JPH0611647A - Ranging device - Google Patents

Abstract

(57) [Abstract] [Purpose] A distance measuring device is capable of measuring distances in a plurality of fields of view with a small number of light receiving units. [Structure] In the distance measuring device, the distance zones of the subjects θ _{1 to} θ are arranged in five stages according to the light receiving positions of the light receiving units D _{1 to} D _7, and the light emitting devices a _{1 to} a ₃ are arranged. It includes a group, a lens for projecting light LA, a lens for receiving light LD, and a group of light receivers D _{1 to} D ₇ . Further, the distance measuring device inputs the detection signals from the amplifier group connected to the rear stage of each of the light receivers D _{1 to} D ₇ and the three amplifiers out of the seven amplifiers, and the object distances are regarded as the same distance. Distance measuring axis 1 despite distance
It comprises a multiplexer _{group 1} to l ₃ corrects the difference between the light receiving position of the light receiver D ₁ to D ₇ group caused by different.

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,
In particular, the present invention relates to an active type distance measuring device suitable for a camera.

[0002]

2. Description of the Related Art Conventionally, in order to maintain accuracy, this type of device projects a small spot light and measures the distance by detecting the angle of reflected light at a distance of the base line.

[0003]

However, in such a small spot light, reflected light cannot be obtained depending on the subject condition, and the distance measuring field of view is narrow. The field of view entered between the two persons, and as a result, there was a defect that the distance could not be measured or the distance was erroneously measured.

An object of the present invention is to prevent erroneous distance measurement by performing a plurality of distance measurement for different distance measuring fields, and also to use a part of the light receiving portion of each light receiving element when measuring distances for different distance measuring fields. An object of the present invention is to provide a distance measuring device capable of measuring distances in a plurality of fields of view with a small number of light receiving parts.

[0005]

SUMMARY OF THE INVENTION A distance measuring device according to the present invention includes a light projecting means for projecting signal light along a plurality of distance measuring axes and a reflection from an object on each of the plurality of distance measuring axes. The light receiving means having a plurality of light receiving portions for receiving the reflected light of the signal light, and the plurality of light receiving portions of the light receiving means for each predetermined range with respect to each of the distance measuring axes and partly in an adjacent range. And a processing unit that divides the light receiving portions of the respective light receiving portions so as to be shared, and forms the object distance information on each of the distance measuring axes according to the light receiving portion outputs within the respective divided ranges.

[0006]

According to the distance measuring device of the present invention, the reflected light of the signal light which is projected from the light projecting means and then reflected from the objects on each of the plurality of distance measuring axes is received by the light receiving means having a plurality of light receiving portions. In addition to receiving light, the processing means divides the plurality of light receiving portions of the light receiving means into predetermined ranges with respect to each distance measuring axis so as to share a part of the light receiving portions in the adjacent ranges, and to measure each distance measuring range. By forming the object distance information on the axis in accordance with the output of the light receiving unit in each divided range, it is possible to partially use the light receiving unit of each light receiving element used for distance measurement for different distance measuring fields. .

[0007]

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

FIG. 1 is an optical explanatory view of a distance measuring apparatus according to an embodiment of the present invention.

The light emitters a ₁ , a ₂ , a ₃ such as light emitting elements are arranged in a straight line. Each of the light emitters a _{1 to} a ₃ outputs pulsed light pl _{1 to} pl ₃ as signal light projected for distance measurement to a plurality of distance measuring axes l at different angles.
Along ₁ to l _3, subject theta ₁ as distance measurement target object on the distance measuring axis _{l 1 ~l 3, θ 2,} θ 3, θ ( the subject theta in infinity not shown) toward the To project. A light projecting lens LA is arranged in front of the light emitters a _{1 to} a ₃ .

The light receiving lens LD includes the distance measuring axes l _{1 to} l ₃
The reflected lights pr ₁ to pr ₃ of the pulsed lights pl _{1 to} pl ₃ reflected from the respective subjects θ ₁ to θ are received. Behind the light receiving lens LD, light receiving devices D ₁ , D ₂ , D such as optical sensors are provided.
₃ , D ₄ , D ₅ , D ₆ , and D ₇ are arranged on a straight line, respectively, and receive the reflected light PR of the Panis light pl _{1 to} pl ₃ via the light receiving lens LD.

The light emitting devices a _{1 to} a ₃ group, the light projecting lens LA, the light receiving lens LD, and the light receiving devices D _{1 to} D ₇ group are arranged as follows, for example.

Projecting lens LA and receiving lens LD
When there is a subject θ ₁ close to, the reflected light p of the pulsed light pl ₁ projected from the first light emitter a _{1 is} reflected by the subject θ _1.
r ₁ is reflected light pr ₂ by the subject θ ₁ of the pulsed light pl ₂ projected from the second light emitter a _{2 on} the fifth light receiver D _5.
There the light receiver D ₆ of the sixth, as the third light emitter a ₃ reflected pr ₃ by the object theta ₁ of the pulsed light pl ₃ projected from are primarily respectively received in the light receiver D ₇ of the seventh Will be placed.

When there is a subject θ ₂ slightly far from the light projecting lens LA and the light receiving lens LD, the reflected light pr ₄ of the subject θ ₂ of the pulsed light pl ₁ projected from the first light emitter a _{1 is present.} To the fourth light receiver D ₄ , reflected light pr ₅ on the subject θ ₂ of the pulsed light pl ₂ projected from the second light emitter a ₂ to the fifth light receiver D ₅ , and to the third light emitter a Reflected light p from the subject θ ₂ of the pulsed light pl ₃ projected from ₃
r ₆ is arranged so as to be mainly received by the _sixth photodetector D ₆ .

Furthermore, when there is a subject θ ₃ far from the light projecting lens LA and the light receiving lens LD, the reflected light pr _{7 from} the subject θ ₃ of the pulsed light pl ₁ projected from the first light emitter a _{1 is} generated. The third light receiver D ₃ has a second light emitter a
The _second reflected light pr ₈ by the object theta ₃ of the projected pulsed light pl ₂ from the fourth light receiver D _4, third light emitter a ₃ light reflected by the object theta ₃ pulsed light pl ₃ projected from each pr ₉ is the light receiver D ₅ of the fifth are arranged to be mainly received.

When there is a subject θ at infinity, the reflected light pr of the pulse light pl ₁ projected from the first light emitter a ₁ by the subject θ is transmitted to the first light receiver D ₁ and the second light emitter. a ₂
The reflected light from the subject θ of the pulsed light pl ₂ projected from the third photoreceiver is the reflected light from the subject θ of the pulsed light pl ₃ projected from the third light emitter a ₃ to the second photoreceiver D _2. Each of them is arranged to receive light mainly in the device D ₃ .

Although not shown, when there is a subject θ ₄ that is closer to the subject θ at infinity and farther than the subject θ ₃ far away, the pulsed light projected from the first light emitter a ₁ is used. The reflected light of the subject θ ₄ of pl ₁ is reflected by the second light receiver D ₂ and the reflected light of the pulse light pl ₂ of the subject θ ₄ projected from the second light emitter a ₂ is reflected by the third light receiver D ₃
In addition, the reflected light of the subject θ ₄ of the pulsed light pl ₃ projected from the third light emitter a ₃ is arranged to be mainly received by the _fourth light receiver D ₄ .

Therefore, in the embodiment shown in FIG. 1, the distance zones of the subjects θ _{1 to} θ are discriminated by being divided into 5 stages according to the light receiving positions of the photo detectors D _{1 to} D _7. .

FIG. 2 is a block circuit showing an embodiment of a circuit configuration for driving the light emitting devices a _{1 to} a ₃ group and processing the light receiving signals of the light receiving devices D _{1 to} D ₇ shown in FIG. It is a figure. 2 that are the same as those in FIG. 1 are designated by the same reference numerals.

The drive circuit M1 for the light emitters a _{1 to} a ₃ group supplies, for example, pulse power pp. Demultiplexer D
M1 is, for example, the pulse power pp from the drive circuit M1.
In sequence with the first, second, and third light emitters a ₁ , a ₂ , a ₃
And output. The control signal CS for synchronization is also output from the demultiplexer DM1. In addition, the pulse power pp of each of the light emitters a _{1 to} a ₃ is the demultiplexer DM.
When it is given from 1, the pulsed lights pl _{1 to} pl ₃ are emitted and projected.

An amplifier A ₁ is provided after the photodetectors D _{1 to} D _7.
To A ₇ group is connected, amplifies and outputs the respective detection signals ds. Each multiplexer MX _{1 to} MX
_{The reference} numeral ₅ inputs the detection signals ds from three amplifiers among the _seven amplifiers A _{1 to} A ₇ , respectively, and the distance measuring axes l _{1 to} l ₃ even though the object distances are considered to be the same distance.
The difference in the light receiving positions of the photoreceivers D _{1 to} D ₇ as described with reference to FIG. That is,
The first multiplexer MX ₁ inputs the detection signals ds from the first, second and third amplifiers A ₁ , A ₂ and A ₃ , respectively, and the second multiplexer MX ₂ outputs the second and third amplifiers. , And the detection signals ds from the fourth amplifiers A ₂ , A ₃ , and A ₄ , respectively. Similarly, the third multiplexer MX
₃ receives the detection signals ds from the third, fourth and fifth amplifiers A ₃ , A ₄ and A ₅ , respectively, and the fourth multiplexer MX ₄ has the fourth, fifth and sixth amplifiers. A ₄ , A ₅ , A ₆
Each of the detection signals ds from is input to the fifth multiplexer MX ₅ , and the fifth, sixth and seventh amplifiers A ₅ ,
The detection signals ds from A ₆ and A ₇ are input respectively.
And further each multiplexer MX ₁ ~MX ₅ has an input terminal ,, is switched in synchronization with the input of the control signal CS from the demultiplexer DM1. That is, the output terminals of the demultiplexer DM1 ...
In response to being switched →→ ......, the input terminal ,, of each multiplexer MX ₁ ~MX _5, →
→→ …… It can be switched.

Therefore, for example, in FIG. 1, all the pulsed lights pl _{1 to} pl ₃ projected from the light emitters a _{1 to} a ₃ are considered to have the same object distance.
_When reflected at _1, the reflected light pr _{1 to} pr ₃ is received by different light receivers D _{1 to} D ₇ as described above, but the pulse projected from the first light emitter a ₁ Light p
The signal of the reflected light pr ₁ of l ₁ is taken in from the fifth light receiver D ₅ to the fifth multiplexer MX ₅ in synchronization with the light emission of the first light emitter a ₁ , and the second light emitter a 1 signal of the reflected light pr ₂ of the projected pulsed light pl ₂ from _2, from the light receiver D ₆ of the sixth in synchronization with the second light emitting device a ₂ 5
The reflected light pr of the pulsed light pl ₃ projected by the _third light emitter a ₃ is taken into the multiplexer MX ₅ of
_{The third} signal is fetched from the _seventh light receiver D ₇ to the fifth multiplexer MX ₅ in synchronization with the light emission of the third light emitter a ₃ .

Similarly, with respect to subjects at other distances, the reflected light from the subjects on different distance measuring axes l _{1 to} l ₃ whose subject distances are regarded as the same distance are different positions on the light receivers D _{1 to} D _7. It is received Te, but none these signals would be incorporated into the same multiplexer MX ₁ ~MX _5.

As a result, each multiplexer MX _{1 to} MX ₁
Each output of X ₅ represents a distance signal from the long distance to the short distance corresponding to the absolute distance in which the difference in the light receiving position due to the difference in the distance measuring axes l _{1 to} l ₃ is corrected to the subject divided into five stages of zones. It will be. That is, each multiplexer MX ₁
Each of the outputs of MX ₅ to MX ₅ corresponds to the object distance from the far distance to the short distance of the five-step distance zone shown in FIG.

Each of the detection circuits DA _{1 to} DA ₅ is composed of a synchronous detector and a comparator provided with a desired threshold level, and each multiplexer M.
They are connected to the subsequent stages of X _{1 to} MX ₅ , respectively. Further, each of the detection circuits DA _{1 to} DA ₅ has a multiplexer MX.
And synchronous detection by the output of the ₁ ～MX from ₅ detection signal ds' from the driving circuit M1 in the synchronous detector, respectively, and the signal level after detection compared against a threshold level by the comparator exceeds the threshold level In that case, that is, only when the subject distance signals are output from the multiplexers MX _{1 to} MX ₅ , the high-level detection signal dts is output.

A group of flip-flops FF _{1 to} FF ₅ for storage is connected to the subsequent stage of each of the detection circuits DA _{1 to} DA ₅ , and is set when a detection signal dts of high level is input, and set to high level. The distance signals d _{1 to} d ₅ are output. Each flip-flop FF ₁ to ff ₅ is reset by a reset signal PUC output from means not shown.

[0026] The subsequent flip-flop FF ₁ to ff ₅ group, and an encoder PE1 having a priority function is connected, either the distance signal d ₁ to d ₅ corresponding to the distance out perspective distance zone It inputs and outputs the distance data dd corresponding to the distance signal. This distance data dd may be digital or analog. For example, the distance signal d ₁ corresponds to the farthest zone. In other words, when there is a subject θ at infinity, the distance signal d ₁
Is input to the encoder PE1, and the infinite distance data dd is output from the encoder PE1. Then, the distance signal d ₅ corresponds to the latest zone, and similarly, in this case, the distance data d indicating the closest distance from the encoder PE1.
d is output.

When a plurality of distance signals d _{1 to} d ₅ are input to the encoder PE1, the priority function of the encoder PE1 operates to select the distance signals d _{1 to} d ₅ indicating the short distance. , The distance data dd corresponding to the distance signals d _{1 to} d ₅ is output, and distance measurement display and automatic focus adjustment are performed.

When the photodetectors D _{1 to} D ₇ themselves such as MOS photosensors have a storage effect and can be selectively read out, the multiplexers MX _{1 to} MX in the embodiment are used. It is also possible to configure ₅ in the sensor and omit the _first- stage amplifiers A _{1 to} A ₇ .

As described above, according to this embodiment,
The light receivers D _{1 to} D ₇ (including the first-stage amplifiers A _{1 to} A ₇ ) are shared, and the narrow pulsed light pl along the plurality of distance measurement axes l _{1 to} l ₃ is shared.
_By performing a plurality of distance measurements using _{1 to} pl ₃ and performing distance measurement display and automatic focusing from the results, distance measurement that is less affected by the patterns and conditions of the subject θ _{1 to} θ can be performed.

Moreover, the number of light receivers D _{1 to} D ₇ on the light receiving circuit side increases only a little, and the circuit, especially the multiplexer MX.
The demodulators from _{1 to} MX _{5 and} later can be shared, and the circuit has the advantage of not becoming too large.

In addition, a plurality of light emitters a _{1 to} a ₇ are integrated,
The integration of the light receivers D _{1 to} D ₇ has the advantage that the adjustment is almost the same as the conventional one.

[0032]

Since the present invention is configured as described above, a plurality of distance measuring operations are performed for different distance measuring visual fields to prevent erroneous distance measurement, and the distance measuring for each visual field is realized by the sensor in the light receiving section. Can be done, and its effectiveness is extremely high.

[Brief description of drawings]

FIG. 1 is an optical explanatory view of a distance measuring device according to an embodiment of the present invention.

FIG. 2 is a block circuit diagram showing an example of a circuit configuration for driving the light emitter group and processing the light reception signal of the light receiver group shown in FIG.

[Explanation of symbols]

θ _{1 to} θ ₃ subject a _{1 to} a ₃ light emitter l _{1 to} l ₃ distance measuring axis pl _{1 to} pl ₃ pulse light D _{1 to} D ₇ light receiver PR reflected light MX _{1 to} MX ₅ multiplexer DA _{1 to} DA ₅ detection Circuit FF _{1 to} FF ₅ Flip-flop PE1 Encoder

Claims (1)

[Claims] 1. A light projecting means for projecting signal light along a plurality of distance measuring axes, respectively, and a plurality of light receiving means for receiving reflected light of the signal light reflected by an object on each of the plurality of distance measuring axes. A light receiving unit having a light receiving unit and a plurality of light receiving units of the light receiving unit are divided so as to share a part of the light receiving units in a predetermined range with respect to each of the distance measuring axes and in an adjacent range. A distance measuring device comprising: processing means for forming object distance information on each of the distance measuring axes according to an output of a light receiving unit within each divided range.