KR101438073B1 - Apparatus for analyzing dynamic characteristics using image processing and method thereof - Google Patents

Abstract

The present invention relates to an apparatus for analyzing dynamic characteristics of an object through image processing and a method for analyzing the dynamic characteristic of an object through image processing, And deriving a dynamic characteristic of the object through a displacement of the specific unit in a plurality of frames of the image.

Description

[0001] APPARATUS FOR ANALYZING DYNAMIC CHARACTERISTICS USING IMAGE PROCESSING AND METHOD THEREOF [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for analyzing dynamic characteristics of an object, and more particularly, to an apparatus and method for analyzing dynamic characteristics of an object using a plurality of frames of moving objects.

Generally, there are methods of using a laser and an accelerometer in order to know the dynamic characteristics of an oscillating object.

In the case of an accelerometer, the speed and acceleration of each point are measured and processed by using the transfer function to determine the characteristics and mode. . However, the disadvantage of lasers is that it is expensive to use equipment or difficult to measure several times at a time.

In the case of accelerometers, it is impossible to measure intuitive data or objects that are difficult to attach accelerometers.

In addition, in the case of a laser, it is only possible to measure one point at a time, and an error may occur when the measurement is performed again.

It is an object of the present invention to provide an apparatus and method for analyzing dynamic characteristics of an object through image processing capable of measuring dynamic characteristics of a plurality of objects or a plurality of objects at a time have.

It is another object of the present invention to provide an apparatus and method for analyzing dynamic characteristics of an object through image processing capable of measuring dynamic characteristics without physical contact with the object.

According to another aspect of the present invention, there is provided a method for analyzing dynamic characteristics of an object including an image sensing unit, an image processing unit, and a characteristic analyzing unit.
The image analyzing unit captures an image of the vibrating body, and the image processing unit sets at least one specific unit to be measured in the vibrating body. The characteristic analyzing unit analyzes the dynamic characteristic and the inherent characteristic of the vibrating body through the displacement of the specific unit in a plurality of frames constituting the image. Wherein the image is an image for a vibrating body without a separate attachment, and the image processing unit converts the image into an image of a gray level, It is expressed in black, and unnecessary parts, which are not the parts to be measured, among the parts represented by white are removed by expressing them as black, and the white parts remaining after the unnecessary parts are removed can be set as specific parts.

Here, the image processing unit distinguishes the specific part from the other part in the image through image processing.

The image processing unit converts the image into a gray level image, expresses the converted image in white and black through threshold processing, and selects a portion of the image represented by white The unnecessary portion is removed by expressing it as black, and then the unnecessary portion is removed and the remaining white portion is set as the specific portion.

Wherein the characteristic analyzing unit derives the natural frequency of the object by expressing the displacement of each frame of the identifying unit in the time domain and fast Fourier transforming the displacement expressed in the time domain in the image, .

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According to another aspect of the present invention, there is provided a method for analyzing dynamic characteristics of an object,
An image capturing step, a specific sub-setting step, a dynamic characteristic, and a natural frequency derivation step.
The image capturing step corresponds to a step of capturing an image including the vibrating body,
The specific sub-setting step corresponds to the step of setting at least one specific part which is a part to be measured in the vibrating body,
The step of deriving the dynamic characteristic and the natural frequency corresponds to the step of deriving the dynamic characteristic and the natural frequency of the vibrating body through the displacement of the specific part in a plurality of frames constituting the image. At this time,
An image is an image for the vibrating body which does not have a separate attachment,
The step of setting at least one specific part may include the steps of converting an image into a gray level image, expressing the converted image in white and black through threshold processing, Removing unnecessary parts, which are not parts, from black, and removing unnecessary parts and setting the remaining white parts to specific parts.

Here, the step of setting the at least one specific part distinguishes the specific part from the other part in the image through image processing.

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Wherein the step of deriving the dynamic characteristic comprises the steps of expressing, in the time domain, the displacement of each frame of the specific unit in the image, and performing Fast Fourier Transform (FFT) on the displacement expressed in the time domain, And deriving a frequency.

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According to the present invention, dynamic characteristics of an object can be measured and a dynamic characteristic of the object can be analyzed only by photographing a moving image with respect to the moving object. At the same time, It is possible to measure the dynamic characteristics of the device.

In addition, by analyzing the dynamic characteristics of the object through moving picture shooting, the object can be prevented from being damaged.

In addition, the method according to the embodiment of the present invention does not use expensive equipment as compared with the conventional method, thereby reducing the cost.

FIG. 1 is a diagram for explaining a configuration of an apparatus for analyzing dynamic characteristics of an object through image processing according to an embodiment of the present invention; FIG.
2 is a flowchart illustrating a method for analyzing dynamic characteristics of an object through image processing according to an embodiment of the present invention;
FIGS. 3 and 4 are views illustrating a method for analyzing dynamic characteristics of an object through image processing according to an exemplary embodiment of the present invention;
5 is a flowchart illustrating a method for deriving a specific unit according to an embodiment of the present invention;
6 is a diagram illustrating a method for deriving a specific unit according to an embodiment of the present invention;
FIG. 7 is a flowchart illustrating a method of deriving a dynamic characteristic of an object according to an embodiment of the present invention; FIG.
8 and 9 are graphs for explaining a method of deriving a dynamic characteristic according to an embodiment of the present invention;
FIG. 10 is a flowchart illustrating a method for deriving a dynamic characteristic of an object according to another embodiment of the present invention; FIG.
11 is a graph for explaining a method of deriving a dynamic characteristic according to another embodiment of the present invention.

Prior to the detailed description of the present invention, the terms or words used in the present specification and claims should not be construed as limited to ordinary or preliminary meaning, and the inventor may designate his own invention in the best way It should be construed in accordance with the technical idea of the present invention based on the principle that it can be appropriately defined as a concept of a term to describe it. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention, and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents It should be understood that water and variations may be present.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that, in the drawings, the same components are denoted by the same reference symbols as possible. Further, the detailed description of known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some of the elements in the accompanying drawings are exaggerated, omitted, or schematically shown, and the size of each element does not entirely reflect the actual size.

1 is a diagram for explaining a configuration of an apparatus for analyzing dynamic characteristics of an object through image processing according to an embodiment of the present invention.

Referring to FIG. 1, an apparatus for analyzing dynamic characteristics according to an exemplary embodiment of the present invention includes an image capturing unit 100, an image processing unit 200, and a characteristic analyzing unit 300.

The image capturing unit 100 captures an image including at least one moving object and provides the captured image to the image processing unit 200 according to an embodiment of the present invention. For this, the image capturing unit 100 may include a lens, a camera sensor, a signal processing device, and an image processing device. The camera sensor captures the image that is incident through the lens. The photographed image is an optical signal, and the camera sensor is an image sensor that converts a photographed optical signal into an electrical signal. Here, the camera sensor preferably uses a CCD (charge-coupled device) sensor. The signal processing apparatus converts the analog video signal output from the camera into a digital video signal. It is preferable that the signal processing apparatus is implemented by a DSP (Digital Signal Processor). The image processing apparatus performs a function of generating data for displaying a video signal output from the signal processing apparatus.

The image processing unit 200 performs processing for specifying only the selected portion for measuring the dynamic characteristic for each frame of the photographed image. For convenience of explanation, only a necessary portion is referred to as a "specific portion ". This specific part can set a plurality of objects for at least one object. The setting of the specific part is performed through image processing, and the other part and the specific part can be specified in the image photographed through the image processing. This is equivalent to distinguishing a specific part from another part by image processing.

The characteristic analyzer 300 measures the dynamic characteristics of the object. For this, the characteristic analyzing unit 300 receives a plurality of frames of an image set by a specific unit from the image processing unit 200, and determines the dynamic characteristics of the object through displacements of the specific units varying according to a plurality of frames of the received image . The specific part set on the moving object will be different for each frame. Therefore, the characteristic analyzing unit 300 can derive the dynamic characteristic through the position of the specific unit that varies according to each frame. This dynamic characteristic includes the natural frequency of the object and the mode of each order of the object.

FIG. 2 is a flow chart for explaining a method for analyzing dynamic characteristics of an object through image processing according to an embodiment of the present invention. FIGS. 3 and 4 are views for explaining dynamic characteristics of an object through image processing according to an embodiment of the present invention This is an example of a screen for explaining the method for analysis.

In Fig. 2, it is assumed that there is only one moving object. However, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit of the present invention, It is easy to understand that the characteristics can be analyzed.

Referring to FIG. 2, the image capturing unit 110 of the dynamic characteristic analyzing apparatus captures an image including a moving object in step S210. Here, the image is a moving image, and FIG. 3 shows one frame of the moving image. As shown in Fig. 3, the illustrated moving object is a rod and is made of a material having elasticity. 3, the right end of the bar is fixed, and the left end of the bar is not fixed. It is assumed that the object vibrates up and down on the screen, and the image capturing unit 110 is for capturing such moving objects.

After the moving object is photographed, the image processing unit 200 receives the photographed image from the image capturing unit 100, and sets at least one specific unit, which is a portion to be measured by the object, in step S220. The setting of the specific part is performed through image processing, and it is possible to distinguish the specific part from the other part in the image photographed through the image processing. FIG. 3 shows a screen example of a result obtained by dividing a specific part from the photographed image. Referring to FIGS. 3 and 4, portions to be measured in the photographed image (FIG. 3) are denoted by reference numerals 31 to 34, and the image as shown in FIG. 4 is derived through image processing. In other words, reference numerals 41 to 44 in FIG. 4 represent specific portions, and correspond to portions 31 to 34 in FIG. The derivation of the specific units 41 to 44 is performed for each frame of the moving picture. In the embodiment of the present invention, the four specific portions are referred to as a first specifying portion 41, a second specifying portion 42, a third specifying portion 43, and a fourth specifying portion 44, respectively, for convenience of explanation. The above-described image processing method will be described in more detail below.

After specifying the specific part, the characteristic analyzing unit 300 receives the image set by the image processing unit 200 and sets the dynamic characteristic of the object through the displacement of the specific unit, which varies according to a plurality of frames of the image received in step S230. . By way of example, the object will vibrate, and the specific part specified above will be different for each frame. Therefore, in step S230, the dynamic characteristic can be derived through the position of the specific part varying according to each frame. This dynamic characteristic includes the natural frequency of the object and the mode of each order of the object. Each will be described in more detail below.

FIG. 5 is a flowchart for explaining a method for deriving a specific unit according to an embodiment of the present invention, and FIG. 6 is an exemplary screen for explaining a method for deriving a specific unit according to an embodiment of the present invention.

FIG. 5 and FIG. 6 illustrate step S220 in more detail. In the embodiment of the present invention, the specific part is derived for all the frames, but only one frame will be described in Fig. 5 and Fig.

Referring to FIGS. 5 and 6, the image processing unit 200 converts the photographed image into a gray level image in step S510 (step S210 of FIG. 2). The image thus converted to the gray level is shown in Fig. 6 (A).

Then, in step S520, the image processing unit 200 expresses the image only in white and black through thresholding. An example of a screen expressed only in white and black is shown in FIG. 6 (B).

Then, the image processing unit 200 removes a portion to be measured, that is, an unnecessary portion that is not a specific portion in step S530. Here, the elimination means to treat the non-specific part as black. An example of the screen in which an unnecessary portion is removed is shown in Fig. 6 (C). As shown, the line has been removed. Accordingly, the specific part (white of the screen) and the remaining part are distinguished.

Next, the image processing unit 200 outputs a result of distinguishing the specific part (white of the screen) from other parts of the image through the image processing as described above in step S540. That is, the unnecessary part is removed and the remaining white part is set as the specific part, and the result is outputted. Here, the output image is as shown in (D) of FIG. The output image is input to the characteristic analyzer 300.

FIG. 7 is a flowchart for explaining a method of deriving an object dynamic characteristic according to an embodiment of the present invention, and FIGS. 8 and 9 are graphs for explaining a method of deriving a dynamic characteristic according to an embodiment of the present invention .

7 to 9, a method of deriving the natural frequency of the object will be described, which corresponds to step S230 in FIG.

A method of deriving a plurality of specifying units 41 to 44 through FIGS. 5 and 6 has been described. After deriving the plurality of specific portions 41 to 44 as described with reference to FIGS. 5 and 6, the characteristic derivation portion 300 extracts, for each of the specific portions 41 to 44 corresponding to the plurality of frames of the image in Step S710 And expresses the change of the position in the time domain. 8 shows an example of a screen in which the positional change with respect to each of the specific units 41 to 44 according to a plurality of frames is expressed in a time domain. As shown in the figure, the first specifying unit 41, the second specifying unit 42, the third specifying unit 43, and the fourth specifying unit 44 are configured to generate the graphs (A), (B), (D). Here, the vertical axis is in units of cm. The image is expressed in pixel units, but the characteristic derivation unit 300 scales it and expresses it in units of cm. Here, the horizontal axis can be a time domain with a frame of sequential images. The right part of the screen is a fixed part and it can be seen that the change of motion is great in the order of the first specifying part 41, the second specifying part 42, the third specifying part 43 and the fourth specifying part 44 have.

After expressing the time domain, the characteristic derivation unit 300 derives the natural frequency of the object by expressing the displacement represented in the time domain in Fast Frequency by FFT (Fast Fourier Transform) in step S720. A graph expressed in the frequency domain through fast Fourier transform is shown in FIG.

FIG. 10 is a flowchart illustrating a method of deriving an object dynamic characteristic according to another embodiment of the present invention, and FIG. 11 is a graph illustrating a method of deriving a dynamic characteristic according to another embodiment of the present invention.

In FIGS. 10 and 11, a method of deriving a mode of an object will be described, which corresponds to step S230 in FIG.

The embodiment described in FIGS. 10 and 11 employs a Fitting Orthogonal Decomposition (POD).

The POD is aimed at finding new principal components represented by the linear combination of the original variables, and by summarizing and easily interpreting the data. Principal component analysis provides a means for future analysis rather than analysis to arrive at a conclusion by itself.

In conclusion, this eigenvector is shown by deriving eigenvalues and eigenvectors in order to know the vibration dynamics of the multi-degree-of-freedom system, showing the main shape of this vibrational motion. However, the image was taken at 315 (number of frames) of freedom, which is more than the four points (specific parts) that I wanted. At this time, POD is the task of reducing the dimension to the original four. POD extracts the four main motions into a 4 * 4 matrix. This matrix is similar to the eigenvalue eigenvectors of the original matrix (4 * 315). So we do the work of transforming to POD, and then we find the dynamic properties of this object by finding the eigenvector eigenvalues of the matrix.

More specifically, assuming that the number of frames is 315, the characteristic derivation unit 300 derives a plurality of specific units 41 to 44 as described in FIGS. 5 and 6, and then, in step S1010, The 4 * 315 matrix A is multiplied by the transpose matrix of the matrix A to calculate a 4 * 4 matrix. Here, the 4 * 4 matrix is a covariance matrix. Then, the characteristic derivation unit 300 derives an eigenvalue Eigenvalue from the covariance matrix calculated in step S1020. Then, the characteristic derivation unit 300 derives an eigenvector from the eigenvalues in step S1020, and expresses the eigenvectors in each dimension mode. A graph representing the derived eigenvectors in the mode of each dimension is shown in Fig. As shown, the eigenvectors may be represented in a first through fourth order mode.

The method for analyzing the dynamic characteristics of an object through image processing according to the present invention can be implemented in a form of software readable by various computer means and recorded on a computer-readable recording medium. Here, the recording medium may include program commands, data files, data structures, and the like, alone or in combination. Program instructions to be recorded on a recording medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. For example, the recording medium may be an optical recording medium such as a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, a compact disk read only memory (CD-ROM), a digital video disk (DVD) A magneto-optical medium such as a floppy disk and a ROM, a random access memory (RAM), a flash memory, a solid state disk (SSD), a hard disk drive (HDD) And hardware devices specifically configured to store and perform the same program instructions. Examples of program instructions may include machine language code such as those generated by a compiler, as well as high-level language code that may be executed by a computer using an interpreter or the like. Such hardware devices may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

While the present invention has been described with reference to several preferred embodiments, these embodiments are illustrative and not restrictive. It will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims.

100:
200:
300: Characteristic Analysis Unit

Claims (10)

An apparatus for analyzing dynamic characteristics of a vibrating body,
An image pickup unit for picking up an image of the vibrating body;
An image processing unit for setting at least one specific unit to be measured in the vibrating body; And
And a characteristic analyzer for deriving a dynamic characteristic and a natural frequency of the vibrator through a displacement of the specific unit in a plurality of frames constituting the image,
Wherein the image includes:
The image for the vibrating body not having a separate attachment,
Wherein the image processing unit comprises:
Converts the image into a gray level image,
The transformed image is represented by white and black through threshold processing,
Wherein an unnecessary portion which is not a portion to be measured is represented by black and removed from the portion represented by white and then the unnecessary portion is removed and the remaining white portion is set as a specific portion. The method according to claim 1,
The image processing unit
And distinguishes the other part from the specific part in the image through image processing.
An apparatus for analyzing dynamic characteristics of objects. delete The method according to claim 1,
The characteristic analyzer
And expressing the displacement of each frame of the specific unit in the time domain in the image, and then performing fast Fourier transform (FFT) on the displacement expressed in the time domain to derive the natural frequency of the object
An apparatus for analyzing dynamic characteristics of objects. delete A method for analyzing dynamic characteristics of a vibrating body,
Capturing an image including the vibrating body;
Setting at least one specific part to be measured in the vibrating body; And
And deriving a dynamic characteristic and a natural frequency of the vibrating body through a displacement of the specific portion in a plurality of frames constituting the image,
Wherein the image includes:
The image for the vibrating body not having a separate attachment,
The step of setting the at least one specific part
Converting the image into a gray level image;
Expressing the converted image in white and black through thresholding;
Removing unnecessary parts, which are not the part to be measured, out of the parts represented by white in black;
And setting a white portion remaining after the unnecessary portion is removed to a specific portion. The method according to claim 6,
The step of setting the at least one specific part
And distinguishes the other part from the specific part in the image through image processing.
How to analyze the dynamic characteristics of objects. delete The method according to claim 6,
The step of deriving the dynamic characteristic
Expressing, in the time domain, a displacement of each frame of the specifying unit in the image;
And deriving a natural frequency of the object by Fast Fourier Transform (FFT) the displacement expressed in the time domain
How to analyze the dynamic characteristics of objects. delete

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