JP2000121353A - Range finder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize wide visual field multipoint rang finding without increasing the light receiving area by constituting a light receiving means of a plurality of light receiving sections, receiving the light reflected from an object located in the center at a plurality of light receiving sections and receiving the light reflected from one and the other of adjacent objects at one and the other of the plurality of light receiving sections. SOLUTION: A CPU 16 lights an IRED (infrared light emitting diode) 5 through an IRED drive circuit 9 and a phase difference operating section 14 receives a signal subjected to amplification 12 and A/D conversion 13 from CCDs 1, 2 through a projection lens 8 and light receiving lenses 3, 4. Distance to an object located in the center is then calculated based on the phase difference thus determined. Subsequently, IREDs 6, 7 are lighted through IRED drive circuits 10, 11 and a center of gravity operating section 15 receives a signal subjected to amplification 12 and A/D conversion 13 from the CCDs 1, 2. Finally, the distances to one and the other of adjacent objects located in the center are calculated based on the center of gravity of respective optical receiving images.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an active distance measuring device.

[0002]

2. Description of the Related Art An active-type distance measuring apparatus receives a projected light by a semiconductor position detecting element (hereinafter, referred to as a PSD) or the like, and determines a reflection position on the PSD (a center of gravity of the reflected light) from a signal output thereof. It is well known that the distance to the object to be measured is obtained by detection.

[0003] Further, in the center-of-gravity position detection method, a contrast object (for example, half of the object has a high reflectance,
The other half is subject to erroneous distance measurement when the contrast is low. Therefore, two light receiving elements such as CCDs are installed in parallel, and skim operation ( charges accumulated in the CCDs) is performed.
It is also known that extraneous light is removed by signal processing that discards part of the light, and the reflected light of the projected light is received by these, and the distance to the measurement object is obtained by the phase difference of the signal output of each light receiving element. ing.

This example will be described with reference to FIG.

FIG. 6 is a diagram for explaining the principle of an active phase difference measuring device having two CCDs.

In FIG. 6, reference numeral 22 denotes a CCD (L) serving as a first light receiving element, and reference numeral 23 denotes a CCD (R) serving as a second light receiving element. 3 and 4 are constant baseline length B
It is a light receiving lens provided side by side only. Reference numeral 21 denotes an infrared light emitting diode (hereinafter referred to as IRED) which is a light projecting means.
And 8 is a light projecting lens.
D21 and the light projecting lens 8 form a light projecting means.
24 is an object to be measured.

In this figure, the distance from the principal point of the light receiving lenses 3 and 4 to the CCDs 22 and 23 is f,
Let H be the distance from the principal point of No. 4 to the measurement object 24. Further, the reflected light from the measurement target 24 located at the distance H from the optical axis of the light receiving lens 3 is collected by the light receiving lens 3,
The amount of movement of the received light image to the center position of the received light image formed on the CCD 22 is x1, and the reflected light from the measurement object 24 at the distance H from the optical axis of the light receiving lens 4 is collected by the light receiving lens 4. When the amount of movement of the received light image up to the center position of the received light image formed on the CCD 23 is x2, the following relationship is established.

H = (B × f) / (x2−x1) (1) Here, from the correlation amount between the signal images obtained by the CCD 22 and the CCD 23, the denominator on the right side of the above equation (1) is obtained. (X2-x
By determining 1), the distance to the measurement target 24 can be measured.

However, in the distance measuring apparatus using the phase difference method, only one object to be measured can be measured. Therefore, a multi-point distance measuring apparatus based on the phase difference method will be described with reference to FIG.

FIG. 7 is a block diagram of a distance measuring device having a plurality of IREDs as the light projecting means and having a plurality of measuring points. FIG.
The same parts as those described above are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 7, reference numerals 41, 42 and 43 denote measurement objects. Reference numeral 5 denotes an IRED for projecting light to the measurement object 41 in the center direction, reference numeral 7 denotes an IRED for projecting light to the measurement object 43 in the left direction, and reference numeral 6 denotes light to the measurement object 42 in the right direction. IRED for

The light projected by the IRDE 5 is reflected by the object 41 to be measured in the center direction, and the reflected light is condensed by the light receiving lenses 3 and 4 to form an image at the positions 5 'and 5 ". The light projected by the IRED 6 is reflected by the measurement object 42 in the right direction, and the reflected light forms an image at positions 6 ′ and 6 ″. The light projected by the IRED 7 is reflected by the measurement target 43 in the left direction, and the reflected light forms an image at the positions 7 'and 7 ".

Here, the positional relationship between the CCD 22, the CCD 23, and the light-receiving images 5 ', 5 ", 6', 6", 7 ', 7 "will be described with reference to FIG.

As shown in FIG. 8A, light-receiving images 5 'and 5 "of the light projected from the IRED 5 are present on the CCDs 22 and 23, and the phase can be detected by the pixel outputs from the CCDs 22 and 23. On the other hand, the light-receiving images 6 ', 6 ", 7', 7" corresponding to the light projected by the IRED 6 and the IRED 7 are all C
It protrudes from the CDs 22 and 23. Therefore, I
In the light emission by the REDs 6 and 7, the phase difference cannot be detected.

Therefore, as a countermeasure against this, a light receiving image 6 ',
6 "and the light-receiving images 7 'and 7"
As shown at 22 'and 23' in FIG. 8B, it is conceivable to lengthen the CCD in the direction of the arrow.

[0016]

However, in a device in which reflected light of the projected light is received by two CCDs and the distance is measured by the phase difference of the signal output, as shown in FIG. If both sides of the CCD are lengthened in order to measure the distance of the object to be measured, an increase in the chip area of the CCD chip and an increase in cost associated therewith are a problem as compared with a distance measuring apparatus having only one object to be measured. .

(Object of the Invention) An object of the present invention is to provide a distance measuring apparatus capable of performing a plurality of measurement objects without increasing the light receiving area of the light receiving means.

[0018]

In order to achieve the above object, the present invention according to claims 1 to 3 and 6 to 8 comprises a light projecting means for projecting light to a substantially central direction and a measuring object adjacent thereto. A distance measuring device comprising: light receiving means for receiving reflected light from a measurement object located substantially in the central direction and its periphery; and calculating means for calculating a distance to the measurement object based on an output from the light receiving means. Wherein the light receiving means comprises two light receiving portions, and reflected light from the measurement object located in the substantially central direction is received by the two light receiving portions, and the reflected light from the measurement object located on the adjacent one is received. The reflected light is received by one of the two light receiving units, and the reflected light from the adjacent measurement object is received by the other of the two light receiving units. As shown in FIG. It is an apparatus.

In the above configuration, the reflected light from the measurement object positioned substantially in the center direction is received by the two light receiving units, and the reflected light from the adjacent one or other measurement object is reflected by the two light receiving units. In order to receive light only in one or the other of the light receiving units, for the measurement object located in the substantially central direction, determine the phase difference between the outputs of the two light receiving units,
The distance is calculated based on the phase difference, and for the measurement object located at the adjacent one or the other, the center of gravity of the light receiving image on one or the other light receiving unit of the two light receiving units is obtained. The distance is calculated based on the position of the center of gravity.

According to another aspect of the present invention, there is provided a light emitting device for projecting light to a substantially central direction and a measuring object adjacent thereto, and A distance measuring apparatus comprising: a light receiving unit that receives reflected light from a measurement object located therein; and a calculation unit that calculates a distance to the measurement object based on an output from the light receiving unit. Consisting of two light receiving sections, the reflected light from the measurement object located in the substantially central direction is received on the left and right of the one light receiving section, and the reflected light from the adjacent one and the other measurement object located on the other side, This is a distance measuring device that receives light reflected by one of different portions sandwiched between left and right portions that receive reflected light from the measurement object positioned in the substantially central direction.

In the above configuration, the reflected light from the measurement object located substantially in the center direction is received by the left and right sides of one light receiving section, and the reflected light from the adjacent one or other measurement object is reflected by the left and right portions. Light is received only at one of the sandwiched portions, and for the measurement object located in the substantially central direction, the phase difference between the outputs of the left and right portions of the one light receiving portion is obtained, and the distance is determined based on the phase difference. For the measurement object located on the adjacent one or the other, the center of gravity of the light-receiving images formed in different portions sandwiched between the left and right portions is obtained, and the distance is calculated based on the center of gravity. It is calculated.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is a block diagram showing a schematic configuration of a distance measuring apparatus according to a first embodiment of the present invention.

In FIG. 1, 1 is a first CCD, 2 is a second CCD, 3 is a first light receiving lens, 4 is a second light receiving lens, 9, 10, and 11 are IRED driving circuits, and 5, 6 , 7
Is an IRED, 8 is a light projecting lens, 12 is a signal amplification circuit, 1
Reference numeral 3 denotes an A / D conversion circuit. Reference numeral 16 denotes a CPU for controlling each unit, performing calculations, and the like, and includes a phase difference calculation unit 14 and a center-of-gravity position calculation unit 15 therein.

The distance measuring apparatus shown in FIG. 1 projects light toward a measuring object whose distance is to be measured, receives reflected light from the measuring object, performs triangulation ranging, and performs distance measurement. We measure distance to.

IREDs 5, 6, 7 and IRED drive circuit 9
-11, a light projecting means is formed by the light projecting lens 8;
The RED driving circuits 9, 10, and 11 are controlled by the CPU 16 to turn on and off the IREDs 5, 6, and 7, and the CPU 16 can select the light emitting direction of the light emitting means.

The CCD 1 and the CCD 2 are arranged with a plurality of sensors, and receive light reflected from the object to be measured and perform photoelectric conversion. Also, CC
D1 and D2 extend the sensor in the direction of the adjacent CCD as shown in FIG. Note that the portion shown by the two-dot chain line in FIG. 2 overlaps the above-described example of FIG. 8B (an example in which the sensor is lengthened for both).

Here, the difference from the CCD in FIG. 8B is that the CCDs 22 and 23 extend the sensors in both sides of each CCD, whereas the CCDs 1 and 2 extend in the direction of the adjacent CCD (arrows). Direction) only where the sensor is extended.

The signal amplifying circuit 12 amplifies the pixel outputs of the CCDs 1 and 2, and the A / D converting circuit 13 amplifies the amplified C
This is for A / D converting the CD pixel output and outputting it to the phase difference calculator 14 and the center of gravity calculator 15 in the CPU 16.

The phase difference calculating section 14 is for calculating the phase difference of the light-receiving image formed by the light projecting in the center direction, of the light projected on the plurality of measurement objects by the light projecting means. Further, the center-of-gravity calculating unit 15 is one that is projected on a plurality of subjects by the projecting unit.
This is for calculating the position of the center of gravity of the light-receiving image formed by light projection other than in the center direction.

An embodiment of the distance measuring apparatus having the above configuration will be described in detail with reference to FIG. The same parts as those in FIG. 7 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 3, reference numeral 42 denotes a measurement object in the right direction, 41 denotes a measurement object in the center direction, and 43 denotes a measurement object in the left direction. The distance from the principal point of the light receiving lenses 3 and 4 to the CCDs 3 and 4 is F, the distance from the principal point of the light receiving lenses 3 and 4 to the measurement target 41 is H ₁ , the distance from the measurement target 42 is H ₂ , the distance to the target 43 is set to H _3. Further, the light receiving lenses 3 and 4 are separated from the optical axis of the light projecting lens 8.
The distances to are B ₁ and B ₂ respectively,
4 of the distance between the optical axes is set to B _3. Further, the light-receiving image movement amounts from the optical axis of the light-receiving lens 3 to the center positions of the light-receiving images 5 'and 7' formed on the CCD 1 are x5 'and x7', respectively. Also, the CCD 2 is moved from the optical axis of the light receiving lens 4 to the CCD 2.
The moving amounts of the received light images up to the center position of the received light images 5 "and 6" formed above are x5 "and x7", respectively.

When the IRED driving circuit 9 is driven, the IR
The projected spot projected by the ED 5 is reflected by the measurement object 41 in the center direction and forms an image like 5 'on the CCD 1 and 5 "on the CCD 2. The CCD 1 and the CCD 2
The phase difference is obtained from the signal image obtained in step (1), and the distance to the measurement target 41 can be calculated by the following equation (2).

H ₁ = (B ₃ × F) / (x5′−x5 ″) (2) When the IRED drive circuit 10 is driven,
The projected spot projected by 6 is reflected by the measurement object 42 in the right direction, and forms an image like 6 ″ on the CCD 2. Then, the center of gravity of the received light image 6 ″ is obtained, and the following equation (3) is obtained. Thus, the distance to the measurement target 42 can be calculated.

H ₂ = (B ₂ × F) / x6 ″ (3) Further, when the IRED drive circuit 11 is driven, the IRE
The projection spot projected by D7 is reflected by the measurement target 43 in the left direction, and forms an image like 7 'on the CCD 1.
Then, the position of the center of gravity of the received light image 7 'is obtained, and the distance to the measurement target 43 can be calculated by the following equation (4).

H ₃ = (B ₁ × F) / x7 ″ (4) FIG. 6 is a flowchart showing the actual distance measuring operation of the above distance measuring apparatus.

First, in step # 101, the CPU
Reference numeral 16 turns on the IRED 5. And the next step #
At 102, the A / D signal amplified from the CCD (L) 1
The converted signal is taken into the phase difference calculation unit 14. In the following step # 103, the signal amplified and A / D-converted from the CCD (R) 2 is taken into the phase difference calculating section 14. Then, in the next step # 104, C
The phase difference is calculated by the phase difference calculation unit 14 based on the A / D conversion values from the CD (L) 1 and the CCD (R) 2, and in the next step # 105, the distance from the phase difference to the measurement object 41 is calculated. Is calculated, and the process proceeds to step # 106, where the IRED 5 is turned off, and the process proceeds to step # 107.

In step # 107, the IRED
Lights 6 and 7. Here, as shown in FIG. 2, the light receiving image 6 ″ by the light emission of the IRED 6 can be received by the CCD (R) 2, but the light receiving image 6 ′ protrudes from the CCD (L) 1, and the correlation operation cannot be performed. , IRED 7 can receive light by CCD (L) 1,
In the CD (R) 2, the received light image 7 "protrudes, and the correlation operation cannot be performed.

Therefore, in the next step # 108, the signal amplified and A / D converted from the CCD (R) 2 is taken into the center-of-gravity position calculating section 15, and the following step # 1
At 09, the center of gravity of the light-receiving image 6 ″ on the CCD (R) 2 is obtained based on the A / D converted value from the CCD (R) 2.
The method of calculating the center of gravity of the light-receiving image 6 ″ on the CD may be a method of calculating the peak of the pixel signal or calculating the pixel pitch more finely than the pixel pitch by complementing the pixels from the tilt angle of the image.
In step # 110, the distance to the measurement target 42 is calculated from the position of the center of gravity of the received light image 6 ″, and step # 1
Proceed to 11.

In step # 111, the CCD
The signal amplified and A / D-converted from (L) 1 is taken into the center-of-gravity position calculating unit 15, and in the next step # 112, the CCD (L) 1 receives the signal based on the A / D converted value.
(L) Find the center of gravity of the received light image 7 ′ on 2. Then, in the next step # 113, the distance to the measurement target 43 is calculated based on the position of the center of gravity of the received light image 7 ', and step # 1 is performed.
Proceed to 14.

In step # 114, the IRE
The IREDs 6 and 7 are turned off via the D drive circuits 10 and 11, and a series of distance measuring operations is completed in the next step # 115.

(Second Embodiment) FIG. 5 is a view showing a CCD of a distance measuring apparatus according to a second embodiment of the present invention.
2 are given the same reference numerals. Further, the other configuration is the same as that of the first embodiment, and the description thereof is omitted.

In FIG. 5, reference numeral 81 denotes a CCD which is a light receiving element. The difference from FIG. 2 is that the CCD (L) 1
And the CCD (R) 2 are extended in the direction of the adjacent CCD, so that there is only one CCD.

A desired signal image is extracted from the signal images obtained from the light-receiving images on the CCD 81, and a correlation operation is performed using the light-receiving images 5 'and 5 ", and a center of gravity is calculated from the positions of the centers of gravity of 6" and 7'. By doing so, the distance to each measurement object can be measured.

According to each of the above-described embodiments, since the light-receiving image from the object to be measured other than the central direction protrudes from the CCD which is the light-receiving element, the CCD is extended only in the direction of the adjacent CCD (center of gravity position). Received image 7 'for obtaining
The sensor portion where 6 ″ is formed is arranged so as to be sandwiched between the sensor portions where the light receiving images 5 ′ and 5 ″ for which the phase difference is to be formed (see FIGS. 2 and 5). Then, when measuring the distance of the object to be measured in the center direction, the phase difference of the received light image formed on the CCD is obtained from the output of the CCD,
The distance to the object to be measured is determined from the phase difference. On the other hand, when measuring the distance of a measurement object other than the center direction, the position of the center of gravity of the received light image formed on the CCD is obtained from the output of the CCD, and the distance from the position of the center of gravity to the measurement object is obtained. .

By doing so, it is possible to perform wide-field multi-point ranging without increasing the CCD chip area.

(Correspondence between the Invention and the Embodiment) In the above embodiment, the IREDs 5, 6, 7,
11 and the light projecting lens 8 are used as the light projecting means of the present invention.
The light receiving lenses 1 and 2 and the light receiving lenses 3 and 4 correspond to the light receiving unit of the present invention, and the phase difference calculating unit 14 and the center of gravity calculating unit 15 correspond to the calculating unit of the present invention.

(Modification) The light projecting means is constituted by a plurality of IREDs and a light projecting lens, but is not limited to this. One IRED and a light projecting lens capable of dividing an optical path into a plurality of light paths are arranged. It may be a configuration.

Although the CCD is used as the light receiving means,
Other light receiving elements may be used. When a CCD is used as the light receiving means, a function of removing extraneous light by a skim operation may be added.

[0050]

As described above, according to the present invention,
An object of the present invention is to provide a distance measuring apparatus capable of performing a plurality of measurement objects without increasing the light receiving area of the light receiving means.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a distance measuring apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a positional relationship between a CCD and a received light image according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining a distance measuring apparatus according to the first embodiment of the present invention.

FIG. 4 is a flowchart showing a series of operations of the distance measuring apparatus according to the first embodiment of the present invention.

FIG. 5 shows a distance measuring device C according to a second embodiment of the present invention.
FIG. 3 is a diagram illustrating a light receiving image formed by a CD and a light receiving lens.

FIG. 6 is a diagram for explaining a conventional one-point phase difference distance measuring type active distance measuring distance measuring apparatus.

FIG. 7 is a diagram for explaining a conventional three-point phase difference distance measuring type active distance measuring distance measuring apparatus.

FIG. 8 is a diagram showing a conventional positional relationship between a CCD and a received light image.

[Description of Signs] 1, 2 CCD 3, 4 Light receiving lens 8 Projection lens 5, 6, 7 IRED 9, 10, 11 IRED drive circuit 14 Phase difference calculation unit 16 Center of gravity calculation unit 16 CPU

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA06 AA17 DD00 DD02 FF09 GG07 GG13 HH14 JJ01 JJ05 JJ25 JJ26 LL04 NN01 PP22 QQ00 QQ03 QQ25 QQ26 QQ28 QQ31 2F112 AA07 AA08 AC03 AC10 BA03 FA04 FA45 FA50 GA01 5J084 AA05 AD02 AD07 BA02 BA06 BA34 BA39 BB02 CA31 CA49 CA67 CA68 CA69 DA01 EA02 EA07 EA31

Claims (8)

[Claims] 1. A light projecting means for projecting light to a substantially central direction and a measuring object adjacent thereto, a light receiving means for receiving reflected light from the measuring object located substantially in the central direction and the periphery thereof, and the light receiving means Calculating means for calculating a distance to the object to be measured based on an output from the means, wherein the light receiving means comprises two light receiving portions, and the light reflected from the object to be measured is located substantially in the central direction. The light is received by the two light receiving portions, and the reflected light from the measurement object located on the adjacent one is received by the light receiving portion of one of the two light receiving portions and is located on the other adjacent side. A distance measuring device, wherein the two light receiving units are arranged so that reflected light from a measurement target is received by the other light receiving unit of the two light receiving units. 2. The calculation means calculates a phase difference between outputs of the two light receiving units for a measurement object located in the substantially central direction, calculates a distance based on the phase difference, and calculates a distance between the two adjacent light receiving units. Alternatively, for a measurement object located on the other side, a center of gravity of a light receiving image on one or the other of the two light receiving units is obtained, and a distance is calculated based on the center of gravity. Item 7. The distance measuring device according to Item 1. 3. A portion of the two light receiving portions where a light receiving image for obtaining a position of a center of gravity is formed so as to be sandwiched between portions where a light receiving image for obtaining a phase difference is formed. The distance measuring apparatus according to claim 2. 4. A light projecting means for projecting light to a substantially central direction and a measuring object adjacent thereto, a light receiving means for receiving reflected light from the measuring object located substantially in the central direction and the periphery thereof, and the light receiving means. Calculating means for calculating a distance to the object to be measured based on an output from the means, wherein the light receiving means comprises a single light receiving part, and the light reflected from the object to be measured is located substantially in the center direction. The light is received at the left and right of the one light receiving unit, and the reflected light from the measurement object located at the adjacent one and the other is the left and right light receiving the reflection light from the measurement object located at the substantially central direction. A distance measuring device characterized in that light is received by one different portion sandwiched between the portions. 5. The calculation means calculates a phase difference between outputs of right and left portions of the one light receiving unit for a measurement target positioned in the substantially central direction, and calculates a distance based on the phase difference. For the measurement object located at the adjacent one or the other, the center of gravity of the light receiving image formed in each of the different portions sandwiched between the left and right portions is obtained, and the distance is calculated based on the center of gravity. The distance measuring apparatus according to claim 4, wherein 6. The distance measuring apparatus according to claim 1, wherein said light receiving means is a CCD. 7. The distance measuring apparatus according to claim 6, wherein said CCD has a function of removing extraneous light by a skim operation. 8. The calculating means, when obtaining a phase difference,
The distance between the plurality of light receiving lenses, which are one of the components of the light receiving means, is defined as the base length, and when determining the position of the center of gravity, the distance between the light emitting lens, which is one of the components of the light emitting means, and each of the light receiving lenses The distance measuring apparatus according to claim 2, wherein the distance to the object to be measured is calculated using the distance as a base line length.