JP2021131313A - Material evaluation device, method for evaluating material, and program - Google Patents

Abstract

To accurately detect a specific phase in a material.SOLUTION: A material evaluation device 200 acquires luminance information of a sintered ore sample 6 and sequentially executes expansion processing and contraction processing on the luminance information of the sintered ore sample 6. The material evaluation device 200 generates detection luminance information in which a luminance value based on the difference between luminance information of an original sintered ore sample 6 before the expansion processing is executed and luminance information of the sintered ore sample 6 after the contraction processing is executed is included as the luminance value of each pixel. The material evaluation device 200 detects a region with pores on the basis of the luminance value of each pixel in the detection luminance information.SELECTED DRAWING: Figure 2

Description

The present invention relates to material evaluation devices, material evaluation methods, and programs, and is particularly suitable for use in detecting a specific phase in a material.

Pore information is an important indicator for materials. Taking sinter, which is a raw material for blast furnaces, as an example, sinter having a dense structure with a small porosity has high strength, while sinter having a structure with many pores and a high specific surface area is reducible. It gets higher. Since not only this porosity but also the size of the pores and their distribution affect the material quality, the porosity evaluation is important in evaluating the material quality. Therefore, a technique for identifying pore information in a material with high accuracy is important for high quality and quality evaluation of the material. Patent Document 1 describes the total number of pixels showing a CT value that is equal to or less than the reference CT value with respect to the total number of all pixels existing in the area surrounded by the outline of the measurement object in the X-ray CT image of the measurement object. It is described that the ratio of is estimated as the crude air pore ratio of the object to be measured. The coarse air pores are pores existing in the entire one pixel region constituting the X-ray CT image of the object to be measured.

Japanese Unexamined Patent Publication No. 2019-82388 Japanese Unexamined Patent Publication No. 2009-30104

In the technique described in Patent Document 1, it is determined whether or not the pores are pores depending on whether or not the CT value is equal to or less than the reference CT value. However, in a material such as sinter, some of the brightness ranges in different phases may overlap in the image within the material. In such a case, the technique described in Patent Document 1 may cause undetection of pores (cannot detect pores) or erroneous detection (detection of a phase other than pores as pores). Such a problem is a problem that exists in common even when detecting a specific phase other than the pores of the material.

The present invention has been made in view of the above problems, and an object of the present invention is to enable accurate detection of a specific phase in a material.

The material evaluation device of the present invention is a material evaluation device that detects a specific phase of a material containing a plurality of phases, and is an acquisition means for acquiring information including a brightness value for each pixel as brightness information of the material. With respect to the brightness information of the material acquired by the acquisition means, the brightness value of the attention pixel is set to the brightness equal to or higher than the brightness value of the attention pixel based on the brightness value of the pixel in the region of a predetermined size around the attention pixel. With respect to the expansion means for executing the expansion process for changing the value for each pixel and the luminance information of the material after the expansion process is performed by the expansion means, the predetermined size around the pixel of interest. A shrinking means for executing a shrinking process for each pixel to change the brightness value of the attention pixel to a brightness value equal to or less than the brightness value of the attention pixel based on the brightness value of the pixel in the region, and the expansion. Based on the difference between the luminance value of each pixel in the original luminance information of the material before the process is executed and the luminance value of each pixel in the luminance information of the material after the shrinkage process is executed by the shrinking means. The specific phase is detected based on the generation means for generating the detection luminance information in which the luminance value is included as the luminance value of each pixel and the luminance value of each pixel in the detection luminance information generated by the generation means. The minimum luminance value in the luminance range of the particular phase is lower than the lowest luminance value in the luminance range of the other phases of the plurality of phases.

The material evaluation method of the present invention is a material evaluation method for detecting a specific phase of a material containing a plurality of phases, and includes an acquisition step of acquiring information including a luminance value for each pixel as the luminance information of the material. Regarding the brightness information of the material acquired by the acquisition step, the brightness value of the attention pixel is set to the brightness equal to or higher than the brightness value of the attention pixel based on the brightness value of the pixel in the region of a predetermined size around the attention pixel. With respect to the expansion step of executing the expansion process of changing to a value for each pixel and the luminance information of the material after the expansion process is performed by the expansion process, the predetermined size around the pixel of interest. A shrinkage step of executing a shrinkage process for each pixel to change the brightness value of the attention pixel to a brightness value equal to or less than the brightness value of the attention pixel based on the brightness value of the pixel in the region, and the expansion. Based on the difference between the luminance value of each pixel in the original luminance information of the material before the process is executed and the luminance value of each pixel in the luminance information of the material after the shrinkage process is executed by the shrinkage step. The specific phase is detected based on the generation step of generating the detection luminance information in which the luminance value is included as the luminance value of each pixel and the luminance value of each pixel in the detection luminance information generated by the generation step. The minimum luminance value in the luminance range of the specific phase is lower than the lowest luminance value in the luminance range of the other phases of the plurality of phases.

The program of the present invention is characterized in that a computer functions as each means of the material evaluation device.

According to the present invention, a specific phase in a material can be accurately detected.

FIG. 1 is a diagram showing an example of the configuration of an image generation system. FIG. 2 is a diagram showing an example of a functional configuration of a material evaluation device. FIG. 3 is a diagram showing an example of an X-ray three-dimensional CT image of a sinter sample. FIG. 4 is a diagram showing an example of a histogram of the luminance values obtained from the luminance information of the sinter sample. FIG. 5 is a diagram illustrating an example of an expansion process and a contraction process. FIG. 6 is a diagram illustrating an example of processing in the material evaluation device. FIG. 7 is a flowchart illustrating an example of a material evaluation method. FIG. 8 is a diagram showing detection luminance information derived using kernels of four sizes and pore regions detected from these four detection luminance information. FIG. 9 is a diagram showing an example of a histogram of the luminance values of the luminance information for detection. FIG. 10 is a diagram showing a stomatal region determined by the method of the invention example. FIG. 11 is a diagram showing the results of detecting pores in a part of the region of FIG. FIG. 12 is a diagram showing an example of the relationship between the sphere-equivalent diameter of the pores and the number of pores.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. It should be noted that the same comparison target such as length, position, size, interval, etc. is not only the case where they are exactly the same, but also the ones which are different within the range not deviating from the gist of the invention (for example, the tolerance determined at the time of design). (Different within the range) shall also be included.

In the present embodiment, the case where the specific phase of the material is the region of the pores of the sinter will be described as an example. Further, in the present embodiment, a case where the luminance information obtained by X-ray CT (Computed Tomography) is used as the luminance information of the material will be described as an example.
<Image generation system>
FIG. 1 is a diagram showing an example of a configuration of an image generation system that generates an X-ray CT image. FIG. 1 shows an example of the configuration of an image generation system when micro focus X-ray CT is used.
The image generation system includes an X-ray source 1, a filter 2, a sample stage 3, and an X-ray detector 4.

The X-ray source 1 is a microfocus X-ray source including a vacuum tube having a cathode and an anode for generating X-rays 5. The X-ray source 1 generates an electron beam at the cathode under vacuum and high voltage, converges and accelerates the electron beam, and causes the electron beam to collide with the focal point of a target (tungsten, etc.) of the anode to generate X-ray 5. ..

The filter 2 is arranged in the passage region of the X-ray 5 between the X-ray source 1 and the sample stage 3 to remove the low energy component of the X-ray 5.
The sample stage 3 is for fixing the sinter sample 6 and rotating the sinter sample 6 around its central axis to change the irradiation direction of the X-ray 5 on the sinter sample 6. ..
The X-ray detector 4 is an image intensifier (I.I.) type for converting X-rays 5 (hereinafter referred to as transmitted X-rays) transmitted through the sinter sample 6 into a visible light image. It is a detector.

By rotating the sample stage 3 on which the sinter sample 6 is placed, the X-rays 5 generated by the X-ray source 1 are irradiated to the sinter sample 6 from a plurality of directions. The transmitted X-rays transmitted through the sinter sample 6 are converted into a visible light image by the X-ray detector 4. From the intensity of the X-rays irradiated from the X-ray source 1 and the intensity of the transmitted X-rays, the spatial distribution of the X-ray absorption coefficient inside the sintered ore sample 6 can be obtained by the reconstruction calculation.

The X-ray absorption coefficient is a relative value (non-dimensional) of CT with respect to water so that the CT value of water (density = 1) is 0 and the CT value of air (density ≈ 0) is, for example, -1000. Then, a shade (brightness) image of 65536 gradations (CT = 0 (CT of air) to 65536) according to the CT value is obtained as a three-dimensional CT image of the sintered ore sample 6. The three-dimensional CT image of the sinter sample 6 is displayed so as to be bright (close to white) in the pixel region having a high CT value and dark (close to black) in the pixel region having a low CT value. The three-dimensional CT image of the sinter sample 6 includes a brightness value for each pixel (voxel). From the three-dimensional CT image of the sinter sample 6, a two-dimensional cross-sectional CT image of the sinter sample 6 can be obtained. The two-dimensional cross-sectional CT image of the sinter sample 6 includes a luminance value for each pixel. FIG. 3 is a diagram (photograph) showing an example of an X-ray three-dimensional CT image of the sinter sample 6. In the following description, the three-dimensional CT image of the sinter sample 6 will be referred to as the luminance information of the sinter sample 6 if necessary. The brightness information of the sinter sample 6 may be a two-dimensional cross-sectional CT image of the sinter sample 6.
The method itself for generating a three-dimensional image of the sinter sample 6 or a two-dimensional cross-sectional image of the sinter sample 6 can be realized by a known technique described in Patent Document 2 and the like. Therefore, the detailed description thereof will be omitted here. Further, the method for generating a three-dimensional image of the sinter sample 6 or a two-dimensional cross-sectional image of the sinter sample 6 is not limited to the above-mentioned image generation system.

<Material evaluation device 200>
FIG. 2 is a diagram showing an example of a functional configuration of the material evaluation device 200. The hardware of the material evaluation device 200 is realized by using, for example, a CPU, a ROM, a RAM, an HDD, an information processing device having various interfaces, or dedicated hardware. An example of the function of the material evaluation device 200 will be described below.

<< Acquisition section 201 >>
The acquisition unit 201 acquires the luminance information of the sinter sample 6 generated by the image generation system. When the information processing device of the image generation system generates the brightness information of the sintered ore sample 6, the acquisition unit 201 receives the brightness information of the sintered ore sample 6 transmitted from the information processing device of the image generation system. Thereby, the brightness information of the sintered ore sample 6 can be acquired. Further, when the brightness information of the sinter sample 6 generated by the information processing apparatus of the image generation system is stored in the storage medium, the acquisition unit 201 reads the brightness information of the sinter sample 6 from the storage medium. Therefore, the brightness information of the sinter sample 6 can be acquired. In addition, the acquisition unit 201 may generate luminance information of the sinter sample 6 based on the visible light image obtained by the X-ray detector 4.

<< Black Top Hat Processing Unit 202 >>
The black top hat processing unit 202 executes the black top hat processing on the luminance information of the sinter sample 6 to generate the luminance information for detection. The detection luminance information is the luminance information (information including the luminance value for each pixel) used for specifying the pore region of the sinter sample 6.

FIG. 4 is a diagram showing an example of a histogram of the luminance values obtained from the luminance information of the sinter sample 6. The unit of the brightness value shown in FIG. 4 is an arbitrary unit. In the example shown in FIG. 4, the luminance range indicated by the pore region of the sinter sample 6 is approximately 0 to 32,500. The luminance range indicated by the Silicate Slag region of the sinter sample 6 is approximately 18,000 to 36,500. The luminance range indicated by the calcium ferrite region of the sinter sample 6 is approximately 32500 to 41000. The luminance range indicated by the hematite and magnetite regions of the sinter sample 6 is approximately 36,500 or more. It should be noted that these luminance ranges are obtained from past knowledge about the luminance information of the sinter sample 6 and are not uniquely determined.

As shown in FIG. 4, the sinter has a plurality of phases, and a part of the brightness range of the plurality of phases overlaps. In this embodiment, the material evaluation device 200 identifies the pore region of the sinter sample 6. A part of the brightness range of the pore region of the sinter sample 6 overlaps with a part of the brightness range of the silicate slag region of the sinter sample 6. Therefore, as described in Patent Document 1, a pixel having a brightness value lower than the threshold value with respect to the brightness information of the sinter sample 6 is specified as a pixel corresponding to the pore region of the sinter sample 6. , Undetected or false detection of stomatal area occurs. For example, when the threshold is less than 18,000, the region of the silicate slag is less likely to be detected as the region of the pores, but the region of the pores that is not detected increases. On the other hand, for example, when the threshold value exceeds 18,000, the undetected pore region is reduced, but the silicate slag region is more likely to be detected as the pore region. Therefore, the present inventor performs a black top hat treatment that emphasizes a low-luminance region surrounded by a high-luminance region on the brightness information of the sinter sample 6 to obtain pores in the sinter sample 6. I came up with the idea of detecting the area of.

Further, the pores of the sinter include open pores in which a part of the region is exposed on the surface of the sinter and closed pores in which the region is not exposed on the surface of the sinter. In addition, the shape and size of the pores of the sinter are various. Therefore, the present inventor has come up with the idea of detecting the pore region of the sinter sample 6 by performing a black top hat treatment using each of a plurality of kernels having different sizes. The kernel is a pixel area that is referred to when changing the brightness value of the pixel of interest. Further, the black top hat process is a process of removing the difference between the closed image of the original image and the original image, and is also called a black hat process or the like.

The black top hat processing unit 202 has an expansion unit 202a, a contraction unit 202b, and a generation unit 202c. FIG. 5 is a diagram illustrating an example of an expansion process and a contraction process. Specifically, FIG. 5A is a diagram illustrating an example of expansion processing. FIG. 5B is a diagram illustrating an example of shrinkage processing. FIG. 6 is a diagram illustrating an example of processing in the material evaluation device 200. FIG. 6 shows how the luminance information of the sinter sample 6 changes in the order of FIG. 6 (a), FIG. 6 (b), FIG. 6 (c), FIG. 6 (d), and FIG. 6 (e).

In FIGS. 5 and 6, for convenience of notation, the luminance information of the sinter sample 6 is shown in two dimensions. Further, in FIGS. 5 and 6, the rectangles arranged vertically and horizontally represent pixels (voxels), and the numerical values in the rectangles represent the luminance values. In FIGS. 5 and 6, it is assumed that the kernel is a rectangular region consisting of a pixel of interest and eight pixels adjacent to the pixel of interest, for a total of nine pixels. In the present embodiment, since the brightness information of the sinter sample 6 is a three-dimensional CT image of the sinter sample 6, the shape of the kernel is also a three-dimensional shape (for example, a cube).

<<< Expansion part 202a >>>
The luminance information of the sinter sample 6 includes the luminance value for each pixel (voxel). The expansion unit 202a executes an expansion process on the brightness information of the sinter sample 6.
In FIG. 5A, it is assumed that pixel 501 is a pixel of interest. In this case, the expansion unit 202a changes the brightness value of the pixel 501 to the brightness value (= 10) of the pixel 502 having the highest brightness value among the nine pixels included in the kernel with respect to the pixel 501.

The expansion unit 202a sequentially selects all the pixels in the brightness information of the sinter sample 6 as the pixels of interest, and changes the brightness value of the pixels of interest as described above. One expansion process is executed by changing the luminance value of the pixel of interest with all the pixels in the luminance information of the sinter sample 6 as the pixels of interest. Here, a case where one expansion process is executed will be described as an example. However, the expansion unit 202a may further perform the expansion treatment on the brightness information of the sinter sample 6 that has been expanded. The number of times the expansion process is executed is preset.

FIG. 6A is a diagram showing an example of luminance information of the sinter sample 6 before the expansion treatment is executed. When the expansion treatment is executed on the luminance information of the sinter sample 6 shown in FIG. 6 (a), the luminance information of the sinter sample 6 is changed as shown in FIG. 6 (b).

<< Shrinkage 202b >>
The shrinkage portion 202b executes the shrinkage treatment on the brightness information of the sinter sample 6 after the expansion treatment is executed by the expansion portion 202a.
In FIG. 5B, it is assumed that pixel 503 is a pixel of interest. In this case, the contraction unit 202b changes the brightness value of the pixel 503 to the brightness value (= 1) of the pixel 504 having the lowest brightness value among the nine pixels included in the kernel with respect to the pixel 503.

The shrinkage portion 202b sequentially selects all the pixels in the brightness information of the sinter sample 6 after the expansion treatment is executed as the pixels of interest, and changes the brightness value of the pixels of interest as described above. One shrinkage treatment is executed by changing the brightness value of the pixel of interest with all the pixels in the brightness information of the sinter sample 6 after the expansion treatment being executed as the pixels of interest. Here, a case where one shrinkage process is executed will be described as an example. However, the shrinkage portion 202b may further perform an expansion treatment on the brightness information of the sinter sample 6 that has undergone the shrinkage treatment. The number of times the shrinkage process is executed is preset. Further, the number of times the expansion process is executed and the number of times the contraction process is executed are the same.

When the shrinkage treatment is executed for the luminance information of the sinter sample 6 after the expansion treatment (the luminance information of the sinter sample 6 shown in FIG. 6B), the sinter sample 6 The luminance information is changed as shown in FIG. 6 (c).

<<< Generator 202c >>>
In the generation unit 202c, the brightness value of each pixel of the brightness information of the original sintered ore sample 6 before the expansion treatment is performed by the expansion unit 202a, and the sintered ore sample after the shrinkage treatment is executed by the contraction unit 202b. The detection luminance information is generated in which the luminance value based on the difference from the luminance value of each pixel in the luminance information of 6 is included as the pixel value of each pixel.

In the present embodiment, the generation unit 202c is based on the brightness value of each pixel in the brightness information of the sintered ore sample 6 after the shrinkage treatment is executed by the shrinkage unit 202b, before the expansion treatment is performed by the expansion unit 202a. The luminance information for detection is generated in which the luminance value obtained by subtracting the luminance value of each pixel from the luminance information of the sintered ore sample 6 is included as the pixel value of each pixel. When generating the luminance information for detection, the luminance information of the sinter sample 6 after the shrinkage treatment is executed and the luminance information of the original sinter sample 6 before the expansion treatment is performed. The brightness values of the pixels at the same positions are subtracted from each other.

From the luminance value of each pixel of the luminance information of the sinter sample 6 (luminance information of the sinter sample 6 shown in FIG. 6 (c)) after the shrinkage treatment is executed, the sintering shown in FIG. 6 (a). When the brightness value of each pixel of the brightness information of the ore sample 6 is subtracted, the detection brightness information shown in FIG. 6D is generated.

<<< Iterative processing >>>
As described above, the black top hat processing unit 202 executes the black top hat processing when one kernel is used. The black top hat processing unit 202 generates the detection luminance information as described above by using a plurality of kernels having different sizes. If the size of the kernel is small, detection omissions in a large region of a specific phase (in this embodiment, the pore region of the sinter sample 6) are likely to occur. Conversely, large kernel sizes are prone to missed detections in small areas of a particular phase. From this point of view, the size of the kernel is preset according to, for example, the size of the sinter sample 6 and the size of a specific phase. For example, when four kernels having different sizes are used, the black top hat processing unit 202 generates four detection luminance information.

<< Detection unit 203 >>
The detection unit 203 is a specific phase (in the present embodiment, the sintered ore sample 6) based on the brightness value of each pixel in the plurality of detection brightness information generated by the top hat processing unit 202 (generation unit 202c). The area of the pores) is detected.
In the present embodiment, the detection unit 203 detects a pixel having a brightness value higher than the threshold value among the brightness values of each pixel in the detection brightness information as a pixel corresponding to the pore region of the sinter sample 6. .. As a threshold value to be compared with the brightness value of each pixel in the detection brightness information, it is preferable to use a different threshold value depending on the size of the kernel. For example, the smaller the size of the kernel used for the expansion and contraction processing performed to generate the detection luminance information, the smaller the threshold value can be used. If different thresholds are used according to the size of the kernel, different thresholds may be used for each size of the kernel, or different thresholds may be used for each of a plurality of sizes of the kernel. Further, instead of doing so, the threshold value to be compared with the brightness value of each pixel in all the detection luminance information may be the same (in this case, the number of threshold values is one).

The detection unit 203 detects the pixels corresponding to the pore regions of the sinter sample 6 as described above for each of the plurality of detection luminance information.
In the detection luminance information shown in FIG. 6 (d), the region of the pixel having the luminance value exceeding 4 (the region shown by the diagonal line) is detected as the pixel corresponding to the region of the pores of the sinter sample 6.
In the present embodiment, the detection unit 203 uses all the pixels corresponding to the pore regions of the sinter sample 6 detected from the plurality of detection luminance information as the pixels corresponding to the pore regions of the sinter sample 6. To determine as.

<< Output section 204 >>
The output unit 204 outputs information regarding the pixels corresponding to the pore regions of the sinter sample 6 determined by the detection unit 203. As the form of output, at least one of display on a computer display, storage in an internal or external storage medium of the material evaluation device 200, and transmission to an external device can be adopted.

<Flowchart>
Next, an example of the material evaluation method by the material evaluation device 200 of the present embodiment will be described with reference to the flowchart of FIG. 7.
In step S701, the acquisition unit 201 acquires the luminance information (luminance information of the material) of the sinter sample 6 generated by the image generation system.

Next, in step S702, the black top hat processing unit 202 selects one unselected size from the plurality of preset kernel sizes.
Next, in step S703, the expansion unit 202a selects one of the unselected pixels among the pixels included in the luminance information of the sinter sample 6 as the pixel of interest.

Next, in step S704, the expansion unit 202a sets the brightness value of the pixel of interest selected in step S703 as a pixel in the area of the pixel centered on the pixel of interest and having a size selected in step S702. Among the pixels in the pixel area included in the kernel, the brightness value of the pixel having the highest pixel value is changed.

Next, in step S705, the expansion unit 202a determines whether or not all the pixels included in the luminance information of the sinter sample 6 are selected as the pixels of interest. As a result of this determination, if all the pixels included in the luminance information of the sinter sample 6 are not selected as the pixels of interest, the process of step S703 is executed again. The processes of steps S703 to S705 are repeatedly executed until the process of step S704 is executed with all the pixels included in the luminance information of the sinter sample 6 as the pixels of interest.

On the other hand, if it is determined in step S705 that all the pixels included in the luminance information of the sinter sample 6 are selected as the pixels of interest, the process of step S706 is executed. In step S706, the expansion unit 202a determines whether or not the expansion processing (processing of steps S703 to S705) has been executed a predetermined number of times. In the present embodiment, since the expansion process is executed once, the process of step S706 may not be performed. As a result of this determination, if the expansion process (process of steps S703 to S705) is not performed a predetermined number of times, the process of step S703 is executed again. In this case, instead of the luminance information of the sinter sample 6 acquired in step S701, the luminance information of the sinter sample 6 after the immediately preceding expansion treatment (the treatments of steps S703 to S705) is executed. , The expansion process (process of steps S703 to 705) is executed. In the following description, the luminance information of the sinter sample 6 after the treatment (final expansion treatment) of step S704 immediately before it is determined that the expansion treatment has been executed a predetermined number of times in step S706 is performed, if necessary. This is referred to as the luminance information of the sinter sample 6 after the expansion treatment has been executed a predetermined number of times.

If it is determined in step S706 that the expansion process (processes of steps S703 to S705) has been executed a predetermined number of times, the process of step S707 is executed. In step S707, the shrinking portion 202b selects one of the unselected pixels in the luminance information of the sinter sample 6 after the expansion treatment is executed a predetermined number of times as the pixel of interest.
Next, in step S708, the contraction unit 202b sets the brightness value of the pixel of interest selected in step S707 to a pixel in the area of the pixel centered on the pixel of interest and having a size selected in step S702. The brightness value of the pixel having the lowest pixel value among the pixels in the pixel area included in the kernel is changed.

Next, in step S709, the contraction portion 202b determines whether or not all the pixels included in the luminance information of the sinter sample 6 after the expansion treatment has been executed a predetermined number of times have been selected as the pixels of interest. As a result of this determination, if not all the pixels included in the luminance information of the sinter sample 6 after the expansion treatment has been executed a predetermined number of times have been selected as the pixels of interest, the processing of step S707 is executed again. The processes of steps S707 to S709 are repeatedly executed until the process of step S708 is executed with all the pixels included in the luminance information of the sinter sample 6 after the expansion process executed a predetermined number of times as the pixels of interest. ..

On the other hand, in step S709, if it is determined that all the pixels included in the luminance information of the sinter sample 6 after the expansion treatment has been executed a predetermined number of times have been selected as the pixels of interest, the processing of step S710 is executed. NS. In step S710, the contraction unit 202b determines whether or not the contraction process (process of steps S707 to S709) has been executed a predetermined number of times. In the present embodiment, the shrinkage process is executed once, so that the process of step S710 may not be performed. As a result of this determination, if the shrinkage process (process of steps S707 to S709) is not performed a predetermined number of times, the process of step S707 is executed again. In this case, instead of the luminance information of the sinter sample 6 after the expansion treatment has been executed a predetermined number of times, the sinter sample 6 after the immediately preceding shrinkage treatment (treatments in steps S707 to S709) has been executed. The shrinkage process (processes of steps S707 to S709) is executed for the luminance information. In the following description, the luminance information of the sinter sample 6 after the treatment (final shrinkage treatment) of step S708 immediately before it is determined that the shrinkage treatment has been executed a predetermined number of times in step S710 is obtained, if necessary. This is referred to as the luminance information of the sinter sample 6 after the shrinkage treatment has been executed a predetermined number of times.

If it is determined in step S710 that the shrinkage process (process of steps S707 to S709) has been executed a predetermined number of times, the process of step S711 is executed. In step S711, the generation unit 202c obtains the luminance information of the sinter sample 6 acquired in step S701 from the luminance value of each pixel of the luminance information of the sinter sample 6 after the shrinkage treatment is executed a predetermined number of times. Generates detection luminance information in which the luminance value of the value obtained by subtracting is included as the luminance value of each pixel.

Next, in step S712, the black top hat processing unit 202 determines whether or not kernels of all preset sizes have been selected. As a result of this determination, if the kernels of all the preset sizes are not selected, the process of step S702 is executed again. Then, the processes of steps S702 to S711 are executed again using the unselected kernel.

If it is determined in step S712 that the kernels of all the preset sizes have been selected, the process of step S713 is executed. In step S713, the detection unit 203 specifies a pixel having a brightness value higher than the threshold value among the brightness values of each pixel in the detection brightness information generated in step S711 as a pore region (specification) of the sinter sample 6. The detection as the pixel corresponding to (Phase) is performed individually for each of the plurality of detection luminance information. The number of detection luminance information is the same as the number of kernels selected in step S702. The detection unit 203 determines all the pixels corresponding to the pore regions of the sinter sample 6 detected from the plurality of detection luminance information as the pixels corresponding to the pore regions of the sinter sample 6.

Next, in step S714, the output unit 204 outputs information regarding the pixel corresponding to the pore region of the sinter sample 6 determined in step S713. When the process of step S714 is completed, the process according to the flowchart of FIG. 7 is completed.

<Summary>
As described above, in the present embodiment, the material evaluation device 200 acquires the luminance information of the sinter sample 6 and executes the expansion treatment and the contraction treatment in this order with respect to the luminance information of the sinter sample 6. .. Then, the material evaluation device 200 has a brightness based on the difference between the brightness information of the original sinter sample 6 before the expansion treatment is executed and the brightness information of the sinter sample 6 after the shrinkage treatment is executed. Generates detection luminance information in which the value is included as the luminance value of each pixel. Then, the material evaluation device 200 detects the pore region based on the brightness value of each pixel in the detection brightness information. Here, the minimum value of the brightness range of the pores is lower than the minimum value of the brightness range of the other phases of the sinter sample 6 (the brightness range of the pores is lower than the brightness range of the other phases). Therefore, even when the brightness range of the specific phase overlaps with a part of the brightness range of the other phase, the specific phase can be detected with high accuracy.

Further, in the present embodiment, the material evaluation device 200 executes the expansion process and the contraction process in this order using each of the kernels having a plurality of preset sizes. Therefore, it is possible to further suppress the detection omission of a specific phase.

Further, in the present embodiment, the material evaluation device 200 detects the pore region as an example of a specific phase based on the result of comparing the brightness value of each pixel of the detection brightness information with the threshold value. Therefore, the region of a specific phase can be automatically detected. In addition, when performing expansion processing and contraction processing in this order using each of a plurality of preset kernel sizes, a specific phase can be set by setting different threshold values according to the kernel size. It is possible to further suppress the detection omission of.

<Modification example>
In the present embodiment, the case where the material is sinter is described as an example. However, the material is not limited to sinter. For example, iron ore, iron ore pseudo-particles (sintered ore raw material before firing), coal, coke, steel material, or the like may be used.

Further, if kernels having a plurality of sizes are used as in the present embodiment, it is possible to suppress the detection omission of the specific phase even when the specific phase is a phase capable of taking various sizes. preferable. However, it is not always necessary to do this. For example, if the size of a particular phase is known in advance to be similar, the size of the kernel may be one. Further, even if a specific phase is a phase having various sizes, if only a phase having a desired size (for example, fine pores) is detected, the kernel size may be one. good.

Further, in the present embodiment, the case where the specific phase is a pore (a hole formed in the material) has been described as an example. However, in the luminance information of the material containing the plurality of phases, if the lowest luminance value in the luminance range of the specific phase is lower than the lowest luminance value in the luminance range of the other phases of the plurality of phases (the plurality of said). The specific phase is not limited to the pores (as long as the brightness range of the specific phase is the lowest brightness range of the brightness range of the phase). For example, a region of rust in a steel material having no pores may be a region of a specific phase.

Further, in the present embodiment, the case where the luminance information of the material is an X-ray CT image has been described as an example. However, the luminance information of the material is not limited to the X-ray CT image. For example, a photographed image of a cross section exposed by polishing the material may be used as brightness information of the material.

Further, in the present embodiment, from the brightness value of each pixel of the brightness information of the sintered ore sample 6 after the shrinkage treatment is executed, the brightness information of the original sintered ore sample 6 before the expansion treatment is executed is obtained. An example of generating detection luminance information in which the luminance value obtained by subtracting the pixel value of each pixel is included as the pixel value of each pixel has been described. However, it is not always necessary to do this. For example, from the pixel value of each pixel of the brightness information of the original sintered ore sample 6 before the expansion treatment is executed, the brightness value of each pixel of the brightness information of the sintered ore sample 6 after the shrinkage treatment is executed. You may generate the detection luminance information in which the luminance value of the value obtained by subtracting is included as the pixel value of each pixel. In this case, the brightness value of each pixel of the detection brightness information can take a negative value (see FIGS. 6 (a) and 6 (b)). Therefore, among the brightness values of each pixel of the detection brightness information, the pixel having the brightness value lower than the threshold value (or the brightness value whose absolute value is larger than the threshold value) corresponds to the pore region of the sinter sample 6. Detect as a pixel.

In the embodiment of the present invention described above, the processing of the material evaluation device 200 can be realized by executing a program by a computer. Further, a computer-readable recording medium on which the program is recorded and a computer program product such as the program can also be applied as an embodiment of the present invention. As the recording medium, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a non-volatile memory card, a ROM, or the like can be used.
In addition, the embodiments of the present invention described above are merely examples of embodiment of the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. It is a thing. That is, the present invention can be implemented in various forms without departing from the technical idea or its main features.

<Example>
Next, an embodiment will be described. The present invention is not limited to this embodiment.
In this embodiment, the pores of the sinter are detected. In the example of the invention, the pore region of the sinter was detected by applying the method of the above-described embodiment to the three-dimensional X-ray CT image of the sinter. In the example of the invention, four sizes are adopted as the kernel sizes. Specifically, kernels in the range of 100 voxels, 10 voxels, 3 voxels, and 1 voxel (kernel with a size of 201 × 201 × 201, 21 × 21 × 21) in each of the left / right, up / down, and front / rear directions of the pixel of interest. A size kernel, a 7x7x7 size kernel, and a 3x3x3 size kernel) were adopted.
In the comparative example, one threshold value was set for the three-dimensional X-ray CT image of the sinter used in the invention example, and the region of the pixel having the brightness lower than the threshold value was detected as the region of the pores of the sinter. ..

FIG. 8 is a diagram showing the detection luminance information derived using the kernels of the four sizes described above and the pore regions detected from these four detection luminance information. As described above, the detection luminance information includes the difference between the luminance information of the original sinter sample 6 before the expansion treatment is executed and the luminance information of the sinter sample 6 after the shrinkage treatment is executed. The brightness value based on is included as the brightness value of each pixel.

Luminance information for detection 801 to 804 is shown on the upper side of FIG. 8 (the base end side of the white arrow line). On the lower side of FIG. 8 (the tip side of the white arrow line), the detection luminance information 810 to 814 that emphasizes the pore region detected from the detection luminance information 801 to 804 is shown. The detection luminance information 810 to 814 shown on the lower side of FIG. 8 is a pixel having a luminance value higher than the threshold value with respect to the detection luminance information 801 to 804 shown on the upper side of FIG. 8 (pixel corresponding to the pore region). The area of is filled with a predetermined density. FIG. 9 shows the detection luminance information 801 generated using the largest kernel (kernel having a size of 201 × 201 × 201) having a range of 100 voxels in each of the left / right, up / down, and front / rear directions of the pixel of interest. It is a figure which shows the histogram of the luminance value. The pixel which has the luminance value higher than 195,000 is highlighted in the detection luminance information 811 shown in FIG. 8 with respect to the detection luminance information 801 shown in FIG. (Filled with a predetermined density) In the detection luminance information 811 to 814 shown on the lower side of FIG. 8, the black region (dense region) is not a pixel corresponding to the pore region.

In the detection luminance information 810 to 814 of FIG. 8, a region obtained by adding all the regions of pixels filled with a predetermined density is determined as a pore region. FIG. 10 is a diagram showing a stomatal region determined by the method of the invention example. In FIG. 10, the pixels determined as the pore regions are filled with a plurality of predetermined densities.

FIG. 11 is a diagram showing the results of detecting pores in a part of the region 1001 of FIG. FIG. 11A shows the results obtained by the method of the invention example. FIG. 11A is an enlarged view of the region 1001 of FIG. FIG. 11B shows the results obtained in the comparative example. FIG. 11B shows a stomatal region determined by the method of the comparative example from the region 1001 of FIG. In FIGS. 11 (a) and 11 (b), the pixels determined as the pore regions are filled with a predetermined density.

Comparing FIG. 11 (a), which is the result obtained by the method of the invention example, with FIG. 11 (b), which is the result obtained by the method of the comparative example, in FIG. 11 (b), the regions 1101 and 1102 It can be seen that the region that was not detected as a pore in the region is detected as a pore in the regions 1101 and 1102 in FIG. 11 (a). In FIG. 11B, the black dot-shaped regions in the regions 1101 and 1102 are not pixels determined as the pore regions.

FIG. 12 is a diagram showing an example of the relationship between the sphere-equivalent diameter of the pores and the number of pores. The sphere-equivalent diameter of a pore is the diameter of a sphere having the same volume as the region of the pore. FIG. 12 (a) shows the relationship when the sphere-equivalent diameter of the pores is relatively small, and FIG. 12 (b) shows the relationship when the sphere-equivalent diameter of the pores is relatively large.
The number of pores determined by the method of the invention example is larger than the number of pores determined by the method of the comparative example, and the smaller the pore size, the more remarkable the difference. In particular, for pores having a sphere-equivalent diameter of 100 μm or less, it can be seen that the method of the invention can significantly reduce undetected pores as compared with the method of the comparative example (see FIG. 12A). ..

1: X-ray source, 2: Filter, 3: Sample stage, 4: X-ray detector, 5: X-ray, 6: Sintered ore sample, 200: Material evaluation device, 201: Acquisition unit, 202: Black top hat Processing unit, 202a: expansion unit, 202b: contraction unit, 202c: generation unit, 203: detection unit, 204: output unit

Claims (11)

A material evaluation device that detects a specific phase of a material containing multiple phases.
As the brightness information of the material, an acquisition means for acquiring information including a brightness value for each pixel, and
With respect to the luminance information of the material acquired by the acquisition means, the luminance value of the pixel of interest is set to the luminance value equal to or greater than the luminance value of the pixel of interest, based on the luminance value of the pixels in the region of a predetermined size around the pixel of interest. An expansion means that executes an expansion process that changes each pixel to a value,
Regarding the luminance information of the material after the expansion treatment is performed by the expansion means, the luminance value of the pixel of interest is set based on the luminance value of the pixel in the region of the predetermined size around the pixel of interest. A shrinkage means for executing a shrinkage process for each pixel to change the brightness value to a brightness value equal to or less than the brightness value of
The difference between the brightness value of each pixel in the original brightness information of the material before the expansion treatment is executed and the brightness value of each pixel in the brightness information of the material after the shrinkage processing is executed by the shrinkage means. A generation means for generating detection luminance information in which the luminance value based on the above is included as the luminance value of each pixel, and
It has a detection means for detecting the specific phase based on the brightness value of each pixel in the detection brightness information generated by the generation means.
A material evaluation device, characterized in that the lowest luminance value in the luminance range of the particular phase is lower than the lowest luminance value in the luminance range of the other phases of the plurality of phases. The expansion means executes the expansion process using each of a plurality of regions having different sizes as the region of the predetermined size.
The shrinking means performs the shrinking process using each of the plurality of regions,
The generation means includes the brightness information of the original material before the expansion treatment is executed, and the plurality of brightness of the material after the shrinkage treatment is executed by the shrinkage means using each of the plurality of regions. Using the information, generate multiple luminance information for detection,
The material evaluation device according to claim 1, wherein the detection means detects the specific phase based on the brightness value of each pixel in the plurality of detection brightness information. The second aspect of the present invention is characterized in that the detection means detects pixels corresponding to the specific phase region based on the result of comparing the brightness value of each pixel in the detection brightness information with the threshold value. The material evaluation device described. The material evaluation device according to claim 3, wherein different threshold values are set according to the sizes of the plurality of regions. The first aspect of the present invention is characterized in that the detection means detects pixels corresponding to the specific phase region based on the result of comparing the brightness value of each pixel in the detection brightness information with the threshold value. The material evaluation device described. The material evaluation device according to any one of claims 1 to 5, wherein the material is a sinter. The material evaluation apparatus according to any one of claims 1 to 6, wherein the specific phase is a region of a hole formed in the material. The aspect of any one of claims 1 to 7, wherein a part of the brightness range of the specific phase overlaps with a part of the brightness range of at least one other phase of the plurality of phases. Material evaluation device. The material evaluation device according to any one of claims 1 to 8, wherein the luminance information is information obtained based on an X-ray CT image of the material. A material evaluation method that detects a specific phase of a material containing multiple phases.
As the brightness information of the material, an acquisition step of acquiring information including a brightness value for each pixel, and
With respect to the luminance information of the material acquired by the acquisition step, the luminance value of the pixel of interest is set to the luminance value equal to or greater than the luminance value of the pixel of interest, based on the luminance value of the pixels in the region of a predetermined size around the pixel of interest. An expansion process that executes an expansion process that changes each pixel to a value,
Regarding the luminance information of the material after the expansion process is performed by the expansion step, the luminance value of the pixel of interest is determined based on the luminance value of the pixels in the region of the predetermined size around the pixel of interest. A shrinking step of executing a shrinking process for each pixel to change to a brightness value equal to or less than the brightness value of
The difference between the brightness value of each pixel in the brightness information of the original material before the expansion process is executed and the brightness value of each pixel in the brightness information of the material after the shrinkage process is executed by the shrinkage step. A generation step of generating detection luminance information in which the luminance value based on the above is included as the luminance value of each pixel, and
It has a detection step of detecting the specific phase based on the brightness value of each pixel in the detection brightness information generated by the generation step.
A material evaluation method, wherein the lowest luminance value in the luminance range of the particular phase is lower than the lowest luminance value in the luminance range of the other phases of the plurality of phases. A program characterized in that a computer functions as each means of the material evaluation device according to any one of claims 1 to 9.

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