JP3069893B2 - Focusing method and focusing device for surveying instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a focusing method and a focusing device for a surveying instrument having a collimating telescope and a distance measuring means.

[0002]

2. Description of the Related Art A surveying instrument such as an optical distance meter or a total station is provided with a collimating telescope for collimating a target (target). The telescope is aimed at a target point, and the focus adjustment knob is manually rotated with respect to the target point to perform focus adjustment on the target point. However, manual focus adjustment has problems such as being unable to concentrate on collimation and having a long time for focus adjustment operation.

Therefore, a surveying instrument having a collimating telescope having an automatic focusing function (AF function) has recently been developed. This AF function guides the object light transmitted through the focusing lens of the collimating telescope to a conjugate plane conjugate with the focal plane,
The focus state on the conjugate plane is detected, the defocus amount of the focus lens is calculated, and the focus lens is moved to the focus position based on the defocus amount. The principle of this AF itself is well known, and A
Widely used in F single-lens reflex cameras.

A surveying instrument equipped with this AF function is convenient, but has the following problems when actually used. AF
Is performed on an object in the focusing area within the field of view of the collimating telescope. For this reason, between the collimating telescope and the target,
When there is an object that becomes a noise, for example, a wire net or a swaying tree leaf, focusing on the target is not performed or hunting occurs.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a focusing method for a surveying instrument capable of reliably focusing on a target object even in a surveying environment where such noise is present without losing the convenience of the AF function. And a focusing device.

[0006]

SUMMARY OF THE INVENTION The present invention focuses on the fact that surveying instruments such as total stations and light wave distance measuring instruments have an extremely accurate distance measuring function, and a focusing function based on distance measuring information (referred to as a distance priority focusing function). This is based on the insight that more convenient focusing can be performed by switching and using the automatic focusing function.

The present invention, according to a method, provides a surveying instrument having a collimating telescope for collimating a target and a distance measuring means for measuring a distance to the target. An automatic focusing function for detecting and focusing the focusing optical system on a target; a distance priority for driving the focusing optical system of the collimating telescope based on the distance to the target measured by the distance measuring means. A focusing function; and selectively using the automatic focusing function and the distance priority focusing function.

According to the present invention, in a surveying instrument having a collimating telescope for collimating a target and a distance measuring means for measuring a distance to the target, the present invention relates to a focus state of the collimating telescope. An automatic focusing function for detecting and focusing the focusing optical system on a target; and a distance priority for driving the focusing optical system of the collimating telescope based on the distance to the target measured by the distance measuring means. A focusing function; and focusing mode selecting means for selecting the automatic focusing function and the distance priority focusing function.

The distance measuring means may be, for example, a light wave distance measuring instrument, and a distance priority focusing function and an automatic focusing function are selected depending on whether the light wave distance measuring element receives reflected light from a target. You can switch between functions. Further, when the lightwave range finder no longer receives the reflected light from the target, the focus adjustment range of the automatic focusing function is determined based on the distance information to the target immediately before the reflected light is no longer received. It can be limited to a narrow range including: When the surveying instrument further has an angle measurement function and a memory function of the angle measurement information, it is possible to switch from the automatic focusing function to the distance priority focusing function at a specific angle measurement position. Of course, it is practical to enable manual focusing by a manual focusing function in addition to the automatic focusing function and the distance priority focusing function. Further, it is also possible to provide a focusing distance input means, and focus on a position corresponding to the input distance. Specifically, for example, a focus distance is input from a keyboard, a communication terminal, or the like, and the focus adjustment optical system is moved to the focus distance.

More specifically, the collimating telescope includes an objective lens, a dichroic prism that transmits visible light, a focus lens system for focusing, an erecting optical system, a light beam splitting system, and a focusing screen, in that order from the target side. And an eyepiece lens system. The lightwave distance measuring device includes a transmitting unit that emits distance measuring light and a light receiving unit that receives distance measuring light reflected by a target. The distance measuring light emitted from the transmitting section is reflected by the dichroic prism, transmitted through the objective lens, reflected by the target, then transmitted through the objective lens, reflected by the dichroic prism, and reflected by the mirror. Light enters the light receiving unit. On the other hand, on the optical path split by the light beam splitting system, a focus detection sensor for detecting a focus state on a conjugate plane conjugate with the reticle is provided, and an output of this focus detection sensor is necessary to focus on the conjugate plane. The amount of movement of the focus lens system is calculated.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A surveying instrument (total station or lightwave distance measuring instrument) shown in FIG. 1 has a lightwave distance measuring instrument and a collimating telescope. The lightwave range finder includes a light transmitting unit 11 for transmitting distance measuring light, a dichroic prism 13 for reflecting distance measuring light,
An objective lens 15 that also functions as a light projecting lens that emits distance measuring light toward the target and a light receiving lens that receives the distance measuring light reflected by the target (for example, a corner cube) O; A mirror 17 that reflects the distance measuring light reflected by the dichroic prism 13, a light receiving unit 19 that receives the distance measuring light reflected by the mirror 17, and controls the light transmitting unit 11 and the light receiving unit 19 and detects a distance measurement value. It has a distance measurement calculation unit 21 for performing the measurement. The light transmitting unit 11 includes a light emitting diode or a laser diode as a distance measuring beam light emitting unit, and a light transmitting unit including an optical system incorporating these elements. The dichroic prism 13 is formed so as to reflect distance measuring light but transmit natural light (visible light). Therefore, light that is out of the visible light range, for example, in the infrared light range, is usually used as the distance measuring light. It should be noted that, in addition to the above-described corner cube O and a mirror placed on the target, a non-prism (non-corner cube) light wave distance measuring device uses the reflection of the surface of the target object.

The distance calculating section 21 is based on the distance measuring light (internal reference light) emitted from the light transmitting section 11 and the distance measuring light received by the light receiving section 19 and is provided with a known method such as a phase difference measuring method or an optical radar method. The distance to the target is calculated by the algorithm described in (1). Although not shown, the calculated distance is displayed on a display panel or the like. The focus lens position calculation unit 23 calculates a movement position of the focus lens 31 necessary for focusing on a target located at the distance based on the distance calculated by the distance measurement calculation unit 21.

[0013] On the other hand, the collimating telescope, in order from the target side,
An objective lens 15, a dichroic prism 13, a focus lens 31, an erect prism 33, a half mirror (light beam splitting system) 34, a focusing plate 35, and an eyepiece 37 are provided. These collimating telescope and the lightwave distance measuring unit are not shown, but are integrally assembled to a surveying instrument main body. This main body is mounted on a base so that the azimuth and the elevation angle can be adjusted with the vertical axis and the horizontal axis as axes. I have.

The target light beam (visible light) incident from the objective lens 15 passes through the dichroic prism 13 and
Through the focus lens 31 and the erecting prism 33, an image is formed on the focusing screen 35 or near the front and rear thereof as an erect real image. The operator observes this image through the eyepiece 37 in an enlarged manner. The focusing screen 35 is provided with a distance measurement mark as a target for irradiating the distance measurement light and other crosshairs necessary for the surveying. The operator can see the image of the target object overlapping the distance measurement mark or the like. And adjust the azimuth and elevation angle of the collimating telescope so that the target enters the distance measurement mark, that is, the distance measuring light hits the collimation object.

On the optical path branched by the half mirror 34, a focus detection sensor 41 for detecting a focus state (a defocus amount) on a conjugate plane 35C conjugate with the reticle 35 is provided. The focus detection sensor 41 has a conjugate plane 35C
Is output to the focus state (defocus amount) calculation unit 42, and various specific configurations are known. FIG. 2 shows an example of the principle, in which a condenser lens 41a, a pair of separator lenses 41b, and CCDs located behind the respective separator lenses 41b are provided behind the conjugate plane 35C.
And a pair of line sensors 41c.

The incident position of the object image on the pair of line sensors 41c is such that when the image of the target is accurately formed on the conjugate plane 35C (in focus), it is formed ahead of the conjugate plane 35C. Respectively (front focus) and when imaging behind the conjugate plane 35C (rear focus), respectively.
The amount of deviation from the in-focus position is also determined by the pair of line sensors 4.
The determination can be made based on the image formation position of the object image on 1c. Focus state calculation unit 4 receiving outputs from a pair of line sensors 41c
2 amplifies this output by a preamplifier (not shown), and then calculates by an arithmetic circuit (not shown) to detect in-focus, out-of-focus, front focus, and rear focus, and to detect on the conjugate plane 35C. And the amount of movement of the focus lens 31 necessary for focusing are detected.

Either of the data of the movement amount (movement position) of the focus lens 31 by the focus lens position calculation unit 23 and the focus state calculation unit 42 is transferred to the focus lens position control unit 45 via a focusing mode selection switch 45. 4
4 given. The focus lens position control unit 44
Focus lens position calculator 23 and focus state calculator 42
Based on one of the outputs and the lens position data of the focus lens 31 detected by the focus lens position detecting device 29, the focus lens driving device 27 using a motor or the like as a driving source is operated to operate the focus lens 3.
1 is moved to the in-focus position.

Therefore, the movement control of the focus lens 31 is performed in the automatic focusing mode when the focus state (defocus amount) calculation section 42 is connected to the focus lens position control section 44 by the focusing mode selection switch 45. In a state in which the focus lens position calculation unit 23 is connected to the focus lens position control unit 44, the focusing is performed in the distance priority focusing mode. Further, the focus lens driving device 27 is provided by the manual focusing device 28.
To move the focus lens 31 to an arbitrary position. Furthermore, a specific distance can be input by the focusing distance input means 30, and the focus lens 31 can be moved via the focus lens position control unit 44 so as to focus on the input distance. The focus distance input means 30 can use, for example, information read from a keyboard, various memories, or communication information.

The focus mode can be changed by the operator manually switching the focus mode selection switch 45. For example, the focus mode can be changed in the following mode. Before the light receiving unit 19 of the light wave distance measuring device receives the reflected light from the target, the automatic focusing mode is set. Switch to focus mode. The fact that the light receiving unit 19 has received the reflected light means that the collimating telescope has correctly collimated the target, so that if the target is focused on the distance, the surveying instrument and the target are During this time, even if an object that becomes noise enters or exits, it is possible to accurately focus on the target. When the surveying instrument is a total station having an angle measurement function and a memory function of the angle measurement information, the mode is switched from the automatic focusing mode to the distance priority focusing mode at a specific angle measurement position. For example, in the paired observation used in reference point surveying or the like, the same target (plural) is collimated and measured a plurality of times, so it is necessary to focus each time. In such a survey, the angle information and the position information at the time of first focusing on each target are stored in the memory unit 46, and when a specific angle measurement position is reached, the distance priority focusing mode is set. The target can be focused on the basis of the distance data to the target.

During the surveying operation, when the light receiving section 19 changes from a state in which it receives the distance measurement reflected light to a state in which it does not receive the distance measurement reflected light, it is assumed that a target (for example, a corner cube O) is being moved. Is done. At this time, the position of the next target often does not largely change from the state where the distance measurement reflected light is received. Therefore, if the focus adjustment range of the automatic focusing function is limited to a narrow range including the distance information immediately before the reflected light is no longer received, based on the distance information immediately before the reflected light is no longer received, the next automatic focusing can be performed. Scorching can be performed more quickly.

The relationship between the distance measurement distance and the lens position of the focus lens 31 that focuses on the target at the distance measurement distance (an image of the target at that distance is formed on the focusing screen 35) is, for example, as follows. Set as follows. These relationships are obtained in advance by calculation from the design values of the optical system or by actual measurement of the target, and these relationships are divided into a number of zones, converted into table data, and stored in a memory means such as a ROM. And
The lens position is obtained by referring to the table data with the distance data calculated by the distance measurement calculation unit 21. In addition, the relationship between the distance measurement distance and the lens position of the focus lens 31 that focuses on the target at that distance is formed into an arithmetic expression, and the arithmetic expression is stored in a ROM or the like. It can also be obtained by calculation.

A focus lens position detecting device 29 for detecting the position of the focus lens 31 includes a code plate extending along the moving direction of the focus lens 31 and an absolute position detecting device for reading a position code formed on the code plate by reading means. The relative position detecting means for detecting the amount of movement of the focus lens 31 from the reference position by counting the number of rotations of the motor of the focus lens driving device 27 can be detected. Further, a configuration is also possible in which the position of the focus lens 31 is roughly detected by the absolute position detection unit and is precisely detected by the relative position detection unit.

In the illustrated embodiment, the objective lens of the collimating telescope is used as the objective lens of the collimating telescope, while the exit lens and the light receiving lens of the ranging light emitted from the light transmitting unit are also used as the objective lens of the collimating telescope. Well, the illustrated optical system,
It goes without saying that the configuration of the light wave distance measuring device such as a control system is an example and is not limited to the illustrated embodiment.

[0024]

The surveying instrument according to the present invention detects the focus state of the collimating telescope, and focuses the focus adjusting optical system on the target object, based on the distance measured by the distance measuring means. It has a distance-priority focusing function for driving the focusing optical system of the collimating telescope, and the automatic focusing function and the distance-priority focusing function can be selectively used, so the convenience of the automatic focusing function is lost. Therefore, even in a surveying environment where there is an object serving as measurement noise between the collimating telescope and the target, it is possible to reliably focus on the target.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of an embodiment of a surveying instrument according to the present invention.

FIG. 2 is a diagram illustrating a specific example of a focus detection sensor unit in FIG. 1;

[Explanation of symbols]

 Reference Signs List 11 light transmitting unit 13 dichroic prism 15 objective lens 17 mirror 19 light receiving unit 21 distance measuring unit 23 focus lens position calculating unit 25 focus lens position control unit 27 focus lens driving device 29 focus lens position detecting device 31 focus lens (focus adjustment optical system) 33) Upright prism 34 Half mirror (beam splitting system) 35 Focusing plate 35C Conjugate plane 37 Eyepiece 41 Focus detection sensor 42 Focus state (defocus amount) calculation unit 44 Focus lens position control unit 45 Focusing mode selection switch

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ identification code FIG02B 7/11 H (56) References JP-A-60-3570 (JP, A) JP-A-10-19561 (JP, A) Japanese Utility Model Showa 57-111931 (JP, U) Japanese Utility Model Showa 63-8687 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B ^7/ 28-7/40 G01C 3/00 -3/32 G01S 7/48-7/50 G01S 17/00-17/88

Claims (13)

(57) [Claims] 1. A surveying instrument having a collimating telescope for collimating a target and a distance measuring means for measuring a distance to the target, wherein a focus state of the collimating telescope is detected and a focusing optical system is provided. An automatic focusing function for focusing the object on a target; and a distance priority focusing function for driving a focusing optical system of the collimating telescope based on the distance to the target measured by the distance measuring means. A focusing method for a surveying instrument, wherein the automatic focusing function and the distance priority focusing function are selectively used. 2. The distance measuring means according to claim 1, wherein the distance measuring means is a light wave distance measuring means, and the distance priority focusing function and the automatic focusing function are selected depending on whether the light wave distance measuring light receives the reflected light from the target. Focusing method of a surveying instrument that automatically switches between focus function. 3. The automatic focusing function according to claim 2, wherein when the lightwave range finder no longer receives the reflected light from the target, based on distance information to the target immediately before the reflected light is no longer received. A focusing method of a surveying instrument that limits a focus adjustment range to a narrow range including the distance information. 4. The surveying instrument according to claim 1, further comprising an angle measuring function and a memory function of the angle measuring information, and switching from an automatic focusing function to a distance priority focusing function at a specific angle measuring position. Focusing method. 5. The focusing method of a surveying instrument according to claim 1, further comprising a manual focusing function capable of performing manual focusing. 6. A focusing method for a surveying instrument according to claim 1, wherein the focusing can be performed at a position corresponding to an input distance by a focusing distance input unit. 7. A surveying instrument having a collimating telescope for collimating a target and a distance measuring means for measuring a distance to the target, wherein a focus state of the collimating telescope is detected and a focusing optical system is provided. An automatic focusing function for focusing on a target; a distance priority focusing function for driving a focusing optical system of the collimating telescope based on a distance to the target measured by the distance measuring means; A focusing device for a surveying instrument, comprising: a focusing mode selecting means for selecting a focusing function and a distance priority focusing function. 8. The distance measuring means according to claim 7, wherein the distance measuring means is a light wave distance measuring means, and the focusing mode selecting means is adapted to determine whether the light wave distance measuring means receives reflected light from a target or not. A focusing device of a surveying instrument that switches between a priority focusing function and an automatic focusing function. 9. The method according to claim 8, further comprising: when the lightwave range finder no longer receives the reflected light from the target, based on distance information to the target immediately before the reflected light is no longer received.
A focusing device of a surveying instrument having a limit function of limiting a focus adjustment range by an automatic focusing function to a narrow range including the distance information. 10. The surveying instrument according to claim 7, further comprising an angle measuring function and a memory function of the angle measuring information, wherein the focusing mode selecting means performs the distance focusing from the automatic focusing function at a specific angle measuring position. Focusing device of a surveying instrument that switches to the focusing function. 11. A focusing device for a surveying instrument according to claim 7, further comprising a manual focusing function. 12. A focusing device of a surveying instrument according to claim 7, further comprising a focusing distance input means, wherein focusing can be performed at a position corresponding to the input distance. 13. The collimating telescope according to claim 8, wherein the collimating telescope includes an objective lens, a dichroic prism that transmits visible light, a focus lens system for focusing, an erecting optical system, a light beam splitting system, A focusing unit and an eyepiece lens system, wherein the lightwave distance measuring device includes a transmitting unit for emitting the distance measuring light and a light receiving unit for receiving the distance measuring light reflected by the target, and the distance measuring unit emitted from the transmitting unit. The light is reflected by the dichroic prism, transmitted through the objective lens, reflected by a target, transmitted through the objective lens, reflected by the dichroic prism, reflected by a mirror, and incident on the light receiving unit, A focus detection sensor for detecting a focus state on a conjugate plane conjugate with the reticle is provided on the optical path split by the light beam branching system, and an output of the focus detection sensor focuses on the conjugate plane. Surveying instrument focusing device moving amount of the focus lens system required is calculated on.