JP3122777B2 - Distance measuring device for unmanned vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring apparatus for an automatic guided vehicle, and more particularly, to a slit-like infrared light reflected on a wall surface of an obstacle or the like, and processing the image by processing the image. The present invention relates to a device capable of obtaining a distance and an attitude angle of an unmanned traveling vehicle.

[0002]

2. Description of the Related Art As a conventional distance measuring apparatus, there is one disclosed in Japanese Patent Application Laid-Open No. 60-81609 previously proposed by the present applicant. This distance measuring device projects an infrared laser beam from a light projecting portion toward an obstacle or the like, detects reflected light of the infrared laser beam by a light receiving portion including a position sensor such as a PSD, and uses a principle of triangulation. The distance to an obstacle or the like can be measured.

In order to determine the attitude angle of an unmanned vehicle with respect to an obstacle or a wall using such a distance measuring device, two of the above distance measuring devices are arranged at a predetermined pitch, and each distance measuring data is obtained. Can be obtained by dividing the difference by the arrangement pitch of the distance measuring device to obtain an arc tangent.

[0004]

However, in such a conventional technique, depending on the characteristics of the PSD and the lens,
There is a problem that the distance measurement range is limited to a certain range. For example, the distance cannot be measured at a short distance or a long distance, which is extremely problematic in practical use. Further, if the angle of the vehicle body of the unmanned traveling vehicle is to be obtained, there is a problem that two or more distance measuring devices must be provided. Further, there is a problem that the measurement accuracy cannot be improved.

The present invention has been devised in view of the above-mentioned circumstances, and has as its object the purpose of being able to measure an extremely wide range without limiting the range of the distance measurement, and to use a single distance measuring device to prevent the body from moving against obstacles or the like. An object of the present invention is to provide a distance measuring device capable of detecting an angle.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an apparatus for measuring a horizontal distance (L) between a vehicle body and a wall surface of an unmanned vehicle, and an infrared imaging apparatus mounted so as to be able to photograph the outside of the vehicle body. An actuator for rotating the infrared imaging device around a horizontal axis; a detecting means for detecting an angle (θk) of the infrared imaging device with respect to a vehicle body; and an optical axis that does not overlap with a central angle of view of the infrared imaging device. An infrared projection device that projects a slit-shaped infrared laser beam in the direction of the field of view of the infrared imaging device and is disposed at a predetermined distance (H) away from the infrared imaging device; Storage means for storing image data obtained by photographing with the infrared imaging device, processing means for binarizing the image data stored in the image storage means, and image binarized by the processing means data Incident angle calculating means for calculating an incident angle (θ0) of the infrared laser beam with respect to the infrared imaging device based on the incident angle (θ0) obtained by the calculating means.
Distance calculation means for calculating a horizontal distance (L) between the vehicle body and a wall surface based on 0), the angle (θk) of the infrared imaging device with respect to the vehicle body detected by the detection means, and the predetermined distance (H); It is characterized by having.

[0007]

According to the present invention, a horizontal and slit-like infrared light reflected on a wall surface of an obstacle or the like (hereinafter simply referred to as a "wall surface") is provided by an infrared imaging device provided on an unmanned traveling vehicle so as to be adjustable in angle. Is imaged, and the image is binarized, whereby a straight line of infrared light on the image data can be obtained.

At this time, the horizontal distance between the wall surface and the unmanned traveling vehicle can be obtained by examining the coordinates of the straight line of the infrared light on the image data in the image area.

In addition, since the center axis of the angle of view of the infrared imaging device does not overlap with the center axis of the infrared light, the unmanned vehicle faces the front of the wall, that is, the posture with respect to the normal drawn from the wall. Only when the angle is zero, the straight line of the infrared light on the image data is horizontal. Therefore, the attitude angle of the unmanned traveling vehicle with respect to the wall surface can be calculated from the inclination of the straight line of the infrared light on the image data.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. Reference numeral 1 denotes an unmanned traveling vehicle, which stores map data serving as a traveling route in advance in an RO described later.
A known guide that is stored in M and calculates the current travel position based on the travel distance detected by a travel distance measuring device (not shown), and can automatically travel a predetermined travel route while comparing with the map data. An example of an autonomous guided vehicle of the less system.

On one side of the body of the unmanned traveling vehicle 1,
The infrared camera 2 is attached via a support bracket 4 so as to be rotatable around a horizontal axis. In this embodiment, a stepping motor 5 is used as an actuator that can adjust the swing angle of the infrared camera 2. This is because the stepping motor 5 does not require a means for separately detecting the camera angle.

In addition, an actuator such as an electric cylinder can also be used. In such a case, a camera angle detector such as a potentiometer may be provided separately. Further, the infrared camera 2 may be provided not only at one place but also at another side of the vehicle body.

In this embodiment, the infrared camera 2 capable of photographing only infrared light is used, but in addition to this, an ordinary visible light camera may be provided with an infrared light filter to be used as an infrared imaging device. it can. The infrared camera 2 may use a wide-angle lens or a normal lens. However, when a wide-angle lens is used, it is necessary to consider a distortion amount.

At a position below the infrared camera 2 of the unmanned vehicle 1, there is provided an infrared projector 3 for projecting infrared laser light R parallel to the ground in front. As shown in FIG. 1, the infrared projector 3 can project the infrared laser beam R in a slit shape along the width direction.
The infrared laser light R can always be projected when the vehicle travels. Also, the center axis CL of the angle of view θG of the infrared camera 2
The optical axis P is set so as not to overlap.

Next, a block diagram of the present invention will be described with reference to FIG. The present invention provides a CPU 9 and a frame memory 10 capable of temporarily storing image data of the infrared camera 2.
A ROM 12 which is a read-only memory in which map data on which the unmanned vehicle 1 can travel, a distance measurement procedure described later, and the like, a RAM 11 which is a readable and writable work memory, and an infrared camera And a camera controller 13 that can control the focusing and stepping motor 5. A traveling controller 14 controls the steering device 15 based on the distance measurement data calculated by the CPU 9. In addition, the infrared projector 3
Is controlled by the CPU 9.

The camera controller 13 includes a focus controller 13A and a camera angle controller 13
B and the focus controller 13
A includes a well-known autofocus device or the like that can automatically focus because the shooting distance can change as the camera angle of the infrared camera 2 changes. The camera angle controller 13B can drive-control the stepping motor 5 by a predetermined amount. Based on the map data, the camera angle controller 13B can know a certain distance between the wall surface S and the unmanned vehicle 1 in advance. The angle of the infrared camera 2 can be automatically controlled.

Next, the distance measuring procedure of the present invention will be described in detail. As shown in FIGS. 3 and 4, the angle of view that can be photographed by the infrared camera 2 is θ G, the camera angle of the infrared camera 2 with respect to the unmanned vehicle 1 is θ K, and the vertical angle between the infrared projector 3 and the infrared camera 2 Distance is H, horizontal distance to wall S is L
Think as. Note that all values other than the horizontal distance L are known values as described above. In addition, the unmanned traveling vehicle 1
Assume that the posture angle of the vehicle body is zero, that is, the vehicle is positioned facing the front. Further, the angle between the central axis CL of the angle of view θG and the optical axis P of the infrared laser light is defined as θ0.

FIG. 5 is an enlarged view of the vicinity of the infrared camera 2 in FIG.
evice). In this case, when image data obtained by imaging the infrared laser light R reflected on the wall surface S is binarized and expressed on two-dimensional coordinates, it is obtained as binarized image data as shown in FIG.

In this example, 512 × 512 pixels are used as the binarized image data in each of the vertical and horizontal directions, and the binarized image data is temporarily stored in 256 steps of 8 bits for each pixel, for example, for each of RGB. In addition, binarization processing is performed according to an instruction from the CPU 9.

The binarization of an image captured by the infrared camera 2 is performed based on a threshold value serving as a reference.
A signal level equal to or higher than the threshold value is “1”, and a signal level equal to or lower than the threshold value is processed as “0”.
It is temporarily stored in AM11.

Since the CCD 8 of the infrared camera 2 can capture only infrared light, only the portion of the infrared laser light R reflected on the wall S has a high signal level without being affected by other disturbance light. In other parts, the signal level becomes low. Moreover, since the attitude angle of the unmanned traveling vehicle 1 is zero, pixels W having a high signal level can be obtained in a state in which the pixels W are arranged in a horizontal line. Based on this, the distance to the wall surface S is obtained as follows.

First, a coordinate position of a pixel W having a high signal level of image data in an arbitrary vertical pixel row along the Y axis is obtained.

Now, the lower limit position of the binarized image data, that is, the relative number of pixels from the Y coordinate (0) in FIG. 6 to the position of the pixel W having a higher signal level is calculated as the total number of vertical pixels (that is, 512 pixels).
) Is represented by “h”. Therefore,
At the lower limit position (Y = 0), h = 0, the intermediate position (Y = 25)
6) h = 0.5, h = 0.5 at the upper limit position (Y = 512)
It becomes 1. In FIG. 5, "h" corresponds to the CCD 8.

Here, when the tangent of the half angle of the angle of view θG of the infrared camera 2 is taken in FIG.

(Equation 1)

From equation (1), the AC, that is, the distance from the focal point to the CCD 8 can be obtained from equation (2).

(Equation 2)

When the tangent of θ0 is obtained, the result is as shown in Expression 3.

(Equation 3)

Equation 4 is obtained by substituting Equation 2 for Equation 3 to obtain θ0.

(Equation 4)

As is apparent from FIG. 4, the angle θ S formed by the reflected light of the infrared laser light R and the optical axis P is represented by θ K and θ
Since the horizontal distance L with respect to the wall surface S can be obtained by the following equation (5).

(Equation 5)

According to the above procedure, the unmanned vehicle 1 and the wall S
And the horizontal angle L with respect to the wall surface S of the unmanned traveling vehicle 1 can be obtained from the binarized image data.

The attitude angle of the unmanned traveling vehicle 1 can be obtained by obtaining two or more Y coordinates of the pixel W having a high signal level in the binary image data, and dividing each difference by a relative distance of the X coordinate. it can. That is, when the binarized image data is represented on two-dimensional coordinates, the inclination of the straight line of the pixel W having a high signal level represents the attitude angle of the unmanned traveling vehicle 1. Here, assuming that the attitude angle of the unmanned traveling vehicle 1 is α, it can be obtained by Expression 6.

(Equation 6)

In this example, since the attitude angle of the unmanned vehicle 1 is zero, the coordinates Y2 and Y1 of the pixel W having a high signal level in the binary image data are equal. Accordingly, the attitude angle α of the unmanned traveling vehicle 1 obtained by the equation 6 is also zero.
In addition, the attitude angle α of the unmanned traveling vehicle 1 is obtained by selecting a plurality of values from the binarized image data, and by averaging them, accuracy can be improved.

Next, as shown in FIG. 8, the unmanned vehicle 1
FIG. 9 shows binarized image data when a predetermined posture angle with respect to the wall surface S is maintained. In this case, since the central angle of view of the infrared camera 2 does not overlap the optical axis of the infrared projector, a pixel W having a high signal level is obtained as an approximate straight line having a predetermined inclination. Also in this case, one or more arbitrary two combinations can be extracted from the binarized image data, and the attitude angle of the unmanned traveling vehicle 1 can be calculated using Expression 6.

The distance to the wall S calculated using one pixel whose X coordinate of the binary image data is X1 corresponds to L1 in FIG. 8, L2 in X2 and L2 in X3.
It becomes 3.

Although described in detail above, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

[0035]

According to the present invention, as a result of employing the above configuration,
Since infrared light is captured as image data using an infrared light camera, there is almost no influence from other disturbance light, and extremely accurate ranging can be performed.

Further, since the photographing area of the infrared camera 2 can be changed by adjusting the photographing angle of the infrared camera, the distance measurement can be performed in an extremely wide range without being limited as in the related art. It becomes possible.

Further, since the distance and the angle between the unmanned vehicle and the wall surface can be obtained simultaneously with one infrared camera, the number of parts can be reduced as compared with the conventional configuration. Moreover, by comparing the map data stored in the ROM or the like with the position of the wall surface or the like at the same time as the distance measurement, the present invention can also be used as a travel guide device capable of sequentially correcting the current travel position calculated based on the travel distance. Furthermore, the present invention can be applied to a visual guidance vehicle that travels while taking an image of an external view with a slight improvement.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining the present invention.

FIG. 2 is a front view for explaining the present invention.

FIG. 3 is a plan view for explaining the present invention.

FIG. 4 is a front view for explaining the present invention.

FIG. 5 is an enlarged view of a main part of the infrared camera.

FIG. 6 is a block diagram of the present invention.

FIG. 7 is a plan view showing binarized image data on two-dimensional coordinates.

FIG. 8 is a plan view for explaining the present invention.

FIG. 9 is a plan view showing binary image data on two-dimensional coordinates.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Unmanned traveling vehicle 2 Infrared camera 3 Infrared light emitting device 4 Support bracket 5 Stepping motor 8 CCD 9 CPU 10 Frame memory 11 RAM 12 ROM 13 Camera controller 14 Travel controller 15 Steering device 13A Focus control unit 13B Camera angle control unit R Infrared laser Light S Wall

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI G08G 1/16 G06F 15/64 C (58) Field surveyed (Int.Cl. ⁷ , DB name) G01C 3/00-3 / 32 G01B 11/00-11/30 102 G05D 1/02 G06T 1/00 G06T 7/00 G08G 1/16

Claims (1)

(57) [Claims] 1. An apparatus for measuring a horizontal distance (L) between a vehicle body and a wall surface of an unmanned traveling vehicle, wherein the infrared imaging apparatus is mounted so as to be able to photograph the outside of the vehicle body. An actuator that rotates around an axis, a detecting unit that detects an angle (θk) of the infrared imaging device with respect to a vehicle body, and a slit-shaped infrared laser beam with an optical axis that does not overlap a central angle of view of the infrared imaging device. An infrared projector that projects in the direction of the field of view of the infrared imaging device and is located at a predetermined distance (H) from the infrared imaging device;
Storage means for storing image data obtained by photographing a laser beam projected on a wall with the infrared imaging device, processing means for binarizing the image data stored in the image storage means, and processing means Incident angle calculating means for calculating an incident angle (θ0) of the infrared laser beam with respect to the infrared imaging device based on the image data binarized in the step (a), the incident angle (θ0) obtained by the calculating means and the detection Distance calculating means for calculating a horizontal distance (L) between the vehicle body and a wall surface based on the angle (θk) of the infrared imaging device detected by the means with respect to the vehicle body and the predetermined distance (H). Characteristic ranging device for unmanned vehicles.