JP3715391B2 - Electronic level - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic level that automatically determines the height.
[0002]
[Prior art]
As this type of conventional one, for example, according to Japanese Patent Application Laid-Open No. 6-241789, a rod-shaped staff that is held substantially vertically is collimated, and an image of the staff is formed on a linear sensor that is a photoelectric conversion means for electric An electronic level is known which is converted into a signal to automatically obtain the height of the collimation position. Note that a shutter is provided in front of the eyepiece at the electronic level to prevent the S / N ratio of the linear sensor from being reduced by light incident from the eyepiece.
[0003]
[Problems to be solved by the invention]
When the distance to the standard is increased, the standard image becomes narrower, and the background part of the standard is imaged on the linear sensor in addition to the standard image. If the background part other than the standard is imaged on the linear sensor, It becomes difficult to identify the mark .
[0004]
SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an electronic level that is not affected by the background of a staff.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention includes photoelectric conversion means for converting a collimated standard image into an electric signal, and automatically sets the height of the collimation position from the image data output from the photoelectric conversion means. A focusing lens that is manually moved according to the distance to the scale at a desired electronic level is provided, and a shutter that moves in conjunction with the movement of the focal point of the focusing lens is provided, and an image is formed on the photoelectric conversion means. among the images, by the movement of the shutter, characterized by being adapted to shield against the photoelectric conversion means only the background portion of the staff regardless perspective of the distance to the leveling rod.
[0006]
Specifically, the photoelectric conversion means is a line sensor arranged in the vertical direction, or a CCD element arranged in the vertical direction and the horizontal direction.
[0007]
By arranging the line sensors of the photoelectric conversion means in the vertical direction, the image of the standard can be displayed in the vertical direction. Further, with arranging the CCD elements of the photoelectric conversion means in the vertical and horizontal directions, by the shutter to move in conjunction with the focus movement of the focusing lens, an image of the leveling rod portion in the photoelectric conversion unit only without imaging The influence of the background part can be excluded.
[0008]
The width of the staff of the image formed on the photoelectric conversion means through the optical system varies depending on the distance to the leveling rod, if close staff within the electronic level width of staff of an image is relatively large, the staff As the distance increases, the width of the image of the scale becomes narrower. Accordingly, when the shutter is set in accordance with the case where the distance to the standard is short, an image of the background portion is formed on the photoelectric conversion means as the distance to the standard increases. On the other hand, if the shutter is set according to the case where the standard is far, only a part of the image of the standard can be used when the standard approaches, and the S / N ratio deteriorates.
[0009]
Therefore, the shutter is moved according to the position of the focusing lens that moves in conjunction with the distance to the staff, and only the background portion is blocked regardless of the length of the distance to the staff.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, reference numeral 1 denotes an electronic level telescope unit, and a focusing lens 12 is held in a focusing tube 13 that is movable back and forth behind an objective lens 11 at the tip. Behind the focusing lens 12, a compensator 14 for compensating for the tilt in the front-rear direction of the telescope unit 1 and a beam splitter 15 for branching light laterally with respect to the optical axis are arranged. The light that has passed without being branched by the beam splitter 15 reaches the focusing screen 16 and forms an image. The focusing screen 16 is engraved with a crosshair, and is configured so that the eyepiece T can be viewed with an eyepiece 17 formed on the crosshair. Further, the light branched by the beam splitter 15 is imaged on the photoelectric sensor 2 which is a photoelectric conversion means disposed on the side of the beam splitter 15. The photoelectric sensor 2, and the line sensor for detecting the intensity of light along the vertical direction, a CCD element for detecting the intensity of vertical and horizontal direction of the light. The image data converted into an electrical signal by the photoelectric sensor 2 is output to the arithmetic control unit 3. The arithmetic control unit 3 reads the scale of the collimation position on the scale T based on the image data from the photoelectric sensor 2 and displays the result on the display unit 31.
[0011]
The focusing lens 12 moves back and forth according to the distance D from the electronic level to the scale T, and clearly forms an image of the scale T on the focusing screen 16 and the photoelectric sensor 2. The potentiometer 4 is attached to the focusing cylinder 13 so that the calculation control unit 3 can detect the distance D from the position before and after the focusing cylinder 13. A shutter unit 5 that opens and closes in the horizontal direction is attached between the beam splitter 15 and the photoelectric sensor 2.
[0012]
As shown in FIG. 2, the opening / closing drive mechanism 6 is composed of a stepping motor 61 that can rotate forward and backward and a left and right screw 63 connected via a coupling 62 that absorbs misalignment. The shutter unit 5 has two shutter blades 52 movably held by a guide 51, and both shutter blades 52 are screwed into the left and right screws 63. Therefore, the interval W between the shutter blades 52 is increased or decreased by rotating the stepping motor 61. The shutter blade 52 is driven by an opening / closing drive mechanism 6 that is driven and controlled by the arithmetic control unit 3, and the opening / closing amount of the shutter unit 5 is controlled to increase / decrease.
[0013]
When the arithmetic control unit 3 detects that the distance D to the scale T is short based on the position signal from the potentiometer 4, the arithmetic control unit 3 releases both shutter blades 52 and widens the interval W. If the distance D is short, the image of the measure T becomes large, and the image of the measure T cannot be accommodated within the interval W unless the interval W is widened (see FIG. 3A). The image of the measure T becomes smaller as the measure T moves away and the distance D increases. Then, since the background of the measure T is imaged on the photoelectric sensor 2 between the image of the measure T and the shutter blade 52, the interval W is made closer to each other as the distance D increases (see FIG. 3 (b) (c)). The relationship between the distance D and the interval W is stored in advance in the arithmetic control unit 3 as table data, and when the position signal from the potentiometer 4 is input, the interval W is obtained from the table data and further becomes the interval W. The stepping motor 61 is driven as described above.
[0014]
By the way, the focusing cylinder 13 is manually moved back and forth by a rack (not shown) and a pinion and a knob for rotating the pinion according to the distance D to the gauge T. The relationship of the position of the focusing cylinder 13 with respect to the distance D is as follows. For example, as shown in FIG. 4, when the distance D is short, the moving amount of the focusing cylinder 13 with respect to the change in the distance D is large, but as the distance D becomes long, the moving amount of the focusing cylinder 13 with respect to the change in the distance D becomes small. . When the distance D becomes longer than the predetermined distance D1, the moving amount of the focusing tube 13 is substantially proportional to the change in the distance D. On the other hand, the image of the measure T becomes thinner in proportion to the increase in the distance D. As a second embodiment, as shown in FIG. 5, the rack 7 is directly attached to the focusing cylinder 13 and the racks 74 are respectively attached to both shutter blades 52, and both racks 7 and 72 are connected via two pinion gears 71 and 72. 7 were connected. However, with respect to one shutter blade 52, an idle gear 73 is interposed between both pinion gears 71 and 72 so that the moving direction of one shutter blade is opposite to the moving direction of the other shutter blade. In this configuration, the amount of movement of the rack 74 relative to the amount of movement of the rack 7 can be adjusted by changing the gear ratio of the both pinion gears 71 and 72. In addition, as shown in FIG. 4, the moving amount | distance of the focusing cylinder 13 increases as the distance D becomes short. In the configuration shown in FIG. 5, when the distance D is shortened, the rate at which the interval W between the shutter blades 52 is larger than the rate at which the width of the image of the measure T is widened. However, when the distance D is shortened and the width of the image of the measure T is increased, only a small amount of the background image of the measure T is formed on the photoelectric sensor 2 even if there is no shutter. There is no practical problem.
[0015]
【The invention's effect】
As is clear from the above description, the present invention is provided with a shutter for cutting the background of the standard in accordance with the width of the standard image, so that when the background image recognizes the standard by the photoelectric conversion means (photoelectric sensor). In the case of backlighting, only the image of the scale is imaged on the photoelectric conversion means, so that the contrast of the scale image does not become ambiguous and the number of measurement errors can be reduced. it can.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a configuration of an electronic level according to the present invention. FIG. 2 is a block diagram showing a configuration of an opening / closing mechanism. FIG. 3 is a diagram showing an imaging state on a photoelectric sensor. Figure (b) showing the case where the distance is short (b) Figure showing the case where the distance is medium (c) Figure showing the case where the distance is long [Figure 4] Figure showing the amount of movement of the focusing cylinder with respect to the distance to the staff Diagram showing another embodiment of mechanism [Explanation of symbols]
1 Telescope unit 2 Photoelectric sensor (photoelectric conversion means)
3 Calculation control unit 4 Potentiometer 5 Shutter unit 6 Open / close drive mechanism T

Claims (3)

A photoelectric conversion means for converting an image of the collimated standard to an electrical signal, and depending on the distance to the standard at the electronic level for automatically obtaining the height of the collimation position from the image data output from the photoelectric conversion means manually focusing lens to be moved is provided Te, shutter moves is provided in conjunction with the focus movement of該合focusing lens, of the image formed on the photoelectric conversion means, by the movement of the shutter, the staff electronic level, characterized in that so as to shield only the background portion of the staff regardless perspective of the distance to respect the photoelectric conversion means.   The electronic level according to claim 1, wherein the photoelectric conversion means is a line sensor arranged in the vertical direction.   3. The electronic level according to claim 1, wherein the photoelectric conversion means is a CCD element arranged in the vertical direction and the horizontal direction.

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