JPH05133723A - Method and device for measuring separateness with laser beam - Google Patents

Abstract

PURPOSE:To determine the closest distance (separation) of an aerial from a tree accurately, quickly, and simply. CONSTITUTION:A distance to an object is determined in the period of time from a beam of pulse laser being cast onto the object till the reflected beam coming back. The reflected light by the inner surface of a collimator lens 17 is led to a photo-receiving element 15 to determine the outgoing timing, while the reflected light by the object is led also via the collimator lens 17 to the photo-receiving element 15 to determine the timing at which the reflected light comes back. The pulse waveform is differentiated to determine the timing of being incident into the photo-receiving element 15, and the timings at which the reflected light and emitted light are left incident into the photo-receiving element are determined strictly. The position of aerial is measured at three points, and the result is approximated by a second order function or cosh function, and thereby the closest distance from tree is determined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overhead power transmission line, a device for measuring the shortest distance (referred to as separation) to an object in the vicinity of an electric wire, and a method for calculating the shortest distance. It is dangerous for trees or structures to come into contact with overhead power lines. Therefore, a device that accurately, quickly, and easily measures the distance between the overhead wire and the object under the electric wire is required.

[0002]

2. Description of the Related Art The following is known as a method for measuring the distance between an overhead power transmission line K and an object F under the wire.

The distance between the electric wire and the object is obtained by transit. When the transit is used, the angle φ in the horizontal direction, the angle θ in the vertical direction, and the distance L are obtained as the base point and the reference. φ,
θ can be found in the direction of the Transit telescope. The distance L is obtained by optically adjusting the focus, but the accuracy is poor. Since the coordinates of the target point are obtained in this way, the coordinates are obtained for a plurality of points and the distance Q thereof is calculated. However, this is time consuming and inaccurate because it is a visual observation. Particularly, since the accuracy of the distance L is poor, it is difficult to accurately obtain the separation Rm.

[0004] The height of the tree is measured by walking to a position below the under-line object F such as a tree which is considered to be dangerous and using a measurement measure. Since the height of the overhead line is known, the approximate distance Rm is calculated from the difference. This is not always possible and is inaccurate.

[0005] By riding on an overhead line (when power transmission is stopped) and approaching the tip of a tree in the vicinity, the distance is directly measured by a measure or the like. This is a straightforward method, but it is dangerous and not always feasible and time consuming. It is also inaccurate due to the problem of deformation of overhead lines due to airborne riding.

Taking an aerial photograph of a certain area from two directions,
A set of two photographs is input to a 3D stereoscopic drawing machine to restore a 3D stereoscopic image, and the shortest distance between the overhead line and the object under the wire is obtained. This is inaccurate unless the altitude of the airplane at the time of shooting is low enough. Since the range of photographs that can be taken at low altitudes is narrow, it means that a large number of shots are taken and appropriate ones are selected from these. Then the cost becomes high.

A self-propelled machine equipped with an ultrasonic wave emitter and a device for observing reflected ultrasonic waves measures the distance to trees by reflection of ultrasonic waves. This is because the reflector for reflecting the ultrasonic wave needs to be attached to the target object, and the accuracy is not always good.

It is an object of the present invention to provide a separation measuring method and apparatus capable of accurately, quickly and easily determining the shortest distance between an overhead power transmission line and an object directly under the electric wire.

[0009]

In order to obtain the shortest distance Rm between the overhead line K and the object F below, the distance measuring apparatus using the laser of the present invention is located at a position where the overhead line and the object below can be seen through. Pulse laser light is emitted from D toward the target point T of the overhead line K or the in-line object F, the horizontal angle φ and the vertical angle θ of the target point are obtained from the emission direction, and the laser from the target point T is obtained. A device for obtaining a distance L from a round-trip time of reflected light to a target point T, wherein the surface reflected light of a collimator lens for applying laser light to the target point T is used as outgoing pulse light, T
It has a configuration that detects emitted pulse light and reflected pulse light with the same light receiving element that has no parallax in the optical axis of the telescope and laser light that is aimed at, and a differentiation circuit that differentiates the signals of the emitted pulse light and the reflected pulse light. It is characterized by the configuration.

[0010]

In the present invention, the laser light is applied to the object, the time until the reflected light returns is measured, and this is multiplied by the speed of light c to obtain 2
Divide by to find the distance L to the object. Since it is the light of the pulse laser, the time at the moment when it leaves the measuring instrument and the time at which it returns are accurately known. However, if two light receiving elements are used, the exact round trip time τ is difficult to understand because of variations in the response characteristics of the light receiving elements.

In the present invention, since the reflected light from the collimator lens is adopted as a signal for giving the emission timing, this lens reflected light and the path of the light reflected upon hitting the target object are the same. Therefore, only one light receiving element is required. Therefore, the problem of variation in the response characteristics of the light receiving element is solved. The intensity of the lens reflected light and the object reflected light does not matter, but the timing of entering the light receiving element. The lens reflected light gives the emission timing. The time when the lens reflected light enters the light receiving element is T _b
And The time when the reflected light from the object returns and enters the light receiving element is T
_Let a. (T _a −T _b ) is the time difference τ required for the round trip of light
Is. However, what happens to the signal of the light receiving element is the emission time T _b, and when is the time when the light is restored to T _a ?

[0012] when the output of the light-receiving element than a certain threshold value there if is increased, these time T _b, and considered that it is T _a, it is incorrect. Since the object-reflected light is weaker, the value of T _a tends to be slower (larger) than it actually is. However, in the present invention, since the light receiving element output is differentiated, it is possible to know the time when the peak is maximized for any signal.

In this way, the distance L to the target object can be known. The vertical angle θ, the horizontal angle φ, etc. can be known from the emitting direction of the laser light. Then, the position of the object in a polar coordinate system centered on this measuring device is known. Coordinate conversion from polar coordinates to three-dimensional Cartesian coordinates is performed. Such measurement and coordinate conversion are performed at three points or more for the overhead line and for the vertices of the object under the overhead line. That is, position measurement at four points or four or more points is performed.

Since points C ₁ , C ₂ and C ₃ on the overhead line are on the overhead line, they should be included in a certain vertical plane.
Therefore, the origin is moved so as to be moved within this vertical plane, and this vertical plane becomes the xz plane. Assuming that the overhead line has a constant linear density, the catenary line z = a ₀ cosh (x / a
_It should be ₀ + a ₁ ) + a ₂ . It is used as it is, or is approximated in the form of a quadratic curve z = a ₀ + a ₁ x + a ₂ x ² . These curves are determined because the coordinates C ₁ , C ₂ , C _{3 of the} three points are known.

On the other hand, the coordinates of the object F under the imaginary line are already known. It results in the problem of finding the shortest distance between the point F and the quadratic curve or catenary. This is from point F to x
A perpendicular line is drawn on the z plane, and this foot is set to H, and the problem is the shortest distance between H and the curve on the xz plane. This is easy to find. For example, if an imaginary line is represented by a quadratic curve z = a ₀ + a ₁ x + a ₂ x ² (a ₂ > 0), a point H (p,
The shortest distance S from q) is G ² = (x−p) ² + (z−q) ² (1) z = a ₀ + a ₁ x + a ₂ x ² (2) The minimum value of the next quantity G is obtained. It is determined by things.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A schematic configuration of a measuring system used in the present invention will be described with reference to FIG. The pulse laser 1 is a laser that generates pulsed light. In the present invention, the distance to the object is measured by obtaining the time difference between the output pulse and the input pulse, and therefore the light must be generated in pulses.

The light of this pulse laser is made to have a large beam diameter by the lens 2, reflected by the mirror 13 and emitted to the outside through the collimator lens 3. In addition to the emitted light, some of the light is reflected by the inner surface of the collimator lens 3. This is reflected by the perforated Mira-4, and further Mira-5.
Is reflected by. The perforated mirror-4 has a hole at the center and serves as a path for the light from the pulse laser 1 to enter the collimator lens 3. Since the reflected light from the collimator lens 3 is wider than this hole, a considerable part of it is reflected by hitting the non-hole of the perforated mirror-4. The light reflected by the mirrors-4 and 5 enters the light receiving element 15.
A differentiation circuit 7 and a time interval measuring circuit 8 are connected to the light receiving element 15.

FIG. 2 shows an optical signal and a differential signal received by the light receiving element 15. The signal of the pulsed light (referred to as outgoing light) reflected on the inner surface of the collimator lens becomes like the waveform Au of FIG. The pulsed light is a rectangular wave, and thus has a waveform with one peak. 2B shows a differential waveform, but since a waveform having a peak is differentiated, the waveform has an upper vertex A, a zero point A, and a lower vertex C.

The light emitted from the collimator lens 3 is
It strikes the target object 12 as parallel light. Part of this is reflected back up the same path. The returning light is collimated
Go through Talens 3 in the opposite direction, with a perforated mirror-4, mirror-
It is reflected by 5 and enters the light receiving element 15. Since the light receiving element 15 converts an optical signal into an electric signal, a pulse signal having one peak can be obtained. It is a waveform shown by Eoka in FIG. Since this is the reflected light from the target object, it is simply called the reflected pulsed light. Reflection Paths Light Eoka is Collimer
Naturally, the intensity is different from that of the emitted pulsed light aiu reflected by the lens. Even if the intensity of the emitted pulsed light is constant, the reflected light from the object varies depending on the reflectance of the object, and thus may be strong or weak.

However, in the present invention, since differentiation is performed to obtain the time of the peak of the pulsed light, the strength of such a signal does not affect the timing. When the differential signal is obtained in FIG. 2B, the reflected pulsed light has a waveform having an upper vertex d, a zero point e, and a lower vertex f. The zero points of the differential waveforms Aiu and Eoka are a and o, and the time difference τ of this zero point io is obtained. Returning to FIG. 2A, since a and o are peak vertices, it means that the time difference of Io is equal to the time difference of the center of the pulsed light.

The time interval measuring circuit 8 generates rectangular pulse signals a to o equal to the time from the zero point a to the differential output zero. Considering the origin of this time difference, the path from the laser 1 to the collimator lens 3 is the same, the path from the collimator lens 3 to the light receiving element is the same, and the electric circuit is also the same. It depends only on the difference in the time that light travels back and forth to the target object. It is important that the light receiving element is common and the amplifier circuit is also the same. Since the speed of light is approximately 3 × 10 ⁸ m / sec, the time for light to reach an object at a distance of 10 ² m, to be reflected and then returned is on the order of μs. To measure this accurately, accuracy on the order of ns is required.
If the light receiving element and the electric circuit are different between the emitted light (transmitted light) and the reflected light (received light), such a short time measurement is difficult due to variations in the light receiving element and the electric circuit. However, in the present invention, the timing at which the emitted light and the reflected light arrive at the light receiving element can be accurately measured by the same light receiving element and the same electric circuit.

Next, regarding the directional angle, this is the optical system 2
It is completely described by a vertical tilt angle θ and a horizontal tilt angle φ with respect to a certain coordinate system of 0. This is achieved by the telescope 6 housed in the optical system 20
It can be obtained by obtaining the direction angles θ and φ when the optical system 20 is facing. The telescope 6 is the collimator lens 1
7, an objective lens 18, and an eyepiece lens 19. Between the perforated mirror 4, the mirror 5 and the light receiving element 15, there is a rotating mirror 14 which can rotate by about 45 degrees. The target object 12 can be seen by the telescope 6 when it is in the position of the dashed line. At this time, the light from the target object enters the optical system 20 through the collimator lens 3, is reflected by the perforated mirror 4, the mirror 5, the rotary mirror 14, and the mirror 16, and enters the telescope 6 through the collimator lens 17.

When the target object 12 is seen at the center of the telescope 6, the target object 12 is aligned so that it exists on the axis of the collimator lens 3 of the optical system 20. In this case, the collimator lens 3 also functions as a condenser lens. The reflected light is reflected by the perforated mirror 4, the mirror 5 and enters the light receiving element 15, and the light from the object passes through the lens 3 and the perforated mirror 4,
It is reflected by the mirror 5, is reflected by the rotating mirror 14, is further reflected by the mirror 16, and enters the telescope 6. Eventually, the centers of the optical paths of the two will be aligned according to the rotation angle of the rotating mirror 14. This axis alignment is performed with the inclination angle θ,
It must be done precisely to accurately determine the horizontal rotation angle φ. However, since this is a problem of alignment of the optical system, it can be performed precisely, and once the alignment is performed, there is no need to readjust it thereafter.

An example of the differentiating circuit 7 will be described with reference to FIG. The signal of the light receiving element is amplified by the high speed AMP 21 whose input is coupled with a resistance of 50Ω. The input signal to the output signal of this circuit are shown in FIGS. The input signal of the high speed AMP 21 is shown in the raw waveform of FIG. The first peak waveform is the signal by the emitted light (reflected light on the inner surface of the collimator lens), and the second peak waveform is the signal by the object reflected light. Since it is the same as (a) in FIG. The output of the high-speed AMP 21 has a positive output and a negative output, and the positive output is shown in FIG.
Shows negative output. Since there is a delay time due to the electric circuit, it will be slightly behind the raw waveform (a). This delay is the same for both the positive generation waveform of (b) and the negative generation waveform of (c), and these are the inverted waveforms. However, the negative output is not completely inverted. An ordinary inverted output has a signal of V and a power supply voltage of Vcc,
(Vcc-V) is output. However, here, a power source (via a resistor) having a voltage V ₁ smaller than Vcc 25
Since the inverted output is lifted by, the inverted output (V
_1- V) is output. Therefore, V ₁ −V <0 may occur. Positive output b and negative output c of the high speed amplifier 21
And are compared by the comparator 22. This comparison input is (d), the solid line is the positive input, and the broken line is the negative input. The output of the comparator 22 is 0 in the portion where the broken line is higher than the solid line. The part where the solid line is higher than the broken line is the comparator 22.
Output becomes Vcc. This output is shown in FIG.
It is as a gate signal.

The gate signal is generated as shown in FIG.
This is when the pulse waveform of (c) exists. The width of the gate signal is not constant, and the width becomes thicker as the pulse wave height becomes higher. In any case, however, the peak position coincides with the center of the pulse because it is formed by subtracting the negative waveform from the positive waveform.

Although the above is related to the processing of the raw waveform which is not differentiated, a circuit for generating a differentiated waveform will be described next. That is the comparator 23. The positive and negative outputs of the high speed AMP 21 are connected to the positive and negative inputs of the comparator 23 via the capacitors 26 and 27. Capacitor 26
Is grounded through the resistor 28 and the power supply 29, the normal waveform b is differentiated by the action of the capacitor 26 and the resistor 28. By the action of the power supply 29, the level is raised by a constant voltage. This is the positive differential waveform f. This is shown in Figure 4 (f).
As shown in FIG. 5, a continuous differential waveform of the upward peak and the downward peak is generated corresponding to the positive pulse. Since the capacitor 27 is grounded via the resistor 30, this acts to differentiate the negative waveform c. The average value is at ground level. The differential waveform is a continuous downward peak and upward peak. This is shown in FIG.

The comparator calculates the difference between the positive differential waveform f with an offset and the negative differential waveform g and gives an output h. This is the waveform of FIG. 4 (h). The AND gate 24 performs an AND operation on the outputs d and h of the comparators 22 and 23. This produces an output that is approximately equal to the signal h. The waveform is as shown in FIG. Of course, it lags behind the center (a) and (e) of the pulse in time, but this delay time is the same for the output pulse Aiu and the reflection pulse AOR, although the heights of the waveforms are different. This is where it matters.

The reason why such identity is assured will be understood by looking at the signal generation shown in FIG. 4 (h). This is because the negative differential waveform g is subtracted from the positive differential waveform f, but when returning to the original waveform of FIG. 4A, this is because the fall of the pulse waveform occurs at the steepest part. .. When the size of the pulse waveform is large, the width naturally becomes long, and when the pulse is small, the width becomes short. However, in the case of a large pulse, the part having the largest negative differential coefficient is biased near the peak, so the pulse ( This means that the time delays caused by h) are the same. Then, the time difference τ between the emitted light pulse and the reflected light pulse is obtained. Naturally, the distance L to the object can be easily obtained by L = cτ / 2.

The distance L is now known. Next, the direction in the absolute coordinate space is calculated. Since this is because the target object is seen by the telescope 6 as described above, the horizontal angle φ and the vertical angle θ at this time can be immediately known from the direction of the telescope 6. This gives the position of the object in the three-dimensional polar coordinate system. The vertical angle may be the rising angle from the horizon or the falling angle from the zenith. It is easy to convert this to three-dimensional Cartesian coordinates. θ is the rising angle from the horizon. x = Lcos θ cos φ (3) y = L cos θ sin φ (4) z = L sin θ (5) In this way, the position of the object is determined. With two objects, each position can be measured individually and their distance calculated. Here, a case where the shortest distance (called separation) between the tree and the electric wire (overhead wire) is obtained will be described. In this case, it is not known in advance which point of the overhead line gives the shortest distance. The position W of the apex of the tree is uniquely determined in advance, but the imaginary line does not know which point is closest to the apex of the tree. Then, it seems that it is necessary to repeat the position measurement of many points on the overhead line, find the distance for each, and search for the smallest one.

However, this is not necessary. Since both ends of the overhead line are suspended by steel towers and the line density is constant, this should be a catenary line, which is a cosh function. When the function is treated as it is, the shape of the curve is determined if the positions of at least three points are known. Since the cosh function is a little difficult to handle, it may be approximated by a quadratic function (parabola). This is because the tree and the overhead line should be close to each other near the minimum height of the overhead line, and in this case, the cosh function has a small error even if it is approximated by a quadratic function.

This will be described with reference to FIG. The point where the measuring device is located is the origin. Tree W, 3 points on the overhead line C ₁ , C
Consider ₂ , C ₃ . The position of these four points is measured by the device of the present invention. Each measurement data is W (L _W , θ _W , φ _W ) (6) C ₁ (L ₁ , θ ₁ , φ ₁ ) (7) C ₂ (L ₂ , θ ₂ , φ ₂ ) (8) C ₃ (L ₃ , θ ₃ , φ ₃ ) (9). This can be substituted into the equations (3) to (5) to obtain a value in the three-dimensional Cartesian coordinate system. W (X _w , Y _w , Z _w ) (10) C _i (X _i , Y _i , Z _i ) (i = 1, 2, 3) (11) Points C ₁ , C ₂ , C ₃ on the overhead line Should be included in a vertical plane. That is, there are k, h, and m (only these values are determined) such that kX _i + hY _i + m = 0 (12) holds for i = 1, 2, 3. For example the ^{_{k (Y 2 -Y 3) -1}} = h (X 3 -X 2) -1 = m (X 2 Y 3 -Y 2 X 3) -1 (1 3). Further, the value of the 3 × 3 determinant having X _i , Y _i , and 1 as row elements is 0. det | X _i , Y _i , 1 | = 0 (14) This expresses the necessary and sufficient condition that C ₁ , C ₂ , and C ₃ are included in a vertical plane. Q of this vertical
Then, the distance S from the original origin O (set as the center of the measurement system) is naturally S = m (k ² + h ² + m ² ) ^−1/2 (15). Therefore, if the coordinate system is translated by Δx in the x direction and Δy Δx = kS (k ² + h ² ) ^−1/2 (16) Δy = hS (k ² + h ² ) ^−1/2 (17) in the y direction, It is converted into a coordinate system having an origin O'on the vertical plane Q. That is, the new coordinates are (x ′ _i , y ′ _i ,
z ′ _i ) and lowercase letters with dashes, x ′ _i = X _i −Δx (18) y ′ _i = Y _i −Δy (19) z ′ _i = Z _i (20). This vertical Q is x'of the new coordinate system
It is still tilted with respect to the y'plane. Therefore, coordinate conversion is performed so that the vertical plane Q includes the x axis. This is easy
It is only necessary to rotate the coordinates around the z axis by tan ⁻¹ (k / h). If the new coordinates are expressed by (xi, yi, zi), then xi = X'icos? + Y'i + sin? (21) yi = X'isin? + Y'i + cos? (22) zi = Z'i (23). Up to this coordinate system, the vertical plane Q overlaps the xz plane. Therefore, the point of the imaginary line has a y-coordinate of 0, and C ₁ (x ₁ ,
0, z ₁ ), C ₂ (x ₂ , 0, z ₂ ), C ₃ (x ₃ ,
It can be expressed as 0, z ₃ ). Since this is a catenary, the catenary approximation Z (x) = a ₀ cosh {(x / a ₀ ) + a ₁ } + a ₂ (24) or the quadratic function approximation Z (x) = a ₀ + a ₁ x + a ₂ x It can be approximated by ² (25). Parameters a ₀ , a
_1, a ₂ are are three, because it're been determined that three points coordinates, which is the completely determined.

When a ₀ , a ₁ and a ₂ are determined, (2
The function form of 4) or (25) is obtained. If the coordinates of the top of the tree W are the same coordinates (x _W , y _W , z _W ),
Distance R between this and the curve k (wherein imaginary ^{line), R 2 = (x-x} W) 2 + y W 2 + (z-z W) determined by ^two (26). In order to obtain the minimum value, this may be differentiated by x so that the value becomes 0. x−x _W + z (x) ′ {z (x) −x _W } = 0 (27). If z (x) is approximated by (25), this becomes a cubic equation. Two are imaginary roots and one is a real root. This real root is the solution. This cubic equation can be easily solved. If the values of x and z obtained there are x ₄ and z ₄ , the minimum value, that is, the separation R _m, is R _W = {(x ₄ −x _W ) ² + y _W ² + (z ₄ −z _W ) ² } ^{1 It} can be calculated by ^{/ 2} (28).

According to the present invention, the emitted light and the reflected light are received by the same light-receiving element, and the light-receiving element is differentiated to accurately determine the timing of incidence on the light-receiving element. Without using the differentiation, a certain threshold value V _h is determined and the signals V and V _{h are set.}
It is also possible to compare the above and to give the incident timing of the emitted light and the reflected light when V> Vh. It is necessary to compare the method based on such a constant threshold with the time interval measurement method based on differentiation.

Therefore, the distance between the target object and the measuring device is about 4
At 0 m, the reflectance of the target object was changed and the time intervals of the emitted light and the reflected light were measured. The actual level of reflected light is changed by placing a reflector with a different reflectance at the measurement point. That is, in FIG. 4A, the pulse (aiu) of the emitted (transmitted) light is unchanged, but the height of the pulse (aore) of the reflected (received) light is changed. Therefore, the time interval measurement was performed by the method of the present invention (differentiation) and the constant threshold method using the ratio of the two as a parameter. FIG. 6 shows this result. The horizontal axis is the emitted light (Aiu), which is the peak of the reflected light (Aore). This value can be increased by increasing the reflectance of the reflector.

The vertical axis represents the distance L = cτ / obtained from the time difference τ.
It is 2. White circles are obtained by the differential method of the present invention. It rides on a nearly horizontal line and shows a value of L = 41.2 m. It is stable with little dependence on the intensity of reflected light, that is, the reflectance. However, the one that is compared with the constant threshold is placed on the straight line to the right as shown by x. Although the distance L has not changed, the measured value of the time interval τ differs because the reflectance is different. When the value of the peak is large, the time to reach a certain threshold value V _h is faster τ is appear in fewer. By comparing the two in this way, it is clear how stable the time interval measurement by the differentiating circuit is.

FIG. 7 shows an example in which the distance between the tree and the overhead line is actually measured. However, it is difficult to make accurate measurements with trees, so a pole is set up instead. Three measurement points were taken for the overhead line. Example 3 will be described. The uppermost column is a front view seen from the measuring device, and the second column is a plan view.
Examples 1 and 2 are where the tree (pole) is closer to the laser than the overhead line, and Example 3 is where the pole is farther. Column 4 shows the angle formed by these two straight lines when the laser optical axis is extended to the straight line obtained from three points on the imaginary line on the plan view. In other words, this angle is Θ = tan
^-1 (k / h). Column 5 is the actual value of separation.
Column 6 shows the results of measurement and calculation by the method of the present invention. Column 7 shows the error. From this result, it is possible to measure a distance of about 2 to 5 m at a distance of about 100 m with an error of 0.1 m or less.

[0037]

According to the method of the present invention, the distance between the overhead line and the trees is obtained from a distance by utilizing the reflection of the laser beam, and therefore, the following effects can be obtained. It is stable because it does not involve flying on overhead lines or measuring the height of trees directly. There is no need to use a self-propelled measuring machine, and since measurement from a certain fixed point O is sufficient, the measuring device is simplified and the operation is also simple. Compared with other measurement methods that use optical means, the number of light receiving elements is one, and the reflected light (emitted light) from the collimator lens and the reflected light from the object are measured by this, so a light receiving element or an amplifier circuit is used. There is no problem of variation in response time. Since the peak time of the pulse of the emitted light (transmission) and the peak of the pulse signal of the reflected light (reception) are obtained by differentiation, the time difference between the two can be obtained with high accuracy. The level of reflected light varies depending on the reflectance and distance of the target object, but is not affected by such variation. Therefore, the distance measuring accuracy is significantly improved. Since the laser light is a parallel light, it can be accurately measured from a distance (since the reflected light is strong). It is not just the distance to the target object, but the distance. Even if you go to the site and hang it on the overhead line and try to find the distance near it, it is difficult to measure because it is not known which point on the overhead line gives the shortest distance. It can be instantly calculated by computer. This is possible because the positions of overhead lines and trees are expressed in a three-dimensional coordinate system.

Since the present invention has such excellent features, (a) management of the under-line object approaching distance (b) determination of a tree approaching dangerous point (c) identification of a tree approaching position (d) tree cutting amount (Length) (e) It can be widely used for determining overhead line support conditions (tower height, position, tension and slack).

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a separation measuring device of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the differentiating circuit of the present invention.

FIG. 3 is a configuration example diagram of a differentiating circuit used in the present invention.

FIG. 4 is a diagram showing an output waveform of each element in the differentiating circuit of FIG.

FIG. 5 is a diagram showing an algorithm for distance calculation according to the present invention.

FIG. 6 shows a time interval between an emitted light pulse and a reflected light pulse,
In order to compare the method of the present invention, which is obtained by differentiating the pulse, with the method of obtaining the interval by comparing the magnitude of the pulse with a certain threshold value, a plate having different reflectance is placed at the target point. The graph which shows the result of having measured the time interval.

FIG. 7 is a diagram showing an example of measurement of separation between trees and overhead lines.

[Explanation of symbols]

 1 pulse laser 2 lens 3 collimator lens and condensing lens 4 holed mirror 5 mirror 6 telescope 7 differentiating circuit 8 time interval measuring circuit 9 horizontal angle measuring device 10 vertical angle measuring device 11 computer 12 target object 13 mirror 14 rotating mirror 15 light receiving Element 16 Mirror 17 Collimator lens 18 Objective lens 19 Eyepiece lens

Front page continued (72) Inventor Junichi Asano, 3-3-22 Nakanoshima, Kita-ku, Osaka City, Kansai Electric Power Co., Inc. (72) Toshio Nagai, 3-32-22, Nakanoshima, Kita-ku, Osaka City, Kansai Electric Power Co., Inc.

Claims (2)

[Claims] 1. The shortest distance Rm between the overhead wire K and the object F under the wire.
In order to obtain, the pulse laser light is emitted from the position D where the overhead line and the underline object can be seen toward the target point T of the overhead line K or the underline object F, and the horizontal angle φ of the target point from the emission direction,
A device for obtaining a vertical angle θ and for obtaining a distance L to the target point T from the round-trip time of the laser reflected light from the target point T,
By using the surface reflected light of the collimator lens for applying the laser light to the target point T as the emitted pulse light, there is no parallax between the telescope aiming at the target point T and the optical axis of the laser light and the same. A separation measuring apparatus using a laser, characterized in that a light receiving element detects emitted pulsed light and reflected pulsed light, and a configuration having a differentiating circuit for differentiating the signals of the emitted pulsed light and the reflected pulsed light. 2. The shortest distance Rm between the overhead wire K and the object F under the wire.
In order to obtain, the pulse laser light is emitted from the position D where the overhead line and the underline object can be seen toward the target point T of the overhead line K or the underline object F, and the horizontal angle φ of the target point from the emission direction,
The vertical angle θ is obtained, the distance L to the target point T is calculated from the round-trip time of the laser reflected light from the target point T, and the coordinates (L, θ, φ) of the target point T with respect to the polar coordinate system fixed at the position D. Is determined, a function approximating the imaginary line is obtained from the coordinates of each measurement point of the imaginary line K, and the minimum distance between the approximation function and the coordinates of the object F under the line is obtained and this is set as the shortest distance Rm. Measuring method of separation using laser.