JPH07198850A - Distance measuring apparatus - Google Patents

Abstract

PURPOSE:To provide a distance measuring apparatus in which load of a signal processing after light receiving means is reduced, increase in scale of a signal processor is avoided while accelerating the signal processing and the cost can be reduced. CONSTITUTION:Light emitting and receiving ranges are divided in one dimensional direction so that dividing directions are crossed, emitting lights from four LD elements 1a-1d of a semiconductor laser are sequentially emitted in a predetermined order, a distance to an object to be measured is detected by a distance detector based on the time from a time when lights are emitted from the elements 1a-1d to a time when the lights are received by photoreceiving elements 4a-4d of a photoreceiver 4, and a region of the object to be measured is detected by a region detector based on a decided result obtained by light emitting and receiving range discriminators. Accordingly, the distance to the object to be measured and the region can be detected by the same measurement as that when the plurality of the elements are arranged in a matrix state to fragment the receiving range in two dimensional manner, i.e., a combination of less information than that.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device for detecting a distance to a measuring object and its direction by using light.

[0002]

2. Description of the Related Art In recent years, for the purpose of improving safety, automation and labor saving, there is an increasing demand for mounting a distance measuring device on a moving body and utilizing distance information. Specifically, the distance measuring device is used in a collision prevention system for robots, automobiles, trains, and the like, a stop position control system for transport vehicles on a factory line, and the like.

As a conventional distance measuring device suitable for these applications, for example, one disclosed in Japanese Patent Laid-Open No. 59-198378 is known. This distance measuring device has a light transmitter that emits an optical pulse signal light, a light receiver that has a plurality of light receiving elements arranged in a matrix, and a light receiver that receives reflected light from an object to be measured, A distance detection unit that detects the distance to the object based on the time from when the pulse is emitted to when the light is received by the light receiving unit, and of the light receiving element that receives the reflected light from the measurement object among the plurality of light receiving elements A region detection unit that detects the region of the object from the position, and a shape detection unit that detects the shape of the object based on the positional relationship between the light receiving elements that received the reflected light from the measurement object among the plurality of light receiving elements. I have it.

[0004]

In the above distance measuring device, a plurality of light receiving elements are arranged in a matrix to subdivide the light receiving range (light receiving portion of the light receiving device) into two dimensions, and a light receiving element in which reflected light exists. The position and the received signal from the position, because it is a configuration to detect the distance to the measurement object and the area of the measurement object, the number of light-receiving elements, information for detecting the distance to the measurement object and Information for detecting the region of the measurement object is required, the amount of information to be processed is very large, and all of this information needs to be processed by signal processing after the light receiver. That is, the load of signal processing performed after the light receiver is large.

Therefore, in order to speed up the signal processing, it is necessary to process the signals from the respective light receiving elements in parallel, which makes the received signal processing circuit for processing the signals from the respective light receiving elements large in scale. On the other hand, in order to prevent the received signal processing circuit from becoming large in scale, if the received signal processing circuit of each light receiving element is made common and the signal processing is sequentially switched between the light receiving elements, the measurement time becomes long. There was a problem that it would become. Further, the light receiver also needs a special device that is formed into a two-dimensional array, which causes a problem of high cost.

The present invention has been made in view of the above-mentioned conventional problems, and its problem is to reduce the load of signal processing after the light receiving means and to speed up the signal processing of the signal processing circuit. An object of the present invention is to provide a distance measuring device that can avoid a large scale and reduce cost.

[0007]

In order to solve the above-mentioned problems, a distance measuring apparatus according to the invention of claim 1 comprises a light-sending means for sending outgoing light to an object to be measured, and a device for measuring the distance from the object to be measured. Light receiving means for receiving reflected light, and distance detecting means for calculating the distance to the object to be measured based on the time from the light transmitting means sending the emitted light to the light receiving means receiving the reflected light. In the distance measuring device including the light-transmitting means, the light-transmitting means divides the light-transmitting area of the emitted light into a plurality of light-transmitting areas in one-dimensional direction, and the light-receiving means divides the light-receiving area of the reflected light into the light-transmitting areas. A light-transmitting and light-receiving dividing unit that divides into a plurality of light-receiving regions in a direction intersecting the direction, and at least one of the light-transmitting unit and the light-receiving unit transmits and receives the plurality of light-transmitting and light-receiving regions in a predetermined order. And the light is transmitted by the light transmitting / dividing means. And a region detecting means for detecting whether the object to be measured to the intersection region between the light receiving region when the received exists by the light-sending region and the receiving dividing means.

According to a second aspect of the present invention, in the distance measuring device, the light-sending and light-receiving dividing means has a plurality of light-emitting and light-receiving regions arranged so as to send and receive light, respectively. A light receiving unit and a control unit for emitting and receiving the plurality of light emitting and light receiving units in a predetermined order are provided.

Further, in the distance measuring device according to the invention of claim 3, the light-sending and light-receiving splitting means is configured to send and receive the plurality of light-sending and light-receiving regions, respectively, so that the emitted light and the reflected light are received. And a control means for controlling the scanning means so that the directions of the emitted light and the reflected light are changed in a predetermined order.

According to a fourth aspect of the present invention, in the distance measuring device, the light transmitting / dividing means divides the outgoing light into a plurality of optical paths so as to respectively transmit the plurality of light transmitting areas. Means, an optical path opening / closing means for selectively opening / closing the plurality of optical paths, and a control means for controlling the optical path opening / closing means so that the divided outgoing lights are emitted from the optical path opening / closing means in a predetermined order. I have it.

Further, in the distance measuring device according to the invention of claim 5, the light receiving division means comprises an optical path combining means for combining the reflected lights from a plurality of optical paths so as to respectively receive the plurality of light receiving areas. An optical path opening / closing means for selectively opening / closing the plurality of optical paths, and the reflected light from the plurality of optical paths entering in a predetermined order from the optical path opening / closing means,
A control means for controlling the optical path opening / closing means.

[0012]

As described above, the light-transmitting range and the light-receiving range are each divided into one-dimensional directions, and the dividing directions are crossed so that the light-transmitting and the light-receiving from at least one of the light-transmitting means and the light-receiving means are predetermined. The light is sent and received in the order of, and the distance detection means detects the distance to the object to be measured based on the time from the emission of light from the light transmission means to the reception of light by the light reception means, and the light transmission range determination Since the area detecting means detects the area of the measuring object based on the determination result obtained by the means and the light receiving area determining means, the light receiving area is two-dimensionally subdivided by arranging a plurality of light receiving elements in a matrix. The same measurement as in the case of conversion, that is, the distance to the measurement object and the detection of the area thereof can be performed with a combination of less information.

Specifically, if the light-transmitting range is divided into m (m is a positive integer of 2 or more) and the light-receiving range is divided into n (n is a positive integer of 2 or more), the area of the object to be measured. In order to detect, the (m × n) directions can be detected by a combination of (m + n) information amounts, which reduces the information amount of the signal processing performed after the light receiving means, and as a whole. The amount of information to process is reduced.

Further, since the power of the light pulse emitted from the light emitting means is lowered due to the division of the light transmission range, safety to the eyes can be secured.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a distance measuring device according to an embodiment of the present invention. In the figure, a light emitting device (light transmitting means) is a semiconductor laser 1 which is an array type light source.
And an LD driver 6 for driving the semiconductor laser 1. In front of the semiconductor laser 1, a light transmitting lens 2 for transmitting the light pulse emitted from the semiconductor laser 1 to a measurement object (not shown) is arranged.

The semiconductor laser 1 includes four semiconductor laser devices (hereinafter referred to as LD devices) 1a, 1b, 1c, 1d.
have. The LD elements 1a to 1d are, as shown in FIGS. 1 and 2, a light transmitting range 6 formed by the light transmitting lens 2.
0 is one of four areas 60a, 60b, 60c,
It is arranged so as to be divided into 60d. That is, when an optical pulse is emitted from the LD element 1a, the optical pulse passes through the region 60a of the light transmission range 60, and when an optical pulse is emitted from the LD element 1b, the optical pulse passes through the region 60b. When the optical pulse is emitted from the element 1c, the optical pulse passes through the region 60c and the LD element 1
When the light pulse is emitted from d, the light pulse passes through the region 60d and is irradiated to the measurement object. In this way, the light-sending region 60 is divided into four regions 60a to 60d in the one-dimensional direction by emitting light pulses from the four LD elements 1a to 1d in a predetermined order.

The input side of the LD driver 6 is connected to the output side of the computer section 5. The LD driver 6 receives the light source selection signal 51 and the light emission permission signal 5 from the computer section 5.
When 2 is input, the LD selected by the light source selection signal 51
LD drive signals 53a, 53b, 53 necessary for emitting an optical pulse from any one of the elements 1a to 1d
c, 53d are created, and the drive signals 53a to 53d are generated.
Are output to the corresponding LD elements 1a to 1d.

A light receiving lens 3 is arranged in front of the array type light receiving device (light receiving means) 4, and the reflected light from the object to be measured is condensed by the light receiving lens 3 and is incident on the light receiving device 4.

The light receiver 4 is, as shown in FIGS. 1 and 3,
It has four light receiving elements 4a, 4b, 4c, 4d.
The light receiving elements 4a to 4d are arranged such that the light receiving range 61 formed by the light receiving lens 3 is divided in a direction intersecting the dividing direction of the light transmitting range 60. That is, the reflected light from the measurement object passing through the region 61a of the light receiving range 61 is received by the light receiving element 4a, and the reflected light passing through the region 61b is received by the light receiving element 4a.
In b, the reflected light passing through the area 61c is received by the light receiving element 4c, and the reflected light passing through the area 61d is received by the light receiving element 4d. In this way, the light receiving range 61 has four regions 61a.
~ 61d.

The output side of the light receiving elements 4a-4d is an amplifier 7a.
.About.7d are connected to the input side, and the output sides of the amplifiers 7a to 7d are connected to the input sides of the comparators 8a to 8d. The light receiving elements 4a to 4d receive the reflected light from the measurement object via the light receiving lens 3 and photoelectrically convert it. Amplifier section 7a
7d are received signals 54a, 5 from the light receiving elements 7a to 7d.
4b, 54c, 54d are amplified, and comparators 8a-8
d outputs a digital signal (reception trigger signals 55a, 55b, 55c, 55d) that becomes a rising edge at the moment when the reception signals 54a to 54d reach the threshold level.

The output terminals of the comparators 8a to 8d are connected to the input terminals of the counter sections 9a, 9b, 9c and 9d, and the output terminals of the counter sections 9a to 9d are connected to the input terminals of the computer section 5 and the counter sections 9a to 9d. 9d is a computer unit 5
It is connected to the. The counter units 9a to 9d receive the trigger signals 55a to 5 from the comparators 8a to 8d from the time when the light emission permission signal 52 from the computer unit 5 is received.
The count number is counted until 5d is received, and the time data 56a, 56b, 56c, 56d is output to the computer unit 5.

The computer section 5 includes LD elements 1a-1d.
Of the light emitting area and the light receiving area, a control section (controlling means) for emitting light in a predetermined order, a distance detecting section (distance detecting means) for calculating the distance to the measurement object based on the time data 56a to 56d. An area detection unit (area detection unit) that detects whether or not a measurement object is present in the intersection area is provided.
In the area detection unit, for example, the area of the light transmission range 60 is the area 60.
c and the region of the light receiving range 61 is the region 61b, as shown in FIG.
Is a region 60c of the light transmitting range 60 and a region 61 of the light receiving range 61
It is determined that the measurement object exists in the area (11) of the measurable range 80 intersecting with b, and the area of the measurement object is detected from the position of the area (11).

Area (1) of the measurable range 80 shown in FIG.
The shape and size of the object are detected based on the mutual positional relationship among the areas in which the reflected light from the measurement object is present among (16). That is, the shape detection unit 8 can measure the reflected light
0 adjacent regions, for example 4 regions (6),
If the reflected lights existing in (7), (10), and (11) and the reflected lights in these areas are at substantially the same distance, the shape and size of the object based on the positional relationship between the four areas. To detect.

Next, the operation of the distance measuring device of this embodiment will be described.

Light source selection signal 51 from the computer section 5
When the light emission permission signal 52 is input to the LD driver 6, the LD driver 6 is required to emit an optical pulse from any one of the LD elements 1a to 1d selected by the light source selection signal 51. The signals 53a to 53d are generated, and the drive signals 53a to 53d are set to the corresponding L
It outputs to D element 1a-1d. Drive signals 53a-5
The LD elements 1a, 1b, 1c and 1d receiving 3d emit light in order (for example, 1a, 1b, 1c and 1d in order),
This light pulse is emitted to the outside via the light transmitting lens 2. That is, first, an optical pulse is emitted from the LD element 1a, this optical pulse is emitted to the outside through the region 60a of the light transmission range 60, then an optical pulse is emitted from the LD element 1b, and this optical pulse is emitted. The light is emitted to the outside through the region 60b. After that, a light pulse is emitted from the LD element 1c, and this light pulse is emitted to the outside through the region 60c. Finally, an optical pulse is emitted from the LD element 1d, and this optical pulse is emitted to the outside through the region 60d.

Each light pulse emitted to the outside through each of the divided regions 60a to 60d is reflected by the measurement object when the measurement object is present, and the reflected light passes through the light receiving lens 3. Then, the light is sequentially received by any of the light receiving elements 4a to 4d.

When the reflected light is received by the light receiving element 4a, a reception signal 54a is output from the light receiving element 4a.
After 4a is amplified by the amplifier 7a, it is input to the comparator 8a and converted into a digital signal.
a is input to the counter unit 9a. The counter section 9a is
From the time when the light emission permission signal 52 is received from the computer unit 5 until the reception trigger signal 55a is received from the comparator 8a, the count number is counted and the time data 56a is output to the computer unit 5. Even when the reflected light is received by any of the other light receiving elements 4b to 4d,
Received signals 54b output from the respective light receiving elements 4b to 4d
54d is processed similarly.

Next, for example, an optical pulse is emitted from the LD element 1c, the optical pulse is reflected by the object to be measured,
The detection of the distance to the measuring object and its direction when the reflected light is received by the light receiving element 4b will be described.

When the reflected light from the object to be measured is received by the light receiving element 4b, the time data 56a is output to the computer section 5 as described above. The distance detection unit of the computer unit 5 detects the distance to the measurement object by converting the time data 56b into a distance using the speed of light.

When the light pulse is emitted from the LD element 1c, the area detection section receives the light source selection signal 51 from the control section, so that the reflected light from the object to be measured is in the light transmission range 60.
It is determined that it exists in the area 60c. Ie area 60
It is determined that the light pulse passing through c is reflected by the measurement target.

When the reflected light from the object to be measured is received by the light receiving element 4b, the area detector receives the reception trigger signal 55b from the comparator 8b, so that the reflected light from the object to be measured is in the area of the light receiving range 61. It is determined to exist in 61b.

In the area detector, the area of the light transmitting range 60 is the area 60c, and the area of the light receiving range 61 is the area 61c.
Therefore, as shown in FIG. 4, the region 70c of the measurable range 80 in which the region 60c of the light-transmitting range 60 and the region 61b of the light-receiving range 61 intersect the reflected light 70 from the measurement object (1
1), the direction of the measuring object is detected from the position of the area (11).

As described above, according to this embodiment, the semiconductor element 1 has the four LD elements 1a to 1d, and the light-sending range 60 formed by the light-sending lens 2 is divided into one-dimensional directions. LD elements 1a to 1d are arranged in the
Has four light receiving elements 4a to 4d arranged so that the light receiving range 61 collected by the light receiving lens 3 is divided in a direction intersecting the dividing direction of the light transmitting range 60, and each LD element 1a to Optical pulses are repeatedly emitted in the order of 1d to LD elements 1a, 1b, 1c, and 1d, and one of the light receiving elements 4a to 4d is emitted after the pulsed light of each LD element 1a to 1d is emitted. The distance to the object to be measured is detected by the distance detection unit based on the time until the light is received, and the area of the object to be measured is detected based on the determination results obtained by the light transmission range determination unit and the light reception range determination unit. Since it is detected by the unit, the same measurement as in the case where the light receiving elements of the light receiving device are arranged in a matrix and the light receiving range (light receiving part of the light receiving device) is two-dimensionally subdivided, that is, the measurement target Things It is possible to perform the distance and the detection of the area in combination with less information.

That is, according to the above embodiment, as shown in FIG. 4, the measurable range 80, which is the light receiving portion of the light receiver 4, can be divided into 16 areas (1) to (16). In addition, in order to detect the region of the measurement object, the directions of the 16 regions are combined by four information amounts on the light pulse emission side and four on the light pulse reception side, for a total of eight information amounts. Can be detected. As a result, the information amount of the signal processing performed by the light receiver 4 and the subsequent devices is reduced, and the information amount to be processed is reduced as a whole. Therefore, it is possible to prevent the signal processing circuit from becoming large in size while increasing the speed of signal processing, and it is not necessary to use a two-dimensional arrayed special device as the photodetector 4, which results in cost reduction. It can be reduced.

Further, according to the above-mentioned embodiment, 4 of the light emitting device 1 is used.
Since the light pulses are emitted from each of the LD elements 1a to 1d to the respective area portions of the light transmission range 60 in a predetermined order, the LD pulses are compared with the case where the light pulses of the LD element are emitted in the entire light transmission area 60. The power of the light pulse emitted from the elements 1a to 1d becomes 1/4, and thus the safety to the eyes can be further ensured. On the other hand, if the safety to the eyes is the same as before, it is possible to measure an object to be measured farther away or an object to be measured with low reflectance.

In the above embodiment, the light transmission range 60 is set to 4
Although the light receiving range 61 is divided into four, the number of divisions of these two ranges 60 and 61 is not limited to four, and may be an integer of 2 or more.

In the above embodiment, the light emitting means is 4
Although the semiconductor laser 1 having the one LD element 1a to 1d is used to emit the light pulse from each of the LD elements 1a to 1d in a predetermined order, the present invention is not limited to this, and the light pulse is emitted. It suffices that at least one of the light-transmitting range of the light-transmitting means that emits light and the light-receiving range of the light-receiving means that receives the reflected light is divided in a one-dimensional direction so that a plurality of lights can be emitted and made incident in a predetermined order. .

That is, for example, the light transmitting means is one light source, and the scanning means for scanning the light emitted from the light source so that the light transmitting range formed by the light transmitting optical system is divided in one dimension. The scanning means may be controlled by the control means so that the emission direction of the emitted light from the light source is switched in a predetermined order. Further, the light receiving means may be composed of scanning means.

Further, the light emitting means has one light source, and the light path dividing means for dividing the light emitted from the light source into a plurality of light paths.
An optical switch or an optical shutter (optical path opening / closing means) that selectively emits light of a plurality of optical paths is provided so that the light sending range sent by the light sending optical system is divided into one-dimensional directions. However, the control unit may control the optical switch or the optical shutter so that the light is emitted from the optical switch or the optical shutter in a predetermined order. Further, the light receiving means may be constituted by an optical path opening / closing means.

[0041]

As described above, according to the distance measuring device of the present invention, the amount of information of the signal processing performed after the light receiving means is reduced, and the signal processing circuit is increased in scale while increasing the speed of signal processing. Can be avoided, and the cost can be reduced. Further, it is possible to further secure the safety to the eyes.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a distance measuring device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between four LD elements and light transmission range division in the embodiment of FIG.

FIG. 3 is an explanatory diagram showing a relationship between four light receiving elements and light receiving range division in the embodiment of FIG.

FIG. 4 is an explanatory diagram showing a relationship among a divided light transmitting range, a divided light receiving range, a measurable range, and reflected light from an object to be measured in the embodiment of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 semiconductor laser 1a-1d semiconductor laser element 2 light-sending lens 3 light-receiving lens 4 light receiver 4a-4d light-receiving element 5 computer part 60 light-sending range 61 light-receiving range

Claims (5)

[Claims] 1. A light sending means for sending outgoing light to a measurement object, a light receiving means for receiving reflected light from the measurement object, and the light receiving means after sending the outgoing light by the light sending means. In a distance measuring device having a distance detecting means for calculating the distance to the object to be measured based on the time until the means receives the reflected light, the light transmitting means includes a light transmitting range of the emitted light in a one-dimensional direction. The light receiving means divides the light receiving range of the reflected light into a plurality of light receiving areas in a direction intersecting the dividing direction of the light transmitting range, and at least the light transmitting means and the light receiving means. One has a light sending and light receiving dividing means for sending and receiving the plurality of light sending and receiving areas in a predetermined order, and the light sending area and the light receiving dividing means when light is sent by the light sending dividing means. Crossing area with the light receiving area when light is received by The measurement target distance measuring device, wherein a and a region detecting means for detecting whether or not present in the. 2. The light-transmitting and light-receiving dividing means has a plurality of light-emitting and light-receiving means arranged to receive and transmit the light-transmitting and light-receiving regions, respectively, and the plurality of light-emitting and light-receiving means are predetermined. 2. The distance measuring device according to claim 1, further comprising a control means for emitting and receiving light in the order of. 3. The light sending and receiving light splitting means, the scanning means for scanning the outgoing light and the reflected light so as to send and receive the plurality of light sending and receiving areas, respectively, and the outgoing light and the reflected light. 2. The distance measuring device according to claim 1, further comprising a control unit that controls the scanning unit so that the direction of the scanning direction changes in a predetermined order. 4. The light sending splitting means splits the outgoing light into a plurality of light paths so as to send light to the plurality of light sending regions, and selectively opens and closes the plurality of light paths. The optical path opening / closing means, and a control means for controlling the optical path opening / closing means so that the divided outgoing light is emitted from the optical path opening / closing means in a predetermined order. Distance measuring device. 5. The light receiving / dividing means includes an optical path synthesizing means for synthesizing the reflected light from a plurality of optical paths so as to respectively receive the plurality of light receiving areas, and an optical path opening / closing for selectively opening / closing the plurality of optical paths. 2. A means for controlling the optical path opening / closing means so that the reflected light from the plurality of optical paths enters from the optical path opening / closing means in a predetermined order. Distance measuring device.