KR101757071B1 - Method of image segmentation assisted entropy - Google Patents

Method of image segmentation assisted entropy Download PDF

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KR101757071B1
KR101757071B1 KR1020150173731A KR20150173731A KR101757071B1 KR 101757071 B1 KR101757071 B1 KR 101757071B1 KR 1020150173731 A KR1020150173731 A KR 1020150173731A KR 20150173731 A KR20150173731 A KR 20150173731A KR 101757071 B1 KR101757071 B1 KR 101757071B1
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entropy
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brightness
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남재욱
김동재
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성균관대학교산학협력단
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Abstract

The present invention relates to an image processing method comprising the steps of: preparing an original image made up of two-dimensional brightness pixel values; Obtaining an entropy image having an entropy value of all pixels of the image by setting a window of a predetermined size, obtaining an entropy value of pixel values of the image in the window, and setting the entropy value as a center pixel of the window; Determining a distribution of each entropy value of the entropy image and setting an entropy threshold value of the pixel; Obtaining a black-and-white entropy-based mask image defined as 1 if the entropy value of the pixel of the entropy image is greater than or equal to the entropy threshold value and 0 if the entropy value is less than the entropy threshold value; Obtaining a filtered image of the original image with the entropy-based mask image; Determining a distribution of the filtered image and setting a brightness threshold value of the pixel; And obtaining a black-and-white image having a value of 1 when the brightness value of the pixel of the filtered image is equal to or greater than the brightness threshold value and 0 when the brightness value of the pixel of the filtered image is less than the brightness threshold value.

Description

{METHOD OF IMAGE SEGMENTATION ASSISTED ENTROPY}

The present invention relates to a method of dividing a monochrome image from an image in which a distinction between an object and a background such as a microscopic image is clear. This method is used for physical property evaluation based on image analysis of a material composed of a silver nanowire network, and relates to a method for deriving a black and white image segmentation for the accuracy of image analysis.

Image analysis has an important place in many engineering fields. Particularly in the field of materials processing, multifunctional films (eg transparent electrodes) or molecular sieve membranes are being produced, and the performance of the films is mainly determined by the nano- or micro-network structure and the performance can be analyzed by detecting defects . For this purpose, images photographed by optical or electron microscopes are used, and high magnification images are required because nanowires, carbon nanotubes, and zeolite crystals are used. Here, it is very important to understand the connectivity, arrangement, and orientation of network structures composed of these nano- and micro-materials. From this microscopic information, it can ultimately be used to select the desired process conditions, or it can be used to design the manufacturing process. In other words, macroscopic processing can be used to reverse the microscopic structure.

Most of the images obtained from the microscope are gray scale images. An image is a matrix composed of two-dimensional arrays, each of which is constituted by a unit of pixels, and the value represents the brightness value in the image. Image segmentation is the most basic and important step, which is the first step in image analysis, which is the process of dividing images into homogeneous parts without overlapping.

Various methods for image segmentation have been proposed until recently, for example edge extraction, partial differential approximation, fuzzy logic approach. Among them, the threshold processing is a technique which is simple and old but is still widely used in image segmentation. The bi-level thresholding is to divide the image into 0 and 1 based on the brightness value of a given pixel, for example, to distinguish between material and background in the image. This classification is classified according to whether the threshold value is based on global information or local information. In the global threshold processing, the entire image is divided by using a threshold value, and Otsu's method of selecting a valley part in the brightness histogram is representative. Local threshold processing is a method of using local information. The threshold value varies according to each area. The most representative method is the method of sauvola. Some methods can use this global thresholding and local thresholding together, which is called the two-stage method. Examples using this method are the indicator kriging method and the active contour method.

In the present invention, the present inventors have been interested in image segmentation from a microscopic image of a network structure composed of a thin object. This is mainly due to a linear feature (a higher sequence of pixels with a higher or higher intensity value than the immediate lateral neighborhood), which can be segmented by a special method called linear feature detection. Although this method has been used in various fields, the examples used in material analysis have been rare.

Global thresholding is criticized because it proceeds with ignoring local information, but it can be useful for microscopic images because the brightness of the image is greatly influenced by the state of the surface of the material. For example, in scanning electron microscopy (SEM) images, the brightness value is determined by the energy value of the secondary electron, which is determined by the structure and ratio of the surface of the material. Therefore, if we combine global threshold processing and local information appropriately, successful image segmentation can be expected.

In the present invention, entropy-based masking (EBM) is used to perform the thresholding process. Here we were able to select the pixels with more information to help rational and easy thresholding.

Japanese Patent Publication No. 3860540

The present invention relates to an image processing method comprising the steps of: preparing an original image made up of two-dimensional brightness pixel values; Obtaining an entropy image having an entropy value of all pixels of the image by setting a window of a predetermined size, obtaining an entropy value of pixel values of the image in the window, and setting the entropy value as a center pixel of the window; Determining a distribution of each entropy value of the entropy image and setting an entropy threshold value of the pixel; Obtaining a black-and-white entropy-based mask image defined as 1 if the entropy value of the pixel of the entropy image is greater than or equal to the entropy threshold value and 0 if the entropy value is less than the entropy threshold value; Obtaining a filtered image of the original image with the entropy-based mask image; Determining a brightness distribution of the filtered image and setting a brightness threshold value of the pixel; And obtaining a black-and-white image of 0 if the brightness value of the pixel of the filtered image is equal to or greater than the brightness threshold value and less than 0 if the brightness value of the pixel of the filtered image is greater than or equal to the brightness threshold value.

And the original image is a microscope image.

The distribution of the entropy values is a distribution estimated from a histogram of the number of entropy values of each pixel, and the entropy threshold value is a sum of an average value and a standard deviation value of the distribution.

The step of obtaining the filtered image of the original image includes multiplying the pixel value of the original image by a value of 0 or 1 of the corresponding pixel of the monochrome entropy based mask image.

FIG. 1A illustrates entropy-based masking (EBM) of the present invention.
FIG. 1B shows the effect of the size of the entropy estimation window.
Figure 2 shows a filtered histogram of a filtered image obtained using a monochrome entropy-based mask.
FIG. 3 shows an algorithm for obtaining a divided monochrome image of the original image of the present invention, and the drawings for the right side show a series of changes according to the algorithm of the silver nanowire network image.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the term "comprises" or "having ", etc. is intended to specify that there is a feature, step, operation, element, part or combination thereof described in the specification, , &Quot; an ", " an ", " an "

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

FIG. 1A illustrates an entropy-based masking (EBM) method for obtaining a black-and-white entropy-based mask image of the present invention. FIG. 1A illustrates a histogram image as a distribution of entropy values of each pixel of the method of obtaining the entropy image of the present invention, And setting an entropy threshold value of the pixel. 1A is an SEM image of a silver nanowire network fabricated by dip coating as an example of an original image of the present invention. (B) is an entropy-estimation window, (C) shows a histogram showing an entropy distribution, and illustrates a method of setting an entropy threshold value.

The original image is an 8-bit grayscale image, and each pixel has a brightness intensity value of an integer from 0 to 255. Assuming that the values of all pixels are statistically independent, the amount of information can be expressed as the relative frequency of the brightness values in the image. The following equation (1) can be used to obtain the entropy value of the information in the area given by the calculation of entropy

Figure 112015119872378-pat00001
Equation (1)

Where p (i) represents the relative frequency of brightness within an entropy-estimating window, and n is the number of brightness values in the region.

As shown in FIG. 1A, a square window having a size of N around one pixel is set, where the size of N is related to the size of the object. The entropy in the window is based on the above equation (1) and is replaced by the center position of the window. If the pixel is located at the end of the image, symmetric padding is used to prevent the window from crossing the image. This is done by filling the current image with a mirror image.

Having a large entropy means that the brightness is more randomly arranged around the pixel. In other words, the change of the brightness value in the window is severe. Therefore, the value of a large entropy can be inferred that the pixel is at the boundary of matter and background. In the present invention, only pixels having a large entropy value are selected, a mask is created using the pixels, and the threshold value is used.

To select the pixels, the present invention has chosen a statistical approach. The entropy histogram is obtained by collecting all entropy values as shown in Fig. 1A (C), and then the distribution is estimated as a Gaussian distribution. Of course, you can use other distributions if necessary. As shown in FIG. 1 (C), only the pixels differing by more than the standard deviation from the average are selected for EBM, which means pixels having a high entropy of 16%.

A successful EBM depends on choosing an appropriate size entropy estimation window. The goal of EBM is to draw the boundaries between material and background. Therefore, the size of the window should be large enough to contain material and background. Due to the noise, the entropy value can become large due to the change in the brightness value even in the homogeneous part like the background. Therefore, if you size a window that is too small for a material, there is a risk that the noise portion will be caught rather than the boundary between the material and the background.

1B shows the effect of the size of the entropy estimation window. The figures in the second column show the results of the EBM in FIG. 3A according to the size of the window. The thickness of the object is about 6-9 pixels. As shown in the third column, the calculated threshold values remain almost constant after 11 by 11 magnitude. Also, the result of image segmentation becomes almost the same. However, if the size of the entropy estimation window becomes too small, the distribution of entropy becomes too much left-tailed rather than Gaussian. For example, if you are going to use a 3 by 3 window, it will only find pixels that are slightly changing, such as noise, since this is only an estimate of 9 pixels. Because EBM only uses pixels above the value of the entropy plus the standard deviation from the mean, it is rare that no pixels are selected. As a result, in terms of stability, it is recommended that the size of the entropy estimation window be larger than the size of the object.

Figure 2 shows a filtered image image using a monochrome entropy-based mask and illustrates a histogram as a distribution of the filtered image. (B) is the corresponding brightness value histogram of each image (where the black bar is the original image and the purple bar is the filtered extracted image), (C) (D) and (E) are the relative frequency of the original image and the cumulative relative frequency of the extracted image.

In the brightness histogram of the original image, the dark brightness value indicating the background dominates the overall brightness value in too much ratio. In FIG. 2 (E), in the cumulative frequency graph of the original brightness histogram, a low brightness value (brightness of about 40 or less) accounts for about 70% of the total. Therefore, it is very difficult to find appropriate threshold values from this histogram using binormal mixture analysis. In contrast, when the EBM method is used, the distribution of the relative frequency is widespread. Therefore, it can be seen that two binomial Gaussian distributions clearly represent the brightness histogram when binormal mixture analysis is performed. It was easy to select the threshold value because it was well satisfied with the condition that can be separated well.

FIG. 3 shows an algorithm for obtaining a divided monochrome image of the original image of the present invention, and the drawings for the right side show a series of changes according to the algorithm of the silver nanowire network image.

(A) is the original image, and (C) is the monochrome entropy-based mask image. (E) is a brightness distribution histogram, such as the (D) after the filtering with a mask image threshold value (in this case two threshold values (T 0, by using the T 1) the value of T 0 or less is treated as zero, and T 1 The above values were treated as 1, and the value between 0 and 1 was given by statistical interpolation.

Claims (4)

Preparing an original image of a wire network configuration consisting of two-dimensional brightness pixel values;
An entropy image having entropy values of all pixels of the image is obtained by setting a window having a size larger than the thickness of the wire, obtaining an entropy value of pixel values of the image in the window, and setting the entropy value as a center pixel of the window step;
Determining a brightness distribution of each entropy value of the entropy image and setting an entropy threshold value of the pixel;
Obtaining a black-and-white entropy-based mask image defined as 1 if the entropy value of the pixel of the entropy image is greater than or equal to the entropy threshold value and 0 if the entropy value is less than the entropy threshold value;
Obtaining a filtered image of the original image with the entropy-based mask image;
Determining a brightness distribution of the filtered image and setting a brightness threshold of the pixel, wherein the brightness threshold comprises a first brightness threshold and a second brightness threshold, and wherein the first brightness threshold comprises a second brightness The threshold being greater than a threshold value;
Wherein the first brightness threshold value and the second brightness threshold value are set to 1 when the brightness value of the pixel of the filtered image is greater than or equal to the first brightness threshold value and to 0 when the brightness value is less than the second brightness threshold value, 0.0 > 0 < / RTI > or 1 to obtain a monochrome image.
A method of deriving a black and white image of a wire network shape image.
The method according to claim 1,
Wherein the original image is a microscope image,
A method of deriving a black and white image of a wire network shape image.
The method according to claim 1,
Wherein the distribution of entropy values is a distribution estimated from a histogram of the number of entropy values of each pixel and the entropy threshold is a sum of the mean values of the distributions and a standard deviation value.
A method of deriving a black and white image of a wire network shape image.
The method according to claim 1,
Wherein the step of obtaining the filtered image of the original image comprises multiplying the pixel value of the original image by a value of 0 or 1 of the corresponding pixel of the monochrome entropy based mask image.
A method of deriving a black and white image of a wire network shape image.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3860540B2 (en) * 2000-12-01 2006-12-20 独立行政法人科学技術振興機構 Entropy filter and region extraction method using the filter
JP2007306083A (en) 2006-05-09 2007-11-22 Konica Minolta Holdings Inc Imaging apparatus and signal processing apparatus
KR101025568B1 (en) 2009-10-12 2011-03-28 중앙대학교 산학협력단 Apparatus and method for focusing position decision using entropy of image
KR101066734B1 (en) 2010-06-21 2011-09-21 중앙대학교 산학협력단 Method and apparatus for texture segmentation based on multi-scale entropy profile
KR101503606B1 (en) 2013-10-15 2015-03-17 창원대학교 산학협력단 Picture Quality Improvement Apparatus and Method based on Detail Information

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3860540B2 (en) * 2000-12-01 2006-12-20 独立行政法人科学技術振興機構 Entropy filter and region extraction method using the filter
JP2007306083A (en) 2006-05-09 2007-11-22 Konica Minolta Holdings Inc Imaging apparatus and signal processing apparatus
KR101025568B1 (en) 2009-10-12 2011-03-28 중앙대학교 산학협력단 Apparatus and method for focusing position decision using entropy of image
KR101066734B1 (en) 2010-06-21 2011-09-21 중앙대학교 산학협력단 Method and apparatus for texture segmentation based on multi-scale entropy profile
KR101503606B1 (en) 2013-10-15 2015-03-17 창원대학교 산학협력단 Picture Quality Improvement Apparatus and Method based on Detail Information

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