JP4317631B2 - Surveyor autofocus device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surveying instrument having an automatic focusing function, and more particularly to an automatic focusing device for a surveying instrument that can adjust individual differences that cannot be adjusted by automatic focusing.
[0002]
[Prior art]
The conventional surveying instrument is an optical instrument composed of a telescope and high-precision optical parts for angle measurement. In addition, since the conventional surveying instrument has no function to directly measure the distance to the target object, the distance measurement is performed using a metal tape with little elongation. However, recent surveying instruments have been digitized, and distance measurement is possible with the surveying instrument itself, and angle measurement has also been digitized. A recent surveying instrument that conducts electrical ranging is called a total station.
[0003]
Although the telescope used in the surveying instrument has a high magnification, a very high resolution is required, and the focusing on the collimating target requires a fine adjustment. However, recent advances in autofocusing technology have been remarkable, and sufficient accuracy has been obtained for surveying instruments, so the total number of stations equipped with autofocusing devices has increased.
[0004]
7, 8 </ b> A and 8 </ b> B show surveying at the total station 1 equipped with autofocus.
[0005]
The pole 2 and the prism 3 placed on the point (point to be surveyed) are collimated from the total station 1 installed at the given point (known point), and the coordinates of the point are obtained by distance measurement. Although not shown, there are normal workers on the total station 1 and the pole 2, and the worker on the pole 2 side moves the pole 2 to the next point according to the surveying procedure, and the total station 1 The worker on the side obtains the distance and direction angle with respect to the pole 2 as the moving destination.
[0006]
The total station 1 is directed to the pole 2. The auto-focusing device is activated, auto-focusing is performed on the pole 2, and the distance and direction angle from the moving point are measured by collimating the center of the prism 3.
[0007]
The autofocus device basically performs focusing control based on a photoelectrically converted signal based on an image formed on a light receiving element.
[0008]
[Problems to be solved by the invention]
The autofocus device is convenient because it can automatically focus on the measurement object, but it has a problem in that it focuses on the measurement position uniformly. Each human eye has differences and individuality, and has a focus position that is easy to see. The manual focusing device can focus on the operator's preferred position, but the focusing performed by the machine does not reflect individual differences, so it is difficult for some people to see or focusing is insufficient. You may feel there is.
[0009]
Some conventional autofocus devices have a manual focusing mechanism. However, the conventional autofocus device is an automatic mechanical type, and the autofocus device and the manual focus device are separate mechanisms. Requires a focusing mechanism. Furthermore, the automatic focusing and the manual focusing require a mechanism switching, and the structure such as a complicated mechanism for switching becomes complicated, resulting in an increase in manufacturing cost. In addition, there are problems such as a large number of failures due to the complicated mechanism.
[0010]
In view of such circumstances, the present invention provides a simple autofocus device for a surveying instrument that can perform manual focusing.
[0011]
[Means for Solving the Problems]
The present invention includes an objective lens unit capable of adjusting a focal position, a drive unit that changes a focal position of the objective lens unit, and a focus control unit that controls the drive unit, and the focus control unit includes: An automatic focus of a surveying instrument comprising an automatic focusing control unit and a manual focusing control unit, wherein the driving unit is selectively driven by either the automatic focusing control unit or the manual focusing control unit. And a photoelectric conversion unit, an imaging optical system that guides incident light from a measurement object onto the photoelectric conversion unit, a drive unit that changes a light collection state of the imaging optical system, and manual focusing. From the input unit, the automatic focusing control unit that drives the driving unit based on the output from the photoelectric conversion unit to form an image of the measurement object on the photoelectric conversion unit, and the manual focusing input unit And an autofocus device for a surveying instrument having a manual focusing control unit for driving the driving unit by a signal of The present invention relates to an automatic focusing device of a surveying instrument that has a display unit and is capable of displaying an approximate distance to a measurement target, and has a detection means for detecting a light collecting state, and is obtained from the detection means. The encoder is provided with an autofocus device for a surveying instrument that calculates a distance from a light collecting state to an object to be measured and displays the calculation result on the distance display unit, and the detection means is an encoder provided in the drive unit. The present invention relates to an automatic focusing device for a surveying instrument.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 shows a total station 1. A gantry 6 is mounted on a tripod (not shown) via a base unit 5, and a collimating telescope unit 7 is supported on the gantry 6. The base unit 5 has leveling screws 8, and leveling is performed by the leveling screws 8 so that the mount 6 is horizontal. The gantry 6 can rotate around a vertical axis, and the collimating telescope unit 7 can rotate around a horizontal axis. The gantry 6 is provided with a manual focusing knob 9 and an operation display unit 26. The operation display unit 26 includes a display unit 27 and operation keys 28. When performing automatic focusing by distance measurement and angle measurement, or when performing manual focusing, the operation keys 28 indicate the work conditions and the like in the total station 1. Further, the distance measurement, the measurement result of the angle measurement, and the like are displayed on the display unit 27.
[0014]
The operation display unit 26 will be further described with reference to FIG.
[0015]
The display unit 27 is provided with a distance display unit 27a that displays an outline of the distance to the measurement object. The distance display unit 27a is a long bar in the vertical direction, with a lower end of 0 and an upper end of ∞. The position of the measurement object is displayed by the position of the horizontal line displayed on the distance display unit 27a. The operation key 28 has a numeric keypad portion 28a and a function selection key portion 28b, and the function selection key portion 28b selects a function such as a distance measurement mode, an automatic focus mode, or a manual focus mode.
[0016]
The focusing knob 9 will be described with reference to FIG.
[0017]
The focus knob 9 is a combination of a coarse dial knob 31 and a fine dial knob 32. The coarse dial knob 31 is rotatably provided as an outer ring of the focus knob 9, and the fine dial knob 32 is It is rotatably provided inside the coarse dial 31. The coarse dial knob 31 is connected to a potentiometer (described later), and the fine dial knob 32 is connected to a rotary encoder (described later).
[0018]
With reference to FIG. 4, the autofocus device provided in the total station 1 will be described.
[0019]
The objective lens unit 11, the beam splitter 12, the focusing screen 13, and the eyepiece lens unit 14 are arranged on the same optical axis to form an imaging optical system, and the imaging optical system is the collimating telescope unit. 7 is stored. On the split optical axis of the beam splitter 12, a linear sensor 15 is disposed at a position conjugate with the focusing screen 13. Arithmetic processing means 16 is electrically connected to the linear sensor 15, and an autofocus driving unit 17 is connected to the objective lens unit 11.
[0020]
The objective lens unit 11 is for forming an image of the pattern of the pole 2 and is composed of an objective lens 18 and an internal lens 19, and the internal lens 19 is illuminated by the drive unit 17. The image of the pole 2 and the prism 3 can be focused on the focusing screen 13 and the linear sensor 15 by moving along the axis.
[0021]
The beam splitter 12 is used to divide light into the eyepiece 14 direction and the linear sensor 15 direction. The eyepiece unit 14 is used by a surveyor to view the pole 2. A cross line with respect to the collimation axis is drawn on the focusing screen 13, and a collimation image is formed on the focusing screen 13. The collimation direction is obtained by making the center of the image coincide with the intersection of the crosshairs. Further, although not shown, an erecting optical system including a reflecting mirror or a prism is placed in front of the focusing screen 13.
[0022]
The linear sensor 15 corresponds to a pattern detection unit and a photoelectric conversion unit, and converts a collimation target pattern image formed by the objective lens unit 11 into an electrical signal. Level detection and automatic focusing are performed based on the detection signal. The linear sensor 15 is, for example, a CCD linear sensor, and any sensor can be adopted as long as it is a linear image sensor in which light receiving elements such as photodiodes are arranged one-dimensionally. In addition, the linear sensor 15 in FIG. 4 is arrange | positioned so that it may become horizontal.
[0023]
The arithmetic processing means 16 is mainly composed of a storage unit 21, an image capture control unit 22, a reference signal forming unit 23, a calculation unit 24, and an automatic focusing control unit 25. The calculation unit 24 includes the operation display unit 26. And the manual focusing control part 33 is connected. The automatic focusing control unit 25 drives the driving unit 17 based on a control signal from the calculation unit 24, and the manual focusing control unit 33 is based on a focusing signal input from the focusing knob 9. The drive unit 17 is driven.
[0024]
The calculation unit 24 validates the signal from the automatic focusing control unit 25 according to the automatic focusing mode / manual focusing mode selection signal from the operation display unit 26 or the manual focusing control unit 33. Decide whether to enable the signal from. Alternatively, when a signal from the manual focus control unit 33 is input, the signal from the manual focus control unit 33 is validated, and the signal from the manual focus control unit 33 is interrupted and a predetermined time elapses. The signal from the automatic focusing control unit 25 may be valid. The signal from the linear sensor 15 is input to the calculation unit 24 and used as a feedback signal for the focusing action.
[0025]
The drive unit 17 is for moving the internal lens 19 by a predetermined amount based on the calculation result of the calculation processing means 16. In the present embodiment, an arc motor is employed as the motor of the drive unit 17. However, any drive means may be used as long as the internal lens 19 can be reciprocated like an ultrasonic motor or the like. Can be adopted. An encoder 20 is attached to the drive unit 17 so that the rotation amount of the motor, that is, the movement amount of the internal lens 19 is detected.
[0026]
The functions of the arithmetic processing means 16 will be described. The arithmetic unit 24 controls the acquisition of signals from the linear sensor 15, and the acquired signals are stored in the storage unit 21. In addition, the image capturing control unit 22 is controlled so that only the signal in the range necessary for focusing among the signals stored in the storage unit 21 is input to the reference signal forming unit 23. The reference signal forming unit 23 forms a reference signal indicating an in-focus state based on the signal input from the image capture control unit 22. That is, the output signal from the image capture control unit 22 is differentiated, and the reference signal is formed from the rising and falling edges.
[0027]
Based on the reference signal, the calculation unit 24 issues a focusing command signal to the automatic focusing control unit 25, and the automatic focusing control unit 25 drives the driving unit 17 to image the linear sensor 15. The internal lens 19 is moved back and forth along the optical axis via the drive unit 17 so that an image is formed. The arithmetic unit 24 detects and focuses the edge of the image on the linear sensor 15 and the position with the highest contrast based on the signal from the reference signal forming unit 23.
[0028]
In this embodiment, the contrast method is used for autofocusing, but the present invention is not limited to this method, and other methods may be used.
[0029]
Further, the in-focus state and the position of the internal lens 19 in the middle of the in-focus state are detected by the encoder 20, and a detection signal of the encoder 20 is input to the calculation unit 24. Based on the position detection signal from the encoder 20, the calculation unit 24 determines a focusing range, and issues a capturing range command signal to the image capturing control unit 22 so as to correspond to the determined focusing range. Thus, the encoder 20, the calculation unit 24, and the image capture control unit 22 constitute a focusing range determination unit.
[0030]
Incident light incident from the objective lens unit 11 is divided by the beam splitter 12 and condensed on the linear sensor 15.
[0031]
An operator may input an approximate distance to the pole 2 from the operation display unit 26 to the calculation unit 24, or the calculation unit 24 captures a position signal from the encoder 20 when the focusing operation starts. The distance to the pole 2 may be calculated. The calculation result of this distance is displayed on the distance display part 27a.
[0032]
The focusing range of the linear sensor 15 at the start of focusing is determined in accordance with the distance to the pole 2, and a capturing range command signal is issued to the image capturing control unit 22. The image capture control unit 22 captures a predetermined range of image signals from the storage unit 21 based on the command signal and outputs the image signal to the reference signal forming unit 23.
[0033]
The manual focusing control unit 33 will be described with reference to FIG.
[0034]
The coarse dial 31 (see FIG. 3) is connected to a potentiometer 35 and connected to a power source (not shown) of + V volts and −V volts. The output of the potentiometer 35 is determined in proportion to the rotation angle of the coarse dial 31, and the output of the potentiometer 35 is a forward / reverse determination circuit 38 via a comparator 36 and via a V / F converter 37. Connected to.
[0035]
The V / F converter 37 outputs a pulse having a frequency proportional to the absolute value of the input voltage. The comparator 36 determines whether the input voltage is positive or negative, and sends to the forward / reverse determination circuit 38 an instruction signal indicating whether the output of the V / F converter 37 is a normal pulse or a negative pulse. Output. The forward pulse output and the negative pulse output of the forward / reverse determination circuit 38 are connected to gate circuits 39 and 41, respectively. The outputs of the gate circuits 39 and 41 are connected to a pulse motor driver 42, and the output of the pulse motor driver 42 is connected to a focusing pulse motor 43. The focusing pulse motor 43 is connected to the internal lens 19 through a required mechanism such as a speed reducer. The pulse motor driver 42 and the focusing pulse motor 43 constitute the drive unit 17 (see FIG. 4).
[0036]
The fine dial knob 32 (see FIG. 3) is connected to a rotary encoder 44, and the rotary encoder 44 is a rotary encoder that outputs two phases different in phase by 90 °, and the two-phase output from the rotary encoder 44. Is input to the forward / reverse determination circuit 45. The normal rotation pulse output and the negative rotation pulse output of the normal / reverse determination circuit 45 are input to the gate circuits 39 and 41, respectively.
[0037]
First, the potentiometer 35 is rotated to perform rough adjustment.
[0038]
When the coarse dial 31 is rotated by a certain angle, the potentiometer 35 generates a voltage proportional to the rotation direction and rotation angle, and the voltage is the comparator 36, V / F converter 37, and forward / reverse determination circuit 38. The normal pulse or negative pulse is supplied to the focusing pulse motor 43, and the focusing pulse motor 43 continues to rotate at a speed proportional to the rotation angle of the coarse dial 31.
[0039]
When the coarse adjustment is completed and the fine adjustment is performed, the fine dial knob 32 is rotated. The rotary encoder 44 generates a pulse number proportional to the rotation angle of the fine dial knob 32, generates a pulse having a phase corresponding to the rotation direction, and supplies the pulse motor driver 42 with the pulse. The pulse motor driver 42 rotates the focusing pulse motor 43 in the direction determined by the phase by the number of pulses.
[0040]
As described above, when manual focusing is performed, the manual focus mode is selected by the function selection key unit 28b. Alternatively, an automatic / manual switching function may be set in the calculation unit 24, and when a signal is input from the manual focusing control unit 33, the signal from the manual focusing control unit 33 may be prioritized.
[0041]
The return from the manual focus mode to the automatic focus mode is such that the automatic focus mode is automatically switched when the signal from the manual focus control unit 33 is not input to the calculation unit 24 for a predetermined time. It has become. In addition, after the focusing operation is completed in the automatic focusing mode, the automatic focusing mode may be switched after a predetermined time has elapsed.
[0042]
In the manual focusing control unit 33, the coarse dial knob 31 is a potentiometer and the fine dial knob 32 is a rotary encoder. However, the coarse dial knob 31 is a rotary encoder, and the fine dial knob 32 is a potentiometer. It may be. The focusing knob 9 may be omitted, and a focusing operation key 28c may be provided in the operation display unit 26, and manual focusing may be performed by the focusing operation key 28c.
[0043]
The automatic focusing operation will be described with reference to FIG.
[0044]
In STEP 1, the reference signal forming unit 23 calculates contrast based on the image signal from the image capture control unit 22. The calculation result is output to the calculation unit 24 as a reference signal.
[0045]
In STEP2, the calculation unit 24 determines whether the contrast value is equal to or greater than a certain value (threshold value). If the contrast does not reach the threshold value in STEP2, the process proceeds to STEP3, where the calculation unit 24 issues a focus command signal to the automatic focus control unit 25 and drives the drive unit 17 to drive the internal lens. 19 is moved. In STEP 3, scanning (coarse measurement) is started with the internal lens 19 from the infinity toward the short distance.
[0046]
In STEP 4, the calculation unit 24 detects a peak value of contrast. In this method, the peak of contrast is detected by detecting the peak of the contrast mountain (hill climbing method).
[0047]
Further, in STEP 5, the calculation unit 24 determines whether or not the peak value is greater than or equal to a threshold value. If the predetermined value is not reached in STEP5, the process proceeds to STEP6, and the arithmetic unit 24 continues scanning (rough measurement) the internal lens 19 further in the short distance direction.
[0048]
In STEP 7, the peak lens position is obtained from the signal from the encoder 20. The distance to the pole 2 is calculated by the calculation unit 24 according to the position of the lens, and the automatic focusing range is determined based on the calculated result. The image capture control unit 22 determines the image signal of the determined capture range. Output to the reference signal forming unit 23. The distance to the pole 2 is displayed on the distance display portion 27a.
[0049]
The determined capture range is displayed on the display unit 27 as a focusing range. Further, a liquid crystal display panel may be used as the focusing screen 13 and the focusing range may be displayed on the liquid crystal display panel. Since the collimation crosshairs are drawn on the display board, it is complicated to display the focusing range at the same time. Therefore, it may be displayed only when necessary by operating the operation key 28. .
[0050]
Note that if the contrast value has reached the threshold value in STEP 2, there is no need for scanning, and the process proceeds to STEP 7. Similarly, when the contrast value reaches the threshold value in STEP5, scanning is not necessary, so that the process proceeds to STEP7. As a result, the time required for the focusing operation can be dramatically shortened. If the threshold value is set to the contrast value of the staff, the focusing operation on the staff is shortened and the working time is shortened.
[0051]
In STEP 8, the calculation unit 24 drives the driving unit 17 through the automatic focusing control unit 25 to move the internal lens 19 to the position of the contrast peak detected by the rough measurement. For this positioning, the detection signal of the encoder 20 is used.
[0052]
In STEP 9, a precise scan (precise measurement) is performed at a low speed near the position of the contrast peak. In STEP 9, since the focusing range is a size suitable for the size of the object in the field of view, high-accuracy peak detection is performed in combination with a reduction in background noise and an increase in contrast. be able to.
[0053]
When the scan (precise measurement) of STEP 9 is completed, the process proceeds to STEP 10 and the position of the contrast peak can be accurately detected.
[0054]
Further, in STEP 11, based on the position of the contrast peak detected in STEP 10, the calculation unit 24 drives the driving unit 17 via the automatic focusing control unit 25, moves the internal lens 19, and performs automatic focusing. Scorching is complete. Note that the detection signal of the encoder 20 is also used for this positioning.
[0055]
If the object is the prism 3 and the distance to the object can be measured, the focusing range may be determined based on the distance measurement result. In this case, the distance measurement result is displayed on the distance display section 27a. Further, the focusing range may be manually selected by the operator by collimating the pole 2 with the collimating telescope unit 7 and according to the size of the image in the telescope field of view.
[0056]
Further, in the focusing range determination means, the signal from the encoder 20 is used. However, when the image signal is scanned, peak values are obtained at both edges of the image. The size may be determined, and the focusing range 29 may be determined according to the size of the object.
[0057]
In the above embodiment, the automatic focusing and the manual focusing are performed independently. However, when the manual focusing is performed after the completion of the automatic focusing, the automatic and manual deviations are calculated as described above. The arithmetic processing means 16 may store the difference, and the next automatic focusing operation may include the deviation.
[0058]
【The invention's effect】
As described above, according to the present invention, since the focus can be manually adjusted so as to be optimal for the eye condition of the operator after completion of the automatic focus, comfortable work can be performed and the focus accuracy can be improved. Furthermore, since automatic / manual is shared for the focusing mechanism, the structure is simplified and the manufacturing cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a front view of an automatic focusing device of a surveying instrument according to the present invention.
FIG. 2 is a front view of an operation display unit of the automatic focusing device of the surveying instrument.
FIG. 3 is a perspective view of a focusing knob used when manual focusing is performed.
FIG. 4 is a block configuration diagram showing an embodiment of the present invention.
FIG. 5 is a block diagram of a manual focusing control unit in the embodiment.
FIG. 6 is a flowchart showing the operation of the embodiment of the present invention.
FIG. 7 is an explanatory diagram showing a state of point finding measurement by a total station.
FIGS. 8A and 8B are explanatory diagrams showing the relationship between the telescope field of view and the size of an object.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Total station 2 Pole 3 Prism 7 Collimating telescope part 9 Focusing knob 11 Objective lens part 12 Beam splitter 13 Focus plate 15 Linear sensor 16 Calculation processing means 17 Drive part 20 Encoder 23 Reference signal formation part 24 Calculation part 25 Automatic focusing control Unit 26 Operation display unit 33 Manual focusing control unit

Claims (5)

  A photoelectric conversion unit, an imaging optical system that guides incident light from a measurement object onto the photoelectric conversion unit, a drive unit that changes a light collection state of the imaging optical system, a manual focusing input unit, an automatic From the manual focusing input unit, an automatic focusing control unit that drives the driving unit based on an output from the photoelectric conversion unit as an in-focus mode and forms an image of the measurement object on the photoelectric conversion unit. A manual focusing control unit that drives the driving unit by a signal of the above, a calculation unit that sets the manual focusing mode when a signal is input from the manual focusing input unit in the automatic focusing mode, and An autofocus device for a surveying instrument, comprising:   2. The automatic focusing device for a surveying instrument according to claim 1, further comprising a display unit including a distance display unit and capable of displaying a rough distance to the measurement object.   3. A surveying instrument according to claim 2, further comprising detection means for detecting a light collection state, calculating a distance to the measurement object from the light collection state obtained from the detection means, and displaying the calculation result on the distance display unit. Auto focus device.   The surveying instrument of claim 3, wherein after the manual focusing mode is enabled, the calculation unit enables the automatic focusing mode after a predetermined time elapses after the signal from the manual focusing input unit is interrupted. Focus device. The arithmetic unit, when performing the focusing manual followed after focusing completed automatically, when storing the automatic and manual deviation became effective mode autofocus again, as including pre Symbol deviation 5. The automatic focusing device for a surveying instrument according to claim 4 , wherein the automatic focusing operation is controlled so that individual differences of workers are reflected in the automatic focusing mode .

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