RU2570835C2 - Recording method of tunnel profile cross-section and device for its implementation - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: invention relates to optoelectronic instruments and can be used for measurement of tunnel profile. According to the method, a narrow light beam is shaped by means of an illumination unit, directed to the tunnel surface by means of a mirror inclined to the tunnel axis and belonging to the illumination unit; the tunnel profile cross-section is shaped in the form of sections in-series illuminated due to rotation of the above mirror; their images are recorded by means of a video camera and the optic axis of the video camera is directed into the centre of the annular zone of tunnel radius variation by means of the mirror belonging to the video camera. The video camera with its mirror is rotated about the tunnel axis synchronously with rotation of the mirror of the illumination unit. Then, images of sections are compared to sections of a standard profile and changes in profile cross-section radius are detected. The inclination angle of the optic axis of the video camera to the tunnel axis is determined by the formula:

where R - cross-section radius of the standard tunnel profile; ΔR - width of the annular zone of radius variation of the tunnel profile cross-section; b - distance between the mirror of the illumination unit and the mirror of the video camera along the tunnel axis; φ₁ - inclination angle of the mirror of the illumination unit to the tunnel axis.

EFFECT: reducing measurement error of a profile cross-section radius.

2 cl, 8 dwg

Description

Field of Invention

The invention relates to optoelectronic devices and can be used to measure the profile of tunnels, for example, in the subway.

State of the art

Known laser scanning system Optech LYNX Mobile. Mapper M1. Optech, Canada (analogue), based on a method for registering a section of a tunnel profile. A known method is as follows:

form a narrow light beam using a pulsed backlight unit, the optical axis of which coincides with the axis of the tunnel;

directing the generated light beam to the surface of the tunnel with the aim of highlighting it with a mirror tilted to the axis of the tunnel and belonging to the backlight unit;

forming a section of the profile of the tunnel in the form of successively illuminated sections of the surface of the tunnel due to rotation around the axis of the tunnel of the mirror of the backlight unit;

directing radiation reflected from the surface of the tunnel using the mirror of the backlight unit to the registration unit with a single-element high-speed radiation receiver, the optical axis of which is parallel to the axis of the tunnel;

sequentially register radiation pulses reflected from the surface of the tunnel, and determine the time intervals between sending radiation pulses and registration of the reflected radiation pulse, which determine the distance from the axis of the tunnel to the highlighted sections of the surface;

transmit information about the recorded distances, compare them with the reference distances of the profile and detect changes in the radius of the cross section of the profile.

A known device for registering a section of a profile of a tunnel located on a movable medium contains:

- pulse backlight unit, the optical axis of which is located on the axis of the tunnel;

- a mirror belonging to the backlight unit, inclined to the axis of the tunnel and rotating around it;

- a registration unit with a single-element high-speed radiation receiver, the optical axis of which is parallel to the axis of the backlight unit.

The disadvantage of the analogue is the high error of distance measurement due to the high frequency of the pulses of the backlight unit. For example, when registering 1000 points on a profile with a frequency of 25 Hz, the minimum pulse frequency is 25 kHz, and at distances of 2000 ... 3000 mm, the error in determining the distance from the axis of the tunnel to the highlighted surface area is tens of mm.

The closest in technical essence and the achieved result is a method and device designed to control the oversized placement of equipment in tunnels by registering the section of the tunnel profile (patent RU 2456544, 01.2006, G01C 7/06, G01B 11/24; it is also adopted as a prototype) .

1. The known method of registering a section of the profile of the tunnel contains the following stages of its implementation:

form a narrow light beam using the backlight unit, the optical axis of which coincides with the axis of the tunnel;

directing the generated light beam to the surface of the tunnel with the aim of highlighting it with a mirror tilted to the axis of the tunnel and belonging to the backlight unit;

forming a section of the profile of the tunnel in the form of sequentially illuminated sections of the surface of the tunnel due to the rotation of the specified mirror around the axis of the tunnel;

registering images of successively illuminated portions of the surface of the tunnel using a video camera with a multi-element matrix image pickup (MPI), the optical axis of which coincides with the axis of the tunnel;

transmit information about the recorded images of successively highlighted sections of the formed section of the profile of the tunnel;

comparing registered images of successively highlighted sections of the formed section of the tunnel profile with the sections of the reference profile; and

identify changes in the radius of the cross section of the profile.

2. A known device for registering a sectional profile of a tunnel located on a movable medium contains:

- a backlight unit, the optical axis of which is located on the axis of the tunnel;

- a mirror belonging to the backlight unit, inclined to the axis of the tunnel and rotating around it;

- a video camera with a multi-element matrix radiation detector, the optical axis of which is located on the axis of the tunnel.

The disadvantage of the prototype is the large angular field of the lens of the camcorder, necessary to reduce the distance from the backlight unit to the registration unit. With a large angular field (for existing MPI), the focal length of the lens is small, which leads to an increase in the error in measuring the radius of the cross section of the tunnel profile.

Disclosure of invention

To eliminate this drawback in the method of registering a section of a tunnel profile, containing the following stages of its implementation:

form a narrow light beam using the backlight unit, the optical axis of which coincides with the axis of the tunnel;

directing the generated light beam to the surface of the tunnel with the aim of highlighting it with a mirror tilted to the axis of the tunnel and belonging to the backlight unit;

forming a section of the profile of the tunnel in the form of sequentially illuminated sections of the surface of the tunnel due to the rotation of the specified mirror around the axis of the tunnel;

registering images of successively illuminated portions of the surface of the tunnel using a video camera with a multi-element matrix image receiver, the optical axis of which coincides with the axis of the tunnel;

transmit information about the recorded images of successively highlighted sections of the formed section of the profile of the tunnel;

comparing registered images of successively highlighted sections of the formed section of the tunnel profile with the sections of the reference profile; and

identify changes in the radius of the cross section of the profile.

When registering images of successively highlighted sections of the tunnel surface:

directing the optical axis of the video camera to the center of the annular zone of changing the radius of the tunnel using a mirror tilted to the axis of the tunnel and belonging to the video camera, the normal of this mirror lying in the same plane as the normal of the mirror of the backlight unit;

rotate the video camera together with its mirror around the axis of the tunnel synchronously with the rotation of the mirror of the backlight unit, forming images of successively highlighted portions of the surface of the tunnel on one line of the image sensor matrix; and

transmit information about images of sequentially illuminated sections of the surface of the tunnel via a wireless communication channel;

in addition, the angle of the optical axis of the video camera to the axis of the tunnel is determined by the formula

where R is the radius of the light section of the reference profile of the tunnel;

ΔR is the width of the annular zone of variation of the radius of the cross section of the profile of the tunnel;

b is the distance between the mirror of the backlight unit and the mirror of the camera along the axis of the tunnel;

φ ₁ - the angle of inclination of the mirror of the backlight unit to the axis of the tunnel.

A device for registering a section of a tunnel profile located on a movable medium, comprising:

- a backlight unit, the optical axis of which is located on the axis of the tunnel;

- a mirror belonging to the backlight unit, inclined to the axis of the tunnel at an angle and rotating around it;

- a video camera with a multi-element matrix radiation detector, the optical axis of which is located on the axis of the tunnel;

the device further comprises a mirror inclined to the axis of the tunnel and belonging to the video camera, which directs the optical axis of the video camera to the center of the annular zone of changing the radius of the section of the tunnel profile, the normal of this mirror lying in the same plane as the normal of the mirror of the backlight unit;

wherein said mirror rotates with the video camera around the axis of the tunnel synchronously with the rotation of the mirror of the backlight unit;

in addition, the angle of inclination of the video camera mirror to the axis of the tunnel is determined by the formula

where R is the radius of the cross section of the reference profile of the tunnel;

ΔR is the width of the annular zone of variation of the radius of the cross section of the profile of the tunnel;

b is the distance between the first mirror and the second mirror along the axis of the tunnel;

φ ₁ - the angle of inclination of the first mirror to the axis of the tunnel.

A positive effect is achieved due to the fact that

with the above image registration of sequentially illuminated sections of the surface of the tunnel:

directing the optical axis of the video camera to the center of the annular zone of changing the radius of the tunnel using a mirror tilted to the axis of the tunnel and belonging to the video camera, the normal of this mirror lying in the same plane as the normal of the mirror of the backlight unit;

rotate the video camera together with its mirror around the axis of the tunnel synchronously with the rotation of the mirror of the backlight unit, forming images of successively highlighted portions of the surface of the tunnel on one line of the image sensor matrix; and

transmit information about images of sequentially illuminated sections of the surface of the tunnel via a wireless communication channel;

in addition, the angle of the optical axis of the video camera to the axis of the tunnel is determined by the formula

where R is the radius of the cross section of the reference profile of the tunnel;

ΔR is the width of the annular zone of variation of the radius of the cross section of the profile of the tunnel;

b is the distance between the mirror of the backlight unit and the mirror of the camera along the axis of the tunnel;

φ ₁ - the angle of inclination of the mirror of the backlight unit to the axis of the tunnel.

Brief Description of the Drawings

The invention is illustrated by the following drawings:

Figure 1 - Registration scheme of the cross section of the profile of the tunnel in the prototype.

Figure 2 - Reference and distorted sections of the surface profile of the tunnel.

Figure 3 - Image of a distorted section of the profile of the tunnel registered on the matrix image receiver in the prototype.

Figure 4 - Calculation scheme for determining the error in measuring the radius of the cross section of the profile of the tunnel 8R in the prototype.

Figure 5 - Scheme of the proposed method and device for registering a section of the profile of the tunnel.

.6 is a diagram of the guidance of the optical axis of the video camera in the center of the annular zone of change of the radius of the profile to $$R-\frac{\mathrm{<figure-callout\; id="2"\; label="\Delta \; R"\; filenames="00000033.png,00000034.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}R}{2}$$

.

7 - The process of forming a section of the profile of the tunnel in the proposed method using a single row of the matrix.

Fig - Calculation scheme for determining the error in measuring the radius of the cross section of the profile of the tunnel δR in the proposed method.

Figure 1 shows a diagram of a device for registering a section of a profile of a tunnel of a prototype, containing a laser backlight unit forming a narrow light beam, the optical axis of which coincides with the axis of the tunnel, a mirror of the backlight unit inclined to the axis of the tunnel and directing the beam to the tunnel surface, a video camera with a wide-angle lens and MPI. The optical axis of the camcorder coincides with the axis of the tunnel and the optical axis of the backlight unit. The mirror of the backlight unit rotates around the axis of the tunnel, due to which a section of the tunnel profile is formed in the form of successively highlighted sections of the tunnel surface.

Figure 2 shows the reference profile of the tunnel and the distorted profile, and figure 3 is an image of a distorted section of the profile recorded on the MPI.

Accuracy is determined by the distance to the illuminated surface Z, IIP element size and _E, the distance b between the mirror and the backlight unit lens cameras, laser beam inclination 2φ ₁ and the camera lens focal distance f 'register profile (4) dimensions.

Wide-angle lenses are synthesized on the basis of a wide-angle telescopic system with multiple angular magnification and a narrow-field photographic lens. Therefore, the magnification of the lens β is approximately equal

where Z is the distance from the camera lens to the surface of the tunnel

R is the radius of the cross section of the profile of the tunnel;

2W is the angular field of the camera lens.

равна произведению размера элемента а _Э на увеличение βThe projection of the MPI element on the plane in which the illuminating laser beam lies, $$a_E^{\text{'}\text{'}}$$

equal to the product of the size of the element a _E and the increase in β

The error of measuring the radius of the tunnel (figure 5)

The base of the system is

An example of a specific implementation of the prototype

Camera matrix parameters:

- the number of elements of the matrix M × N = 800 × 600;

- dimensions of the matrix a _M × b _M = 6.4 × 4.8 mm ² ;

- size of the matrix element and _e = 0.008 mm;

- matrix frame rate f _M = 25 Hz;

- matrix frame exposure time t _M = 0.04 s.

и частоте кадров матрицы f_M=25 Гц расстояние между регистрируемыми сечениями профиля равноAt speed $$V=\mathrm{fifty}\frac{\mathrm{to}m}{h\mathrm{but}\mathrm{from}}=\mathrm{fourteen}\frac{m}{\mathrm{from}}$$

and the matrix frame rate f _M = 25 Hz, the distance between the recorded profile sections is

To form a complete profile during the matrix frame time t _M = 0.04c, the angular velocity of rotation of the scanning mirror should be equal

An example of calculating the prototype error is given for a particular case of a perpendicular beam incidence on the tunnel surface, i.e. for 2φ ₁ = 90 °, at which the error in measuring the radius is defined as

For the radius of the tunnel R = 2.5 m and the base b = 300 mm

the angular field of the camera lens 2W = 166 °.

The focal length of a wide-angle lens is determined by the formula

$$f\text{'}\text{'}=\frac{{\mathrm{<figure-callout\; id="2W"\; label="b\; M"\; filenames="00000029.png"\; state="\{\{state\}\}">b\; </figure-callout>}}_M}{2W}$$

and with an angular field of 2W = 166 ° = 2.9 rad, the focal length is

The distance from the lens to the highlighted area is

Prototype measurement error

A large error is obtained due to the small focal length of the camera lens. The reduction in error can be achieved by increasing the base, which leads to an increase in the size of the system.

Figure 5 presents a diagram of a device that implements the proposed method.

The proposed device (figure 5) contains a laser backlight unit, the optical axis of which coincides with the axis of the tunnel, a mirror inclined to the axis of the tunnel and belonging to the backlight unit, a video camera with MPI, the optical axis of which coincides with the optical axis of the backlight unit, the video camera being inclined to the axis of the tunnel with a mirror that directs the optical axis of the specified video camera to the center of the annular zone of change in the radius of the section of the profile of the tunnel. In this case, the normal of this mirror lies in one plane with the normal of the mirror of the backlight unit.

The mirror of the backlight unit directs the beam to the tunnel surface and rotates around the axis of the tunnel, due to which a section of the tunnel profile is formed in the form of successively highlighted sections of the tunnel surface.

A video camera with a mirror rotates around the axis of the tunnel synchronously with the rotation of the mirror of the backlight unit and registers images of successively highlighted sections of the tunnel surface on one line of the MPI.

The angle of the mirror of the video camera to the axis of the tunnel φ ₂ is determined by the formula

where R is the radius of the cross section of the reference profile of the tunnel;

ΔR is the width of the annular zone of variation of the radius of the cross section of the profile of the tunnel;

b is the distance between the first mirror and the second mirror along the axis of the tunnel;

φ ₁ - the angle of inclination of the first mirror to the axis of the tunnel.

In this case, the optical axis of the video camera is tilted to the axis of the tunnel by an angle

Figure 6 shows a diagram of the guidance of the optical axis of the video camera in the center of the annular zone of change of the radius of the profile.

When registering changes in the formed section of the profile of the tunnel in the form of images of successively highlighted sections of the surface of the tunnel, elements of only one line of the specified MPI are used, on which images of successively highlighted sections of the surface of the tunnel are located,

Figure 6 shows 8 positions of one row of the matrix at which 8 points of the profile cross section are recorded.

The position of the light spot on the row of the matrix (Fig.7) characterizes the deviation of the radius of the cross section of the profile from the reference.

The error in measuring the radius of the tunnel (Fig) is determined in the same way as in the prototype

Since in accordance with the proposed method, the camera is rotated, the signal is transmitted from the MPI via a wireless communication channel.

An example of a specific implementation of the proposed method and device for registering a section of a tunnel profile is given for the same conditions as in the prototype.

The width of the annular zone, in the center of which the optical axis of the video camera is induced, ΔR = 1 m with a tunnel radius R = 2.5 m.

The angle of the optical axis of the video camera is equal to φ ₁ = 45 ° and 2φ ₁ = 90 ° and b = 300 mm (Fig. 8)

The angle of the mirror of the camera to the axis of the tunnel

angular field of the camcorder lens

Focal length of the camcorder lens

The measurement error of the proposed method and device

At the same time, to register 1000 points on the profile (through 0.36 degrees or after 16 mm), the line frequency f _STR is required to be 1000 more than the matrix frame rate f _M

which is easily implemented in practice.

Thus, due to the use of a narrow-field lens with an increased focal length, the error in measuring the radius of the cross section of the tunnel profile is reduced by more than 50 times compared with the prototype.

Claims (2)

1. A method for registering a section of a tunnel profile, comprising the following stages of its implementation:
form a narrow light beam using the backlight unit, the optical axis of which coincides with the axis of the tunnel;
directing the generated light beam to the surface of the tunnel with the aim of highlighting it with a mirror tilted to the axis of the tunnel and belonging to the backlight unit;
forming a section of the profile of the tunnel in the form of sequentially illuminated sections of the surface of the tunnel due to the rotation of the specified mirror around the axis of the tunnel;
registering images of successively illuminated portions of the surface of the tunnel using a video camera with a multi-element matrix image receiver, the optical axis of which coincides with the axis of the tunnel;
transmit information about the recorded images of successively highlighted sections of the formed section of the profile of the tunnel;
comparing recorded images of successively highlighted sections of the surface of the tunnel with the reference profile of the tunnel; and
detect changes in the radius of the cross section of the profile,
characterized in that
when registering images of successively highlighted sections of the tunnel surface:
directing the optical axis of the video camera to the center of the annular zone of changing the radius of the tunnel using a mirror tilted to the axis of the tunnel and belonging to the video camera, the normal of this mirror lying in the same plane as the normal of the mirror of the backlight unit;
rotate the video camera together with its mirror around the axis of the tunnel synchronously with the rotation of the mirror of the backlight unit, forming images of successively highlighted portions of the surface of the tunnel on one line of the image sensor matrix,
then transmit information about images of sequentially illuminated sections of the surface of the tunnel via a wireless communication channel;
in addition, the angle of the optical axis of the video camera to the axis of the tunnel is determined by the formula

where R is the radius of the cross section of the reference profile of the tunnel;
ΔR is the width of the annular zone of variation of the radius of the cross section of the profile of the tunnel;
b is the distance between the mirror of the backlight unit and the mirror of the camera along the axis of the tunnel;
φ ₁ - the angle of inclination of the mirror of the backlight unit to the axis of the tunnel. 2. A device for registering a section of a tunnel profile located on a movable medium, comprising:
- a backlight unit, the optical axis of which is located on the axis of the tunnel;
- a mirror belonging to the backlight unit, inclined to the axis of the tunnel and rotating around it;
- a video camera with a multi-element matrix radiation detector, the optical axis of which is located on the axis of the tunnel,
characterized in that
the device further comprises: a mirror belonging to the video camera, inclined to the axis of the tunnel, which directs the optical axis of the video camera to the center of the annular zone of changing the radius of the section of the tunnel profile, the normal of this mirror lying in the same plane as the normal of the mirror of the backlight unit; wherein said mirror rotates with the video camera around the axis of the tunnel synchronously with the rotation of the mirror of the backlight unit,
in addition, the angle of inclination of the video camera mirror to the axis of the tunnel is determined by the formula

where R is the radius of the cross section of the reference profile of the tunnel;
ΔR is the width of the annular zone of variation of the radius of the cross section of the profile of the tunnel;
b is the distance between the first mirror and the second mirror along the axis of the tunnel;
φ ₁ - the angle of inclination of the first mirror to the axis of the tunnel.

Images