KR20210061705A - Apparatus for imaging power data and method thereof - Google Patents

Abstract

Disclosed are a device for imaging power data which can be applied to image-based machine learning models without network modification, and a method thereof. The device for imaging power data comprises: a data input unit receiving time series three-phase power data; an image conversion unit converting a domain of the three-phase power data input from the data input unit to express a grayscale image, and allocating an RGB channel to the grayscale image to generate a color image; and an output unit outputting the image generated by the image conversion unit.

Description

Power data imaging device and its method TECHNICAL FIELD [APPARATUS FOR IMAGING POWER DATA AND METHOD THEREOF]

The present invention relates to an apparatus and method for imaging power data, and more particularly, by converting each phase information of three-phase power data into a two-dimensional domain and expressing it as a single image, in order to compare the information of each phase. The present invention relates to an apparatus and method for imaging power data in order to reduce the inconvenience of comparing one by one.

In general, for reasons such as economical transmission and distribution, constant power supply, or operation of power machinery, three-phase alternating current is widely used rather than single-phase in various industrial groups. Power operation through three-phase alternating current is an important factor in efficient power distribution and power systems.

A normal three-phase alternating current consists of a sinusoidal wave in which the maximum current between the phases is the same and each phase has a phase difference of 120 degrees from each other. On the contrary, abnormal three-phase alternating current has different maximum currents between each phase, or a phase delay or distortion occurs in a specific phase. The unique characteristics and changes of these phases become important information for power analysis and operation.

When analyzing time series data such as current and voltage, it is possible to directly analyze time series data, but by considering the frequency characteristics of each phase together, more effective analysis is possible.

Here, as a widely used frequency characteristic analysis method, there is a spectrogram, which is a time-frequency characteristic analysis method through domain transformation of data.

The background technology of the present invention is disclosed in Korean Patent Application Publication No. 10-1875704 (announcement on July 6, 2018, a data processing apparatus, a medical imaging system, and a method of generating a diagnostic image).

However, each phase information of the three-phase power data is independently expressed and expressed separately and can be effectively analyzed by comparing it with other phase information, but there is an inconvenience of comparing the information of the phases one by one for comparison analysis.

In addition, when comparing the phase information with each other, there is a problem that it is difficult to recognize the difference between the phase information at a glance.

The present invention was conceived to improve the above problems, and an object of the present invention according to an aspect is to convert information of each phase of three-phase power data into a two-dimensional domain and express it as a single image. It is to provide an apparatus and method for imaging power data to reduce the inconvenience of comparing information one by one in order to compare information.

An apparatus for imaging power data according to an aspect of the present invention includes: a data input unit receiving three-phase power data of a time series; An image conversion unit converting the domain of the three-phase power data input from the data input unit to represent a grayscale image, and generating a color image by allocating an RGB channel to the grayscale image; And an output unit for outputting the image generated by the image conversion unit.

In the present invention, the image conversion unit includes: a domain conversion unit for converting input three-phase power data into a two-dimensional domain; A grayscale image converter configured to generate a grayscale image of each phase by applying and correcting each phase information of the power data converted by the domain converter by applying a normalization process and a quantization process; And an RGB channel allocator configured to generate a color image by allocating an RGB channel to the grayscale image of each image generated by the grayscale imaging unit.

In the present invention, the domain conversion unit is characterized in that it converts the three-phase power data into a time-frequency domain for each phase.

In the present invention, the grayscale imaging unit includes: a normalization unit for normalizing by applying a relative size difference between image information converted by the domain conversion unit; A quantization unit that allocates information of each image normalized by the normalization unit as a value between quantization levels and converts it into a grayscale image; And a correction unit for gamma correction for each image information normalized by the normalization unit or a grayscale image converted by the quantization unit.

In the present invention, the quantization unit is characterized in that the quantization is performed by adjusting a resolution based on a quantization level set according to the number of color information constituting an image.

In the present invention, the RGB channel allocator generates one color image by allocating a grayscale image of each phase to an RGB channel according to an order of each phase.

According to another aspect of the present invention, a method of imaging power data includes: receiving, by an image conversion unit, three-phase power data of a time series through a data input unit; Converting a domain of the input three-phase power data by an image conversion unit; Generating, by an image conversion unit, a grayscale image based on information on each phase of the domain-converted three-phase power data; Generating a color image by allocating an RGB channel to a grayscale image of each phase by an image conversion unit; And outputting the color image generated by the image conversion unit.

In the present invention, the step of converting the domain is characterized in that the image conversion unit converts the input three-phase power data into a two-dimensional domain.

In the present invention, the two-dimensional domain is characterized in that it includes a time-frequency domain.

In the present invention, generating a grayscale image may include performing a normalization process by applying a relative size difference between each phase information of the domain-converted power data by an image conversion unit; Generating a grayscale image of each image by assigning the normalized image information to a value between quantization levels and performing quantization by the image conversion unit; And gamma-correcting the normalized image information or the generated grayscale image of each image by an image conversion unit.

In the present invention, when quantization is performed, the image conversion unit quantizes by adjusting a resolution based on a quantization level set according to the number of color information constituting an image.

In the present invention, the step of generating a color image is characterized in that the image conversion unit generates one color image by allocating a grayscale image of each phase to an RGB channel according to an order of each phase.

In the power data imaging apparatus and method according to an aspect of the present invention, each phase information of three-phase power data is converted into a two-dimensional domain and expressed as a single image, and is compared one by one in order to compare the information of each phase. In addition to reducing inconvenience, it is possible to apply an image-based machine learning model to an image-based machine learning model without network modification by expressing it as a single image, and an image-based analysis method can be applied to power data analysis.

1 is a block diagram illustrating an apparatus for imaging power data according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating in detail a grayscale imaging unit in the power data imaging apparatus according to an embodiment of the present invention.
3 is an exemplary view showing three-phase power data input from the power data imaging apparatus according to an embodiment of the present invention.
4 is an exemplary view showing data converted to a 2D domain in the power data imaging apparatus according to an embodiment of the present invention.
5 is an exemplary diagram showing a grayscale image in the power data imaging apparatus according to an embodiment of the present invention.
6 is an exemplary diagram illustrating a color image to which an RGB channel is allocated in the power data imaging apparatus according to an embodiment of the present invention.
7 is an exemplary view showing a single image generated by the power data imaging apparatus according to an embodiment of the present invention.
FIG. 8 is an exemplary diagram showing a gamma-corrected image in the power data imaging apparatus according to an embodiment of the present invention.
9 is a flowchart illustrating a power data imaging method according to an embodiment of the present invention

Hereinafter, an apparatus and method for imaging power data according to the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of users or operators. Therefore, definitions of these terms should be made based on the contents throughout the present specification.

1 is a block diagram illustrating a power data imaging apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram specifically showing a grayscale imaging unit in a power data imaging apparatus according to an embodiment of the present invention. , FIG. 3 is an exemplary view showing three-phase power data input from the power data imaging apparatus according to an embodiment of the present invention, and FIG. 4 is a conversion into a two-dimensional domain in the power data imaging apparatus according to an embodiment of the present invention. 5 is an exemplary diagram showing a grayscale image in the power data imaging apparatus according to an embodiment of the present invention, and FIG. 6 is an RGB channel in the power data imaging apparatus according to an embodiment of the present invention. FIG. 7 is an exemplary view showing a single image generated by the power data imaging apparatus according to an embodiment of the present invention, and FIG. 8 is an exemplary view showing a color image to which is assigned, and FIG. 8 is an exemplary view showing power data according to an embodiment of the present invention. This is an exemplary diagram showing an image that has been gamma-corrected in an imaging device.

As shown in FIG. 1, the power data imaging apparatus according to an embodiment of the present invention may include a data input unit 10, an image conversion unit 20, and an output unit 30.

As shown in FIG. 3, the data input unit 10 receives time-series three-phase power data for imaging.

Here, each phase information of the three-phase power data may be separately obtained as time series data in a one-dimensional form.

The image conversion unit 20 may convert a domain of power data input from the data input unit 10 to represent a single grayscale image, and generate an image by allocating an RGB channel.

Here, the image conversion unit 20 may include a domain conversion unit 210, a grayscale imaging unit 220, and an RGB channel allocation unit 230.

The domain conversion unit 210 may convert the input three-phase power data into a two-dimensional domain as shown in FIG. 4. At this time, it is possible to convert the single-phase information in the 1-dimensional form into the 2-dimensional form by selectively applying from among various domain transformation techniques.

Here, the one-dimensional form refers to a form with one instantaneous value, and the values depend on time, which is the main axis of the time domain, and the two-dimensional form differs from the one-dimensional form. ) Depends on

The domain conversion unit 210 effectively represents each phase information by converting and re-expressing each phase of the three-phase time series power data into a time-frequency domain through time-frequency domain transformation such as a spectrogram during 2D domain transformation. I can.

Here, the spectrogram is a representative two-dimensional form of information that can be obtained through a Fourier transform-based time-frequency domain transformation. The spectrogram is a technique for visualizing sound or wave. Changes can be visualized by expressing changes in display colors and changes in color density.

As shown in Equation 1, the spectrogram can be obtained by taking a short-time Fourier transform (STFT) to the input x[n], and the short-time Fourier transform is achieved through a window. ; Fast Fourier Transform) can be implemented by sliding and applying to the input. In Equation 1, a Hamming window is used as the window function k[n] in the short-time Fourier transform.

Meanwhile, since the image conversion unit 20 can apply various conversion methods to the 2D domain conversion for image conversion, it can provide information as various single images as needed.

Therefore, in addition to the spectrogram, information such as MFCC (Mel Frequency Cepstral Coefficient) or Mel-Spectrogram that can be obtained through 2D domain transformation can be applied. Multiple information can also be applied.

The grayscale imager 220 may convert information of each phase of the power data converted into two dimensions by the domain converter 210 into a grayscale image as illustrated in FIG. 5.

Here, the grayscale imaging unit 220 may generate a grayscale image whose brightness is corrected by applying a process of normalizing and quantizing each image information, and applying gamma correction.

As shown in FIG. 2, the grayscale imaging unit 220 may include a normalization unit 222, a quantization unit 224, and a correction unit 226.

Here, the normalization unit 222 is not independently performed within each phase information converted by the domain conversion unit 210, and may be normalized by applying a relative size difference between the phase information.

In this case, the normalization unit 222 may perform normalization as shown in Equation 2.

Here, N is the number of each phase, meaning the R phase, S phase, and T phase of the three-phase power data, DATA_2D _N is the phase information converted into a two-dimensional form by the domain conversion unit, and DATA_Pos _N is a positive number of the converted phase information. hwahan information, MAX_Intra _N is the largest value, MAX_Inter is the largest value of _N in MAX_Intra DATA_Pos _N, DATA_N _N represents the normalized information.

In this case, by normalizing each phase based on the largest value in the entire image information without independently normalizing each phase based on the largest value in each phase information, a difference in size of the relative values of each phase may be considered.

The quantization unit 224 allocates information of each phase normalized by the normalization unit 222 as a value between quantization levels and converts it into a grayscale image.

Here, the quantization unit 224 is set to the number of color information constituting the image, and may adjust the resolution of the grayscale image using any one of 8-bit, 16-bit, and 32-bit quantization levels constituting the RGB image.

In this case, the quantization unit 224 may be performed by Equation 3.

In this case, Q _{Level _max} is the largest value at the set quantization level q (bit/channel), and since the quantization level can be selectively set, the clarity of the generated image can be adjusted as needed.

DATA_Q _N represents the grayscale image finally generated after normalization and correction.

The correction unit 226 may gamma-correct each image information normalized by the normalization unit 222 or a grayscale image converted by the quantization unit 224 to correct the brightness of a color image to be generated later.

Here, by applying gamma correction, it is possible to compensate information in a dark portion of the generated color image as illustrated in FIG. 8 and improve image quality.

In the quantization process, data loss may occur due to the limitation of information expression, so if the brightness of the image changes in a dark area to the eyes of a person who cannot see the brightness of the image completely linearly, it is not smooth but appears disconnected and the brightness changes in bright areas. May appear to have changed less than the actual change.

Therefore, in order to compensate for this, gamma correction, a technique for compensating information by adding nonlinearity, can be applied.

Here, the gamma correction in the correction unit 226 may be performed by Equation 4.

In this case, I _i is an input image, γ is a constant determining the degree of correction of the image, and I _o is an output image, which is an image in which nonlinearity is corrected in the input image.

The RGB channel allocating unit 230 allocates the grayscale image of each phase generated by the grayscale imaging unit 220 to R, G, and B channels as shown in FIG. 6 in the order of R, S, and T of each phase, This can generate one color image as shown in FIG. 7.

The output unit 30 outputs a single image generated by the image conversion unit 20 so that a machine learning model or the like can compare the distribution and difference of colors appearing in the image based on the image.

For example, in a single image generated by applying the spectrogram as a conversion technique of the domain conversion unit 210, if information of each phase shows a pattern in the same frequency band, each R, G, B color is synthesized to form one color. The color assigned to the image information having strong information is strongly displayed according to the difference in the size of each image information. Conversely, if there is image information having a pattern in an independent frequency band, only color information allocated to the corresponding image is displayed. For pattern analysis of other image information, an existing spectrogram analysis method can be applied.

As described above, according to the power data imaging apparatus according to an embodiment of the present invention, each phase information of three-phase power data is converted into a two-dimensional domain and expressed as a single image to compare the information of each phase. In addition to reducing the inconvenience of comparing one by one, it is possible to apply an image-based machine learning model to an image-based machine learning model without network modification by expressing it as a single image, so that an image-based analysis method can be applied to power data analysis.

9 is a flowchart illustrating a power data imaging method according to an embodiment of the present invention

As shown in FIG. 9, in the method of imaging power data according to an embodiment of the present invention, first, the image conversion unit 20 receives time series three-phase power data through the data input unit 10 (S10).

After receiving the three-phase power data of the time series in step S10, the image conversion unit 20 converts the input three-phase power data into a two-dimensional domain, which is a time-frequency domain (S20).

At this time, the image conversion unit 20 converts each phase of the three-phase time series power data into a time-frequency domain through a time-frequency domain conversion such as a spectrogram, and re-expresses each phase information. Can be expressed effectively.

Here, the spectrogram is a representative two-dimensional form of information that can be obtained through a Fourier transform-based time-frequency domain transformation. The spectrogram is a technique for visualizing sound or wave. Changes can be visualized by expressing changes in display colors and changes in color density.

Meanwhile, since the image conversion unit 20 can apply various conversion methods to the 2D domain conversion for image conversion, it can provide information as various single images as needed.

Therefore, in addition to the spectrogram, information such as MFCC (Mel Frequency Cepstral Coefficient) or Mel-Spectrogram that can be obtained through 2D domain transformation can be applied. Multiple information can also be applied.

After converting to the 2D domain in step S20, the image conversion unit 20 normalizes by applying a relative size difference between the phase information of the three-phase power data (S30).

Here, the image conversion unit 20 does not independently normalize each of the images based on the largest value in each image information, but normalizes each image based on the largest value in the entire image information. You can take into account the size difference.

After performing the normalization process in step S30, the image conversion unit 20 allocates the normalized phase information as a value between the quantization levels and performs quantization to generate a grayscale image of each phase (S40).

Here, the image conversion unit 20 is set to the number of color information constituting the image, and may adjust the resolution of the grayscale image using any one of 8-bit, 16-bit, and 32-bit quantization levels constituting the RGB image.

After generating a grayscale image of each phase in step S40, the image conversion unit 20 compensates for clarity of brightness of a color image to be generated later by performing gamma correction on the grayscale image of each phase (S50).

That is, by applying gamma correction, information in a dark part of a color image can be compensated and image quality can be improved.

Since the image conversion unit 20 may lose data due to the limitation of information expression during the quantization process, if the brightness changes in a dark part to the eyes of a person who cannot see the brightness of the image completely linearly, it is not smooth and is disconnected. Since the brightness change in the visible and bright part may appear to be changed less than the actual change, information is compensated by adding nonlinearity through gamma correction to compensate for this.

In the present embodiment, a grayscale image is generated and then corrected. However, three-phase power data may be normalized and then corrected for each phase information.

After correcting the image in step S50, the image conversion unit 20 allocates the grayscale image of each phase to the R, G, and B channels in the order of R, S, and T of each phase (S60).

In step S60, an RGB channel is allocated to the grayscale image of each phase and converted into a color image, and then the image conversion unit 20 generates it as a single color image (S70).

After generating a single color image in step S70, the image conversion unit 20 outputs a single color image so that a machine learning model or the like can compare the distribution and difference of colors appearing in the image based on the image (S80).

By expressing the three-phase power data as a single image, it is possible to easily visually compare the unique characteristics or patterns of the power data, and to analyze the equipment consuming power or to classify the equipment or determine the abnormal condition of the equipment. Can be used as. In addition, by imaging time series data, an image-based analysis method can be applied to power data analysis.

As described above, according to the method for imaging power data according to an embodiment of the present invention, in order to compare the information of each phase by converting each phase information of three-phase power data into a two-dimensional domain and expressing it as a single image. In addition to reducing the inconvenience of comparing one by one, it is possible to apply an image-based machine learning model to an image-based machine learning model without network modification by expressing it as a single image, thereby applying an image-based analysis method to power data analysis.

The implementation described herein may be implemented in, for example, a method or process, an apparatus, a software program, a data stream or a signal. Although discussed only in the context of a single form of implementation (eg, only as a method), the implementation of the discussed features may also be implemented in other forms (eg, an apparatus or program). The device may be implemented with appropriate hardware, software and firmware. The method may be implemented in an apparatus such as a processor, which generally refers to a processing device including, for example, a computer, a microprocessor, an integrated circuit or a programmable logic device, or the like. Processors also include communication devices such as computers, cell phones, personal digital assistants (“PDAs”) and other devices that facilitate communication of information between end-users.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is only illustrative, and those of ordinary skill in the field to which the technology pertains, various modifications and other equivalent embodiments are possible. I will understand.

Therefore, the true technical protection scope of the present invention should be determined by the following claims.

10: data input unit 20: image conversion unit
30: output unit 210: domain conversion unit
220: grayscale imaging unit 222: normalization unit
224: quantization unit 226: correction unit
230: RGB channel allocation unit

Claims (12)

A data input unit for receiving time series three-phase power data;
An image conversion unit converting the domain of the three-phase power data input from the data input unit to represent a grayscale image, and generating a color image by allocating an RGB channel to the grayscale image; And
And an output unit that outputs the image generated by the image conversion unit.
The method of claim 1, wherein the image conversion unit,
A domain conversion unit converting the inputted three-phase power data into a two-dimensional domain;
A grayscale image converter configured to generate the grayscale image of each phase by applying and correcting each phase information of the power data converted by the domain converter by applying a normalization process and a quantization process; And
And an RGB channel allocator configured to generate the color image by allocating an RGB channel to the grayscale image of each image generated by the grayscale imaging unit.
The apparatus of claim 2, wherein the domain conversion unit converts the three-phase power data into a time-frequency domain for each phase.
The method of claim 2, wherein the grayscale imaging unit,
A normalization unit for normalizing by applying a relative size difference between the phase information converted by the domain conversion unit;
A quantization unit for converting the grayscale image by allocating information of each phase normalized by the normalization unit as a value between quantization levels; And
And a correction unit for gamma correction for each phase information normalized by the normalization unit or the grayscale image converted by the quantization unit.
The apparatus of claim 4, wherein the quantization unit performs quantization by adjusting a resolution based on the quantization level set according to the number of color information constituting an image.
The power data imaging apparatus of claim 2, wherein the RGB channel allocator generates one color image by allocating the grayscale image of each phase to an RGB channel according to an order of each phase.
Receiving, by an image conversion unit, three-phase power data of a time series through a data input unit;
Converting a domain of the three-phase power data input by the image conversion unit;
Generating, by the image conversion unit, a grayscale image based on information on each phase of the domain-converted three-phase power data;
Generating a color image by allocating an RGB channel to the grayscale image of each image by an image conversion unit; And
And outputting the color image generated by the image conversion unit.
The method of claim 7, wherein the converting of the domain comprises converting the three-phase power data input by the image conversion unit into a two-dimensional domain.
The method of claim 8, wherein the two-dimensional domain comprises a time-frequency domain.
The method of claim 7, wherein generating the grayscale image comprises:
Performing a normalization process by applying a relative size difference between the phase information of the domain-converted power data by the image conversion unit;
Generating the grayscale image of each image by assigning the normalized image information to a value between quantization levels and performing quantization by the image conversion unit; And
And gamma-correcting, by the image conversion unit, the normalized image information or the grayscale image of each generated image.
The method of claim 10, wherein when performing the quantization process, the image conversion unit performs quantization by adjusting a resolution based on a quantization level set according to a number of color information constituting an image.
The power data according to claim 7, wherein the generating of the color image comprises generating one color image by allocating the grayscale image of each phase to an RGB channel according to an order of each phase by the image conversion unit. Method of imaging.

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