CN102042817B - Terrain roughness tester - Google Patents

Abstract

The surface roughness tester of the present invention comprises: an electric moving unit, an adjusting bracket platform unit, an imaging unit and a computer; the electric moving unit is fixedly connected to the table of the adjusting bracket platform unit, and the imaging unit is fixedly connected with the electric moving unit Finally, face the ground and place it under the adjustment bracket platform unit. Under the control of the computer, the electric mobile unit drives the imaging unit to complete the scanning and imaging of the measured area. After processing, the three-dimensional space coordinate information of the measured ground is obtained, which is convenient. The calculated surface roughness parameters. The surface roughness tester of the present invention is used to test the surface roughness parameters, without on-site calibration of the instrument, without pasting marking points on the measured area, and can quickly and automatically obtain the surface roughness parameters of the measured area. The surface roughness tester of the present invention is simple in structure, easy to use and low in cost, can be widely used in the measurement of farmland and the earth, and provides reliable data support for agricultural production and grain production estimation and microwave inversion.

Description

Surface Roughness Tester

technical field

The invention belongs to a device for obtaining three-dimensional information of the earth surface, in particular to an earth surface roughness parameter tester.

Background technique

Surface roughness is the roughness of the soil surface. A rough soil surface increases the soil surface area, which can accumulate part of the rainfall, reduce the wind speed, and increase the solar radiation area. At the same time, it increases the evaporation of the soil and reduces the moisture content of the soil profile. Soil surface roughness is an important parameter that characterizes soil hydrological characteristics and affects soil properties, and affects the scattering and thermal radiation characteristics of the soil surface.

There are usually two measurement methods for surface roughness: non-contact measurement and contact measurement. The contact measurement methods mainly include stylus method, chain method and rod ruler method. Most of the non-contact measurement methods are based on the principle of computer vision, which need to combine the images captured by the camera and the positional relationship between the target and the camera, without manual participation, and can automatically complete the acquisition of three-dimensional information. In non-contact measurement, there are mainly two categories. One is an optical method, and the other is a method other than optics. Optical method measurement can be divided into active and passive. The active type refers to projecting a specific structured light on the measured object, making it modulated by the object, and then obtaining the three-dimensional information of the measured object after demodulation. The passive type does not require additional light sources, and uses certain techniques to obtain three-dimensional information of objects under natural light illumination. In recent years, with the development of laser technology, the laser triangulation method based on the principle of geometric optics triangulation has gradually been widely used. The basic principle of the laser triangulation method is that the laser emitted by the semiconductor laser forms a light spot on the measured surface, and the surface information such as the shape and size of the measured object is extracted by analyzing the characteristics of the light spot. It has fast scanning speed, high precision, non-destructive and easy to realize automation, and can be adjusted and processed by software. Calculate the surface roughness parameters.

Most of the current surface roughness testers are based on contact measurement methods. As Chinese patent application CN03114152.8 discloses a soil roughness measurement method, it includes the following steps: 1) random sampling in the target land, and two point, and the distance between the two points is L; 2) On the straight line where the two points are fixed, use an inelastic soft rope close to the rough surface of the soil to lay it flat, and obtain the straightened distance L' of the soft rope between the two points; 3) Determination of each sample plot by analogy; 4) According to the measured data, the soil roughness Ci=Li'/L (i=1, 2, 3...n) of each sample plot is obtained, and then the whole target is obtained The soil roughness of the land.

Chinese invention patent application 2008100893194.0 discloses a method for measuring soil surface roughness with a probe. The device used is: a fixed fulcrum is fixed on a frame, and at least two parallel and A stylus that can move along the upper and lower borders of the frame and a height indicator that can measure the height change of the stylus. In the device of this patent application, a water level gauge is also provided to establish the same reference point in the horizontal direction between the measurement points. The patent application includes the following steps: 1) measuring with the device; 2) correcting the measured data; 3) calculating.

Invention patent application 200910161433.4 discloses a surface roughness measurement device: a container for measuring liquid is fixed on the support rod with a channel connected to the outside at its top, and a container for measuring liquid is also provided with a flexible material. One end of the communication pipe made to communicate with the liquid inside the container, and the other end of the liquid communication pipe communicates with a pressure gauge. The pressure gauge is fixed on the movable measuring rod.

The measurement cost of the device used in the contact method in the prior art is low, but the measurement value needs to be obtained by measuring with a ruler, and the measurement process requires manual participation, which takes a long time, and the accuracy and speed of the measurement are difficult to meet the requirements.

Contents of the invention

The surface roughness tester is characterized in that its composition includes: an electric mobile unit, an adjustment bracket platform unit, an imaging unit and a computer; After the fixed connection, face the ground and place it under the platform unit of the adjustment bracket, the computer is connected with the electric mobile unit and the imaging unit, and the operating software of the surface roughness tester is stored in the computer; the imaging unit is composed of a CCD camera and a laser .

The adjustment bracket platform unit is composed of an upper adjustment platform, a fine adjustment base, a lower adjustment platform, a pillar, and a coarse adjustment base; the adjustment bracket platform unit is used to support and ensure that the electric mobile unit is in a stable horizontal state; among them,

The bottom end of the pillar is pointed, and the bottom of the pillar has an external thread that matches the internal thread of the coarse adjustment base; there are 4 pillars in total, which are respectively fixed on the 4 corners of the lower adjustment platform;

The coarse adjustment base is a square metal plate with a round hole in the center and internal threads on the wall of the round hole; there are 4 coarse adjustment bases in total, which are matched with the pillars one by one;

The coarse adjustment base and the pillar are connected by threads and the coarse adjustment base is in contact with the ground, and the height of the coarse adjustment base and the bottom of the pillar inserted into the soft soil is adjusted;

The upper adjustment platform and the lower adjustment platform are square plates with exactly the same shape and size, and each side of the center line of the upper adjustment platform and the lower adjustment platform corresponds to a rectangular hole symmetrical to the center line; the four sides of the upper adjustment platform There is a bubble in the middle of the calibration platform to adjust the level of the platform;

Three fine-tuning bases arranged in a triangle are fixed on the square plate of the lower adjustment platform to connect with the upper adjustment platform;

The fine-tuning base is composed of a circular screw, a knob and a base; among them, the screw and the knob are tightly connected; the middle of the base is a circular hole, the inner wall of the hole has internal threads, the screw has external threads, and the screw and the base Through the threaded connection, adjust the height of the fine-tuning base by rotating the knob to adjust the depth of the screw rod and the middle hole of the base;

There are more than 2 screw holes on the square plate of the upper adjustment platform, which are used to fasten and connect with the bottom plate of the electric mobile unit through bolts; A057 model;

The motor of the electric mobile unit drives the screw to rotate, and the rotation of the screw drives the upper table of the electric mobile unit to make a reciprocating linear motion;

The imaging unit is composed of a left CCD camera, a laser, a right CCD camera and a supporting board; the left CCD camera, laser and right CCD camera are fixed on the supporting board;

The connection method between the electric moving unit and the imaging unit is as follows: two U-shaped slots have the same shape and size and are respectively placed in rectangular holes symmetrical on both sides of the center line of the upper adjustment platform and the lower adjustment platform. The two ends of the groove are respectively fastened to the upper table of the electric mobile unit) and the supporting plate of the imaging unit, and the two ends of another U-shaped groove placed opposite are also fastened to the supporting plate of the electric mobile unit and the imaging unit, respectively. The imaging unit completes linear motion driven by the electric moving unit, and the laser 8 in the imaging unit emits a laser beam in a vertical direction to the surface to be measured, forming a laser light belt on the surface; the left CCD camera 7 and the right CCD camera 9 are synchronized at the same time Collect images of laser light bands and scan and image the surface to be measured;

The left CCD camera and the right CCD camera are black and white CCD, such as PointGrey’s digital camera model FFMV-03M2M, which has a maximum pixel of 752×480 and a frame rate of 60FPS. It is equipped with a 5mm lens produced by Computer and uses a 1394 interface for image processing. collection and transmission;

The laser adopts semiconductor line structure light source, such as the laser produced by Changchun Bosheng Quantum Co., Ltd. with a wavelength of 650nm and an adjustable power of 5-20mw;

The running software is stored in the computer, and the software flow is as follows;

Execute step 100 to start; the surface roughness tester is initialized, the tester is self-inspected, and the default value of the system parameter is read in;

Execute step 105, the electric translation stage unit moves linearly; the computer issues a command, the motor of the electric translation stage unit starts to rotate, and drives the electric translation stage unit to move at a constant speed according to the specified zero position and limit position, the specified speed and the specified range linear motion;

Execute step 110, data acquisition; computer sends out order, and the laser device 8 in the imaging unit that is connected with electric translation stage unit emits the laser beam of vertical direction to the ground surface to be measured, forms a laser light band on the ground surface; Left CCD camera 7 and right The CCD camera 9 synchronously collects the image of the laser light band at the same time, and scans and images the ground surface to be measured;

Execute step 115, image processing; obtain the image pixel coordinates of the center position of the laser light band through the noise point deletion algorithm and the light band extraction algorithm on the obtained image;

Execute step 120, coordinate transformation; convert the pixel coordinates of the image into the x, y, z three-dimensional coordinates of the space through the characteristic parameters of the instrument;

Execute step 125, calculate the surface roughness data; bring the obtained x, y, z coordinate values into the roughness parameter calculation formula, and calculate the surface roughness parameters within the measured range;

Execution of step 130, data display or printing; the information of the roughness of the ground surface within the measured range can be displayed on the display or the test results can be printed by the printer as required;

Execute step 135, end;

The formula for calculating the roughness is as follows: the roughness of a random surface is characterized by a statistical parameter with wavelength as the unit of measure, and two basic parameters that characterize the surface roughness: one is the standard deviation of the surface height variable; the other is surface correlation length;

The standard deviation of the surface height variable: (1) Assume that there is a surface in the xy plane, and the height of a point (x, y) above the xy plane is z(x, y); (2) take statistics on the surface A representative piece in the sense of dimensions L _x and L _y , and assuming that the center of the surface is at the origin, the average height of the surface is

$\stackrel{\‾}{z}=\frac{1}{L_x{L}_{\mathrm{the\; y}}}{\∫}_{-\mathrm{Lx}/2}^{\mathrm{Lx}/2}{\∫}_{-\mathrm{Ly}/2}^{\mathrm{Ly}/2}z(x,\mathrm{the\; y})\mathrm{dxdy}$ Formula 1

Its second moment is

$\stackrel{\‾}{z^2}=\frac{1}{L_x{L}_{\mathrm{the\; y}}}{\∫}_{-\mathrm{Lx}/2}^{\mathrm{Lx}/2}{\∫}_{-\mathrm{Ly}/2}^{\mathrm{Ly}/2}{z}^2(x,\mathrm{the\; y})\mathrm{dxdy}$ Formula 2

The standard deviation of the surface height is then σ

$\mathrm{\σ}={(\stackrel{\‾}{z^2}-{\stackrel{\‾}{z}}^2)}^{1/2}$ Formula 3

Surface correlation length:

The normalized autocorrelation function of one-dimensional surface section value z(x) can be defined as:

$\mathrm{\ρ}\left(x^{\′}\right)=\frac{{\∫}_{-\mathrm{Lx}/2}^{\mathrm{Lx}/2}z\left(x\right)z(x+x^{\′})\mathrm{dx}}{{\∫}_{-\mathrm{Ly}/2}^{\mathrm{Ly}/2}{z}^2\left(x\right)\mathrm{dx}}$ Formula 4

It is a measure of the similarity between the height z(x) of point x and the height z(x+x') of another point x' away from x, for discrete data, the distance x'=(j-1)Δx The normalized autocorrelation function of is given by the following formula, where j is an integer ≥ 1,

$\mathrm{\ρ}\left(x^{\′}\right)=\frac{\underset{i=1}{\overset{N+1-j}{\mathrm{\Σ}}}{z}_i{z}_{j+i-1}}{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{z}_i^2}$ Formula 5

The interval x' value when the correlation coefficient ρ(x') is equal to 1/e is defined as the surface correlation length l,

ρ(l)=1/e

The surface correlation length value l provides a benchmark for estimating the independence of two points on the surface, that is, if the two points are separated by a distance greater than l in the horizontal distance, then the height values of the two points are approximately independent in a statistical sense ;

In the limit case, ie when it is a perfectly smooth (mirror) surface, every point on a perfectly smooth (mirror) surface is correlated with every other point by a correlation coefficient l, so l = ∞ in this special case.

The automatic measurement of the surface roughness can be completed respectively according to the following steps with the surface roughness tester of the present invention.

First stand the bottom of the pillar 5 on the surface of the soil to be measured, insert the tip into the soil, adjust the coarse adjustment base 6 that touches the ground, and keep the lower adjustment platform 4 roughly level.

Adjust the three fine-tuning bases 3 between the lower adjustment platform 4 and the upper adjustment platform 2 until the air bubbles in several directions are located in the center of the water column, so that the upper adjustment platform 2 is in a horizontal state;

Through the software stored in the computer 12, the surface roughness tester works according to the program flow, and automatically collects and processes the test data of the surface roughness parameters.

Beneficial effects: the composition of the surface roughness tester of the present invention includes: an electric moving unit 1, an adjustment bracket platform unit, an imaging unit and a computer 12; After being fixedly connected with the electric mobile unit 1, it is placed under the adjustment bracket platform unit 1 facing the ground. Under the control of the computer, the electric mobile unit drives the imaging unit to complete the scanning and imaging of the measured area, and the measured ground is obtained after processing. The three-dimensional space coordinate information of the ground surface can be calculated conveniently. The surface roughness tester of the present invention is used to test the surface roughness parameters, without on-site calibration of the instrument, without pasting marking points on the measured area, and can quickly and automatically obtain the surface roughness parameters of the measured area. The surface roughness tester of the present invention is simple in structure, easy to use and low in cost, can be widely used in the measurement of farmland and the earth, and provides reliable data support for agricultural production and grain production estimation and microwave inversion.

Description of drawings

Fig. 1 is the front view of the schematic diagram of the surface roughness tester of the present invention.

Fig. 2 is a schematic diagram of the structure of the adjustment bracket platform unit of the surface roughness tester of the present invention.

Fig. 3 is a schematic diagram of the structure of the fine-tuning base of the surface roughness tester of the present invention.

Fig. 4 is a cross-sectional view of Fig. 1 at position A-A of the present invention. This figure shows the connection relationship between the imaging unit and the electric mobile unit 1 of the surface roughness tester.

Fig. 5 is a flow chart of the operation of the surface roughness tester of the present invention.

Detailed ways

Embodiment 1: as shown in Figure 1, the composition of the surface roughness tester of the present invention comprises: electric mobile unit 1, adjustment support platform unit, imaging unit and computer 12; Described electric mobile unit 1 is fixed on the adjustment support On the platform unit table, after the imaging unit is fixedly connected with the electric mobile unit 1, it is placed under the platform unit 1 of the adjustment bracket facing the ground, and the computer 12 is connected with the electric mobile unit 1 and the imaging unit;

As shown in Figure 2, the adjustment bracket platform unit is composed of an upper adjustment platform 2, a fine adjustment base 3, a lower adjustment platform 4, a pillar 5, and a coarse adjustment base 6; the adjustment bracket platform unit is used to support and ensure that the electric mobile unit 1 is stable The horizontal state of ; among them,

The bottom end of the pillar 5 is pointed, and the bottom of the pillar 5 has an external thread that matches the internal thread of the coarse adjustment base 6; there are four pillars 5, which are fixedly connected to the four corners of the lower adjustment platform 4 respectively;

The coarse adjustment base 6 is a square metal plate with a round hole in the center and an internal thread on the wall of the round hole; there are four coarse adjustment bases 4, which are respectively matched with the pillars 5 one by one;

The coarse adjustment base 6 and the pillar 5 are connected by threads and the coarse adjustment base 6 is in contact with the ground, and the height of the bottom of the coarse adjustment base 6 and the pillar 5 inserted into the soft soil is adjusted;

The upper adjustment platform 2 and the lower adjustment platform 4 are square plates with exactly the same shape and size, and each of the two sides of the center line of the upper adjustment platform 2 and the lower adjustment platform 4 corresponds to a rectangular hole symmetrical to the center line; the upper adjustment platform There is a bubble in the middle of the four sides of 2 to mark the levelness of the upper adjustment platform 2;

Three fine-tuning bases 3 arranged in a triangle are fixed on the square plate of the lower adjustment platform 4 to connect with the upper adjustment platform 2;

The fine-tuning base 3 is composed of a circular screw rod 13, a knob (14) and a base 15; wherein, the screw rod 13 and the knob 14 are tightly connected; the middle of the base 15 is a circular hole, and the inner wall of the hole has internal threads , the screw rod 13 has an external thread, the screw rod 13 is connected to the base 15 through the thread, and the height of the fine-tuning base 3 is adjusted by rotating the knob 14 to adjust the depth of the middle hole between the screw rod 13 and the base 15;

There are more than 2 screw holes on the square plate of the upper adjustment platform 2, which are used to fasten and connect with the bottom plate of the electric mobile unit 1 through bolts;

The motor of the electric mobile unit 1 drives the lead screw to rotate, and the rotation of the lead screw drives the upper table of the electric mobile unit 1 to perform reciprocating linear motion;

The imaging unit is composed of a left CCD camera 7, a laser 8, a right CCD camera 9 and a supporting plate 10; the left CCD camera 7, the laser 8 and the right CCD camera 9 are fixed on the supporting plate 10;

The connection method between the electric moving unit and the imaging unit is as follows: two U-shaped slots have the same shape and size and are respectively placed in rectangular holes symmetrical on both sides of the center line of the upper adjustment platform and the lower adjustment platform. The two ends of the groove are respectively fastened to the upper table of the electric mobile unit) and the supporting plate of the imaging unit, and the two ends of another U-shaped groove placed opposite are also fastened to the supporting plate of the electric mobile unit and the imaging unit, respectively. The imaging unit completes linear motion driven by the electric moving unit, and the laser 8 in the imaging unit emits a laser beam in a vertical direction to the surface to be measured, forming a laser light belt on the surface; the left CCD camera 7 and the right CCD camera 9 are synchronized at the same time Collect images of laser light bands and scan and image the surface to be measured;

The left CCD camera 7 and the right CCD camera 9 are black-and-white CCDs, both of which are PointGrey digital cameras with the model number FFMV-03M2M. The maximum pixel size is 752×480, and the frame rate is 60FPS. Interface for image acquisition and transmission;

Laser 8 adopts semiconductor line structure light source produced by Changchun Bosheng Quantum Co., Ltd., with a wavelength of 650nm and an adjustable power of 5-20mw;

Running software is stored in the computer 12, and the software flow is as follows;

Execute step 100 to start; the surface roughness tester is initialized, the tester is self-inspected, and the default value of the system parameter is read in;

Execute step 105, the electric translation stage unit moves linearly; the computer issues a command, the motor of the electric translation stage unit starts to rotate, and drives the electric translation stage unit to make a straight line at a constant speed according to the specified zero position and limit position, the specified speed and the specified range sports;

Execute step 110, data acquisition; computer sends out order, and the laser (8) in the imaging unit that is connected with electric translation stage unit emits the laser beam of vertical direction to the ground surface to be measured, forms a laser light belt on ground surface; Left CCD camera ( 7) Simultaneously and synchronously collecting images of the laser light band with the right CCD camera (9), scanning and imaging the ground surface to be measured;

Execute step 115, image processing; obtain the image pixel coordinates of the center position of the laser light band through the noise point deletion algorithm and the light band extraction algorithm on the obtained image;

Execute step 120, coordinate transformation; convert the pixel coordinates of the image into the x, y, z three-dimensional coordinates of the space through the characteristic parameters of the instrument;

Execute step 125, calculate the surface roughness data; bring the obtained x, y, z coordinate values into the roughness parameter calculation formula, and calculate the surface roughness parameters within the measured range;

Execution of step 130, data display or printing; the information of the roughness of the ground surface within the measured range can be displayed on the display or the test results can be printed by the printer as required;

Execute step 135, end;

The formula for calculating the roughness is as follows: the roughness of a random surface is characterized by a statistical parameter with wavelength as the unit of measure, and two basic parameters that characterize the surface roughness: one is the standard deviation of the surface height variable; the other is surface correlation length;

The standard deviation of the surface height variable: (1) Assume that there is a surface in the xy plane, and the height of a point (x, y) above the xy plane is z(x, y); (2) take statistics on the surface A representative piece in the sense of dimensions L _x and L _y , and assuming that the center of the surface is at the origin, the average height of the surface is

$\stackrel{\‾}{z}=\frac{1}{L_x{L}_{\mathrm{the\; y}}}{\∫}_{-\mathrm{Lx}/2}^{\mathrm{Lx}/2}{\∫}_{-\mathrm{Ly}/2}^{\mathrm{Ly}/2}z(x,\mathrm{the\; y})\mathrm{dxdy}$ Formula 1

Its second moment is

$\stackrel{\‾}{z^2}=\frac{1}{L_x{L}_{\mathrm{the\; y}}}{\∫}_{-\mathrm{Lx}/2}^{\mathrm{Lx}/2}{\∫}_{-\mathrm{Ly}/2}^{\mathrm{Ly}/2}{z}^2(x,\mathrm{the\; y})\mathrm{dxdy}$ Formula 2

The standard deviation of the surface height is then σ

$\mathrm{\σ}={(\stackrel{\‾}{z^2}-{\stackrel{\‾}{z}}^2)}^{1/2}$ Formula 3

Surface correlation length:

The normalized autocorrelation function of one-dimensional surface section value z(x) can be defined as:

$\mathrm{\ρ}\left(x^{\′}\right)=\frac{{\∫}_{-\mathrm{Lx}/2}^{\mathrm{Lx}/2}z\left(x\right)z(x+x^{\′})\mathrm{dx}}{{\∫}_{-\mathrm{Ly}/2}^{\mathrm{Ly}/2}{z}^2\left(x\right)\mathrm{dx}}$ Formula 4

It is a measure of the similarity between the height z(x) of point x and the height z(x+x') of another point x' away from x, for discrete data, the distance x'=(j-1)Δx The normalized autocorrelation function of is given by the following formula, where j is an integer ≥ 1,

$\mathrm{\ρ}\left(x^{\′}\right)=\frac{\underset{i=1}{\overset{N+1-j}{\mathrm{\Σ}}}{z}_i{z}_{j+i-1}}{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{z}_i^2}$ Formula 5

The interval x' value when the correlation coefficient ρ(x') is equal to 1/e is defined as the surface correlation length l,

ρ(l)=1/e

The surface correlation length value l provides a benchmark for estimating the independence of two points on the surface, that is, if the two points are separated by a distance greater than l in the horizontal distance, then the height values of the two points are approximately independent in a statistical sense ;

In the limit, ie when it is a perfectly smooth (mirror) surface, every point on a perfectly smooth (mirror) surface is correlated with every other point by a correlation coefficient l, so l = ∞ in this special case.

The automatic measurement of the surface roughness can be completed respectively according to the following steps with the surface roughness tester of the present invention.

First stand the bottom of the pillar 5 on the surface of the soil to be measured, insert the tip into the soil, adjust the coarse adjustment base 6 that touches the ground, and keep the lower adjustment platform 4 roughly level.

Adjust the three fine-tuning bases 3 between the lower adjustment platform 4 and the upper adjustment platform 2 until the air bubbles in several directions are located in the center of the water column, so that the upper adjustment platform 2 is in a horizontal state;

Through the software stored in the computer 12, the surface roughness tester works according to the program flow, and automatically collects and processes the test data of the surface roughness parameters.

Claims (1)

1. The surface roughness tester comprises the following components: the device comprises an electric moving unit (1), an adjusting bracket platform unit, an imaging unit and a computer (12); the device is characterized in that a computer (12) is connected with the electric moving unit (1) and the imaging unit, and running software of a surface roughness tester is stored in the computer (12); the imaging unit consists of a CCD camera and a laser;

the adjusting bracket platform unit comprises an upper adjusting platform (2), a fine adjusting base (3), a lower adjusting platform (4), a support column (5) and a coarse adjusting base (6); wherein,

the bottom end of the strut (5) is a pointed end, and the bottom of the strut (5) is provided with an external thread matched with the internal thread of the coarse adjusting base (6); the number of the pillars (5) is 4, and the pillars are respectively and fixedly connected with 4 angles of the lower adjusting platform (4);

the coarse adjustment base (6) is a square metal plate, the center of the coarse adjustment base is provided with a round hole, and the wall of the round hole is provided with internal threads; the number of the coarse tuning bases (6) is 4, and the coarse tuning bases are respectively matched with the supporting columns (5) one by one; the coarse adjustment base (6) is connected with the support column (5) through threads, the coarse adjustment base (6) is in contact with the ground, and the height of the coarse adjustment base (6) inserted into soft soil from the bottom of the support column (5) is adjusted;

the upper adjusting platform (2) and the lower leveling platform (4) are square plates with the same shape and size, and two rectangular holes which are symmetrical with a central line are respectively arranged on two sides of the central line of the upper adjusting platform (2) and the two sides of the central line of the lower leveling platform (4) correspondingly; the middle of each of the four sides of the upper adjusting platform (2) is provided with a bubble for calibrating the levelness of the upper adjusting platform (2);

three fine adjustment bases (3) which are arranged in a triangular shape are fixedly connected to the square plate of the lower adjustment platform (4) and are connected with the upper adjustment platform (2);

the fine adjustment base (3) consists of a round screw rod (13), a knob (14) and a base (15); wherein the screw rod (13) is fixedly connected with the knob (14); the middle of the base (15) is a circular hole, the inner wall of the hole is provided with internal threads, the screw rod (13) is provided with external threads, the screw rod (13) is connected with the base (15) through the threads, and the depth of the middle hole of the screw rod (13) and the base (15) is adjusted through rotating the knob (14) to adjust the height of the fine adjustment base (3);

the square plate of the upper adjusting platform (2) is provided with more than 2 screw holes for being fastened and connected with the bottom plate of the electric mobile unit (1) through bolts;

the motor of the electric moving unit (1) drives the screw rod to rotate, and the screw rod rotates to drive the upper table surface of the electric moving unit (1) to do reciprocating linear motion;

the imaging unit consists of a left CCD camera (7), a laser (8), a right CCD camera (9) and a supporting plate (10); the left CCD camera (7), the laser (8) and the right CCD camera (9) are all fixedly connected on the supporting plate (10);

the electric moving unit (1) and the imaging unit are connected in the following way: the shape and the size of 2U type grooves (11) are the same and are respectively and correspondingly placed in the symmetrical rectangular holes of the two sides of the central line of the upper adjusting platform (2) and the lower adjusting leveling platform (4), the two ends of one U type groove (11) are respectively and fixedly connected with the upper table board of the electric moving unit (1) and the supporting plate (10) of the imaging unit, the two ends of the other U type groove which is oppositely placed are also respectively and fixedly connected with the electric moving unit (1) and the supporting plate (10) of the imaging unit, the imaging unit completes linear scanning movement under the driving of the electric moving unit (1), and the left CCD camera (7), the laser (8) and the right CCD camera (9) are matched to complete scanning imaging on the ground.