RU2584370C2 - Video measurement device to monitor irregularities of internal vertical cylindrical surface - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: invention relates to the field of measurement equipment and may serve for contactless automated control of irregularities of an inner vertical cylindrical surface, for instance, a missile pit. The video measurement device to monitor irregularities of an inner vertical cylindrical surface comprises a TV camera and a screen, fixed above the monitored surface, and a body moved inside this surface with sight marks, which are within the TV camera field of vision. At the same time in the device body there is a vertical hollow axis and a step motor and an angle sensor connected to it. Inside the hollow axis there is a laser range scope, on the hollow axis there is a rotated mirror fixed, and parallel to it, when it is in the initial angular position, there is a fixed mirror. Besides, when the rotated mirror is in the initial position, the beam of the laser range scope deviates in the horizontal direction to the fixed mirror, which deviates it in the vertical direction to the screen, and under other positions of the rotary mirror the beam of the laser range scope is directed in the horizontal plane to the monitored surface.

EFFECT: increased accuracy of measurements.

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Description

The invention relates to the field of measurement technology and can be used for contactless automated control of irregularities of the internal vertical cylindrical surface, for example, a missile shaft.

A device for monitoring the inner surface of the pipe (RVP-457), containing an annular illuminator and a visual observation system [1].

A device for controlling the inner surface of bodies, containing an annular illuminator with a focus and a visual observation system with an industrial television installation [2].

A device is known that comprises an annular light source, a reflector and a photodetector based on a multi-element two-dimensional matrix, the output signal of which is processed in a recording device [3], installed on both sides and inside a controlled surface;

A device for controlling the roughness of the inner vertical cylindrical surface, containing a camera with a CCD matrix, an annular light source and a number of other nodes [4].

The disadvantage of the first two devices is the visual removal of information, which leads to operator errors.

The disadvantage of the third device is the location of nodes from two ends of the controlled surface, which is not acceptable, for example, for measurements in a rocket mine.

The disadvantage of the fourth device is a very complex structure containing many nodes.

Closest to the claimed invention by the totality of features (prototype) is a video device for controlling the irregularities of the inner vertical cylindrical surface [5], containing a fixed television camera, mounted in the upper part of the controlled surface, and the body, moved inside this surface, the sight marks are fixed on the body, located in the field of view of a fixed television camera, in the housing behind the upper and lower annular windows, a second television camera and an annular light source are respectively installed, and in the field of view of the second camera is a controlled surface illuminated by the narrow light of an annular light source.

The main disadvantage of the prototype is the dependence of the measurement accuracy on the height position of the body inside the surface to be monitored and on the optical distortions of the camera lens mounted in the body.

The aim of the present invention is to improve the accuracy of measurements by eliminating the disadvantages inherent in the prototype.

The complexity of the problem lies in the fact that when moving the case inside the controlled surface, it can be shifted and rotated relative to the initial position and this must be taken into account in order to avoid the corresponding measurement errors.

The proposed video measuring device for controlling the irregularities of the inner vertical cylindrical surface, containing a camera and a screen, fixedly mounted above the surface to be controlled, and a body moved inside this surface with mounted sighting marks that are in the field of view of the camera, in contrast to the prototype and in accordance with the invention a vertical hollow axis and a stepper motor and an angle sensor associated with it are installed in the housing, a laser range finder is installed inside the hollow axis, the rotary mirror is fixed to the hollow axis and in parallel with it, when it is in the initial position, a fixed mirror is installed, while when the rotated mirror is in the initial position, the laser rangefinder beam is deflected in the horizontal direction to the fixed mirror, which deflects it in the vertical direction to the screen , and at other positions of the rotating mirror, the beam of the laser rangefinder is directed in the horizontal plane to the controlled surface.

This goal in the claimed video measuring device is achieved by the fact that the measurement of the height of the housing inside the controlled surface and the measurement of the radii of the points of this surface are carried out using a laser rangefinder, characterized by constant accuracy.

Figure 1 shows a diagram of the proposed video measuring device containing a camera 1 and a screen 2, mounted above a controlled surface 6, and the housing 5, moved inside this surface. Target marks 3 and 4 are installed on the housing 5, a hollow axis 11 with a rotating mirror 7 mounted on it, a fixed mirror 8, a laser range finder 12 inside the hollow axis 11, a stepper motor 9 and an angle sensor 10 connected to the hollow axis 11 are installed inside the housing. The circuit also contains a computer, not shown in figure 1, which receives the output signals of the camera 1, the angle sensor 10 and the laser range finder 12 and from which the control signals of the stepper motor 9 and the laser range finder 12 are transmitted.

Figure 2 shows the images 13 and 14 of the target marks 4 and 6 in the video frame of the camera 2, located at an angle φ to the coordinate axis X of the video frame.

The operation of the video measuring device is as follows.

The housing 5 is installed in the upper fixed position inside the controlled surface 6, in which:

- based on computer processing of images 13 and 14 of the target marks 3 and 4 in the video frame of camera 1, the upper angle φ _{B of} these images is calculated;

- using a laser range finder 12, a rotatable mirror 7 in the initial position, and a stationary mirror 8, the beam of the laser range finder 12 is directed to the screen 2 and the upper height h _{B of the} housing 5 is measured;

- based on computer processing of images 13 and 14 of the target marks 3 and 4 in the video frame of camera 1, the coordinates X _B , Y _{B of the} common center of these images are calculated.

The housing 5 is installed in the lower fixed position inside the controlled surface 6, in which:

- based on computer processing of images 13 and 14 of the target marks 3 and 4 in the video frame of camera 1, the lower angle φ _{H of} these images and the angle difference α _H = φ _H -φ _{B are} calculated;

- using a laser range finder 12, a rotatable mirror 7 in the initial position, and a stationary mirror 8, the beam of the laser range finder 12 is directed to the screen 2 and the lower height h _{H of the} housing 5 is measured;

- based on computer processing of images 13 and 14 of the target marks 3 and 4 in the video frame of the camera 1 and taking into account the difference in angles α _{H, the} coordinates X _H , Y _{H of the} common center of these images are calculated.

The housing 5 is installed in a predetermined section of the controlled surface 6, in which:

- based on computer processing of images 13 and 14 of the target marks 3 and 4 in the video frame of camera 1, the current (at the time of measurement) angle φ of these images and the current angle difference α = φ-φ _{B are} calculated;

- using a laser range finder 12, a rotating mirror 7, which is in the initial position, and a stationary mirror 8, the beam of the laser range finder 12 is directed to the screen 2 and the current height h of the housing 5 is measured;

- based on computer processing of images 13 and 14 of the target marks 3 and 4 in the video frame of the camera 1 and taking into account the current difference in angles α, the current coordinates X, Y of the common center of these images are calculated;

- by solving the equation of the line connecting the top with the coordinates h _B , X _B , Y _B and the bottom with the coordinates h _H , X _H , Y _H points, the current coordinates X ₀ , Y _{0 of the} point of this line in the video frame of camera 1 are calculated;

- taking into account the current difference of the angles α and the current coordinates X, Y, the current displacements ΔX = X-X ₀ and ΔY = YY _{0 of the} body 5 are calculated in the directions of the coordinate axes of the video frame of the camera 1;

- using a stepper motor 9 and an angle sensor 10, the rotatable mirror 7 is rotated at a fixed angle at which the laser rangefinder beam is directed to a controlled surface 6, then it is rotated with a given angular step and current distances S ₁ ... S _n are measured at each of n steps points of the controlled surface 6;

- taking into account the current distances S ₁ ... S _n , the current displacements ΔX, ΔY and the current angle of rotation β of the rotated mirror 7, the desired radii of the points of the surface 6 are calculated:

, $$R=\Delta Y\sin \beta +\Delta X\cos \beta \pm \sqrt{{\left(\Delta Y\sin \beta +\Delta X\cos \beta \right)}^2-\Delta X^2-\Delta Y^2+{\left(S_n-S_0\right)}^2}$$

,

where S ₀ - constant ("zero place"), determined on the basis of calibration measurements.

The sign in front of the root is determined depending on the magnitude of the current angle β of rotation of the rotating mirror 7 and the signs of the current displacements ΔX and ΔY.

Similarly, the radii of points in other sections of the surface 6 are determined.

Measurements are performed under the control of a computer program in automatic mode. The measurement results in the form of a digital image of the controlled surface are recorded in the computer memory.

Roughnesses of the controlled surface are determined based on the processing of a digital data array recorded in the computer's memory.

Information sources

1. Device viewing RVP-457, technical description and instruction manual.

2. Patent SU No. 1793210 dated 06/03/1991. Device for monitoring the inner surface of the bodies.

3. Patent RU No. 2245516 dated 04/15/2003. Device for controlling holes in parts.

4. US patent No. 4899277 And from 06.02.1996. Bore hole scanner with position detecting device and light polarizers.

5. Patent RU No. 2425327 of 07/27/2011. Video device for controlling the roughness of the inner vertical cylindrical surface.

Claims (1)

A video measuring device for controlling the irregularities of the inner vertical cylindrical surface, comprising a television camera and a screen fixedly mounted above the surface to be monitored, and a housing moving inside this surface with sighting marks mounted on it, which are in the camera’s field of vision, characterized in that a vertical hollow axis is installed in the housing and associated with it a stepper motor and an angle sensor, a laser range finder is installed inside the hollow axis, a rotatable mirror and a parallel are mounted on the hollow axis Along with it, when it is in the initial angular position, a fixed mirror is installed, while when the rotating mirror is in the initial position, the laser rangefinder beam is deflected in the horizontal direction to the fixed mirror, which deflects it in the vertical direction to the screen, and for other positions of a rotating mirror, the beam of the laser rangefinder is directed in a horizontal plane to a controlled surface.

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