JP4201924B2 - Surveyor autofocus mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic focusing mechanism of a surveying instrument that is provided in a surveying instrument such as an electronic level equipped with a telescope that collimates a scale and automatically focuses the telescope.
[0002]
[Prior art]
As a conventional surveying instrument of this type, for example, Japanese Patent Publication No. 5-184042 describes a level that is a surveying instrument equipped with a telescope. The level is obtained by collimating a scale on which a barcode is displayed with a telescope and comparing a previously stored barcode pattern with a collimated barcode to obtain a collimation position. A photoelectric element that converts a collimated image into an electrical signal is provided in the level, and the focusing lens can be moved in the front-rear direction by manual operation to form a collimated image on the photoelectric element. Has been.
[0003]
[Problems to be solved by the invention]
In the conventional surveying instrument, since focusing must be performed manually, the focusing operation takes time, and the time required for focusing varies greatly depending on the skill level of the operator who performs the focusing operation. There is a problem that. A plurality of autofocus mechanisms are known in the field of cameras and the like, but each autofocus mechanism requires an optical mechanism such as a dedicated sensor or mirror, and these conventional autofocus mechanisms are added to conventional surveying instruments. To add, it requires a significant increase and the cost is high.
[0004]
In view of the above problems, an object of the present invention is to provide an automatic focusing mechanism that can automatically perform focusing on a scale without significantly modifying a conventional surveying instrument.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the first present invention includes a telescope that collimates a scale on which patterns of equal intervals are displayed, and a surveying instrument that includes a photoelectric element that converts an image collimated by the telescope into an electric signal. In the automatic focusing mechanism that is mounted on the machine and automatically focuses on the scale, driving means for driving the focusing lens of the telescope is provided, and the focusing lens is moved from one end of the driving range of the focusing lens to the other. Drive toward the end, determine that the amplitude of the output signal of the photoelectric element has exceeded a predetermined value, and position the focus pattern on the photoelectric element at the position before focusing on the scale. A pitch calculation means for detecting the position where the pitch can be obtained and obtaining the pitch, and a fine adjustment for obtaining the distance from the pitch obtained by the pitch calculation means to the measuring scale and moving the focusing lens to a position corresponding to the distance Means and equipment Characterized in that was.
[0006]
When the focusing lens is driven from one end of the driving range toward the other end, the focusing scale is gradually focused. When the focus is advanced to some extent, the pitch of the scale pattern can be obtained even if the focus is not completely focused. Since the pitch of the standard is constant and known in advance, the distance from the obtained pitch to the standard can be calculated. That is, the pitch is small when the distance to the standard is long, and the pitch is large when the distance to the standard is short. When the distance to the standard is obtained in this way, the position of the focusing lens corresponding to the distance is determined. Therefore, if the focusing lens is moved to a position corresponding to the distance to the standard, the distance to the standard is determined. It can be accurately focused.
[0007]
The focusing lens is temporarily moved to one end of the driving range of the driving range and driven from the one end. Generally, the measuring rod is disposed at a relatively far position from the surveying instrument, and a telescope is used to view the vicinity. In the same state, the depth of focus of the telescope is shallow, and conversely, when collimating far away, the depth of focus becomes deep. Therefore, if one end of the driving range of the focusing lens is a position corresponding to infinity, the focusing lens is driven in the direction in which the focusing position approaches the telescope, and the pitch is calculated by the pitch calculation means. The focusing lens is moved from a state where the depth of focus is deep, and it is possible to focus on the scale in a shorter time than when the focusing lens is moved from the other end corresponding to a short distance.
[0008]
The second aspect of the present invention includes a telescope that collimates a scale on which patterns of equal intervals are displayed, and is mounted on a surveying instrument that includes a photoelectric element that converts an image collimated with the telescope into an electrical signal. In the automatic focusing mechanism for automatically focusing on the scale, driving means for driving the focusing lens of the telescope is provided, and the focusing lens is within the driving range of the focusing lens and corresponds to the previous focusing position. is moved to the position or multiple positions corresponding to the average distance distance averaged for each survey, the pitch calculation means for calculating a pitch of the pattern of the staff on the photoelectric device, staffs from the pitch determined by the pitch calculation means And a fine adjustment means for moving the focusing lens to a position corresponding to the distance.
[0009]
Especially when the distance between the measuring scale and the surveying instrument is set to a relatively medium distance or more, it corresponds to a predetermined position that covers a relatively well-set distance of the focusing lens, that is, the previous focusing position. Since the depth of focus is relatively deep if moved to a position corresponding to an average distance obtained by averaging the positions or distances of a plurality of surveys, it is not necessary to move the focusing lens from one end as in the first invention. Also, the pitch of the pattern displayed on the scale can be obtained.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, reference numeral 1 denotes a scale, which is collimated at an electronic level 2 equipped with a telescope and is used to measure the height h of the collimation position. On the scale 1, a plurality of black marks 11 are displayed on the surface of a white background at an equal pitch in the vertical direction of the scale 1. The staff 1 is normally set in an upright state, but may be set in an inverted state in which the staff 1 is inverted up and down with respect to the ceiling surface C as shown. In this case, the distance h from the ceiling surface C to the collimation position (hereinafter referred to as the collimation position height h as in the upright state) is measured. By the way, although not shown in the figure on the back surface of the staff 1, numbers are printed so that the staff 1 can be used when the operator collimates by visual observation. . As will be described later, the vertical widths of the marks 11 are not all the same, but a plurality of types of dimensions are arranged in a predetermined order.
[0011]
Referring to FIG. 2, a telescope 20 is built in the electronic level 2. The telescope 20 is provided with an optical system 21 including an objective lens 21a and a focusing lens 21b, and an automatic tilt compensation mechanism (compensator) 22. The received image of the staff 1 is transmitted to a line sensor 24 by a beam splitter 23. Branch off. What passes through the beam splitter 23 is a collimating optical system, and what is branched to the line sensor 24 is an image optical system. The collimating optical system includes the optical system 21, the automatic tilt compensation mechanism 22, the beam splitter 23, the focusing screen 20a, and the eyepiece 20b. The image optical system includes an optical system 21, an automatic tilt compensation mechanism 22, a beam splitter 23, and a line sensor 24. The line sensor 24 converts the received image of the staff 1 into an electrical signal and outputs it to the amplifier 25. The signal amplified by the amplifier 25 is sampled and held in synchronization with the clock signal of the clock driver 26, and the held signal is converted into a digital signal (A / D). The signal converted into the digital signal is stored in the RAM 28. The microcomputer 3 obtains the width dimension of each mark 11 based on the signal stored in the RAM 28. Then, the height h of the collimation position is obtained from the width dimension of the mark 11 and the table value stored in advance in the ROM 31. The drive circuit 29 is a circuit that controls the operation of the line sensor 24. Further, since the optical axis of the collimation optical system and the optical axis of the image optical system are matched with each other, the collimation point on the scale 1 and the collimation point of the image optical system are coincident with each other. The survey result is displayed on the display unit 32.
[0012]
By the way, when collimating the scale 1, it is necessary to move the focusing lens 21b in the optical axis direction so that the scale 1 is focused. Therefore, in the present invention, the stepping motor 41 is attached to the focusing lens 21b, the stepping motor 41 and the focusing lens 21b are mechanically connected via a mechanism such as a rack and pinion, and the stepping motor 41 is operated. The focal lens 21b is configured to automatically move in the optical axis direction. Reference numeral 4 denotes a drive circuit for the stepping motor 41, and the microcomputer 3 controls the operation of the stepping motor 41. The microcomputer 3 is connected to an autofocus button (not shown). When the autofocus button is pressed, the microcomputer 3 moves the focusing lens 21b to the eyepiece 20b side within the movable range of the focusing lens 21b. Move once to the end. In this state, the telescope 20 is in a focused state at an infinite position. The image projected on the line sensor 24 at this time is not clear enough to specify the scale 1 and is congested as a whole, and the output signal of the line sensor 24 is flat as shown in FIG. Yes. The microcomputer 3 sets a range α from the peak of the output signal of the line sensor 24, and moves the focusing lens 21b to the objective lens 21a side until the signal becomes α or more. As shown in FIG. 3B, when the output signal of the line sensor 24 becomes equal to or larger than α, the focusing lens 21b is temporarily stopped to obtain the length β of the portion within α and the center that is the center position of β. The line CL is obtained. Since there are a plurality of portions where the output signal of the line sensor 24 is within α, the position of the center line CL is obtained for each portion. When the intervals between the center lines CL are averaged, the average value corresponds to the pitch of the marks 11 of the scale 1 in the image on the line sensor 24. The pitch becomes smaller when the distance between the gauges 1 is longer, and becomes longer when the gauge 1 is set nearby. Therefore, the distance between the electronic level and the staff 1 is obtained from the average value between the center lines CL. When the distance to the staff 1 is obtained in this way, the microcomputer 3 moves the focusing lens 21b to a position corresponding to the distance so as to accurately focus on the staff 1. Thus, when the focus 1 is accurately focused, the output signal of the line sensor 24 is as shown in FIG. After that, the collimated position height is obtained, for example, according to the procedure shown in Japanese Patent Application No. 9-350620. In addition, although the example in which the α value is set has been given, this may be set to a case where the level difference γ of the shading bar code is set and larger than γ. As yet another embodiment, the distance may be obtained by performing a Fourier transform to obtain the period.
[0013]
By the way, in the above embodiment, when the auto-focus button is pressed, the focusing lens 21b is once moved to the end of the moving range, and the focusing lens 21b is moved from the end. When the distance between the electronic level 2 and the staff 1 does not change much when moving, the position to the previous staff is memorized, and when collimating the staff set at the next survey point, the autofocus button When pressed, the focusing lens 21b may be moved to the previous focusing position without moving to the end of the moving range. Then, an average value between the center lines CL is obtained at that position, and the current measuring stick 1 is focused. Alternatively, the distance to the gauge is stored for each of a plurality of surveys, and the plurality of distances are averaged and the focusing lens 21b is once moved to a position corresponding to the average distance at the next surveying. Good.
[0014]
【The invention's effect】
As is clear from the above description, the present invention can automatically focus the telescope of the surveying instrument without adding a new sensor.
[Brief description of the drawings]
FIG. 1 is a diagram showing a usage form of an electronic level. FIG. 2 is a block diagram showing a configuration of an electronic level. FIG. 3 is a diagram showing a change in an output signal of a line sensor accompanying movement of a focusing lens.
1 Standard 2 Electronic Level 21b Focusing Lens 24 Line Sensor 41 Stepping Motor

Claims (3)

Automatic equipped with a telescope that collimates a standard on which patterns of equal intervals are displayed, and equipped with a photoelectric device that converts an image collimated with the telescope into an electrical signal, and automatically focuses on the standard In the focusing mechanism, driving means for driving the focusing lens of the telescope is provided, and the focusing lens is driven from one end to the other end of the driving range of the focusing lens, and the amplitude of the output signal of the photoelectric element Is a position where it is determined that has exceeded a predetermined value, and the position before focusing on the scale and the position where the pitch of the scale pattern on the photoelectric element can be obtained is detected to obtain the pitch An automatic surveying instrument comprising: calculating means; and fine adjusting means for obtaining a distance from the pitch obtained by the pitch calculating means to the staff and moving the focusing lens to a position corresponding to the distance. Focus mechanism   One end of the driving range of the focusing lens is a position corresponding to infinity, and the focusing lens is driven in a direction in which the focusing position approaches the telescope, and the pitch is calculated by the pitch calculating means. An automatic focusing mechanism for a surveying instrument according to claim 1. Automatic equipped with a telescope that collimates a standard on which patterns of equal intervals are displayed, and equipped with a photoelectric device that converts an image collimated with the telescope into an electrical signal, and automatically focuses on the standard In the focusing mechanism, driving means for driving the focusing lens of the telescope is provided, and the focusing lens is within the driving range of the focusing lens and corresponds to the previous focusing position, or a distance for each of a plurality of surveys. are moved to a position corresponding to the average distance obtained by averaging, the pitch calculation means for calculating a pitch of the pattern of the staff on the photoelectric device, determine the distance to the leveling rod from the pitch determined by the pitch calculation means, to the distance An automatic focusing mechanism for a surveying instrument, comprising fine adjustment means for moving a focusing lens to a corresponding position.

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