Image creation system

Abstract

An image creation system includes an FIB device, an SEM device, a control device, and an image processing device for analyzing a three-dimensional structure of a target object, the image processing device performing a process of: calculating a brightness average value, which is an average value of brightness of pixels constituting a plurality of captured images; a brightness correction unit that corrects the brightness between the plurality of captured images by correcting the brightness of each pixel of the plurality of captured images so as to reduce the deviation in the brightness of the pixel between the plurality of captured images on the basis of the difference between the brightness of each pixel and the average brightness value; and correcting the brightness in each of the first corrected captured images by correcting the brightness of the pixels of each of the corrected first corrected captured images so as to reduce the brightness difference between the pixels constituting each of the first corrected captured images for each of the corrected first corrected captured images.

Description

Technical Field

[0001] This invention relates to an image creation system. Background Technology

[0002] For example, as a technology of this kind, Patent Document 1 discloses an image creation system that combines a focused ion beam (FIB) device and a scanning electron microscope (SEM) device. In the technology described in Patent Document 1, after cutting the surface of a target object by irradiating the target object with a focused ion beam from the FIB device to expose a new surface, the exposed new surface is photographed using the SEM device to obtain an image.

[0003] Patent Document 1: Japanese Patent No. 4426871 Summary of the Invention

[0004] However, in the technology described in Patent Document 1, there are sometimes cases where the brightness difference between pixels in the image acquired using a SEM device increases, which may make it difficult to accurately analyze the image. When performing three-dimensional structure analysis by alternating between cutting based on a FIB device and imaging based on a SEM device a predetermined number of times, it is conceivable that the brightness deviation of each pixel between multiple image images will increase.

[0005] The present invention was made in view of this, and its object is to provide an image creation system that can perform high-precision three-dimensional structural analysis of a target object by alternating and repeating cutting based on an FIB device and imaging based on a SEM device a predetermined number of times.

[0006] In view of the aforementioned issues, the image creation system of the present invention comprises: a FIB device that exposes a new surface by cutting a predetermined volume of the target object from the surface by irradiating the surface of the target object with a focused ion beam; a SEM device that captures images of the exposed new surface and acquires photographic images by scanning electron microscopy; a control device that controls the FIB device and the SEM device to alternately repeat the cutting based on the FIB device and the imaging based on the SEM device a predetermined number of times; and an image processing device that performs image processing on the multiple photographic images repeatedly captured using the SEM device, wherein the image creation system analyzes the three-dimensional structure of the target object based on the image-processed multiple photographic images. The image processing apparatus is characterized by performing the following processing: calculating the average brightness of the pixels constituting the plurality of camera images, i.e., the average brightness, and correcting the brightness of each pixel in the plurality of camera images in a manner that reduces the brightness deviation of the pixels between the plurality of camera images based on the difference between the brightness of each pixel and the average brightness, thereby correcting the brightness between the plurality of camera images; and for each corrected camera image, correcting the brightness of the pixels in each corrected camera image in a manner that reduces the brightness difference of the pixels constituting each camera image, thereby correcting the brightness within each camera image.

[0007] Invention Effects

[0008] According to the present invention, when cutting based on a FIB device and imaging based on a SEM device are alternately repeated a predetermined number of times, the brightness deviation between multiple imaging images and the brightness deviation within each imaging image can be reduced, thereby enabling high-precision three-dimensional structural analysis of the target object. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the overall image creation system involved in this embodiment.

[0010] Figure 2 This is a flowchart illustrating the steps of performing a three-dimensional structural analysis of a target object using the image creation system described in this embodiment.

[0011] Figure 3 (A) is an example of a camera image obtained from a SEM device. Figure 3 (B) is a method to reduce the brightness deviation of pixels between multiple camera images. Figure 3 The first corrected image is obtained by performing brightness correction on the image shown in (A). Figure 3 (C) is based on reducing the composition. Figure 3(B) shows the second corrected image obtained by performing brightness correction on the brightness difference within the pixels of the first corrected image.

[0012] Figure 4 (A) is correct Figure 3 (A) is a camera image that is automatically drawn by distinguishing pixels according to the three-dimensional structure of the target object without brightness correction. Figure 4 (B) is correct. Figure 3 After the brightness of the second corrected camera image shown in (C) is corrected, the pixel-by-pixel image is automatically drawn in accordance with the three-dimensional structure of the target object.

[0013] Figure 5 (A) is a graph showing the brightness deviation of the pixels that make up one of the images in all the images obtained from the SEM device. Figure 5 (B) is a graph showing the brightness deviation of the pixels of the first corrected image, which is constructed to reduce the brightness deviation of pixels between multiple images.

[0014] Figure 6 It is a graph showing the change in brightness deviation when the brightness of a pixel is corrected for a first corrected image in a way that reduces the brightness difference of the pixels constituting the first corrected image. Detailed Implementation

[0015] [Implementation Method]

[0016] The following is for reference. Figures 1 to 6 The accompanying drawings illustrate embodiments of the present invention in detail. Furthermore, the embodiments shown below are one approach to the present invention and do not limit the scope of the invention.

[0017] <Structure>

[0018] Figure 1 This is a schematic diagram of the overall image creation system 1 according to this embodiment. The image creation system 1 includes a FIB device 11 for irradiating a focused ion beam B, and a scanning electron microscope 121 for acquiring a photographic image 31 of the target object 2 (shown in the following description). Figure 3The system includes a SEM device 12, a control device 13 that controls the operation of the FIB device 11 and the SEM device 12, and an image processing device 14 that processes multiple photographic images 31 repeatedly captured by the SEM device 12. The image processing device 14 can ultimately create a three-dimensional image of the target object 2 based on the multiple photographic images 31. In this embodiment, when creating a three-dimensional image of the target object 2, the image processing device 14 first uses the SEM device 12 to photograph the surface 21 of the target object 2 and acquires photographic images 31. The SEM device 12 has an electron gun (not shown) inside the scanning electron microscope 121. An electron beam E is irradiated from the electron gun and scans the surface 21 of the target object 2 with the electron beam E. This generates secondary electrons or reflected electrons, which are reflected on the surface 21 and reach the first detector 122 inside the scanning electron microscope 121, thereby enabling the surface 21 to be photographed.

[0019] Next, using the FIB device 11, a focused ion beam B is irradiated onto the surface 21 of the target object 2, thereby cutting a predetermined volume of the target object 2 from the surface 21 to expose a new surface 22. Then, using the SEM device 12, the exposed new surface 22 is photographed in the same manner as described above, and an image 31 is acquired again. The control device 13 controls the FIB device 11 and the SEM device 12 to alternately repeat the cutting based on the FIB device 11 and the imaging based on the SEM device 12 a predetermined number of times, thereby enabling the acquisition of multiple image images 31.

[0020] At this time, as the target object 2 is gradually cut by the FIB device 11, the distance from when the electron beam E is irradiated by the electron gun to when it reaches the exposed surface of the target object 2 increases as the cutting based on the FIB device 11 proceeds. Therefore, the amount of secondary electrons or reflected electrons reaching the first detector 122 decreases, resulting in a larger deviation in pixel brightness between multiple images 31 compared to the brightness difference within a single image 31. Specifically, as images 31 are acquired sequentially, the brightness of the pixels in the images 31 tends to decrease overall, making it conceivable that precise analysis is impossible when attempting to analyze different parts of the same structure between images 31.

[0021] Therefore, in this embodiment, in order to correct the brightness deviation of pixels among multiple captured images 31, the image processing device 14 calculates the average brightness of the pixels constituting the multiple captured images 31, namely the average brightness A1 (illustrated later). Figure 5(A) and, based on the difference between the brightness of each pixel and the average brightness A1, correct the brightness of each pixel in the multiple camera images 31 in a way that reduces the brightness deviation of pixels among the multiple camera images 31, thereby correcting the brightness among the multiple camera images 31. Thus, multiple first corrected camera images 32 (illustrated later) can be obtained from the multiple camera images 31. Figure 3 (B) and reduce the brightness deviation of pixels among multiple first-corrected camera images 32. Details are described later. Figure 5 (A) and Figure 5 (B) Provide an explanation.

[0022] Here, if multiple first corrected images 32 are obtained by correcting the brightness between multiple images 31, the deviation of the corrected brightness within each first corrected image 32 becomes greater than the deviation of the brightness within each image 31 before correction. Therefore, in this embodiment, for each corrected first corrected image 32, the brightness of the pixels in each corrected first corrected image 32 is corrected in a way that reduces the brightness difference of the pixels constituting each first corrected image 32, thereby correcting the brightness within each first corrected image 32 and obtaining multiple second corrected images 33. As a result, both the brightness deviation between multiple second corrected images 33 and the brightness deviation within each second corrected image 33 can be reduced, enabling high-precision three-dimensional structural analysis of the target object 2 based on the three-dimensional image of the target object 2 obtained by synthesizing multiple second corrected images 33. (Details will be described later.) Figure 6 Please provide an explanation.

[0023] Furthermore, the SEM device 12 has a second detector 123 for detecting reflected electrons and the like generated by the electron beam E, and the second detector 123 can be configured to be fixed at a specific position. In addition to the first detector 122, the second detector 123 can also detect reflected electrons and the like. By using the second detector 123, a contrast difference can be generated within the captured image 31.

[0024] <Flowchart>

[0025] The following uses Figure 2 The steps for performing three-dimensional structural analysis of the target object 2 using the image creation system 1 according to the embodiment will be described. Figure 2 In the flowchart shown, steps S1 to S3 are mainly processes involving FIB device 11 or SEM device 12, step S4 is the process involving control of control device 13, and steps S5 to S8 are mainly processes involving image processing device 14.

[0026] First, in step S1, the SEM device 12 is used to photograph the surface 21 of the target object 2, and an image 31 is acquired. Next, in step S2, the FIB device 11 is used to cut a predetermined volume of the target object 2 from the surface 21, exposing a new surface 22. In step S3, the SEM device 12 is used to photograph the exposed new surface 22, and another image 31 is acquired. Next, in step S4, the control device 13 determines whether steps S2 and S3 have been repeated a predetermined number of times. Here, the predetermined number of times refers to the value obtained by dividing the total volume of the target object 2 by the predetermined volume cut by the FIB device 11 in step S2. If the predetermined number of times has not been repeated (step S4: No), steps S2 and S3 are executed again.

[0027] After repeating the process a predetermined number of times (step S4: Yes), in step S5, the image processing device 14 corrects the brightness of each pixel in the plurality of captured images 31 in a manner that reduces the brightness deviation of pixels between the plurality of captured images 31, thereby correcting the brightness between the plurality of captured images 31 and acquiring a plurality of first corrected captured images 32. Next, in step S6, the image processing device 14 corrects the brightness within each first corrected captured image 32 in a manner that reduces the brightness difference of pixels constituting each first corrected captured image 32 generated in step S5, and acquires a plurality of second corrected captured images 33.

[0028] Next, in step S7, the image processing device 14 distinguishes and renders the pixels of each second corrected image 33 according to the brightness of the pixels, corresponding to the three-dimensional structure. Here, in this embodiment, distinguishing and rendering according to the three-dimensional structure means distinguishing and rendering different parts of the target object 2 based on a predetermined threshold. Finally, in step S8, the image processing device 14 synthesizes the second corrected image 33 with pixel-distinct rendering to create a three-dimensional image of the target object 2. More specifically, the image processing device 14 creates the three-dimensional image of the target object 2 by connecting the second corrected image 33 with pixel-distinct rendering using straight lines.

[0029] Figure 3 (A) shows an example of a camera image 31 acquired from the SEM device 12. By performing brightness correction on this camera image 31 as described in step S5 above, a result can be obtained. Figure 3 (B) shows the first corrected image 32. Through this correction, the brightness deviation of pixels among the multiple first corrected images 32 is reduced, but the brightness deviation within each first corrected image 32 is greater than the brightness deviation within each image 31. Therefore, by performing the brightness correction in step S6 above on the first corrected image 32, the desired brightness can be obtained. Figure 3 (C) shows the second corrected image 33. Through this correction, the brightness difference of the pixels constituting each second corrected image 33 is less than the brightness difference of the pixels constituting each first corrected image 32.

[0030] In addition, in the case of Figure 3 (A) The image 31 shown above, without brightness correction in steps S5 and S6, automatically distinguishes and renders pixels according to the three-dimensional structure of the target object 2, can obtain the following: Figure 4 (A) shows a differentiated image 34. Because the brightness difference of the pixels constituting this differentiated image 34 is large, it is dark overall and it is difficult to visually identify the camera part of the target object 2.

[0031] To prevent the camera's focus area from being difficult to visually identify, after performing brightness correction in steps S5 and S6, the differentiation rendering in step S7 is automatically performed, thereby obtaining... Figure 4 (B) shows the distinction drawn in the photographic image 35. Compared with the brightness difference of the pixels constituting the photographic image 31, the brightness difference of the pixels constituting the second corrected photographic image 33 is smaller. Therefore, the boundaries formed based on the brightness of the pixels are clear, and the photographed parts of the target object 2 are easily visually identified. Therefore, based on the three-dimensional image of the target object 2 created by synthesizing the second corrected photographic image 33, the three-dimensional structure of the target object 2 can be analyzed with high precision.

[0032] use Figure 5 (A) and Figure 5 (B) The specific steps of step S5 above will be explained. Figure 5 (A) is a graph showing the deviation of the brightness of the pixels of one of the camera images 31, which is acquired from the SEM device 12, and the number of pixels representing the brightness of each pixel. Figure 5 The chart in (A) can be obtained for all 31 camera images. Here, Figure 5 (A) and Figure 5 In graph (B), the vertical axis represents the number of pixels, which corresponds to the frequency of brightness per pixel. Furthermore, Figure 5 The average brightness A1 and standard deviation σ1 of the pixels shown in (A) are values ​​calculated based on the brightness of the pixels in all the captured images 31 obtained from the SEM device 12.

[0033] Figure 5(B) is a graph showing the brightness deviation of the pixels in the first corrected image 32, which has undergone brightness correction to reduce the brightness deviation of pixels among multiple image images 31. The image processing apparatus 14 is equipped with a target average brightness A2 and a target standard deviation σ2 that can be drawn to differentiate pixels in accordance with the three-dimensional structure of the target object 2. The image processing apparatus 14 corrects the brightness among multiple image images 31 such that the average brightness A1 becomes the target average brightness A2 and the standard deviation σ1 becomes the target standard deviation σ2. Compared to the average brightness A1 and the standard deviation σ1, the values ​​of the target average brightness A2 and the target standard deviation σ2 are smaller, resulting in a reduction in the brightness deviation of pixels among the multiple image images 31. Here, regarding... Figure 5 The brightness of the pixel shown in (B) can be expressed by the following formula for all 31 captured images.

[0034] (([ Figure 5 (A) The brightness of each pixel shown is (brightness) - (average brightness A1) / standard deviation σ1) × target standard deviation σ2 + target average brightness A2

[0035] As mentioned above, if the brightness of multiple camera images 31 is corrected, the brightness deviation of pixels among the multiple first corrected camera images 32 will decrease, but... Figure 5 (A) and Figure 5 As shown in (B), if a comparison is made between the images before and after the correction, it can be seen that the brightness deviation of the pixels constituting the first corrected image 32 increases after the correction. Therefore, in addition to reducing the brightness deviation of pixels among multiple images 31, the pixels of the corrected second corrected image 33 can be drawn with high precision in accordance with the three-dimensional structure of the target object 2.

[0036] Figure 6 This is a graph showing the change in brightness deviation when the brightness of pixels in a first corrected image 32, which has undergone brightness correction as described above, is corrected to reduce the brightness difference of the pixels constituting the first corrected image 32. First, the image processing device 14 calculates the average brightness of the pixel columns arranged along one side of the rectangular first corrected image 32 as the pixel column brightness average for each first corrected image 32, and performs this calculation for each pixel column. Here, the pixel column brightness average is the value obtained by dividing the average brightness of the pixels in a given pixel column by the number of pixels constituting that pixel column. Specifically, in... Figure 6In this process, the image processing device 14 calculates the average brightness of the pixel columns arranged along the X-axis direction of the first corrected image 32 of the rectangle as the average brightness of the pixel columns, and performs the calculation for each pixel column. However, instead of the average brightness of the pixel columns, the average brightness of the pixel columns can also be the value calculated along the Y-axis direction of the first corrected image 32 of the rectangle.

[0037] Next, the image processing device 14 calculates the average brightness of each pixel column and the column position of each pixel column arranged along the other side of the first corrected image 32 (equivalent to...). Figure 6 The first graph g1 is drawn based on the pixel positions recorded in the image, and the first fitted line r1 is calculated for each first corrected camera image 32. Specifically, in Figure 6 In the diagram, the first graph g1 plots the average brightness of each pixel column calculated along the X-axis and the column position of each pixel column arranged along the Y-axis. Specifically, when the average brightness of the pixel columns is calculated along the Y-axis of the first corrected image 32 of the rectangle, it becomes a graph plotting the column position of each pixel column arranged along the X-axis. Furthermore, the first graph g1 can be fitted with a quadratic or cubic function instead of the first fitted line r1, which is a linear function.

[0038] Finally, the image processing device 14 corrects the brightness within each first corrected image 32 based on the column position and the gradient of the first fitted line r1, such that the gradient of the second fitted line r2 calculated from the second graph g2 drawn based on the average pixel column brightness and column position of each first corrected image 32 is less than the gradient of the first fitted line r1. The average pixel column brightness of the first graph g1 tends to decrease as the column position along the Y-axis increases. As the average pixel column brightness of the first graph g1 decreases, the average pixel column brightness increases, thereby obtaining the second graph g2 from the first graph g1. The gradient of the second fitted line r2 calculated from the second graph g2 is approximately 0, thereby enabling a high-precision reduction of deviations within the second corrected image 33 obtained through this correction.

[0039] As described above, multiple camera images 31 acquired from the SEM device 12 are subjected to... Figure 5 After correcting the brightness of the pixels between the images 31 shown in (B), the following steps are performed: Figure 6The brightness correction of pixels in the first corrected image 32 shown reduces the brightness deviation between multiple second corrected images 33 and the brightness deviation within each second corrected image 33. As described above, by creating a three-dimensional image by distinguishing and drawing the pixels of each of the multiple second corrected images 33 in accordance with the three-dimensional structure of the target object 2, the three-dimensional structure analysis of the target object 2 can be performed with high precision.

[0040] Additionally, chart g3 is in progress. Figure 5 (A) shows a graph plotted before correction between the camera images 31, plotting the average pixel column brightness calculated along the X-axis and the column position of each pixel column arranged along the Y-axis. The gradient of the third fitted line r3 calculated by fitting the third graph g3 is approximately 0. The third graph g3 was then subjected to... Figure 6 In the case of correction within the first corrected image 32 shown, since the gradient of the calculated fitted curve after correction is greater than the gradient of the third fitted line r3, it is applicable... Figure 5 After correction between the camera images 31 shown in (B), the correction is applied again. Figure 6 The correction is shown in the first corrected photographic image 32. That is, the correction is performed by... Figure 5 (B) shows the correction between the captured images 31. If the brightness deviation in each of the first corrected captured images 32 becomes greater than the brightness deviation in the captured images 31 acquired from the SEM device 12, it can be said that... Figure 6 The correction shown in the first corrected photographic image 32 is effective.

[0041] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Various design changes can be made without departing from the spirit of the present invention as set forth in the claims.

[0042] Symbol Explanation

[0043] 1-Image creation system, 11-FIB device, 12-SEM device, 121-Scanning electron microscope, 13-Control device, 14-Image processing device, 2-Target object, 21-Surface, 22-New surface, 31-Photographed image, 32-First corrected photographed image, 33-Second corrected photographed image, B-Focused ion beam, A1-Brightness average, A2-Target brightness average, σ1-Standard deviation, σ2-Target standard deviation, g1-First graph, g2-Second graph, r1-First fitted line, r2-Second fitted line.

Claims

1. An image creation system, characterized in that, have: The FIB device exposes a new surface by irradiating the surface of a target object with a focused ion beam, cutting a predetermined volume of the target object from the surface. The SEM device photographs the exposed new surface and acquires photographic images using a scanning electron microscope; A control device that controls the FIB device and the SEM device to alternately repeat the cutting based on the FIB device and the imaging based on the SEM device a predetermined number of times; and An image processing device that performs image processing on the multiple video images repeatedly captured using the SEM device. The image creation system analyzes the three-dimensional structure of the target object based on the multiple image-processed camera images. The image processing device performs the following processing: The average brightness of the pixels constituting the multiple camera images is calculated, and the brightness of each pixel in the multiple camera images is corrected in a way that reduces the deviation of the brightness of the pixels between the multiple camera images, based on the difference between the brightness of each pixel and the average brightness. This corrects the brightness between the multiple camera images. and For each corrected camera image, the brightness of the pixels in each corrected camera image is corrected in a manner that reduces the brightness difference of the pixels constituting each camera image, thereby correcting the brightness within each camera image.

2. The image creation system according to claim 1, characterized in that, After correcting the brightness of each of the captured images, the image processing device distinguishes and renders the pixels of each captured image according to the brightness of the pixels in each captured image, corresponding to the three-dimensional structure. The image processing device is configured with a target average brightness value and a target standard deviation of the brightness, which are capable of distinguishing and drawing pixels in accordance with the three-dimensional structure. Brightness correction is performed between the multiple camera images by using the average brightness of all pixels in the multiple camera images as the target average brightness and the standard deviation relative to the standard deviation of the brightness of all pixels in the multiple camera images as the target standard deviation.

3. The image creation system according to claim 1, characterized in that, The image processing device performs the following processing: For each of the camera images, the average brightness of the pixel columns arranged along one side of the rectangular camera image is calculated as the average brightness of the pixel columns, and this calculation is performed for each pixel column. A first fitted straight line is calculated for each of the camera images based on a first chart plotted using the calculated average pixel column brightness for each pixel column and the column position of each pixel column arranged along another side of the camera image; and Brightness correction is performed in each of the camera images based on the column position and the gradient of the first fitted line, in such a way that the gradient of the second fitted line calculated from the second chart plotted based on the average pixel column brightness of each corrected camera image and the column position is less than the gradient of the first fitted line.

Images