KR102392900B1 - 3D measurement method of mechanical vibration using camera and distance sensor - Google Patents

Abstract

The present invention relates to a three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor, and more specifically, measuring the X and Y axis vibration of a mechanical device using a camera, A method for three-dimensionally measuring the vibration of a mechanical device in operation by measuring the Z-axis vibration of the device.
A three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor, which is a first embodiment according to the present invention,
To measure the X and Y-axis displacement of the mechanical device
(a-1) acquiring an image of a mechanical device to be measured through a camera;
(a-2) extracting a plurality of feature positions for specifying the mechanical device by performing a corner detection method on the mechanical device in the image;
(a-3) measuring a disparity of the feature positions;
(a-4) dividing the variation of the feature positions into X-axis and Y-axis variation;
(a-5) obtaining an average X-axis disparity and a Y-axis disparity of the feature positions;
(a-6) performing the step of displaying the average value of the X-axis variation and the Y-axis variation average value in real time,
To measure the Z-axis displacement of the mechanical device
(b-1) the process of analyzing the background frequency of the mechanical device by receiving the first reflected signal reflected after transmitting the radio signal from the distance measuring sensor to the predetermined position of the mechanical device in the non-operation state at least once obtaining the background frequency characteristic by carrying out;
(b-2) After the step (b-1), in a state in which the mechanical device is maintained in an operating state, the distance measuring sensor transmits the radio signal to the predetermined position of the mechanical device and then reflects the second analyzing a foreground frequency characteristic of the mechanical device by receiving a reflected signal;
(b-3) measuring a Z-axis shift of the mechanical device by calculating a difference frequency characteristic that is a difference between the background frequency characteristic and the foreground frequency characteristic;
(b-4) displaying the Z-axis shift in real time; characterized in that it is performed.
When the "three-dimensional measurement method of mechanical device vibration using a camera and a distance measuring sensor" proposed in the present invention is used, there is an advantage that the degree of wear or deformation of a vibrating mechanical device can be grasped in real time.

Description

3D measurement method of mechanical vibration using camera and distance sensor

The present invention relates to a three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor, and more specifically, measuring the X and Y axis vibration of a mechanical device using a camera, A method for three-dimensionally measuring the vibration of a mechanical device in operation by measuring the Z-axis vibration of the device.

Vibration occurs in mechanical devices due to rotation, etc., and this vibration causes continuous deformation of mechanical devices or causes malfunctions.

Rotating mechanical devices also suffer from wear, which causes vibrations.

In this case, the wear state of the mechanical device may be analyzed by measuring the vibration of a specific position of the mechanical device.

Conventionally, since a vibration sensor is attached to a mechanical device to measure vibration in order to measure vibration, a separate power supply for the vibration sensor is required, and there is a problem in that a separate power line and a signal line must be connected.

In addition, the vibration sensor has a problem in that the sensor malfunctions due to the vibration of the mechanical device.

1. Patent application number: 10-2014-0078067, title of invention: "Method for measuring vibration displacement using camera image"

The present invention relates to a method for measuring three-dimensional vibration of a mechanical device using a camera and a distance measuring sensor.

In the present invention, vertical and horizontal vibrations (X-axis, Y-axis vibration) are measured using a camera, and vibration (Z-axis vibration) of a mechanical device is measured using a distance measuring sensor.

A three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor, which is a first embodiment according to the present invention,
To measure the X and Y-axis displacement of the mechanical device
(a-1) acquiring an image of the entire mechanical device to be measured through the one camera;
(a-2) extracting a plurality of feature positions for specifying the mechanical device by performing a corner detection method on the mechanical device in the image;
(a-3) measuring a disparity of the feature positions;
(a-4) dividing the variation of the feature positions into X-axis and Y-axis variation;
(a-5) obtaining an average X-axis disparity and a Y-axis disparity of the feature positions;
(a-6) performing the step of displaying the average value of the X-axis variation and the Y-axis variation average value in real time,
To measure the Z-axis displacement of the mechanical device
(b-1) the process of analyzing the background frequency of the mechanical device by receiving the first reflected signal reflected after transmitting the radio signal from the distance measuring sensor to the predetermined position of the mechanical device in the non-operation state at least once obtaining the background frequency characteristic by carrying out;
(b-2) After the step (b-1), in a state in which the mechanical device is maintained in an operating state, the distance measuring sensor transmits the radio signal to the predetermined position of the mechanical device and then reflects the second analyzing a foreground frequency characteristic of the mechanical device by receiving a reflected signal;
(b-3) measuring a Z-axis shift of the mechanical device by calculating a difference frequency characteristic that is a difference between the background frequency characteristic and the foreground frequency characteristic;
(b-4) displaying the Z-axis shift in real time; characterized in that it is performed.
The second embodiment of the present invention, a three-dimensional measuring method of mechanical device vibration using a single camera and a distance measuring sensor,
To measure the X and Y-axis displacement of the mechanical device
(a-1) acquiring an image of the entire mechanical device to be measured through the one camera;
(a-2) extracting a plurality of feature positions for specifying the mechanical device by performing a corner detection method on the mechanical device in the image;
(a-3) measuring a disparity of the feature positions;
(a-4) dividing the mechanical device into a plurality of regions;
(a-5) dividing the variation of feature positions within each of the plurality of regions into X-axis and Y-axis displacement;
(a-6) obtaining an average X-axis disparity and a Y-axis disparity of the feature positions included in each region;
(a-7) summing the average X-axis variance and the Y-axis variance of each region to obtain the final X-axis variance average and the final Y-axis variance mean value, respectively
(a-8) performing the step of displaying the final X-axis variance average value and the final Y-axis variance average value in real time,
To measure the Z-axis displacement of the mechanical device
(b-1) the process of analyzing the background frequency of the mechanical device by receiving the first reflected signal reflected after transmitting the radio signal from the distance measuring sensor to the predetermined position of the mechanical device in the non-operation state at least once obtaining the background frequency characteristic by carrying out;
(b-2) After the step (b-1), in a state in which the mechanical device is maintained in the operating state, the distance measuring sensor transmits the radio signal to the predetermined position of the mechanical device and then reflects the second analyzing a foreground frequency characteristic of the mechanical device by receiving a reflected signal;
(b-3) measuring a Z-axis shift of the mechanical device by calculating a difference frequency characteristic that is a difference between the background frequency characteristic and the foreground frequency characteristic;
(b-4) displaying the Z-axis shift in real time; characterized in that

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In the case of using the "three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor" proposed in the present invention, there is an advantage that the degree of wear or deformation of a vibrating mechanical device can be grasped in real time.

1 is a functional block diagram illustrating "a three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor" proposed in the present invention.
2 is a functional block diagram illustrating a method of measuring X and Y-axis vibration by analyzing an image of a camera.
3 is a functional block diagram illustrating a method of measuring the Z-axis vibration of a mechanical device by using the distance measuring sensor proposed in the present invention.
4 is a diagram showing the broadband characteristics of UWB.

Hereinafter, "a three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor" proposed by the present invention will be described with reference to the drawings.

1 is a functional block diagram illustrating "a three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor" proposed in the present invention.

As shown, in order to implement the three-dimensional measuring method of vibration of a mechanical device according to the present invention, a camera such as a CCTV camera, a distance measuring sensor, a three-dimensional disparity measuring device, and a state analysis and alarm device are provided. .

In the present invention, the camera provides an image for measuring X-axis and Y-axis displacement of a vibrating mechanical device, and a distance measuring sensor at a predetermined distance from the mechanical device uses a radio signal (eg, Ultra wide band signal) can be transmitted and received

Next, the 3D disparity measuring device of the present invention shown in FIG. 1 analyzes the image captured by the camera and the wireless signal received through the distance measurement sensor to calculate the X, Y, and Z-axis displacement of the vibrating mechanical device. .

Lastly, the state analysis and alarm device of the present invention is a machine that vibrates by applying frequency characteristic analysis, machine learning (SVM, deep learning, etc.) It is possible to estimate the mechanical wear state of the device, and to propagate a step-by-step alarm or status information based on this.

Hereinafter, among the "three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor" proposed in the present invention, (1) a method of measuring the X and Y-axis vibration of a mechanical device using a camera and (2) distance A method of measuring the Z-axis vibration of a mechanical device using a measuring sensor will be described.

(1) How to measure the X, Y axis vibration of a mechanical device using a camera

2 is a functional block diagram illustrating a method of measuring X and Y-axis vibration by analyzing an image of a camera.

First, a feature position of the mechanical device is extracted by performing corner detection from an image of the mechanical device captured by the camera. A specific position extracted by corner detection is specified as a point

Next, the motion vector (motion vector) of the feature position included in the image of the vibrating mechanical device is extracted. In the figure, each part indicated in blue represents the maximum value of the motion vector corresponding to the feature position, respectively. For reference, a method of extracting a motion vector may apply various motion vector extraction algorithms known in the art. In the present invention, Farneback's Algorithm was used.

In order to calculate the X, Y axis displacement of the motion vector, the motion vector within a predetermined block area that is set arbitrarily for the mechanical device is extracted, and then the motion vector is separated into the X and Y axes within each block area. X, Y axis displacement was calculated (for reference, in the present invention, after extracting a motion vector within a predetermined block area arbitrarily set with respect to the mechanical device for calculating the X, Y axis displacement of the motion vector, the above-described process is performed Alternatively, after motion vector extraction, a predetermined block area may be selected and then the average value of the X and Y axis displacements may be calculated.)

And, in the present invention, in order to reduce the measurement error, the average value of the X and Y-axis displacement within each block area is calculated, and then they are summed to calculate the average value of the X and Y-axis displacement for the entire vibrating mechanical device.

Through this process, in the present invention, the X-axis and Y-axis displacement for each region of the vibrating mechanical device can be calculated in real time, and the average value of the X-axis and Y-axis displacement of the entire mechanical device can be calculated in real time.

On the other hand, for calculating the X, Y axis displacement of the motion vector, the entire motion vector for the mechanical device is extracted without setting a predetermined block area arbitrarily set for the mechanical device, and then each motion vector is separated into the X and Y axes, respectively. After calculating the overall average of the X and Y-axis displacement after

That is, in the practice of the present invention, the final X and Y axis variance can be calculated in real time by summing the average values of the X and Y axis variances for the block area, and the average of the X and Y axis variances can be calculated without specifying the block area. will be able

The displacement graph of FIG. 2 shows the displacement on the X-axis and the displacement on the Y-axis, and the horizontal axis is the time axis and the unit is [ms].

As can be seen from the drawing, the X and Y axis transitions of the vibrating mechanical device can be viewed in real time. For reference, as can be seen in FIG. 2 , the entire mechanical device, which is an object to be extracted with a motion vector, is photographed through one camera.

(2) How to measure the Z-axis vibration of a mechanical device using a distance measuring sensor

3 is a functional block diagram illustrating a method of measuring the Z-axis vibration of a mechanical device by using the distance measuring sensor proposed in the present invention.

를 측정한다.First, in order to analyze the frequency characteristics of the surrounding environment of the mechanical device, in a state where the mechanical device is not operated, a wireless signal is transmitted using a distance measuring sensor and a reflected signal is received to receive the reflected signal, that is, the frequency characteristic of the surrounding environment of the mechanical device, that is, the background frequency characteristic.

measure

For reference, in order to analyze the background frequency characteristic, the background frequency characteristic may be estimated through averaging by performing the transmission of the radio signal and the reception of the reflected signal several times. Also, this process can take several minutes.

Next, after analyzing the background frequency characteristics, the operation of the machinery is started.

을 한다.When driving machinery, using the distance measuring sensor in the same way as the background frequency characteristic analysis, transmits a wireless signal, measures the signal reflected from the machinery, and analyzes the foreground frequency.

do

과 전경 주파수 특성

의 차이로부터 차 주파수 특성

를 계산한다.Next, the background frequency characteristics

and foreground frequency characteristics

The difference frequency characteristic from the difference of

to calculate

In the case of a vibrating mechanical device, a difference occurs in the transmission/reception time of the signal transmitted from the distance measuring sensor, which causes a change in the frequency characteristic of the received signal.

Therefore, the distance can be calculated from the propagation speed and difference frequency characteristics, and the Z-axis vibration can be measured by changing the distance.

(3) Distance measurement process for measuring Z-axis displacement

Examples of the radio signal and reflected signal transmitted from the distance measuring sensor to analyze the background frequency characteristics, or the radio signal and the reflected signal transmitted to measure the distance between the distance measuring sensor and the mechanical device, that is, the variation in the Z-axis direction is shown in FIG. 4 , and FIG. 5 is a flowchart for measuring Z-axis displacement and an exemplary diagram of displacement results.

As can be seen from FIG. 4 , it can be seen that there is a difference in the pattern of the radio signal transmitted to a predetermined position of the mechanical device and the signal reflected therefrom.

Even if the transmitted radio signal is the same, the background frequency characteristic reflected by the mechanical device in a stationary state and the foreground frequency characteristic reflected by the mechanical device in the operating state are different. Also, the reflected foreground frequency characteristics vary according to the vibration characteristics of the mechanical device.

With respect to the received signal, the embodiment measures the distance in the same manner as in FIG. 5 . In the embodiment, the received signal is sampled at 23.328 GHz.

Considering the amount of calculation of the transmitted and received signal, 1,536 samples per frame are sampled (sampling), and a frequency bin is obtained through frequency conversion.

이 된다.Based on the sampling frequency of the embodiment, the pulse repetition interval is

becomes this

으로 계산된다. 즉 주파수 영역에서 1,535 빈은 센서로부터 특정 물체까지의 거리가 약 9.9 m 가 되는 것을 의미한다.Street,

is calculated as That is, 1,535 bins in the frequency domain means that the distance from the sensor to a specific object is about 9.9 m.

In the implementation example, considering the amount of computation, frequency bins are converted to 1/8 and converted to 192 bins, and frequency characteristics are analyzed for 180 bins and the distance is measured.

As described above, the three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor proposed in the present invention measures the X, Y-axis displacement of a vibrating mechanical device spaced apart at a predetermined distance by using a camera. And, by using a distance measuring sensor, the Z-axis displacement of a vibrating mechanical device can be calculated in real time.

The technical idea of the present invention described so far is summarized as follows.

A three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor, which is a first embodiment according to the present invention,

To measure the X and Y-axis displacement of the mechanical device

(a-1) acquiring an image of a mechanical device to be measured through a camera;

(a-2) extracting a plurality of feature positions for specifying the mechanical device by performing a corner detection method on the mechanical device in the image;

(a-3) measuring a disparity of the feature positions;

(a-4) dividing the variation of the feature positions into X-axis and Y-axis variation;

(a-5) obtaining an average X-axis disparity and a Y-axis disparity of the feature positions;

(a-6) performing the step of displaying the X-axis variance average value and the Y-axis variance average value in real time,

To measure the Z-axis displacement of the mechanical device

(b-1) the process of analyzing the background frequency of the mechanical device by receiving the first reflected signal reflected after transmitting the radio signal from the distance measuring sensor to the predetermined position of the mechanical device in the non-operation state at least once obtaining the background frequency characteristic by carrying out;

(b-2) After the step (b-1), in a state in which the mechanical device is maintained in an operating state, the distance measuring sensor transmits the radio signal to the predetermined position of the mechanical device and then reflects the second analyzing a foreground frequency characteristic of the mechanical device by receiving a reflected signal;

(b-3) measuring a Z-axis shift of the mechanical device by calculating a difference frequency characteristic that is a difference between the background frequency characteristic and the foreground frequency characteristic;

(b-4) displaying the Z-axis shift in real time; characterized in that

The second embodiment of the present invention is a three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor,

As a three-dimensional measurement method of mechanical device vibration using a camera and a distance measuring sensor,

To measure the X and Y-axis displacement of the mechanical device

(a-1) acquiring an image of a mechanical device to be measured through a camera;

(a-2) extracting a plurality of feature positions for specifying the mechanical device by performing a corner detection method on the mechanical device in the image;

(a-3) measuring a disparity of the feature positions;

(a-4) dividing the mechanical device into a plurality of regions;

(a-5) dividing the variation of feature positions in each of the plurality of regions into X-axis and Y-axis displacement;

(a-6) obtaining an average X-axis disparity and a Y-axis disparity of the feature positions included in each region;

(a-7) summing the average X-axis variance and the Y-axis variance of each region to obtain the final X-axis variance average and the final Y-axis variance mean value, respectively

(a-8) performing the step of displaying the final X-axis variance average value and the final Y-axis variance average value in real time,

To measure the Z-axis displacement of the mechanical device

(b-1) the process of analyzing the background frequency of the mechanical device by receiving the first reflected signal reflected after transmitting the radio signal from the distance measuring sensor to the predetermined position of the mechanical device in the non-operation state at least once obtaining the background frequency characteristic by carrying out;

(b-2) After the step (b-1), in a state in which the mechanical device is maintained in an operating state, the distance measuring sensor transmits the radio signal to the predetermined position of the mechanical device and then reflects the second analyzing a foreground frequency characteristic of the mechanical device by receiving a reflected signal;

(b-3) measuring a Z-axis shift of the mechanical device by calculating a difference frequency characteristic that is a difference between the background frequency characteristic and the foreground frequency characteristic;

(b-4) displaying the Z-axis shift in real time; characterized in that

Therefore, when the vibration characteristics of a mechanical device are analyzed using the method proposed in the present invention, there is an advantage in that the wear characteristics of the mechanical device can be determined in a stable state.

Claims (2)

As a three-dimensional measurement method of mechanical device vibration using one camera and a distance measuring sensor,
To measure the X and Y-axis displacement of the mechanical device
(a-1) acquiring an image of the entire mechanical device to be measured through the one camera;
(a-2) extracting a plurality of feature positions (specified by a plurality of points) for specifying the mechanical device by performing a corner detection method on the mechanical device in the image;
(a-3) measuring a disparity of the feature positions;
(a-4) dividing the variation of the feature positions into X-axis and Y-axis variation;
(a-5) obtaining an average X-axis disparity and a Y-axis disparity of the feature positions;
(a-6) performing the step of displaying the average value of the X-axis variation and the Y-axis variation average value in real time,
To measure the Z-axis displacement of the mechanical device
(b-1) the process of analyzing the background frequency of the mechanical device by receiving the first reflected signal reflected after transmitting the radio signal from the distance measuring sensor to the predetermined position of the mechanical device in the non-operation state at least once obtaining the background frequency characteristic by carrying out;
(b-2) After the step (b-1), in a state in which the mechanical device is maintained in an operating state, the distance measuring sensor transmits the radio signal to the predetermined position of the mechanical device and then reflects the second analyzing a foreground frequency characteristic of the mechanical device by receiving a reflected signal;
(b-3) measuring a Z-axis shift of the mechanical device by calculating a difference frequency characteristic that is a difference between the background frequency characteristic and the foreground frequency characteristic;
(b-4) displaying the Z-axis shift in real time; a three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor, characterized in that performing. As a three-dimensional measurement method of mechanical device vibration using one camera and a distance measuring sensor,
To measure the X and Y-axis displacement of the mechanical device
(a-1) acquiring an image of the entire mechanical device to be measured through the one camera;
(a-2) extracting a plurality of feature positions (specified by a plurality of points) for specifying the mechanical device by performing a corner detection method on the mechanical device in the image;
(a-3) measuring a disparity of the feature positions;
(a-4) dividing the mechanical device into a plurality of regions;
(a-5) dividing the variation of feature positions within each of the plurality of regions into X-axis and Y-axis displacement;
(a-6) obtaining an average X-axis disparity and a Y-axis disparity of the feature positions included in each region;
(a-7) summing the average X-axis variance and the Y-axis variance of each region to obtain the final X-axis variance average and the final Y-axis variance mean value, respectively
(a-8) performing the step of displaying the final X-axis variance average value and the final Y-axis variance average value in real time,
To measure the Z-axis displacement of the mechanical device
(b-1) the process of analyzing the background frequency of the mechanical device by receiving the first reflected signal reflected after transmitting the radio signal from the distance measuring sensor to the predetermined position of the mechanical device in the non-operation state at least once obtaining the background frequency characteristic by carrying out;
(b-2) After the step (b-1), in a state in which the mechanical device is maintained in an operating state, the distance measuring sensor transmits the radio signal to the predetermined position of the mechanical device and then reflects the second analyzing a foreground frequency characteristic of the mechanical device by receiving a reflected signal;
(b-3) measuring a Z-axis shift of the mechanical device by calculating a difference frequency characteristic that is a difference between the background frequency characteristic and the foreground frequency characteristic;
(b-4) displaying the Z-axis shift in real time; a three-dimensional measuring method of mechanical device vibration using a camera and a distance measuring sensor, characterized in that performing.

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