JP3244438B2 - Object information detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an object information detecting device. In particular, the present invention relates to a device for detecting information about a target object using electromagnetic waves.

[0002]

2. Description of the Related Art Information on a target object through electromagnetic waves, that is, the presence or absence and number of objects in a detection area, the position, distance, direction, size, moving speed, object temperature,
An object information detecting device for detecting code information such as a bar code is widely used. For example, there are a photoelectric sensor, a distance measuring device, a speed sensor, a barcode reader, and the like. These object information detection devices emit electromagnetic waves (including light and radiation) toward a detection object and receive reflected signals reflected by the object, or by receiving electromagnetic waves emitted from the object. , Object information is detected.

Incidentally, such an object information detecting device is generally housed in a case, and emits electromagnetic waves or receives electromagnetic waves through a front window. Therefore, the front window becomes sensitive to dirt, dust, snow, water droplets and the like, and if the front window becomes heavily soiled, erroneous detection may occur. For this reason, there has been proposed an apparatus provided with a dirt detection function to notify the user when the front window becomes dirty.

(Conventional distance measuring device provided with dirt detection function) As a conventional example provided with such a dirt detection function,
There is a laser distance measuring device 1 as shown in FIGS. FIG. 1 is a perspective view showing a conventional laser distance measuring apparatus 1 provided with a dirt detection function, FIGS. 2A and 2B are schematic horizontal sectional views and schematic vertical sectional views, and FIG. 3 is a block diagram showing its configuration. It is. In the case of a laser distance measuring device 1 using a laser beam, as shown in FIGS. 1 and 2, a case 3 having a front window 2 made of a glass plate or a transparent plastic plate fitted on the front surface.
A distance measuring light projecting unit 4, a distance measuring light receiving unit 5, a dirt detecting unit 6, and the like are housed therein.

[0005] As shown in FIG. 3, the distance measuring light projecting section 4 includes a scanner 8, a laser diode (LD) 9, a laser diode drive circuit 10, and a scanning position detecting device 11. The control circuit 7 includes a laser diode driving circuit 10
Is controlled, the laser light (laser pulse) L is emitted from the laser diode 9 as a pulse, the scanner 8 is driven, and the laser light L is reflected by the scanner 8, thereby scanning the laser light L within a predetermined light scanning area. Then, the target object is irradiated with the laser beam L.

[0006] The light receiving section 5 for distance measurement includes a photodiode (P
D) as shown in FIG. The light receiving element 12 receives the laser light L reflected by the target object.
The light receiving circuit 13 A / D converts a light receiving signal from the light receiving element 12 into a digital signal, and then transmits the digital signal to the control circuit 7. The control circuit 7 compares the light receiving signal level transmitted from the light receiving circuit 13 with a light receiving threshold level set inside, and monitors whether or not the light receiving element 12 receives the laser light L having a light receiving threshold level or more. .

The control circuit 7 generates a constant light emission timing, starts a counter (not shown) in synchronization with the light emission timing, and simultaneously emits the laser light L from the distance measuring light emitting section 4 in synchronization with the light emission timing. Is emitted and scanned,
The reflected laser beam L reflected by the target object and returned is received by the distance measuring light receiving unit 5. When the control circuit 7 determines that the light receiving element 12 has received the reflected laser light L having a light receiving threshold level or more, the control circuit 7 stops the counter. , A propagation delay time td until light reception is measured, and a distance to the target object is calculated based on the propagation delay time td.

In the case of the laser distance measuring apparatus 1 mounted on a vehicle, the distance to a target object such as a preceding vehicle may be calculated in consideration of the speed of the own vehicle measured by the vehicle speed sensor 16. . Further, the emission direction (scanning direction) of the laser light L by the scanner 8 is determined by the scanning position detecting device 11.
And the scanning position information is transmitted to the control circuit 7, so that the direction in which the target object exists can also be detected.

In such a laser distance measuring apparatus 1, there is a front window 2 for transmitting the laser beam L and receiving the reflected light. The dirt on the front window 2 greatly affects the basic performance of the laser distance measuring device 1 because the laser light L is attenuated and diffused by the dirt due to the use environment.
If it is very dirty, it will not serve as the laser distance measuring device 1.

Therefore, the laser distance measuring device 1 is provided with a dirt detecting section 6 comprising a dirt detecting photodiode 14 and a dirt detecting light receiving circuit 15, and as shown in FIG. Laser light L emitted and scanned
Is reflected at the end of the scanning area at the interface between the outer surface of the front window 2 and the air, and the reflected laser light L (dirt detection light R) is detected by the dirt detector photodiode 14. The light receiving circuit 15 converts the light receiving signal of the dirt detecting photodiode 14 into a digital signal by A / A.
After the D conversion, it is transmitted to the control circuit 7. The control circuit 7
The light receiving signal level received from the light receiving circuit 15 is compared with a predetermined stain determination threshold level, and when the light receiving signal level of the light receiving element 12 becomes higher than the stain determination threshold level as shown in FIG. It is determined that the reflected light has increased due to dirt.

[0011]

However, in the conventional dirt detection processing system, the detection accuracy of dirt in the laser distance measuring device has been reduced for various reasons as described below, for example.

[0012]

[0013]

[0014]

( First Problem ) First , in the conventional dirt detection processing method, dirt is detected only at the end of the scanning area of the laser beam L. That is, as shown in FIG. 5A, the dirt detecting unit 6 adjusts the detection area A to the end of the scanning range on the front surface of the front window 2 of the laser beam L emitted from the distance projecting unit 4. The laser beam L emitted to the end of the scanning range is received by the dirt detector 6 to determine the presence or absence of dirt.

For this reason, as shown in the laser pulse for one scan in FIG. 5B, the dirt on the window position at the timing of detecting the dirt and the dirt on the window position at the timing of actually performing the distance measurement process. May not match, which is one of the causes of lowering the accuracy of dirt detection.

( Second Problem ) Secondly , in the conventional dirt detection processing method, only when dirt is detected in a part of the scanning region of the laser beam (particularly, at the end of the scanning region), laser distance measurement is performed. All distance measurement data of the device was invalidated. However, even if dirt is detected in a part of the scanning area, if it is judged as the entire scanning area of the laser beam,
In some cases, the distance could still be measured sufficiently, and the operable state of the laser distance measuring device did not match the dirt determination, and the reliability of the dirt determination was low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a variety of object information detecting devices that can reduce the contamination of transparent or almost transparent members through which electromagnetic waves pass. It is to enable detection with detection accuracy.

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

DISCLOSURE OF THE INVENTION The object information detecting device according to claim 1 is
Electromagnetic wave radiating means including at least an electromagnetic wave detecting means of the electromagnetic wave radiating means and the electromagnetic wave detecting means, and transmitting a transparent or almost transparent member in a wavelength range of the electromagnetic wave radiated from the electromagnetic wave radiating means or the electromagnetic wave received by the electromagnetic wave detecting means. A device for detecting information on an object by radiating electromagnetic waves from or receiving electromagnetic waves by electromagnetic wave detecting means, wherein a dirt detecting transmitter for transmitting electromagnetic waves for detecting dirt attached to the transparent or almost transparent member And a dirt detection receiver that receives an electromagnetic wave for dirt detection, and splits the electromagnetic wave received by the electromagnetic wave detection unit,
Signal receiving means for invalidating a signal due to an electromagnetic wave passing through a portion where the dirt detection receiver has detected dirt.

In the object information detecting device according to the first aspect , even if the dirt is detected by the dirt detecting receiver, the object information cannot be detected due to the dirt without immediately stopping the operation of the object information detecting device. It is possible to invalidate only possible portions and continue the operation of the object information detection device in the remaining portions. Therefore, even if the object information detection device becomes dirty, the object information detection device can be operated as long as it can be operated, and the operation of the object information detection device can be stopped when the device cannot be used finally. improves.

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040] The object information detecting device according claim 1, Among the electromagnetic wave light (visible light, infrared, ultraviolet, etc.) those using a typical, receives the light emitted from the light emitting element by a light receiving element Information on the object,
That is, it is common to detect the presence or absence and number of objects in the detection area, the position, distance, direction, size, moving speed, object temperature, and code information such as a barcode of the object.

The transparent or almost transparent member is a member in an environment where dirt adheres. In particular, a front window of a case accommodating the electromagnetic wave radiating means and the electromagnetic wave detecting means, an object information detecting device. When the is mounted on a vehicle or the like, there is a windshield or the like.

Further, the transmitter for contamination detection may also serve as an electromagnetic wave radiating means. The dirt detection receiver may also serve as the electromagnetic wave detection means.

[0043]

FIG. 6 is an external perspective view of a laser distance measuring apparatus (laser radar) 21 according to an embodiment of the present invention, FIG. 7 is a schematic longitudinal sectional view thereof, and FIG. 8 is a schematic horizontal sectional view thereof. . The laser distance measuring device 21 is housed in the case 3, and a front opening 2 made of a glass plate or a transparent plastic plate is provided in a front opening of the case 3. Thus, the distance measuring light emitting unit 4 housed in the case 3
From there, the laser light L for distance measurement is emitted and scanned to the detection area through the front window 2, and the reflected laser light L reflected by the target object is received by the distance light receiving unit 5 through the front window 2.

An eave portion 22 extends forward from an upper edge portion of the front surface of the case 3, and two dirt detecting light emitting portions 23 a and 23 b are accommodated in the eave portion 22.
On the other hand, in the vicinity of the distance measuring light projecting unit 4, a light detecting unit 24 for detecting dirt on the light projecting side is arranged. Further, the light receiving section 5 for distance measurement in the case 3 also serves as a light receiving section for detecting dirt on the light receiving side. Thus, the dirt detection light (laser light) R is emitted from the dirt detection light emitting units 23a and 23b accommodated in the eaves 22 toward the dirt detection light receiving unit 24 and the distance measuring light receiving unit 5, respectively. Thus, the dirt on the front window 2 on the light emitting side and the light receiving side is monitored.

FIG. 9 is a block diagram showing the configuration of the laser distance measuring device 21. The structures and functions of the distance-measuring light projecting unit 4, the distance-measuring light-receiving unit 5, the scanning position detecting device 11, the vehicle speed sensor 16, etc., the algorithm for the distance measurement of the control circuit, and the like are the same as those in the conventional example. The description is omitted again, and the same reference numerals are given to the same components.

Each of the dirt detecting light emitting portions 23a and 23b accommodated in the eave portion 22 includes a dirt detecting light emitting element (laser diode) 25 and a light emitting element driving circuit 27. The dirt detection light-receiving unit 24 includes a dirt detection light-receiving element (photodiode) 28 and a light-receiving circuit 30.

When the control circuit 17 controls the light emitting element drive circuit 27, the light emitting units 23a and 23b
The dirt detection light R is emitted in a pulse form from each of the dirt detection light emitting elements 25, and the dirt detection light R passes through the front window 2 and enters the dirt detection light receiving unit 24 and the distance measuring light receiving unit 5. The dirt detection light receiving unit 24 receives the dirt detection light R that has entered on the light receiving surface of the dirt detection light receiving element 28. The light receiving circuit 30
Converts the light receiving signal of the dirt detecting light receiving element 28 into a digital signal
After the A / D conversion, the received light signal level information is transmitted to the control circuit 1
Send to 7. The distance measuring light receiving unit 5 also receives the incident dirt detection light R on the light receiving surface of the distance measuring light receiving element 12. The light receiving circuit 30 A / D converts the light receiving signal of the distance measuring light receiving element 12 into a digital signal, and then transmits the light receiving signal level information to the control circuit 17.

The control circuit 17 compares the light receiving signal level received from the light receiving circuit 30 of the light detecting section 24 for dirt detection with a predetermined dirt determination threshold level. If dirt adheres to the outer surface of the front window 2, the transmitted light is blocked and the light reception signal level of the dirt detection light-receiving element 28 is reduced. As shown in FIG. If the light receiving signal level of the element 28 is an abnormal level equal to or lower than the dirt determination threshold level, it is determined that the front window 2 is dirty, and the light receiving signal level of the dirt detecting light receiving element 28 is equal to or higher than the dirt determination threshold level. , It is determined that the front window 2 is not dirty. When the control circuit 17 determines that the dirt is severe, the control circuit 17 sounds an alarm buzzer or displays a warning message on a display panel or the like. Note that a plurality of stain determination threshold levels may be set, and the output of the distance measurement data may be stopped when the stain becomes more severe.

The user, who has received the warning that the front window 2 is very dirty, cleans the front window 2 and presses a reset button or the like to operate the dirt detection function again.

When receiving the light receiving signal level information from the light receiving circuit 13 of the distance measuring light receiving section 5, the control circuit 17 determines whether the received light receiving signal level information is due to the distance measuring laser light, It is determined whether the detection light R is generated. When it is determined that the light reception signal level information is based on the dirt detection light R, the dirt determination threshold level is set in the same manner as when the light reception signal level information is received from the light receiving circuit 30 of the dirt detection light receiving unit 24. Then, it is determined whether or not a predetermined amount or more of dirt is attached to the front window 2, and necessary processing such as an alarm buzzer is executed according to the determination result.

FIG. 11 is a view for explaining an example of a method for distinguishing between the laser beam L for distance measurement and the dirt detection light (laser light) R. FIG. 11A shows a light emitting section for distance measurement. The light emission timing of No. 4 and FIG.
The light emission timing of FIG.
The light emission timing of 3a, FIG.
FIG. 11 (e) shows the light receiving timing of No. 4 and FIG. After the distance measuring light projecting unit 4 emits the distance measuring laser light L as shown in FIG. 11A, the distance measuring light receiving unit 5 is irradiated with the distance measuring laser light L as shown in FIG. 11D. Is obtained from the propagation delay time td until the light is received. During the period deviating from the distance measurement timing, the dirt detection light emitting units 23a, 23
3b emits dirt detection light R, and the dirt detection light-receiving unit 2
The degree of dirt is determined from the level of the received light signal of the dirt detection light R received by the light receiving unit 4 and the light receiving unit 5 for distance measurement. Accordingly, the distance measuring light receiving unit 5 receives the distance measuring laser light L and the dirt detection light R, but since the light receiving periods are different, the distance measuring laser light L and the dirt detection light R can be distinguished. It has become.

FIG. 12 is a flowchart showing an algorithm for the control circuit 17 to make a dirt determination. When the dirt determination is made N times in succession, an alarm or the like is output to perform error processing. That is, when the control circuit 17 receives the light receiving signal level information from the light receiving circuit 30 or 13 (S
31) The light receiving signal level is compared with the contamination determination threshold level (S32). If the received light signal level is equal to or less than the contamination determination threshold level, the error counter is increased by "1" (S33). If the level is equal to or higher than the dirt determination threshold level, the error counter is reset to "0" (S34). When the error counter is incremented, it is determined whether or not the value of the error counter is equal to or more than a predetermined value N (S35). Counter is N
If so, error processing is performed (S36). That is, an alarm is sounded or displayed on the display panel.

As described above, in the dirt detection system provided in the laser distance measuring apparatus 21, dirt is detected by the dirt detection light R transmitted through the front window 2, so that dirt can be detected accurately. it can. Therefore, even when the laser distance measuring device 21 is attached to the lower part of the vehicle (for example, at the bumper position) and is easily contaminated, it is possible to call attention before the contamination becomes severe and erroneous distance measurement is performed.

(Second Embodiment) FIG. 13 is a schematic sectional view showing a laser distance measuring device 37 according to another embodiment of the present invention. In this embodiment, the dirt on the front window 2 is detected by the transmitted light transmitted through the front window 2 of the laser distance measuring device 37.
a, 23b or dirt detecting light emitting elements 25, 25 are arranged on the front side surface of the case 3.

That is, in this embodiment, the case 3 has two side walls 38 extending forward from one side surface.
The two dirt detecting light emitting portions 23a and 23b or the dirt detecting light emitting elements 25 and 25 are accommodated. The dirt detecting light receiving portion 24 in the case 3 and the distance measuring device from the dirt detecting light emitting portions 23a and 23b through the front window 2. The dirt detection light R is emitted to the light receiving unit 5 for use.

As exemplified in this embodiment, the position where the dirt detecting light emitting portions 23a and 23b are arranged may be any position outside the front window 2.

(Third Embodiment) FIG. 14 is a schematic sectional view showing a laser distance measuring apparatus 39 according to still another embodiment of the present invention. In this embodiment, two dirt detecting light receiving portions 24a and 24b or dirt detecting light receiving elements 28 and 28 are provided in a side wall portion 38 extending forward of the front window 2 from the case 3.
In the case 3, a light emitting unit 23 for detecting dirt is provided in the case 3 together with the light projecting unit 4 for distance measurement and the light receiving unit 5 for distance measurement.

After the dirt detection light R emitted from the dirt detection light emitting section 23 is transmitted through the front window 2, one of the dirt detection light receiving sections 24b and the dirt detection light receiving element 28
Then, it is determined whether or not the front window 2 is dirty in front of the distance measuring light receiving unit 5 from the light receiving signal level.
Further, the distance measuring light projecting section 4 also serves as a dirt detecting light emitting section, and a part of the laser light L emitted from the distance measuring light projecting section 4 is transmitted to the front window 2 as dirt detecting light R. By allowing the other dirt detection light receiving section 24a or the dirt detection light receiving element 28 to receive light, it is determined from the light reception signal level whether the front window 2 is dirty in front of the distance measuring light emitting section 4.

As shown in this embodiment, of the dirt detecting light emitting portion 23 and the dirt detecting light receiving portions 24a and 24b,
Any may be outside the front window 2 and any may be inside the front window 2.

(Fourth Embodiment) FIG. 15 is a schematic perspective view showing a laser distance measuring apparatus 41 according to still another embodiment of the present invention. In this embodiment, the distance-measuring light projecting section 4 and the distance-measuring light-receiving section 5 are arranged on the left and right, and the laser light L emitted from the distance measuring light projecting section 4 is scanned left and right. I have. Further, the dirt detection light receiving unit 24 is disposed below and slightly forward of the distance measuring light emitting unit 4.

The detection area of the dirt detection light receiving section 24 is shown in FIG.
As shown in FIG. 6A, the laser beam L emitted from the distance measuring light projecting unit 4 and scanned left and right is set to include the scanning range on the front surface of the front window 2. Therefore, the laser beam L emitted from the distance measuring light projecting unit 4 is transmitted to the front window 2
And is used for distance measurement, and a part thereof is reflected by the front surface of the front window 2. As shown in FIG. 16B, a part of the laser light L reflected on the front surface of the front window 2 is received as the dirt detection light R by the dirt detection light-receiving unit 24, and its light receiving signal level and dirt determination are performed. By comparing with the threshold level, it is determined whether or not the front window 2 is dirty (see FIG. 4).

FIG. 17 is a block diagram showing the configuration of the laser distance measuring device 41. The laser distance measuring device 41 includes a data selection circuit 42 for selecting and outputting distance measurement data output from the light receiving section 5 for distance measurement. The data selection circuit 42 determines the scanning direction of the laser light (laser pulse) L causing the contamination on the basis of the contamination data received from the contamination detection light-receiving unit 24. The distance measurement data from the scanning direction that is present is invalidated, and only the distance measurement data from the scanning direction that does not cause contamination is output to the control circuit 17 as valid data.

As shown in FIG. 18A, the laser beam L emitted from the distance measuring light projecting unit 4 and scanned [FIG. 18A shows a laser pulse for one scan] As shown in FIG. 18B, the light is received by the distance measuring light receiving unit 5.
At this time, since the light beam (laser pulse) L scanned in the direction in which the target object exists is received by the distance measuring light receiving unit 5 at a large light receiving signal level, as shown in FIGS. The distance from the propagation delay time td to the target object is measured.

When the front window 2 is not dirty,
Although the reflection by the front window 2 is small and the light reception signal level in the dirt detection light receiving unit 24 is also small as shown in FIG. 18C, the reflection of the laser beam L emitted in that direction when the front window 2 becomes very dirty. Since the amount increases, the amount of light received by the dirt detecting light receiving unit 24 increases, and becomes equal to or higher than the dirt determination threshold level as shown in FIG.

Therefore, in this dirt detection method, the dirt on the front window 2 can be monitored over the entire scanning range of the light beam L for distance measurement, and the dirt on the window position at the timing of detecting dirt is actually measured. The dirt at the window position at the timing of performing the distance processing matches, and the accuracy of dirt detection can be improved. In addition, a dirty portion of the front window 2 can be determined.

Further, in this embodiment, it is possible to extract a portion (scanning direction) where the dirt is severe and the light receiving signal level is higher than the dirt determination threshold level.
As shown in FIG. 18 (e), the data selection circuit 42 invalidates the distance measurement data from the heavily soiled portion of the laser light L received by the distance measurement light-receiving unit 5 (the invalid data is replaced with the invalid data in FIG. 18). (E) is indicated by a two-dot chain line pulse), and other distance measurement data is made effective (effective data is shown in FIG. 18).
The distance to the target object can be measured (shown by a solid line pulse in (e)). Whereas conventional laser distance measuring equipment invalidates all distance measurement data when detecting dirt even in a part, this method can expand the effective range of distance measurement data and laser measurement for dirt The operating life of the distance device 41 can be extended.

(Fifth and Sixth Embodiments) FIG. 19 is a side view showing a vehicle (automobile) 57 equipped with a laser distance measuring device 56 according to still another embodiment of the present invention, and FIG. It is an enlarged view. This laser ranging device 56
Is mounted on the dashboard of the vehicle 57, and within the case 3, a distance measuring light emitting unit 4 (also serving as a dirt detecting light emitting unit), a distance measuring light receiving unit 5, and a dirt detecting light receiving unit 24 are built-in.

Thus, the laser beam L emitted from the distance measuring light projecting section 4 is projected forward through the windshield 58 of the vehicle 57 and scanned in the vertical direction or the vertical and horizontal directions. The distance measuring light receiving unit 5 receives the laser beam L reflected by the target object and returns, and measures the distance to the target object from the propagation delay time td from the emission to the light reception. The emblem 60 provided on the hood 59 of the vehicle 57 is selected as a reference object for detecting dirt, and a part of the laser light L emitted from the distance measuring light emitting unit 4 and scanned. Is reflected by the emblem 60 on the hood 59 and returned, and is received by the dirt detection light receiving unit 24. The dirt detection light receiving unit 24
The dirt on the windshield 58 is detected by comparing the light receiving signal level with the dirt determination threshold level.

The reference object to be selected is not limited to the emblem 60 but may be any one. For example, besides the emblem 60, a grill can be selected as the reference object. That is, as in the embodiment shown in FIG.
Connect the laser distance measuring device 61 to the grill 62 on the bumper 63
Of the laser light L emitted from the distance measuring projector 4 for distance measurement, the laser light L passing through the gap of the grill 62 is used. For detecting dirt on the front window 2, the grill 62 is used. The laser light L reflected by the light source may be used as the dirt detection light R.

In these dirt detection systems, as in the first embodiment, dirt is detected using transmitted light.
Dirt can be accurately detected, and detection accuracy is improved. Further, it is possible to warn the user before erroneous distance measurement is performed due to heavy contamination.

(Seventh to Ninth Embodiments) FIG. 22 is a schematic horizontal sectional view showing a laser distance measuring apparatus 71 according to still another embodiment of the present invention. In this laser distance measuring device 71, the side wall portions 38 extend from both sides of the case 3 in which the distance measuring light projecting portion 4 and the distance measuring light receiving portion 5 are accommodated.
The dirt detecting light emitting unit 23 and the dirt detecting light receiving unit 24 are arranged so as to face each other at a position forward of the front window 2 in the inside 8. The front surfaces of the dirt detection light emitting unit 23 and the dirt detection light receiving unit 24 are covered by side windows 72 extending from the front window 2.

The dirt detecting light (laser light) R emitted from the dirt detecting light emitting unit 23 passes near the front window 2 in parallel with the front surface of the front window 2 and passes through the dirt detecting light receiving unit 24. Incident on If a relatively large dirt D such as mud or snow adheres to the front window 2, as shown in FIG. 23, the dirt detection light R is blocked by the dirt D such as mud or snow. When the light receiving signal level decreases and becomes equal to or lower than the dirt determination threshold level, it is determined that dirt is present.

In these dirt detection systems, as in the first embodiment, dirt is detected using transmitted light, so that dirt can be detected accurately and detection accuracy is improved. Further, it is possible to warn the user before erroneous distance measurement is performed due to heavy contamination.

The laser distance measuring device 73 shown in FIG. 24 is a modification of the above-described embodiment, and includes a dirt detecting light emitting portion inside an eave portion 22 and a bottom portion 74 extending forward from the upper and lower portions of the case 3. 23 and a dirt detection light receiving section 24 are arranged.

The laser distance measuring device 75 shown in FIG.
Is also a modification of the above-described embodiment, in which a recess 76 is formed in a part of the front window 2, and the recess 76 is sandwiched between the recess 76.
A dirt detecting light emitting unit 23 and a dirt detecting light receiving unit 24 are disposed on both side surfaces of the front window 2, and the dirt on the front window 2 is determined by detecting the dirt on the concave portion 76.

(Tenth to Twelfth Embodiments) FIGS. 26 and 27 are sectional views showing a laser distance measuring apparatus 81 according to still another embodiment of the present invention. This laser ranging device 8
In 1, the distance measuring light projecting unit 4 also functions as a dirt detecting light emitting unit, and the distance measuring light receiving unit 5 also functions as a dirt detecting light receiving unit. The distance measuring light receiving section 5 is composed of a plurality of sets of distance measuring light receiving elements 12a, 12b,... And light receiving circuits 13a, 13b,.
are arranged in a grid pattern close to the front window 2.

FIG. 28 shows a laser distance measuring device 8 of the above.
1 is a block diagram showing a configuration of FIG. Each light receiving circuit 13a,
The light-receiving signal level information output from 13b,... Is input to the dirt determination circuit 82 and the data selection circuit 42. The dirt discriminating circuit 82 determines the level of the light receiving signal output from each of the light receiving circuits 13a, 13b,... When the distance measuring light projecting unit 4 is off and the distance measuring laser light L is not projected. Compare. When the distance measuring light projecting unit 4 is off, disturbance light such as sunlight is incident on the distance measuring light receiving unit 5.
In this case, if the front window 2 is clean, the light receiving signals received by the respective light receiving elements 12a, 12b,... Of the distance measuring light receiving section 5 and output from the light receiving circuits 13a, 13b,. The levels are almost equal to each other. However, if a part of the front window 2 becomes dirty, the corresponding light receiving elements 12a and 12
b,... the amount of light received by the light receiving circuit 1 is reduced.
The levels of the light receiving signals output from 3a, 13b,. Therefore, the dirt discriminating circuit 82 is connected to each light receiving circuit 13
By comparing the levels of the light receiving signals output from the a, 13b,..., the distance measuring light receiving elements 12a, 12b,. For example, when the light receiving signal level is shifted by a predetermined ratio or more with respect to the average value of all the light receiving signals, it is determined that the received signal is the laser light L that has passed through the dirt. Then, the dirt determining circuit 82 determines the distance measuring light receiving elements 12a and 12a.
.. are transmitted to the data selection circuit 42. When the data selection circuit 42 receives the element numbers of the light receiving elements 12a, 12b,... Corresponding to the dirt from the dirt determination circuit 82, the data selection circuit 42 registers the element numbers.

The distance measuring light projecting section 4 is turned on, the distance measuring laser light L is projected and scanned by the scanner 8, and the laser light L reflected by the target object is reflected by the distance measuring light receiving section 5. When light is received, the data selection circuit 42
The light receiving signals output from 3a, 13b,... Are transferred to the control circuit 17. At this time, an invalid marker signal is added to the light receiving signals output from the light receiving elements for distance measurement 12a, 12b,.
Transfer to The control circuit 17 measures the distance to the target object based on all the remaining light receiving signals excluding the light receiving signal to which the invalid marker signal is added.

Therefore, according to this embodiment, the front window 2
It is not necessary to immediately invalidate the detection result of the laser distance measuring device 81 even if dirt is detected in a part of the distance measuring device 81. The distance measuring light receiving element 12a, which receives the laser light L that has passed through or is blocked by dirt, is not necessary. 12b are invalidated, and the measurement can be continued with the remaining light receiving elements for distance measurement 12a, 12b,. Therefore, it is possible to prevent a problem that the laser range finder 81 stops operating immediately when dirt is detected in a part of the front window 2.

In this embodiment, the position of the front window 2 where dirt is adhered and the distance measuring light-receiving element 12
There is a problem that the correspondence with a, 12b,... may change with time due to a change in the sun position or the like. One method of solving this problem is to always correct the relationship between the portion of the front window 2 where the dirt is adhered and the light receiving elements for distance measurement 12a, 12b,... At short time intervals. That is, for example, a method is employed in which the distance measuring light receiving elements 12a, 12b,... Receiving light passing through the dirt are checked every few minutes, and the element numbers for adding invalid marker signals are constantly updated.

As another method, as shown in FIG. 27, the front window 2 and the light receiving elements 12a, 12b,.
Is made as close as possible so that the shift of the light receiving position due to the direction of the light beam becomes as small as possible. As still another method, a laser distance measuring device 8 shown in FIG.
As shown in FIG. 3, the hood 84 extends from the periphery of the case 3 to cut off disturbance light from an oblique direction, so that the light transmitting position of the front window 2 and the light receiving positions of the distance measuring light receiving elements 12a, 12b,. There is a method of making a one-to-one correspondence.

In the above embodiment, the light receiving section 5 for distance measurement is used.
Used a number of light emitting elements for distance measurement 12a, 12b,..., But the light receiving surface was divided like a photodiode (PD) array like a laser distance measuring device shown in FIG. The distance measuring light emitting element 12 may be used.

In this embodiment, the dirt detection light (laser light) R is spatially divided by using a plurality of distance measuring light receiving elements or an array type distance measuring light receiving element. The fourth embodiment is one in which the dirt detection light (laser light) R is temporally divided using one distance measuring light receiving element.

(Thirteenth Embodiment) FIG. 31 is a sectional view showing a laser distance measuring apparatus 86 according to still another embodiment of the present invention. In this laser distance measuring device 86, a prism-shaped projection 87 is provided on a part of the front window 2, and the dirt detection light emitting unit 23 is arranged so as to emit the dirt detection light R toward the projection 87. The dirt detection light receiving unit 24 is arranged so as to receive the dirt detection light R emitted from the dirt detection light emitting unit 23 and totally reflected twice by the projection 87.

If no water droplets (dirt) such as rain or melted snow adhere to the front window 2, FIG.
As shown in FIG. 7, the dirt detection light R emitted from the dirt detection light emitting unit 23 and totally reflected twice by the projection 87 is received by the dirt detection light receiving unit 24. The level is equal to or higher than a predetermined value (dirt determination threshold level). On the other hand, when the water droplet 88 adheres to the front window 2 and adheres to the surface of the projection 87, the water droplet 8
Since the refractive index of FIG. 8 is larger than the refractive index of air, FIG.
As shown in (b), a part of the dirt detection light R emitted from the dirt detection light emitting unit 23 and incident on the projection 87 is a water drop 88.
And the amount of the dirt detection light R incident on the dirt detection light receiving unit 24 decreases, and becomes less than a predetermined value. Therefore, the presence or absence of dirt can be determined from the light receiving signal level at the dirt detecting light receiving unit 24.

(Fourteenth Embodiment) FIG. 33 is a sectional view showing a laser distance measuring apparatus 89 according to still another embodiment of the present invention. In this laser distance measuring device 89, the dirt detection light R emitted from the dirt detection light emitting unit 23 is condensed in a spot shape on the front surface of the front window 2, and the dirt detection light reflected on the front surface of the front window 2. R is received by the dirt detection light receiving unit 24.

When no water drops 88 adhere to the front of the front window 2, as shown in FIG. 34A, the dirt detection light R is collected on the front of the front window 2 and reflected there. Therefore, the light receiving signal level of the light receiving unit 24 for detecting contamination becomes equal to or higher than a predetermined value (contamination determination threshold level). On the other hand, when the water drops 88 adhere to the front window 2, FIG.
As shown in (b), the condensing position of the dirt detection light R changes from the boundary between the front window 2 (glass) and the air to the boundary between the water droplet 88 and the air, so that the reflectance of the dirt detection light R is small. Become. Therefore, the reflection of the dirt detection light R is weakened, and the light reception signal level in the dirt detection light receiving unit 24 becomes equal to or less than a predetermined value. Therefore, the presence or absence of dirt can be determined from the light receiving signal level at the dirt detecting light receiving unit 24.

(Fifteenth Embodiment) FIG. 35 is a block diagram showing a configuration of a laser distance measuring apparatus 91 according to still another embodiment of the present invention. In the laser distance measuring device 91, the light receiving circuit 13 and the control circuit 17 of the light receiving unit 5 for distance measuring are used.
And a dirt determination circuit 92 is inserted between them, and the dirt determination circuit 92 is provided with a timer (counter) 93. When the level of the received light signal output from the light receiving circuit 13 is equal to or lower than the predetermined level, the contamination determination circuit 92 measures the duration during which the level of the received light signal is equal to or lower than the predetermined level by the timer 93. If the time exceeds a predetermined time (for example, 5 minutes), it is determined that the front window 2 is dirty. Here, as the predetermined level for comparing the light receiving signal levels, for example, if the light receiving signal levels are classified into eight ranks, the light receiving signal levels of the second highest rank can be used. Therefore, in this case, the dirt determination circuit 92 generates dirt on the front window 2 unless the laser light L having the highest light receiving signal level is received by the distance measuring light receiving unit 5 continuously for, for example, 5 minutes. Judge that there is.

FIG. 36 is a flowchart showing an example of the processing algorithm of the dirt determination circuit 92. The operation of the dirt determination circuit 92 will be described with reference to the flowchart. Dirt determination circuit 9
2 compares the level of the light receiving signal output from the light receiving circuit 13 with a predetermined level (for example, the light receiving signal level of the second rank) (S101), and stops the timer if the light receiving signal level is equal to or higher than the predetermined level. Then, the timer is reset to zero (S105), and when the light receiving signal level falls below a predetermined level, a timer is started (S102). And
If the light receiving signal level is lower than the predetermined level and the timer 93 continues the time counting operation, it is determined whether the predetermined time has elapsed and the timer 93 has counted up (S10).
3), when the timer 93 counts up after a predetermined time, it is determined that the front window 2 is dirty (S104).

If the front window 2 is in a normal state in which the front window 2 is not contaminated, the state in which light of a high light receiving signal level is not received usually does not continue for a long time. If the object cannot be detected, the principle of the present embodiment is to judge that the front window 2 is dirty.

Note that the dirt detection method according to this embodiment can improve the reliability of dirt detection by combining it with another dirt detection method.

(Sixteenth Embodiment) FIG. 37 is a block diagram showing a configuration of a laser distance measuring apparatus 94 according to still another embodiment of the present invention. This laser distance measuring device 94
The output of the light receiving circuit 30 of the dirt detecting light receiving section 24 is output to the control circuit 17 and also to the differential operation section 95.
The light receiving signal level is output from the light receiving circuit 30 to the differential operation unit 95 at a constant timing.
Calculates the difference between the light receiving signal levels received from the light receiving circuit 30, that is, the difference between the received light receiving signal level and the previous light receiving signal level. The difference amount of the light receiving signal level calculated by the differential calculation unit 95 is output to the control circuit.

Thus, the control circuit 17 determines whether or not the front window 2 is dirty by comparing the light receiving signal level output from the light receiving circuit 30 of the light detecting unit 24 for soil detection with the soil determination threshold level. At the same time, the control circuit 17 determines the presence or absence of dirt on the front window 2 based on the difference amount of the light receiving signal level output from the differential operation unit 95. By determining the contamination based on the level of the received light signal output from the light receiving circuit 30, it is possible to determine the presence or absence of the gradually accumulated contamination. On the other hand, by judging dirt based on the difference amount of the light receiving signal level output from the differential operation unit 95, it is possible to monitor a sudden dirt change such as mud adhesion due to mud splash or snow adhesion due to snowfall. Can be. Therefore, by monitoring dirt on the front window 2 by both methods, it is possible to improve the reliability of detection of the presence or absence of dirt.

(Seventeenth Embodiment) FIG. 38 is a block diagram showing a configuration of a laser distance measuring apparatus 96 according to still another embodiment of the present invention. This laser distance measuring device 96
An initial dirt level storage unit 97 is provided for storing an initial dirt level (light receiving signal level when the front window 2 is not dirty at all, such as at the time of shipment).

When the light receiving signal level is output from the light receiving circuit 30 of the light receiving section 24 for stain detection to the control circuit 17, the control circuit 17 stores the light receiving signal level and the initial stain level storage section 97. The difference between the initial stain level and the light receiving signal level is determined, and the difference between the initial stain level and the light receiving signal level is compared with a stain determination threshold level to determine the stain on the front window 2.

In this embodiment, the laser distance measuring device 96
The contamination of the front window 2 is determined in consideration of the different initial contamination levels, so that the contamination can be detected with high accuracy regardless of the variation of each laser range finder 96, and the reliability of the contamination detection is improved. improves.

(Eighteenth Embodiment) FIG. 39 is a block diagram showing a configuration of a laser distance measuring apparatus 111 according to still another embodiment of the present invention. This laser distance measuring device 111
Is provided with a sunlight detecting unit 112 for detecting sunlight (disturbance light from the outside). Sunlight detector 1
Reference numeral 12 includes a light receiving element (photodiode) 113 and a light receiving circuit 114, and outputs a signal of a light receiving signal level corresponding to the intensity of sunlight to the control circuit 17.

Thus, the dirt detecting light emitting section 23 emits the dirt detecting light R toward the front window 2, and the dirt detecting light R reflected on the front surface of the front window 2 is received by the dirt detecting light receiving section 24. You. The control circuit 17 determines the degree of dirt on the front window 2 from the level of the received light signal at the dirt detecting light receiving unit 24.

The sunlight detecting section 112 receives the sunlight passing through the front window 2 and entering. The control circuit 17
The dirt on the front window 2 is determined from the received light intensity of the sunlight detecting unit 112.

Table 1 below shows the relationship between the presence or absence of dirt on the front window 2 and the presence or absence of direct sunlight, the received light signal level at the dirty detection light receiving unit 24, and the received light signal level at the sunlight detection unit 112. It is a summary.

[0101]

[Table 1]

The light receiving signal level in the light receiving section 24 for detecting dirt becomes a very small level when there is no dirt on the front window 2 and a maximum level when there is dirt irrespective of the presence or absence of direct sunlight. (See FIG. 4). On the other hand, the light receiving signal level in the sunlight detecting unit 112 is 0 when the front window 2 is dirty because no sunlight enters the front window 2. Since the level is the maximum level and the level is very low when there is no direct light, if it is not 0 level, it is determined that there is no contamination. As described above, the dirt judgment in the dirt detecting light receiving unit 24 and the dirt judgment in the sunlight detecting unit 112 are independent. However, by performing both dirt judgments comprehensively, the accuracy of the dirt judgment is improved. Can be improved.

The object information detecting device according to the present invention may have only the electromagnetic wave detecting means of the electromagnetic wave radiating means and the electromagnetic wave detecting means. This is because, for example, in the case of an object information detection device that detects a heat ray radiated from an object, a human body or an animal to measure the temperature, or detects an intruder, the electromagnetic wave emission means is not necessary.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing a conventional laser distance measuring apparatus.

FIGS. 2A and 2B are a schematic cross-sectional view and a schematic vertical cross-sectional view showing a configuration of the laser distance measuring device according to the first embodiment.

FIG. 3 is a block diagram showing a configuration of the laser distance measuring device according to the first embodiment;

FIG. 4 is a diagram illustrating a dirt determination method in the laser distance measuring device of the above.

5A is a diagram showing a dirt detection position in the laser distance measuring device of the above, and FIG. 5B is a diagram showing an area for distance measurement of laser light (laser pulse) and an area for dirt detection.

FIG. 6 is a perspective view showing a laser distance measuring apparatus according to the first embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of the embodiment.

FIG. 8 is a horizontal sectional view of the embodiment.

FIG. 9 is a block diagram showing a configuration of the embodiment.

FIG. 10 is a diagram illustrating a stain determination method according to the embodiment.

FIG. 11 is a time chart showing light projection timing and light reception timing in the embodiment.

FIG. 12 is a flowchart illustrating an algorithm for determining dirt in the embodiment.

FIG. 13 is a horizontal sectional view showing a laser distance measuring apparatus according to a second embodiment of the present invention.

FIG. 14 is a horizontal sectional view showing a laser distance measuring apparatus according to a third embodiment of the present invention.

FIG. 15 is a schematic perspective view showing a laser distance measuring apparatus according to a fourth embodiment of the present invention.

FIGS. 16 (a) and (b) are explanatory diagrams of the operation of the laser distance measuring device of the above.

FIG. 17 is a block diagram showing a configuration of the laser distance measuring device of the above.

FIG. 18 is a time chart illustrating a dirt detection operation in the embodiment.

FIG. 19 is a side view showing a vehicle equipped with a laser distance measuring device according to a fifth embodiment of the present invention.

FIG. 20 is a partially enlarged view showing the embodiment in a partially broken manner.

FIG. 21 is a partially broken side view showing a part of a vehicle equipped with a laser distance measuring apparatus according to a sixth embodiment of the present invention.

FIG. 22 is a sectional view showing a laser distance measuring apparatus according to a seventh embodiment of the present invention.

FIG. 23 is an operation explanatory view of the embodiment.

FIG. 24 is a sectional view showing a laser distance measuring apparatus according to an eighth embodiment of the present invention.

FIG. 25 is a sectional view showing a laser distance measuring apparatus according to a ninth embodiment of the present invention.

FIG. 26 is a sectional view showing a laser distance measuring apparatus according to a tenth embodiment of the present invention.

FIG. 27 is a horizontal sectional view of the embodiment.

FIG. 28 is a block diagram showing a configuration of the laser distance measuring device of the above.

FIG. 29 is a horizontal sectional view showing a laser distance measuring apparatus according to an eleventh embodiment of the present invention.

FIG. 30 is a sectional view showing a laser distance measuring apparatus according to a twelfth embodiment of the present invention.

FIG. 31 is a sectional view showing a laser distance measuring apparatus according to a thirteenth embodiment of the present invention.

FIGS. 32 (a) and 32 (b) are action explanatory views of the above.

FIG. 33 is a sectional view showing a laser distance measuring apparatus according to a fourteenth embodiment of the present invention.

34 (a) and (b) are explanatory diagrams of the operation of the above.

FIG. 35 is a block diagram showing a configuration of a laser distance measuring apparatus according to a fifteenth embodiment of the present invention.

FIG. 36 is a flowchart showing an algorithm for dirt determination in the dirt determination circuit of the laser distance measuring device according to the third embodiment.

FIG. 37 is a block diagram showing a configuration of a laser distance measuring apparatus according to a sixteenth embodiment of the present invention.

FIG. 38 is a block diagram showing a configuration of a laser distance measuring apparatus according to a seventeenth embodiment of the present invention.

FIG. 39 is a block diagram showing a configuration of a laser distance measuring apparatus according to an eighteenth embodiment of the present invention.

[Explanation of symbols]

 2 Front Window 4 Distance Measuring Projection Unit 5 Distance Measuring Light Receiving Unit 17 Control Circuit 23, 23a, 23b Dirt Detection Light Emitting Unit 24, 24a, 24b Dirt Detection Light Receiving Unit 42 Data Sorting Circuit 92 Dirt Judgment Circuit 95 Differentiation Operation Unit 97 Initial dirt level storage unit 112 Sunlight detection unit L Laser light R Dirt detection light

Continuation of the front page (56) References JP-A-59-145982 (JP, A) JP-A-6-102092 (JP, A) JP-A-6-242239 (JP, A) JP-A-6-342071 (JP) , A) Japanese Utility Model 63-78435 (JP, U) Japanese Utility Model 7-34384 (JP, U) Japanese Utility Model Utility Model 60-137389 (JP, U) Japanese Patent Application 3-30116 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01S 17/10 G01B 11/00 G01N 21/88

Claims (3)

(57) [Claims] At least one of an electromagnetic wave radiating means and an electromagnetic wave detecting means includes an electromagnetic wave detecting means, and transmits through a transparent or almost transparent member in a wavelength range of an electromagnetic wave radiated from the electromagnetic wave radiating means or an electromagnetic wave received by the electromagnetic wave detecting means. In the device for detecting information on an object by emitting electromagnetic waves from the electromagnetic wave emitting means or receiving the electromagnetic waves by the electromagnetic wave detecting means, an electromagnetic wave for detecting dirt attached to the transparent or almost transparent member is transmitted. A dirt detection transmitter, a dirt detection receiver that receives an electromagnetic wave for dirt detection, an electromagnetic wave that is received by the electromagnetic wave detection means, and passes through a portion where the dirt detection receiver detects dirt. An object information detecting device, comprising: signal selecting means for invalidating a signal due to an electromagnetic wave. 2. The object information detecting device according to claim 1 , wherein the dirt detecting transmitter is also used as the electromagnetic wave radiating means. 3. The object information detecting apparatus according to claim 1 , wherein the dirt detecting receiver is also used as the electromagnetic wave detecting means.