JP2000009429A - Obstacle sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small, low-cost, and safe obstacle sensor with a long life wherein a lighting beam is quickly deflected without depending on mechanical action such as a motor when identifying an obstacle on a road surface which is to be detected, by providing a light-emitting means for lighting beam, its deflecting means, deflection control means, projection direction means, camera, its image memory, and a statistical calculation means for an image to a car. SOLUTION: A plurality of scan lines are arrayed with a specified interval for a bright line pattern to be projected on a surface 2 which is to be detected, and its video is imaged with a CCD camera 6 and stored in an image memory 7. The replay pattern based on the stored information is compared to a reference value relative to the bright line pattern, and an obstacle is judged to be present if the relationship between both is high while judged not present if it is low. An optical scan element formed in a semiconductor process is preferred to be used to direct the lighting beam to the surface 2 to be detected, for deflection scanning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an obstacle sensor for deflecting and irradiating irradiation light toward a surface to be detected and capturing an image of the scanned image to identify an obstacle on the surface to be detected.

[0002]

2. Description of the Related Art In Japan, more than 10,000 people have died per year due to traffic accidents, and the number of accidents has become an important social problem. Most traffic accidents are related to cars. To reduce these car accidents, it is effective to increase the intelligence of cars themselves.
Various researches on ITS (Intelligent Transportation System) are being conducted worldwide.

A typical research theme is a collision prevention system in which an obstacle detection sensor is mounted on a vehicle. According to this obstacle detection sensor, it is possible to detect an obstacle in the traveling direction, an approaching vehicle from both sides and from behind, and issue a warning to a driver, and at the same time, automatically stop the vehicle by automatically braking. Although there are various types of obstacle detection sensors, there are advantages and disadvantages in each of them, and there are few optimal ones.

For example, using a stereo camera in which two cameras are arranged at a predetermined interval, an object is photographed by both cameras at the same time, and if the difference between the two images is large, it is assumed that the obstacle is the nearest obstacle. There are sensors. According to this, an image almost equal to the driver's field of view can be obtained, and obstacles can be identified based on the actual driving environment. However, not only two precise CCD cameras are required, It is necessary to cut out an object and perform pattern matching, which increases the cost of the apparatus.

Therefore, there is a camera in which the number of expensive cameras is reduced to reduce the overall price. FIG. 12 is a diagram illustrating an example of a conventional obstacle sensor. The conventional example shown in FIG. 12 is a traveling robot 201 disclosed in JP-A-6-83442, which travels on a floor surface 208 while pulling a working mechanism 202 for cleaning the floor to the rear, and slits a laser device 204. Illuminated light L on the obstacle 206 ahead,
An image in the irradiation direction is captured by the camera 205 disposed at the upper front. To obtain the slit-shaped irradiation light L, a polygon mirror, a cylindrical lens, or the like is used.

FIG. 13 is a diagram illustrating an example of a polygon mirror. The polygon mirror 241 shown in FIG. 13 is a rotating body 242 having a hexagonal column shape, and each of the six side surfaces is a reflecting mirror 243. The rotation axis 244 of the polygon mirror is supported by the frame of the laser device 204, and is continuously rotated in one direction so that the light beam from the laser 242 hits each of the reflecting mirrors 243, and the light beam is deflected toward the obstacle 206. Then, an image 261 a of the irradiation light L is formed in a slit shape on the surface 261 of the obstacle 206.

[0007] The cylindrical lens is a light scattering lens formed in a strip shape by cutting out both sides of the concave lens except for the central part. When a light beam from the laser 242 is applied to one concave surface of the cylindrical lens, the transmitted light diverges from the other concave surface and irradiates the obstacle 206,
The image of the slit-shaped irradiation light L is displayed on the surface 26 of the obstacle 206.
1a. In addition, the laser device 2
There is also a method in which the irradiation light L is repeatedly turned toward the obstacle 206 by repeatedly rotating the light source 04 by a stepping motor.

Next, when the slit-shaped image 261a is photographed by the camera 204, the image 261a is
In order to bend along the surface of No.06, image processing simpler than the pattern matching is performed only on the bent portion,
The distance and the size to the obstacle 206 can be measured and calculated.

[0009]

However, when these conventional obstacle sensors are mounted on a vehicle to detect an obstacle on a running road surface, there are the following problems. First, when a mechanical scanning unit such as a stepping motor is used, it takes a long time to operate a mechanical structure part and cannot quickly deflect the irradiation light. Obstacles approaching can not be detected quickly.

In addition, the wear of the mechanically operating portion of the scanning means not only shortens the life of the obstacle sensor but also requires a sufficiently wide operating space for the operation. Eventually, there is a problem that a large arrangement space is required for the entire sensor.

Second, in order to obtain a clear image suitable for image processing, it is necessary to irradiate a sufficiently powerful laser beam onto the road surface from a laser device. May be dazzled. According to the radiation safety standards for laser products (JISC: 1991), in order for the laser light to be harmless to the human body, its output must be suppressed to 3 mW or less. There is a problem that detection by processing becomes difficult.

There is also a method for obtaining slit-shaped irradiation light using a cylindrical mirror. However, in order to obtain a whole image of an obstacle by this, a plurality of irradiation lights must be formed. It is necessary to equip multiple mirrors and irradiate each with laser light,
Inevitably, the size of the sensor is inevitably increased, and removal of such a problem has been an important issue.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a small, inexpensive, and safe obstacle sensor that deflects irradiation light quickly without relying on a mechanical operation of a motor or the like. To provide.

[0014]

In order to solve the above-mentioned problems, an obstacle sensor according to the present invention comprises: a light emitting means for irradiating light; a deflecting means; a deflection control means for its deflection angle;
An obstacle sensor for identifying an obstacle on the detected surface, comprising a camera for capturing an image of the detected surface, an image memory of the image, and a statistical calculation means for the stored image. A scanning line generating unit for generating the scanning lines at a predetermined cycle, and a repetitive irradiation unit for repeatedly sending out each scanning line to the deflection control means a predetermined number of times, and then issuing a write signal to the image memory. The image memory includes a storage control unit that acquires an image reception signal of a bright line pattern by each scanning line from a camera in accordance with the write signal. The arithmetic unit includes a reproduction pattern formation unit based on information stored in the image memory. A setting unit for setting a reference value of the bright line pattern, and a correlation determining unit for determining that there is an obstacle if the correlation of the reproduction pattern with respect to the reference value is high, and that there is no obstacle if the correlation is low. And wherein the door.

Therefore, after the irradiation instruction means repeatedly instructs the deflection control means to irradiate each scanning line a predetermined number of times, the image memory stores an image reception signal of a bright line pattern by the predetermined number of irradiations. A sufficiently clear image can be obtained even if the luminance of the scanning line is reduced by the irradiation of the second time.

An obstacle sensor according to a second aspect of the present invention is:
The deflecting means is characterized in that an optical scanning element formed by a semiconductor process is provided with a reflecting mirror.

By this deflecting means, the reflected light can be quickly and accurately deflected by a small driving current.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram illustrating an obstacle sensor according to an embodiment of the present invention. As shown in FIG. 1, in this embodiment, an irradiation system having a light emitting means 1 for irradiating light L, a deflecting means 3, its deflection control means 4, and an irradiation instruction means 5 for deflecting scanning, and a detection surface 2, an image memory 7 for the camera 6, an image memory 7 for the camera 6, and an imaging system having a statistical calculation means 8 for stored image information. Then, the obstacle sensor 10 entirely housed in the casing with the light projecting window for the irradiation light L
0.

First, the irradiation system will be described. The light emitting unit 1 is a known laser device, and irradiates the deflecting unit 3 with irradiation light L in a fine beam shape. The deflecting means 3 is an optical scanning element formed by a semiconductor manufacturing process. As an example, a galvano mirror 3a described later is used. This galvanometer mirror 3a
Are arranged such that the optical axis of the irradiation light L is located at the center of the built-in reflecting mirror.

The deflection control means 1 comprises a microcontroller, its control memory and peripheral circuits, a digital-analog / analog-digital converter, a comparator, a driver and the like. Then, control is performed to supply the rotating current S1 of the built-in reflecting mirror of the galvanometer mirror 3a in accordance with the scanning signal S2 from the irradiation instruction means 5 while correcting the turning current S1 in accordance with the actual turning angle of the built-in reflecting mirror. Having a part. For example, the built-in detector can detect the actual rotation angle.

This scanning signal S2 is represented by a 2 in the XY orthogonal coordinate system.
A signal for performing horizontal scanning or vertical scanning along two coordinate axes X and Y. A plurality of scanning lines based on the coordinate system are generated by the scanning signal S2, and each scanning line is projected on the traveling road surface 2. Thus, a certain bright line pattern is formed.

FIG. 2 is a block diagram of a main part of the irradiation instruction means shown in FIG. As shown in FIG. 2, the irradiation instruction means 5 is also used as an MP
U, a control memory, and its peripheral circuits. Then, a generation unit 5 of a scanning frame composed of a plurality of scanning lines
1. It has a repetitive irradiation unit 52 that repeatedly sends out a scanning signal S2 based on this scanning frame.

The generation unit 51 generates scanning information corresponding to one scanning frame and sends it to the repetitive irradiation unit 52. In this scanning frame, each scanning line has a coordinate axis X. Or it is formed in parallel with Y,
Each scanning line is arranged at a predetermined interval.

The generator 51 further includes a selector 53 for selecting coordinate axes X and Y for performing horizontal and vertical scanning. The selector 53 receives an input of the bright line pattern switching signal S3 from the arithmetic means 8. The wires are connected. In addition, the repetitive irradiation unit 5
2 includes a counter 54 for the number of irradiations of the scanning frame, and an output line of the write signal S4 to the image memory 7 is connected to the counter 54.

The irradiation of the scanning frame may be performed by scanning each scanning line once to form one scanning frame and repeating the scanning frame by the number of times of irradiation. It may form a scanning frame.

Next, the imaging system will be described. The camera 6 is an accumulation type image sensor for a bright line pattern on the traveling road surface 2, and is preferably a CCD camera, and accumulates an image of the bright line pattern as an image receiving signal S 5 and sends it to the image memory 7. Is done.

The image memory 7 receives an image signal S from the camera 6.
5, a storage control unit (not shown) for storing the received image signal S5 in accordance with the write signal S4 from the irradiation instruction means 5.
And an output line of the storage information S6 is wired from the image memory 7 to the arithmetic means 8. This stored information S
Numeral 6 stores the image of each scanning line of the bright line pattern as a grayscale image. In addition, in addition to this, the write signal S5
May be input to the normal camera 6 to regulate the exposure time of the camera 6, and the image reception signal S5 may be stored in the image memory 7 after the exposure time corresponding to the number of irradiations described above has elapsed.

FIG. 3 is a block diagram of a main part of the arithmetic means shown in FIG. As shown in FIG. 3, the calculating means 8 includes the MPU, control memory,
These peripheral circuits are also used, and a reproducing pattern forming unit 81 based on the stored information S6 from the image memory 7, a reference value setting unit 82 for the bright line pattern, and a correlation judging unit between the reference value and the reproducing pattern. 83.

In the setting section 82, reference values of two different bright line patterns are learned and registered immediately after the power is turned on and the like, and one of the reference values is based on a lateral bright line pattern orthogonal to the traveling direction of the vehicle. , Horizontal scanning is performed in parallel with the coordinate axis X. The other reference value is based on a vertical bright line pattern parallel to the running direction, and performs horizontal scanning in parallel with the coordinate axis Y.

An input line for storage information S6 from the image memory 7 is wired to the forming unit 81, and an output line for a correlation signal S7 is wired from the correlation determining unit 83 to the avoidance device 9 to be described later. From the setting unit 82, an output line of the switching signal S3 is wired to the irradiation instruction unit 5.

Next, the operation of the obstacle sensor according to the present embodiment will be described. 4A and 4B are explanatory diagrams of a case where an obstacle on the traveling road surface is detected by the obstacle sensor shown in FIG. 1, wherein FIG. 4A is a plan view of the traveling road surface viewed from directly above, and FIG. It is a sectional side view of (a). As shown in FIG. 4, according to this embodiment, an obstacle sensor 100 according to the present invention is mounted on a front roof or the like of a general vehicle 110 and detects an obstacle appearing on a traveling road surface 2 in front of the vehicle in advance. Collisions can be avoided.

That is, when the main switch is turned on to activate the obstacle sensor 100, the detection program in the control memory described above is started. Hereinafter, the flow of processing based on this detection program will be described. In addition, the function of each unit can be realized by a predetermined logic circuit.

First, the operation of the irradiation system will be described. When, for example, the above-described setting of the horizontal bright line pattern is selected by a pattern selection switch or the like (not shown), the setting unit 82 of the arithmetic unit 8 sends a switching signal S3 indicating that the horizontal direction is selected, and selects the coordinate axis of the irradiation instruction unit 5. It is sent to the unit 53. The setting unit 82 also sends a reference value for the horizontal bright line pattern to the correlation determination unit 83.

The irradiation instruction means 5 includes a coordinate axis selection unit 53
The switching signal S3 is introduced to select the coordinate axis X as the horizontal scanning direction of the scanning line and select the coordinate axis Y as the vertical scanning direction. Then, the scanning frame generation unit 51
Thus, a horizontal scanning frame is formed and sent to the repetitive irradiation unit 52.

Subsequently, the scanning signal S2 based on the introduced horizontal scanning frame is adjusted by the repetitive irradiation section 52,
A scanning signal S2 corresponding to a plurality of irradiations is repeatedly sent to the deflection control means 4. Then, the irradiation number counter 54 counts up for each irradiation, and when the counter 54 indicates a predetermined number, the above-described write signal S4 is sent to the image memory 7.

When the scanning signal S2 for one irradiation is introduced into the deflection control means 4, the deflection control means 4 supplies a rotation current S1 of the built-in reflecting mirror according to the scanning signal S2 to the galvano mirror 3a. At the same time, the laser device 1 is operated to generate the irradiation light L. Then, while repeatedly oscillating the built-in reflecting mirror of the galvanometer mirror 3a in accordance with a series of turning currents S1, the irradiation light L is deflected and scanned to scan the traveling road surface 2.
Irradiation.

On the traveling road surface 2 shown in FIG.
The coordinate axis Y is set along the traveling direction of the coordinate system, and the coordinate axis X is set in the orthogonal direction.
To 2e (five in this figure) are projected.

Next, the operation of the image pickup system will be described. When the bright line pattern is projected on the traveling road surface 2, the camera 6 captures an image of the bright line pattern. In this case, the laser output by one irradiation can be suppressed to, for example, 3 mW or less of the radiation safety standard of laser products (JISC: 1991), and sufficient protection and safety for human vision can be achieved. The irradiation light L whose laser output is suppressed in this manner
However, each of the scanning lines 2a to 2e can be
Can be increased to such an extent that it can be easily detected by the inexpensive camera 6.

Subsequently, when the write signal S4 is introduced into the image memory 6, the image memory 6 takes in the image of the bright line pattern from the camera 6 and stores it. In this case, the camera 9 continuously captures an image of the traveling road surface 2 or repeatedly captures an image for each irradiation until the writing signal S4 is transmitted from the irradiation number counter 54. Thus, the scanning lines 2a to 2e can be used as the storage information S6 of the image memory 7.

FIGS. 5A and 5B are views for explaining image processing when the vehicle shown in FIG. 4 approaches an obstacle. FIG. 5A shows an image of the obstacle by a camera, and FIG. , The luminance level of this video is shown graphically. As shown in FIG. 5, when the bright line pattern is projected on the traveling road surface 2, some of the scanning lines 2 a to 2 e are bent along the surface of the obstacle 120, and the obstacle 120 is It will be different from the bright line pattern when it does not exist above.

Therefore, in the arithmetic means 8, the forming section 81 forms a reproduction pattern based on the stored information S6, and measures the measurement lines 2f... 2f at predetermined intervals in a direction orthogonal to the scanning lines 2a to 2e (8 in this figure). Book). Then, an average value is obtained from the luminance level B at each pixel position i along each measurement line 2f... 2f, and the average value is calculated as 100%
2f and each scanning line 2a to 2e
Normalizes the brightness level B at each pixel position i where
The normalized calculation result NOB (i) is used as the correlation determination unit 83
To send to.

In this case, the reflected light from the traveling road surface 2 includes near-infrared rays due to the rise in the road surface temperature, and the illuminance of the image on the traveling road surface 2 is entirely increased by the near-infrared rays. However, since this increase in illuminance tends to cause halation in an image, if normalization of the luminance level is simply performed by an absolute value, each of the scanning lines 2a to 2e is buried in the image of the traveling road surface 2 with high illuminance. Inaccurate detection. Therefore, by normalization using the average value of the luminance levels B described above, halation due to such an increase in illuminance can be eliminated, so that each of the scanning lines 2a to 2e can be accurately detected.

Subsequently, the correlation determination unit 83 compares the calculation result NOB (i) by the forming unit 81 with a reference value NR (i) for the horizontal bright line pattern to determine the correlation between the two. For example, a difference between the calculation result NOB (i) and the reference value NR (i) is obtained for each coordinate position of the video, and the absolute value of each difference is summed to obtain a correlation value P. Alternatively, a predetermined statistical coefficient or correlation ratio may be obtained and used for determining the correlation.

Then, the obtained correlation value P is compared with two different threshold values TH by the correlation judgment section 83.
(+), TH (-) are compared to determine whether there is an obstacle in the video. That is, a hysteresis width is provided between the first threshold value TH (+) when there is an obstacle and the second threshold value TH (−) when there is no obstacle,
When the correlation value P is larger than the first threshold value TH (+), it is determined that there is an obstacle, and when it is smaller than the second threshold value TH (−), it is determined that there is no obstacle.

In this case, by providing a hysteresis width to the first and second threshold values TH (+) and TH (-), a hunting phenomenon occurs due to the presence or absence of an obstacle, and the correlation signal S7 is tuned. The oscillation of the correlation signal S7 can be avoided. continue,
The correlation signal S7 obtained in this way is converted to the avoidance device 9 described above.
To warn the driver and automatically brake the vehicle to avoid obstacles.

Next, an obstacle sensor according to another embodiment will be described. 6A and 6B are explanatory diagrams in a case where an obstacle on a traveling road surface is detected by an obstacle sensor according to another embodiment. FIG. 6A is a plan view of the traveling road surface seen from directly above, and FIG. 2 is a side sectional view of FIG. As shown in FIG. 6, in this alternative embodiment, the obstacle sensor 100 scans the irradiation light L in parallel to the traveling direction of the vehicle,
The vertical bright line pattern is projected on the traveling road surface 2 in front of the vehicle.

FIG. 7 is a diagram for explaining an image when the vehicle shown in FIG. 6 approaches an obstacle. As shown in FIG. 6, a vertical bright line pattern is projected on the traveling road surface 2, and some of the scanning lines 2 g to 2 k are bent along the surface of the obstacle 120, and the obstacle 120 travels. It is different from the bright line pattern when it does not exist on the road surface 2.

In this case, the obstacle 120 on the traveling road surface 2
However, even if it is short in the running direction of the vehicle and long in the orthogonal direction, for example, which cannot be detected by the above-mentioned horizontal bright line pattern, it can be reliably detected by this vertical bright line pattern. Preferably, by combining with a horizontal bright line pattern, it is possible to detect a short one in both the traveling direction and the orthogonal direction, and it is possible to further improve the detection accuracy of the obstacle.

Next, the galvanomirror 3a used in the obstacle sensor 100 of this embodiment will be described. FIG.
FIG. 3 is a perspective view of a configuration example of a galvanomirror shown in FIG. 2. The galvanomirror 3a shown in FIG. 8 is disclosed by the present applicant in Japanese Patent Application Laid-Open No. 7-218857.
Both surfaces of a silicon substrate 152 made of a semiconductor are sandwiched between an upper glass substrate 153 and a lower glass substrate 154 made of borosilicate glass or the like, and the respective substrates 152 to 154 are overlapped in a sandwich shape and joined to form a three-layer structure. This is a planar type galvanometer mirror having a displacement detection function. In addition to this, the present applicant has disclosed Japanese Patent Application Laid-Open No. 7-1750.
Japanese Patent Laid-Open No. 05-2005 discloses a planar galvanomirror only.

The upper glass substrate 153 and the lower glass substrate 154 are provided with recesses 153a and 154a at the center by, for example, ultrasonic processing.
The substrates 152 to 154 are joined so that the substrates a and 154a face the direction of the silicon substrate 152.

In the silicon substrate 152, a frame-shaped groove is double-cut by anisotropic etching, and an outer movable plate 155 a formed of a frame and a flat inner movable plate 15 inside the frame are formed.
5b are integrally formed of the same material. Then, the outer movable plate 155a is pivotally supported on the outer frame of the silicon substrate 152, the support shaft is used as first torsion bars 156a, 156a, and the inner movable plate 155b is pivotally supported inside the outer movable plate 155a. The support shaft is connected to the second torsion bars 156b and 156b,
6b.

Therefore, the lower and upper glass substrates 15
A sealed space is formed in both the concave portions 153a and 154a of the outer and inner movable plates 155a and 155.
b can swing individually around the first or second torsion bar 156a or 156b in the enclosed space. Furthermore, if the inside of the closed space is evacuated, both movable plates 155
a, 155b can be reduced to improve the followability with respect to the rotation drive. Further, if an inert gas is sealed in the inside, the influence of heat generation due to the rotation current S1 of the two planar coils 157a, 157b can be reduced. It can be reduced compared to vacuuming.

FIG. 9 is a plan view of the silicon substrate shown in FIG. As shown in FIG. 9, a flat coil 157a is formed on one surface of the outer movable plate 155a by an electroformed coil method using electrolytic plating, and the surface is covered with an insulating layer by surrounding the frame. Then, both ends of the planar coil 157a are pulled out onto the same surface of the silicon substrate 152 via one first torsion bar 156a to form a pair of outer electrode terminals 159a, 159a.

Similarly, a plane coil 157b is formed and coated on the same side surface of the inner movable plate 155b, and both ends thereof are connected to one second torsion bar 156b and the outer movable plate 155b.
a, and the other first torsion bar 156a is pulled out onto the silicon substrate 152 to form a pair of inner electrode terminals 159b, 159b. Also, the inner movable plate 1
A total reflection mirror 158 (constituting the built-in reflection mirror according to the present embodiment) is provided at the center of 55b.

FIG. 10 is a sectional view taken along the line BB of FIG. 9, and FIG. 11 is a sectional view taken along the line C-B of FIG.
It is sectional drawing seen from C direction. As shown in FIG. 10, two pairs of columnar permanent magnets 160a to 160g are provided on the upper and lower glass substrates 153 and 154, respectively.
163a, 160b to 163b are arranged as shown in FIG. For this reason, the opposing 2
A pair of permanent magnets 160a, 161a or 162a, 16
A magnetic field is formed by 3a and two pairs of permanent magnets 160b, 161b or 162b, 163b of the lower glass substrate 154 facing each other.

At this time, two pairs of permanent magnets 160a, 161a of the upper glass substrate 153 facing in the left-right direction of the drawing.
Alternatively, the two pairs of permanent magnets 160b, 161b or 162b, 163b of the lower glass substrate 154 have opposite polarities, for example, the N pole of the permanent magnet 160a or 162a and the permanent magnet The S pole of 161a or 163a is arranged toward silicon substrate 152.

Further, two pairs of permanent magnets 160a, 160b or 161a, 161b opposed in the vertical direction of the drawing are used.
The two pairs of permanent magnets 162a, 162b or 163a, 163b have the same polarity,
For example, the permanent magnets 160a, 161b or 162a,
The north pole of the magnet 163b and the south pole of the permanent magnets 160b and 161a are opposed to each other with the silicon substrate 152 interposed therebetween, and the positions of both magnets are shifted in the left and right directions in the drawings shown in FIGS.

With such an arrangement, each magnetic flux can be formed so as to be parallel to both ends of each of the planar coils 157a or 157b of the outer and inner movable plates 155a and 155b so as to cross each coil.
In addition, since the outer and inner movable plates 155a and 155b are turned in opposite directions at both side ends, the planar coil 157a
Alternatively, a rotational moment is generated by the Lorentz force with the rotation current S1 flowing through the first torsion bar 1
The outer movable plate 155a having the axis 56a as an axis,
Movable plate 15 with the torsion bar 156b of
5b is rotated.

As described above, according to the galvanomirror 3a having this configuration, the deflection control means 3 of the obstacle sensor 100
Rotating current S according to scanning signal S3 from irradiation instruction means 6
1 is supplied to the planar coils 157a and 157b via electrode terminals 159a and 159b outside and inside the galvanometer mirror 3a. Then, by the reflecting mirror 158,
The camera 6 can obtain an image of the bright line pattern on the traveling road surface 2 while projecting the irradiation light L on the traveling road surface 2 in front of the vehicle.

As an example of the galvanometer mirror 3a, the rotation angle of each movable plate 155a, 155b is +/- 25.
Degree, rotation speed 2.5KHz, or rotation angle +/- 45
The rotation speed of 1.5 KHz is suitable, and within these ranges, each of the torsion bars 156a, 156
b is not excessively stressed. Further, a current consumption of 220 mA or less is suitable, which is preferable as a component for a general logic circuit. Further, a sensor having a weight of about 100 g is suitable as a vehicle-mounted sensor.

Preferably, as the obstacle sensor 100,
A galvanomirror 3a having a displacement detection function capable of detecting an actual rotation angle may be used. In this case, the traveling road surface 2
Because the above image can be converted into an image signal more precisely, even if the sensor-equipped vehicle is running on the road at relatively high speed,
Even if the image is taken from an oblique direction with respect to the traveling road surface 2, it is suitable for the process of performing the identification after correcting the coordinates and the position of the obstacle and the outer shape.

Next, an example of the configuration of the displacement detecting function will be described. On the lower surface of the lower glass substrate 154, two pairs of detection coils 165a, 165b or 166a, 166b (constituting a built-in detection unit according to the present embodiment) arranged so as to be electromagnetically coupled to the planar coil 157a or 157b are printed. I do. One of the detection coils 165a and 165b is connected to the first torsion bar 156.
a, and each of the other detection coils 1
66a and 166b are arranged at symmetrical positions with respect to the second torsion bar 156b.

Each detection coil 165a, 165b or 1
66a and 166b, the mutual inductance with the planar coil 157a, the outer movable plate 155a or the inner movable plate 1
Since it changes according to the rotation angle of 55b, the amount of change can be detected to calculate the rotation angle. That is, the planar coil 15
7a and 157b are superimposed on the rotation current S1 and a detection current is supplied.
a, 165b or 166a, 166b. Then, a change in the mutual inductance is detected based on the change in the induced current, and each rotation angle can be known by calculating from the result.

The rotation angle of the outer movable plate 155a can correspond to, for example, the deflection angle of the irradiation light L reflected by the total reflection mirror 158 around the coordinate axis Y. Similarly, the rotation angle of the inner movable plate 155b can be coordinate-converted to a position in a rectangular coordinate system corresponding to the deflection angle about the coordinate axis X, and the two-dimensional coordinate position in the image on the road surface 2 can be changed. Scanning can be performed accurately.

This galvanomirror 3a with a displacement detecting function
According to this, the deflection control means 3 of the obstacle sensor 100 can supply the turning current S1 while accurately correcting the turning current S1 according to the actual turning angle of the built-in reflecting mirror 158. In addition, in addition to this, a plurality of obstacle sensors 100.
By arranging also on the front and rear portions and both side portions of the vehicle 10, obstacles approaching from the rear and both sides of the vehicle can be detected.

[0066]

As described above, according to the obstacle sensor of the present invention, the brightness of the irradiation light can be reduced each time, so that the user's visual sense is not impaired, and the optical scanning mechanism is not used. Since the scanning element is used, it is possible to provide a small, inexpensive, and safe obstacle sensor that deflects irradiation light quickly without relying on a mechanical operation of a motor or the like, and has a long life. Further, according to the obstacle sensor of the second aspect of the present invention, the deflection means can be specifically reduced in size by using the semiconductor process technology, and the power consumption thereof can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an obstacle sensor according to an embodiment of the present invention.

FIG. 2 is a block diagram of a main part of the irradiation instruction means shown in FIG.

FIG. 3 is a block diagram of a main part of the calculation means shown in FIG. 1;

FIG. 4 is an explanatory diagram when an obstacle on a traveling road surface is detected by the obstacle sensor shown in FIG. 1;

FIG. 5 is a view for explaining an image when the vehicle shown in FIG. 4 approaches an obstacle;

FIG. 6 is an explanatory diagram when an obstacle on a traveling road surface is detected by an obstacle sensor according to another embodiment;

FIG. 7 is a view for explaining an image when the vehicle shown in FIG. 6 approaches an obstacle;

FIG. 8 is a perspective view of the configuration of the galvanometer mirror shown in FIG. 1;

9 is a plan view of the silicon substrate shown in FIG.

FIG. 10 is a cross-sectional view as seen from the direction of arrows BB shown in FIG. 9;

FIG. 11 is a cross-sectional view as seen from the direction of arrows CC in FIG. 9;

FIG. 12 illustrates an example of a conventional obstacle sensor.

FIG. 13 illustrates an example of a polygon mirror.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light emission means, 2 ... Detection surface, 3 ... Deflection means, 3a ... Galvano mirror, 4 ... Deflection control means, 5 ... Irradiation instruction means,
6 camera, 7 image memory, 8 arithmetic means, 9 avoidance device, L irradiation light, S1 rotating current, S2 scanning signal,
S3: switching signal, S4: writing signal, S5: image receiving signal, S
6: stored information, S7: correlation signal.

Continued on the front page F-term (reference) 2F065 AA00 BB05 CC11 DD00 DD02 DD06 FF04 FF42 FF65 FF67 GG04 HH12 HH14 JJ03 JJ08 JJ26 LL13 LL62 MM16 NN17 NN19 PP01 QQ03 QQ13 QQ24 QQ25 QQ41 QQ12 BA01A02 AB01 BB28 CA22 CA32 CA67 CA68 CA70 CA76 DA01 DA02 DA07 EA05 EA22 EA29 EA31

Claims (2)

[Claims] 1. Light emitting means (1) for irradiating light (L), deflecting means
(3), deflection control means for the deflection angle (4), irradiation instruction means
(5), a camera (6) for imaging the surface to be detected (2), an image memory of the video (7), a statistical calculation means (8) of the stored image,
In the obstacle sensor (100) for identifying an obstacle on the detected surface (2), the irradiation instruction means (5) includes a scanning line generation unit that generates a plurality of scanning lines at a predetermined cycle. A repetitive irradiating unit that repeatedly sends out each scanning line to the deflection control means (4) a predetermined number of times, and then issues a write signal to an image memory (7), wherein the image memory (7) According to a write signal, a storage control unit for acquiring an image reception signal of a bright line pattern by each scanning line from a camera (6), wherein the arithmetic unit (8) is a reproduction pattern based on an image stored in an image memory (7). And a setting unit for setting a reference value of the bright line pattern, and a correlation determining unit that determines that there is an obstacle if the correlation of the reproduction pattern with the reference value is high, and that there is no obstacle if the correlation is low. An obstacle sensor, characterized in that: 2. The obstacle sensor according to claim 1, wherein said deflecting means comprises an optical scanning element formed by a semiconductor process and a reflecting mirror.