changes like IZI.

Now, as shown in FIG. 4, the detection area of the ultrasonic unit 5 has a petal-shaped horizontal cross section.

In other words, the width at which obstacles can be detected differs depending on the distance.
For example, at a distance of 0.5 m, the detectable width is approximately 0.
5m, but at a distance of 111.25m, the detectable width expands to about 0.75m.

The computer 2 stores the detection result for one detection direction as 1 byte of data.

That is, the first bit D0 is set to 1 if there is an obstacle within the range of distance NO to 0.25 m, and set to 0 if there is no obstacle.

The presence or absence of an obstacle within a distance range of 0.25 to 0.5 m is stored in the second bit D1 (170). Similarly, 0
．． The presence or absence of obstacles between 5 and 0.75 m is determined by the third focus D2.
The presence or absence of an obstacle between 0.75 and 1.0 m is determined by the fourth bit D3.
The presence or absence of an obstacle between 1.0 and 1.25 m is determined by the fifth bit D.
4, the presence or absence of an obstacle between 1.25 and 1.5 m is indicated in the sixth bit D8, the presence or absence of an obstacle between 1.5 and 1.75 m is indicated in the seventh pit DG, and the presence or absence of an obstacle between 1.75 and 1.75 m is indicated in the seventh pit DG. The presence or absence of obstacles is the eighth
Each bit is stored as 110 in bit D7.

On the other hand, the surveillance space is divided into small sections A, B, and C.

. . . is a square section of lm×1m.

Therefore, since the shape of the detection area of the ultrasonic unit 5 and the shape of the small section do not match, the problem is how to determine the presence or absence of an obstacle in one small section. Determine as follows.

For example, when determining the presence or absence of an obstacle in subdivision A, the combiator 2 performs the following steps as shown in ta+ in FIG.
Detection result data for detection direction a (ao, a(
, a2. a3+ a4+ a! Attention is paid to the data aε of the 7th bit and the data a7 of the 8th bit among the data (l+a5, al). In addition, the detection result data for the detection direction (bo + b+ +b,,b,,bu,b
s, bt, , by), the seventh bit data b6 and the eighth bit data b7 are noted. And these 4
If any of the three data aG, al, bG, and by is 1, it is determined that there is an obstacle in subdivision A.

Figure 5 (as understood from al, l, N in the a direction
The area of the ultrasonic unit that can be detected is only the left half of subdivision A.In the 0th order b direction, the area of the ultrasonic unit that can be detected is only the right half of subdivision A. Therefore, although it is not possible to make the subdivision A look cool by using either the a direction or the b direction alone, if the detection results from both directions are combined, it becomes possible to cover almost the entire surface of the subdivision A. In this way, obstacle detection is carried out in the small section A without too much or too little.

Next, regarding the small compartment entrance, as shown in Figure 5 (b),
Data of detection results for direction b (bo.

1) l r b2+ b3. b4* b6r bG, b
? ), the presence or absence of an obstacle is determined based on the fifth bit data b and the sixth bit data b5.

This is because, as can be understood from the figure, the detection area by these and the small compartment opening almost match.

Next, regarding the subdivision C, the third bit of the data regarding the C direction is
The presence or absence of an obstacle is determined based on the second and fourth positions C3.

Next, for small section 2, as shown in FIG. 5Fdl, the first bit data d0 and the second bit data d of the detection result data in the d direction.

The presence or absence of an obstacle is determined based on 0 in the first bit of the detection result and 1 in the second bit of the detection result for the directions. This is because by combining these, a detection area that almost covers small section 2 can be obtained.

Similarly, for other small sections off, by appropriately selecting one or more combinations of detection direction and distance,
It is possible to form a detection area that almost covers the small section, thereby making it possible to accurately determine whether there are any obstacles in the small section.

As mentioned above, the determination result is displayed on the LED matrix 20, and the driver can accurately know the presence or absence of an obstacle in each small section by the blinking state of each LED of the LED matrix 20. .

Another embodiment is one in which the present invention is applied to a device in which the detection direction is changed by switching and selecting two or more sensor means having different detection directions, instead of changing the detection direction by moving the sensor means.

Furthermore, the present invention can be applied to a theft alarm system using a radar.

Furthermore, the present invention can be used in a three-dimensional space.

"Effects of the Invention" According to the present invention, there is a sensing area with a directional petal-shaped cross section, and the relationship between the distance and the presence or absence of an object is detected within the sensing area, and two or more sensing directions are provided. a direction/distance selection means for selecting one or more combinations of direction and distance such that the detection area overlaps a small section set within the monitoring space; For each combination of direction and distance,
An object detection device is provided, characterized in that it is equipped with a determination means for determining that an object is present in the small section when the presence of an object is detected in a combination of two combinations, and the shape of the detection area V4 of the sensor means is Regardless of the discrepancy in the shape of the small sections set in the monitoring space, the presence or absence of obstacles can be accurately determined for each small section.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the configuration of an example of a scanning sonar for an automobile, which is an embodiment of the object detection device of the present invention. FIG. 2 is a perspective view of a vehicle equipped with the scanning sonar shown in FIG. Figure 3 is a conceptual diagram showing the relationship between sonar detection directions and small sections of monitoring space, Figure 4 is a characteristic diagram of sonar detection areas, and Figure 5 is a diagram showing the relationship between sonar detection directions and small sections of monitoring space.
(d+ is an explanatory diagram for determining the presence or absence of obstacles in each subdivision A11B and H2. (Explanation of symbols) l... Automobile scanning sonar 2... Computer 5... Ultrasonic unit 5
8... Transmission sensor 5b... Receiving sensor 24.
...Rotary table a, b, c,..., k...Detection direction A11B, C...
..., fu...small section.

Claims (1)

[Scope of Claims] 1. (a) A sensing area having a petal-shaped cross section with directivity, detecting the relationship between the distance and the presence or absence of an object within the sensing area, and detecting in two or more sensing directions. (b) direction/distance selection means for selecting one or more combinations of direction and distance such that the detection area overlaps a small section set within the monitoring space; and (c) the direction/distance selection means. - An object characterized by being equipped with a determination means that determines that an object is present within the small section if the presence of an object is detected in at least one combination of direction and distance selected by the distance selection means. Detection device.