JPH0769174B2 - Distance measuring method for distance measuring module - Google Patents

Description

TECHNICAL FIELD The present invention relates to a distance measuring test method for a distance measuring module used for a camera, a video, etc. for autofocus,
More specifically, it relates to a distance measuring test method for an active distance measuring module.

(Prior Art) An active distance measuring module projects a beam from a light emitting unit to a subject, forms a spot beam image projected on the subject by this beam on a light receiving unit, and at this time, the spot beam image is formed. The distance from the receiving direction or the beam projection direction of the light emitting unit to the subject is measured.

Generally, in a distance measuring module that measures the distance from the direction in which the spot beam image is received in the light receiving unit to the subject, the projection direction of the beam in the light emitting unit is fixed, and the distance from the beam projection direction in the light emitting unit to the subject is fixed. In the distance measuring module that measures the distance, the direction in which the spot beam image is received is constant in the light receiving unit.

The distance measuring principle of these distance measuring modules is to measure the distance to a subject based on the angle formed by the direction of beam projection in the light emitting section and the direction of receiving the spot beam image in the light receiving section by the triangulation method. is there.

It is necessary to test whether such an active distance measuring module actually performs a correct distance measuring operation, and a distance measuring test is performed before or after being incorporated in a camera, a video, or the like.

FIG. 6 shows a schematic view of a distance measuring test method for a conventional distance measuring module.

In FIG. 6, reference numeral 31 is a distance measuring test device, 1 is a camera, and the camera 1 has a distance measuring module 3 incorporated therein.

The distance measuring module 3 includes a light emitting section 5 including an infrared light emitting element and a light projecting lens, and a light receiving section 7 including a condensing lens and a light receiving element. The light emitting unit 5 and the light receiving unit 7 are separated by a distance Xo (baseline length).

The distance measuring module 3 is of a type that measures the distance from the direction B that receives the spot beam image in the light receiving section 7 to the subject, and the infrared beam is projected from the light emitting section 5 in a fixed direction A.

Distance measuring plates 31 ₁ , 33 ₂ , 33 ₃ , ... Are arranged in the distance measuring test device 31 at predetermined distances D ₁ , D ₂ , D ₃ ,.

In the test method, first, the camera 1 is installed at a predetermined position of the distance measuring test device 31.

Then, for example, if the relative distance D ₁ to obtain a measurement distance data of the distance measuring module 3 sets the distance plate 33 ₁ at a distance D ₁ in the projection optical path of the light emitting portion 5.

Here, when projected toward the light emitting unit 5 an infrared beam at a distance plate 33 _1, a distance plate 33 _one spot beam image is projected, the spot beam image is formed on the light receiving element of the light receiving portion 7.

Spot light image to any part on the light receiving element in the light receiving section 7 detects whether the imaged capture the arithmetic unit (not shown) the detection signal, measures the distance to the distance plate 33 _1.

Then, from the angle θ1 formed by the beam projection direction A and the direction B for receiving the spot beam image at the light receiving unit 7,
That is, since the projection direction A of the infrared beam is constant, the distance from the angle θ1 at which the light receiving unit 7 receives the spot beam image to the subject is measured based on the triangulation method.

Next, the measurement data calculated by the distance measuring module 3 and the distance plate
And the distance D ₁ of the up 33 _1, by comparing with previously provided target table or the like, it is checked whether the distance measuring module 3 is distance measurement operation correctly. Further, the distance measurement test for the distances D ₂ , D ₃ , ... Is performed by the distance plates 33 ₂ , 33 ₃ ,.

This test method is the same in the case of the test of the distance measuring module that measures the distance to the subject by using the reflection of the beam in the light emitting unit and effectively uses the space.

(Problems to be solved by the invention) Therefore, in the conventional method, a large space is required to install a distance plate at an actual distance where the distance measurement is desired to be performed, and a problem arises that the test apparatus becomes large. there were.

Especially for a distance measuring module for a camera equipped with a zoom mechanism, a test device is further enlarged because a distance of 10 m or more is required, and such a large and occupying space test device is used in a camera assembly line. There was a problem that was extremely disadvantageous when incorporating.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to reduce the size and space of a distance measuring test device, and further to measure various distances with a small and simple device. It is an object of the present invention to provide a distance measuring test method for a distance measuring module capable of performing a distance test.

(Means for Solving the Problem) In order to achieve the above object, the present invention provides a plurality of objects in which distance-measuring objects are arranged at a desired distance from a distance-measuring module and the beam path is bent at different degrees. Of the optical member, at least one of the optical members is arranged in the optical path connecting the light emitting unit, the object to be measured, and the light receiving unit, and the distance measuring test is performed while exchanging the optical members. It is characterized by having done.

Further, the present invention provides an optical member in which a distance-measuring object is arranged at a desired distance from a distance-measuring module, and a path of a beam is bent in an optical path connecting the light emitting unit, the distance-measuring object and the light receiving unit. Is provided, and the distance measuring test is performed while moving the object to be measured toward and away from the distance measuring module.

(Operation) The light receiving unit considers the spot beam image from the object to be measured at the actual distance, and the distance is measured by this.

Therefore, it is possible to perform a distance measuring test without requiring an actual distance as in the conventional case, and it is possible to reduce the size and space of the test apparatus.

Further, the distance measuring test can be performed for various distances by exchanging the optical member or by moving the object to be measured toward and away from the distance measuring module.

(Example) Hereinafter, the Example of this invention is described based on drawing.

FIG. 1 is a schematic diagram of a distance measuring test method for performing a distance measuring test while exchanging optical members.

First, the test apparatus 11 will be described. 1 is a camera installed at a predetermined position of the test apparatus 11, and the distance measuring module 3 incorporated in the camera 1 has a predetermined interval (baseline length X
The light emitting unit 5 and the light receiving unit 7 are provided.

13 is a distance plate, 15 is a rotating plate, the distance plate 13 approaches the camera to a desired distance (for example, 1 m) in front of the distance measuring module 3,
The distance plate 13 is arranged so as to be movable in the direction of separation (arrow E), and in the embodiment, the distance plate 13 corresponds to the distance measurement object.

The rotating plate 15 is rotatably arranged in front of the light receiving unit 7. As shown in FIG. 2, a plurality of concave lenses 17 having different focal lengths are incorporated around the rotary plate 15 at predetermined intervals.

The center of rotation 15A of the rotating plate 15 is shifted outward from the center of the light receiving unit 7, and when the rotating plate 15 is rotated appropriately, each concave lens
The center 17A of 17 is disposed so as to be located on the extension of the center of the light receiving unit 7.

Next, the test method will be described.

When an infrared beam is projected from the light emitting unit 5, a spot beam image is projected on the range plate 13 by this beam, and the path of the spot beam image is bent by the concave lens 17 and is imaged on the light receiving unit 7.

At this time, the projection direction (constant) of the infrared beam on the light emitting unit 5 is A, the direction receiving the spot beam image on the light receiving unit 7 is B ', and the angle θ2 formed by the direction A and the direction B'
And The angle θ2 is the projection direction A of the infrared beam.
Is constant, it is also the angle at which the light receiving unit 7 receives the spot beam image.

In FIG. 1, reference numeral 21 designates a distance plate on the assumption that it is arranged at an actual distance for distance measurement.

If an infrared beam is projected on the distance plate 21, a spot beam image on the distance plate 21 by this beam is formed on the light receiving unit 7. At this time, the direction of receiving the spot beam image in the light receiving unit 7 is B, and the angle between the direction A and the direction B is θ1. This angle θ1 is also the angle at which the spot beam image is received by the light receiving section 7 because the projection direction A of the infrared beam is constant.

Therefore, the concave lens that makes the angle θ1 and the angle θ2 the same
17, that is, the concave lens 17 that makes the direction B ′ for receiving the spot beam image in the light receiving unit 7 the same as the direction B
If so, in the light receiving section 7, it is as if the distance plate 21 that is at the actual distance.
It is regarded as a spot beam image from and the distance measurement is performed by this.

Here, if the rotating plate 15 is rotated and the concave lens 17 is replaced with another one, the angle θ2 changes discontinuously, and the actual distance for distance measurement changes discontinuously for each concave lens 17. Become.

Therefore, the distance measuring test can be performed for various distances by replacing the concave lens 17.

Further, when the distance plate 13 is moved in the direction of the arrow E within a predetermined range, the angle θ2 continuously changes, and the actual distance follows the movement of the distance plate 13 to measure the distance within a predetermined range. It will change continuously.

Therefore, even if the distance is long for distance measurement, the distance plate 13
And the combination of the concave lenses 17 make it possible to perform a distance measurement test while continuously changing a long distance for distance measurement in a narrow space.

Next, this principle will be described with reference to FIG.

In FIG. 3, numeral 23 indicates a portion where a virtual image is formed, and a concave lens
The focal length of 17 is f, the distance from the concave lens 17 to the distance plate 13 is L, and the distance from the light receiving portion 7 to the concave lens 17 is l.
Then, the distance plate 13 seen from the light receiving portion through the concave lens 17
The distance up to is optically equivalent to D derived by the following equation, and is optically the same as when the distance plate 13 'is placed at the distance of D.

D = L {FL-l ( L-f)} / fL ( where, f <0) also, the movement range of the distance plate 13 From L ₁ and L _2, the range of distances that can range finding by the following formula It is in the range D ₁ to D ₂ shown.

D ₁ = L ₁ {fL ₁ −l (L ₁ −f)} / fL ₁ D ₂ = L ₂ {fL ₂ −l (L ₂ −f)} / fL ₂ Therefore, the test distance is from D ₁ to D ₂ If the test distance is out of the range of D ₁ to D ₂ , the distance measurement test can be performed by exchanging with another concave lens 17 within the range of ₁ It is convenient to perform the test if the distances that can be measured are overlapped. In this case, the concept is the same even if the concave lens 17 is positioned in front of the light emitting unit 5 with its core shifted outward.

Therefore, according to the present embodiment, it is possible to replace the concave lens 17 by rotating the rotating plate 15 without requiring an actual distance to be tested.
For example, a distance measurement test can be performed at various distances of about 1 m, the test apparatus can be downsized and the space can be saved, and the test apparatus can be easily incorporated in a camera assembly line.

If the concave lens 17 is replaced and the distance plate 13 is moved as in the embodiment, it is possible to continuously perform the distance measuring test for various distances.

Further, since the concave lens 17 is used to bend the optical path, the position of the concave lens 17 is not required to be highly accurate, and therefore the distance measuring test device can be configured easily and inexpensively.

In the embodiment, the case where the concave lens 17 is used has been described, but it is also possible to dispose a convex lens in front of the light emitting section 5 or to dispose the core inward and dispose in front of the light receiving section 7. Is the same.

Further, the method of exchanging the concave lens 17 is arbitrary. For example, the concave lens 17 may be exchanged by incorporating a plurality of concave lenses 17 in an elongated plate and sliding the plates.

Further, the optical member is not limited to the concave lens 17 and the convex lens, and may be any optical member as long as it bends the path of the beam, and other mirrors, prisms or the like can be used as the optical member.

Further, if a zoom lens is used as an optical member from the same idea, it is possible to perform a distance measurement test while continuously changing the distance so as to measure the distance without moving the distance plate by changing the magnification.

Further, in the embodiment, the distance measuring module 3 that performs distance measurement based on the direction in which the light receiving unit 7 receives the spot beam image.
Although the case has been described, the present invention can be similarly applied to the case of a distance measuring module that performs distance measurement based on the beam projection direction in the light receiving unit 5.

Furthermore, if the moving range of the distance plate 13 is set to be sufficiently long to some extent, the distance measuring test of the distance measuring module 3 can be performed even if there is only one optical member for bending the path of the beam. Also in this case, the test apparatus can be downsized and the space can be saved.

Next, the distance measuring test system thus constructed will be described with reference to FIGS. 4 and 5 together with its test procedure.

FIG. 4 shows a schematic view of the whole distance measuring test system.

This distance measuring test system is composed of a machine body 40 and a general controller section 50 that comprehensively controls the machine body 40.

The machine body 40 includes a base 41, and a camera mounting mechanism 42 for removably fixing the camera 1 to be tested is provided on the base 41.

Further, on the base portion 41, a single-axis robot 43 for controlling the one-dimensional movement of the movable table 43a is provided, and on the movable table 43a, a distance plate operating mechanism 44 for operating the distance plate 13 is attached. .

Further, the base portion 41 is provided with a power supply / controller unit 45 for supplying electric power to and controlling the camera mounting mechanism 42, the single-axis robot 43, and the distance plate operating mechanism 44.

In this embodiment, a wedge prism 17A is used as an optical member, and the wedge prism 17A is fixed to a prism mounting portion provided in the camera mounting mechanism 42.

The general controller section 50 is mainly composed of a computer set 51 such as a personal computer, and the computer set 51 is connected to a power supply / controller unit 45 via a first interface 52.

Also, the computer set 51 has a second interface.
It is configured to be connectable to an electronic control circuit inside the test camera 1 via 53 and a connector (not shown).

The second interface 53 is for allowing the computer set 51 and the test camera 1 to communicate their electrical command signals and distance signals.

Due to the function of the electronic control circuit inside the test camera 1, the light emitting section 5 is caused to emit light by an electric signal from the outside, and the distance is measured based on the direction in which the light receiving section 7 receives the spot beam image. It is configured to be able to output an electric distance signal representing the distance to the outside.

The test camera 1 may be placed on the camera mounting mechanism 42 automatically by using a transfer robot or manually.

The camera mounting mechanism 42 includes an air solenoid (not shown). By operating the air solenoid with an electric signal from the outside, the mounted test camera 1 is fixed at a predetermined position and fixed. Cancellation is performed.

The single-axis robot 43 is a commercial product of a type controlled by an electric signal from the outside, and, for example, a movable table 43a guided one-dimensionally by a guide rail and a movable table 43a.
It is composed of a high precision lead screw for moving the lead screw, a DC servo motor for rotating the lead screw, an encoder for reading the rotational position of the DC servo motor and performing feedback control, an electronic control circuit, and the like.

The distance plate operating mechanism 44 mounted on the movable table 43a of the single-axis robot 43 is a rotary actuator for rotating the distance plate 13 by 180 degrees in this embodiment.

The distance plate 13 has different light reflectances on the front side and the back side, and when it is desirable to change the light reflectance of the distance plate 13 during the execution of the distance measurement test, an electric signal from the outside is transmitted. The distance plate operating mechanism 44 is controlled by this to rotate the distance plate 13.

The computer set 51 includes, for example, a main body 51a, a CRT display 51b, and a key board 51c, and the first interface 52 connecting the computer set 51 and the power supply / controller unit 45 is, for example,
It is based on the RS-232-C standard.

The camera mounting mechanism 42, the single-axis robot 43, and the distance board operating mechanism 44 described above are controlled by electric signals sent from the power supply / controller unit 45 under the control of the computer set 51.

Next, a specific procedure of the distance measuring test method by the above distance measuring test system will be described with reference to the flowchart of FIG.

First, in step S1, the power of each part constituting the system is turned on.

In the next step S2, the program for the distance measurement test is loaded into the memory of the computer set 51 and the execution is started.

When the execution of the program is started, the computer set 51 enters a standby state waiting for an instruction to start the ranging test routine from the key board 51c.

In the next step S3, the test camera 1 is mounted on the camera mounting mechanism 42 by, for example, a manual operation, and then in step S4.
At, the start instruction of the ranging test routine is input from the key board 51c.

When this routine is started, in step S5, a command signal is sent from the computer set 51 to the camera mounting mechanism 42, the air solenoid of the camera mounting mechanism 42 is operated, and the test camera 1 is fixed. At this time,
The second interface 53 and the electronic control circuit of the test camera 1 are also connected.

Then, in step S6, a distance variable representing the test distance is set.

This test distance is not the actual distance from the test camera 1 to the distance plate 13 in the distance measuring test system, but the distance to the distance plate 13 on the assumption that the optical path is not bent.

For this test distance, for example, one for short distance, one for medium distance, and one for long distance, a total of three distances may be set in advance, and the values of these predetermined distances may be written in the program in advance. Accordingly, it is possible to input a desired value or change a specified value by operating the key board 51c.

Then, if the test is performed for the above three distances (short distance, medium distance, long distance), step
In S6, the distance variable is set to the first of them (short distance in this example).

In the next step S7, the machine body 40 of the system is set to the set test distance.

That is, the uniaxial robot 43 is operated to move the distance plate 13 in the direction toward and away from the distance measuring module 3 of the test camera 1 (arrow M in FIG. 4), and thereby the actual test set at that time is performed. The light receiving unit 7 receives the spot beam image at the same angle as when the distance plate is present in the distance.

Then, in step S8, the test camera 1 is operated to perform the auto focus (AF) operation, and in the next step S9, the distance signal output from the test camera 1 as a result of the AF operation is read and the signal is output. The distance value represented by is stored in the memory of computer set 51.

In the next step S10, it is determined whether or not a predetermined number of tests have been completed within the test distance at that time.

In order to make the test more accurate, it is preferable to repeat the test a plurality of times (for example, 5 times) for the same distance.

If the prescribed number of tests has not been completed, the process will
Returned to S8.

If the test has been completed a predetermined number of times, the process proceeds to step S11, where it is determined whether or not the test by the last test distance (a long distance in this example) of the plurality of test distances has been completed.

If the determination result is "NO", the process proceeds to step S12, the test distance setting is changed, and the step
Return to S7.

On the other hand, if the result of this determination is "YES", then the process proceeds to step S13.

In step S13, the camera attachment mechanism 42 is operated to release the fixation of the test camera 1, and the distance measuring test routine ends in step S13.

Then, in step S14, the final result of the distance measuring module 3 of the test camera 1 is judged by comparing the result obtained in the distance measuring test routine with a predetermined judgment criterion, and the judgment result is set in a computer. 51 CRT
Display on display 51b.

In the next step S15, the camera 1 that has been tested is detached from the camera mounting mechanism 42 by hand or the like, and according to the pass / fail judgment result displayed on the CRT display 51b,
In the subsequent step S16, it is determined whether or not the next camera 1 should be tested, and if it is tested, the process returns to step S3.
Otherwise, in step S17, computer set 51
Cause the end action to be performed.

In that case, when an instruction of an ending operation is input from the key board 51c, data that needs to be saved is saved.

Next, in step S18, turn off the power of each part of the system,
This completes this procedure.

Although the procedure has been schematically described above, the identification number of the test camera 1 and the like may be further input to the computer set 51 as necessary to save the distance test result as information for each camera. You may

Further, in particular, when the distance measuring module 3 of the camera 1 is configured to perform the distance measurement stepwise, that is, the distance from the closest distance to infinity is divided into several distance ranges, and the distance measurement distance In the case where the distance signal indicating which one of the distance ranges belongs is generated, a more accurate test result can be obtained by setting the test distance at the boundary of those distance ranges.

In that case, if the distance immediately before the boundary and the distance immediately after the boundary are used as the test distance, a more accurate test can be performed.

(Effects of the Invention) As is clear from the above description, according to the distance measuring test method for the distance measuring module of the present invention, it is possible to reduce the size and space of the test apparatus, and further, to reduce the size and size of the apparatus. The distance measurement test can be performed for various distances.

[Brief description of drawings]

FIG. 1 is a schematic view of a distance measuring test method according to an embodiment of the present invention,
2 is a front view of the rotary plate, FIG. 3 is an explanatory view of the test method,
FIG. 4 is a schematic diagram of the whole distance measuring test system, FIG. 5 is a flowchart showing a test procedure by the distance measuring test system, and FIG. 6 is a schematic diagram of a conventional distance measuring test method. In the figure, 1 is a camera, 3 is a distance measuring module, 5 is a light emitting unit, 7 is a light receiving unit, 13 is a distance plate, 15 is a rotating plate, 17 is a concave lens, X ₀ is a base line length, and A is a beam projection direction. , B, B ′ are directions for receiving the spot beam image, 40 is a machine body, 43 is a single-axis robot, 50 is a general controller, and 51 is a computer set.

Claims (2)

[Claims] 1. A beam is projected from a light emitting unit onto a subject, a spot beam image projected onto the subject by this beam is formed on a light receiving unit, and a beam projection direction at the light emitting unit at that time and a spot beam image at the light receiving unit. In the distance measuring module that measures the distance to the subject from the angle formed by the receiving direction, the distance measuring module is arranged at a desired distance from the distance measuring module, and the degree of bending of the beam path is different. A plurality of optical members are prepared, at least one of the optical members is arranged in an optical path connecting the light emitting unit, the object to be measured, and the light receiving unit, and the distance measuring test is performed while exchanging the optical members. The distance measurement test method for the distance measurement module characterized by the above. 2. A beam is projected from a light emitting unit to a subject, a spot beam image projected onto the subject by this beam is formed on a light receiving unit, and a beam projection direction at the light emitting unit at that time and a spot beam image at the light receiving unit. In a distance measuring module for measuring a distance to an object from an angle formed by a receiving direction, a distance measuring object is arranged at a desired distance from the distance measuring module, and the light emitting unit, the distance measuring object, and the light receiving unit are arranged. An optical member that bends the path of the beam is disposed in the optical path connecting to and the distance measuring test is performed while moving the object to be measured toward and away from the distance measuring module. Distance measuring test method for distance measuring module.