JP2015201304A - Image processing system and image processing method, and sem device using image processing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to handle multi-channel image input and improve resolution, without increasing a circuit scale.SOLUTION: A SEM device using an image processing system comprises: a scanning electron microscope; an image processing unit for processing an image obtained by imaging a sample by using the scanning electron microscope; and a display unit including a display screen for displaying the image obtained by imaging the sample by using the scanning electron microscope and a result of the image processing unit's processing. The image processing unit determines a correction expression for correcting a contrast of an image obtained by imaging a sample by using the scanning electron microscope and displayed on the display screen of the display unit, on the basis of a condition set on the display screen of the display unit in which the image obtained by imaging the sample by using the scanning electron microscope is displayed; and corrects, by using the determined correction expression, the contrast of the image obtained by imaging the sample by using the scanning electron microscope. The display unit displays the sample image whose contrast is corrected by the image processing unit, on the display screen.

Description

  The present invention relates to an image processing system and an image processing method for processing an image obtained by imaging a sample with a scanning electron microscope (SEM), and an SEM apparatus using the image processing system.

  In the case of observing a sample using an SEM, as a method of improving the visibility of the sample in an image (SEM image) acquired by the SEM, contrast enhancement that enhances a slight luminance of the sample in the SEM image and improves the image. There is a way. As this contrast enhancement method, a method using a look-up table (LUT) stored in a memory as described in Japanese Patent Laid-Open No. 10-172491 (Patent Document 1) is used. Yes.

  In this patent document 1, as a problem, there is to realize an image processing method and apparatus of a charged particle beam apparatus that can easily and accurately improve the quality of an image of a region of interest on a screen. The minimum luminance I1 and the maximum luminance I2 of the selected area obtained by the luminance distribution calculation function 9 are supplied to and stored in the data holding unit 11. The operator inputs the minimum luminance J1 and the maximum luminance J2 on the cathode ray tube 6 corresponding to I1 and I2 using the input / output device 13. Based on these J1, J2 and I1, I2, the γ correction function 8 of the computer 7 automatically defines the γ function. This image conversion is based on a look-up table (LUT) 17 created by the γ function. It is described that the γ correction is performed.

JP-A-10-172491

  Patent Document 1 describes a mechanism for contrast correction of a scanning electron microscope (SEM). However, Patent Document 1 uses a look-up table for contrast correction processing. In order to cope with multi-channel image input and increase in the number of image bits accompanying resolution improvement, the scale of the look-up table is used. Must be increased.

  In such a scanning electron microscope (SEM), for example, in order to cope with multi-channel image input, the look-up table must be multiplied by n by the number of channels. Further, when the number of image bits increases as the resolution is improved, the circuit scale of the look-up table increases, which may increase the cost. Moreover, the set time of conversion data becomes long and usability falls.

  Therefore, the present invention provides an image processing system, an image processing method, and an SEM apparatus using the image processing system that can cope with multi-channel image input and improve resolution without increasing the circuit scale. To do.

In order to solve the above-described problems, in the present invention, an image processing system includes an input unit that inputs an image obtained by imaging a sample with a scanning electron microscope, and a contrast correction for an image input to the input unit. A contrast calculation unit for obtaining a correction formula, an image processing unit for processing an image input to the input unit using the correction formula for correcting the contrast of the image obtained by the contrast calculation unit, and an image and an image input from the input unit A display unit that displays an image processed by the processing unit, and the image processing unit is configured to display an image displayed based on conditions set on the display unit on which the image input from the input unit is displayed. The correction formula for correcting the contrast is determined, the contrast of the image input from the input unit is corrected using the determined correction formula, and the display unit corrects the contrast by the image processing unit. And to display on the display screen an image of the sample.

  In order to solve the above problems, in the present invention, an image obtained by imaging a sample with a scanning electron microscope is input, and the contrast of the image obtained by imaging the sample with the input scanning electron microscope is corrected. In an image processing method, a correction formula is obtained, and an image obtained by imaging a sample with a scanning electron microscope is processed using the correction formula for correcting the contrast of the obtained image to obtain a contrast-corrected image. The correction formula for correcting the contrast of the displayed image is determined based on the conditions set on the display screen on which the image obtained by imaging the sample with the input scanning electron microscope is displayed. The contrast of the image obtained by imaging the sample with the scanning electron microscope was corrected using the correction formula, and the image of the sample with the corrected contrast was displayed on the display screen.

  Furthermore, in order to solve the above-described problems, in the present invention, an SEM apparatus using an image processing system includes a scanning electron microscope, and an image processing unit that processes an image obtained by imaging a sample with the scanning electron microscope. A display unit having a display screen for displaying an image obtained by imaging a sample with a scanning electron microscope and a result processed by the image processing unit, and the image processing unit includes scanning electrons displayed on the display unit. The contrast of the image obtained by imaging the sample with the scanning electron microscope displayed on the display screen based on the conditions set on the display screen of the display unit on which the image obtained by imaging the sample with the microscope is displayed. The correction formula to be corrected is determined, the contrast of the image obtained by imaging the sample with the scanning electron microscope is corrected using the determined correction formula, and the display unit displays the image of the sample whose contrast has been corrected by the image processing unit. Display screen It was to be displayed on.

  According to the present invention, it is possible to cope with multi-channel image input and improve resolution without increasing the circuit scale by adopting a memory-less configuration, shortening setting time, and enhancing contrast in real time. Functions can be realized at low cost.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is a block diagram showing a schematic configuration of an SEM apparatus using an image processing system according to Embodiment 1 of the present invention. It is a block diagram which shows the schematic structure of the contrast calculating part of the SEM apparatus using the image processing system which concerns on Example 1 of this invention. It is a GUI screen for contrast adjustment according to the first embodiment of the present invention. It is a graph showing the relationship of the input-output pixel value when the change point is 1 point in contrast adjustment which concerns on Example 1 of this invention. It is a flowchart which shows the flow of the process of contrast adjustment which concerns on Example 1 of this invention. It is a graph showing the relationship of the input-output pixel value when the change point is four points in contrast adjustment which concerns on Example 1 of this invention. It is a figure which shows the structure of the contrast calculating part which concerns on Example 1 of this invention, and is a block diagram which shows the structure corresponding to the case where a change point is four points. It is a figure which shows the example of a circuit resource outline | summary in the SEM apparatus using the image processing system which concerns on Example 1 of this invention, and is a graph which compares the RAM usage amount in the system by the conventional system using a LUT, and the system by a present Example. It is a figure which shows the example of a circuit resource outline | summary in the SEM apparatus using the image processing system which concerns on Example 1 of this invention, and is a graph which compares the usage-amount of the logic in the conventional system using a LUT, and the system by a present Example. . It is a block diagram which shows the schematic structure of the SEM apparatus using the image processing system which performs a linear complementation from the histogram which concerns on Example 2 of this invention. The graph which shows the relationship between an input pixel value and the number of data of the SEM apparatus using the image processing system which performs linear interpolation from the histogram which concerns on Example 2 of this invention, and the relationship of the input-output pixel value based on the graph It is a graph which shows. It is the flowchart which showed the flow of the process which performs linear complementation from the histogram in the SEM apparatus using the image processing system which performs linear complementation from the histogram which concerns on Example 2 of this invention. It is a GUI screen for peak selection of the SEM apparatus using the image processing system which performs linear interpolation from the histogram which concerns on Example 2 of this invention. It is a GUI screen for parameter setting of the SEM apparatus using the image processing system which performs linear interpolation from the histogram which concerns on Example 2 of this invention. It is a flowchart which shows the procedure which calculates the inclination, change point, and offset of the SEM apparatus using the image processing system which performs linear complementation from the histogram which concerns on Example 2 which concerns on embodiment of this invention. It is an example of the image displayed on the GUI screen of the SEM apparatus using the image processing system which performs linear complementation from the luminance value display which concerns on Example 3 of this invention. It is a flowchart which shows the flow of the process which performs a linear complement from the luminance value display in the SEM apparatus using the image processing system which performs a linear complement from the luminance value display which concerns on Example 3 of this invention. It is a flowchart which shows the procedure which calculates the inclination, a change point, and an offset in the SEM apparatus using the image processing system which performs linear complementation from the luminance value display which concerns on Example 3 of this invention. It is a block diagram which shows the schematic structure of the histogram calculating part in the SEM apparatus using the image processing system which performs linear complementation from the luminance value display which concerns on Example 2 of this invention. It is an example of the figure which shows the GUI screen displayed at the time of correction | amendment of a display image in the SEM apparatus using the image processing system which concerns on Example 4 of this invention. It is a GUI screen of a two-point correction histogram in the SEM device using the image processing system according to the fourth embodiment of the present invention. It is a GUI screen of the histogram for four-point correction in the SEM apparatus using the image processing system which concerns on Example 4 of this invention. It is a GUI screen when correcting a part of display image in the SEM apparatus using the image processing system according to the fourth embodiment of the present invention. It is a GUI screen displayed when the luminance value of a display image is observed and corrected in the SEM apparatus using the image processing system according to the fifth embodiment of the present invention.

  The present invention provides an image processing system, an image processing method, and an SEM apparatus using the image processing system that can cope with multi-channel image input and increase resolution without increasing the circuit scale. It is.

In the present invention, contrast enhancement in an SEM image is realized by a linear approximation calculation without using a look-up table. For example, according to the physical quantity of each sensor, parameters are set for multi-channel, and a contrast enhancement function is realized in real time by linear approximation calculation processing. Since the conversion characteristic is linearly approximated at n points to make a memory-less configuration, and it is possible to realize multi-channel image input at low cost, an image processing system excellent in terms of cost reduction of the apparatus and its use are used. Realized the SEM device.
Embodiments of the present invention will be described below with reference to the drawings.

  In this embodiment, an example of an image processing system that performs contrast adjustment by a linear interpolation method and a scanning electron microscope (SEM) apparatus using the image processing system will be described.

  FIG. 1 is an example of a configuration of a scanning electron microscope (SEM) apparatus 100 using an image processing system that performs contrast adjustment by a linear interpolation method. A scanning electron microscope (SEM) apparatus 100 includes an SEM 1, image generation units 2a to 2n, an electron beam control unit 12, an image processing system 14, and a personal computer 15 (hereinafter abbreviated as a PC) having a display as a display unit. Is done. The image processing system 14 includes AD converters 3 a to 3 n and a scan / image capturing unit 13. The scan / image capturing unit 13 includes contrast calculation units 4 a to 4 n, an image transfer unit 5, image processing units 6 a to 6 n, and a scan control unit 7.

  The SEM 1 includes an electron gun 101 that emits an electron beam, a scanning coil 103 that controls the irradiation position of the electron beam 102 emitted from the electron gun 101, and secondary electrons 111 that are emitted from the sample 110 by irradiation of the electron beam 102. And a secondary electron detection unit 104 for detecting. The SEM 1 in this embodiment includes n detectors such as the secondary electron detector 104. The configuration of the SEM 1 is general and will not be described here. In FIG. 1, it is described that a plurality of outputs are output from one secondary electron detection unit 104, but this is described for explanation, and actually, the secondary electron detector 104 is There are n, and one output from one of the secondary electron detectors 104 is connected to one of the image generation units 2a to 2n.

  The SEM apparatus 100 is an apparatus for observing a sample such as a semiconductor device, electronics, advanced nanotechnology material, living organism, pharmaceutical, etc., and sequentially irradiates an electron beam with a predetermined acceleration voltage along a plurality of scanning lines. This is performed by scanning the upper observation target region, detecting the emitted secondary electrons, and acquiring image information of the observation target region.

  Acquisition of image information is performed in units in which processing is performed by the electron beam apparatus. For example, when observing a wafer of a semiconductor integrated circuit, an image of the entire wafer cannot be acquired at one time, and thus the image is acquired by dividing it into an image size of 640 × 480 pixels or the like. The divided image size is used as one unit, and an image is acquired by scanning the electron beam 102 in this range, that is, the target region. The reference point of the divided unit is performed by moving the stage 105 (the part on which the sample to be the object is mounted) inside the SEM. The image size has increased from 640 × 480 pixels to 5120 × 3840 pixels with the miniaturization of the semiconductor integrated circuit as the target sample 110 and the advancement of nanotechnology.

  Hereinafter, scanning performed within one image size, which is a divided unit, will be described.

  First, the scan control unit 7 generates scan coordinates and a scan control signal in order to scan (scan) the electron beam 102 in the image acquisition region on the sample 110 inside the SEM 1. The generated scan coordinates and scan control signal are converted from a digital signal to an analog signal by the electron beam control unit 12 to scan the electron beam 102. For example, in a normal scan when the image size is 640 × 480 pixels, X and Y coordinates are set to 0, and X coordinates are generated in order from 0 to 639. Next, the Y coordinate is set to 1, and similarly, the X coordinate is generated in order from 0 to 639. This is repeated to generate coordinates until the Y coordinate becomes 479. A scan in which the X and Y coordinates are sequentially set from 0 in this way may be called a raster scan.

  The PC 15 inputs the parameter setting information 48 to the contrast calculation units 4a to 4n.

  Signals output from the secondary electron detection unit 104 that detects secondary electrons generated from the sample 110 irradiated with the electron beam 104 are input to the image generation units 2a to 2n and generated by the image generation units 2a to 2n. The analog signals are converted into digital signal image data 40a to 40n by the AD converters 3a to 3n.

  The image data 40a to 40n converted by the AD converters 3a to 3n are input to the contrast calculation units 4a to 4n of the scan / image capturing unit 13.

  The contrast calculation units 4a to 4n perform image contrast calculation using the image data 40a to 40n input from the AD converters 3a to 3n and the parameter setting information 48 input from the PC 15.

  The contrast calculation units 4a to 4n transfer the calculation results to the image processing units 6a to 6n.

  The image processing units 6a to 6n perform image processing such as frame integration and two-dimensional conversion.

  The image processing units 6 a to 6 n transfer the image processing result to the image transfer unit 5.

  The image transfer unit 5 collects the image processing results of the image processing units 6 a to 6 n and transfers them to the PC 15.

  In the contrast calculation units 4a to 4n of the scanning electron microscope (SEM) apparatus 100 in FIG. 1, contrast enhancement is performed to enhance the observation image by enhancing the slight luminance of the sample. Hereinafter, the contrast enhancement processing will be described in detail with reference to FIGS.

  FIG. 2 is an example of a diagram illustrating the contrast calculation units 4a to 4n. As a representative example, an example of the contrast calculation unit 4a is shown.

The contrast calculation unit 4a includes a change point setting unit 45a, an inclination setting unit 43a, an inclination offset setting unit 44a, an inclination calculation unit 41a, an inclination offset calculation unit 42a, and a change point comparison unit 46a, and is input from the A / D converter 3a. The processed pixel data 40a is processed using the parameter setting information 48a input from the PC 15.
The pixel data 40a input from the A / D converter 3a is input to the inclination calculation unit 41a and the change point comparison unit 46a.

  The parameter setting information 48a output from the PC 15 is input to the change point setting unit 45a, the inclination setting unit 43a, and the inclination offset setting unit 44a.

  The parameter setting information 48a is obtained by calculation in the PC 15 based on information set by a user operating the scanning electron microscope (SEM) apparatus 100 on the parameter adjustment GUI screen displayed on the screen display unit 151 of the PC 15. .

  FIG. 3 is an example of a parameter adjustment GUI (Graphic User Interface) screen displayed on the screen display unit 151 of the PC 15 in this embodiment.

  GUI: 071 representing the relationship between the input pixel and the output pixel indicates an example of the relationship between the input pixel and the output pixel before setting the inclination, the change point, and the offset.

  In GUI: 071 representing the relationship between the input pixel and the output pixel, the user operates the pointer 073 to set conditions for setting the tilt, change point, and offset.

  GUI: 072 representing the relationship between the input pixel and the output pixel shows an example of a polygonal line 074 representing the relationship between the input pixel and the output pixel after setting the inclination, change point, and offset.

  After setting the polygonal line 074 of GUI: 072 representing the relationship between the input pixel and the output pixel, the PC 15 sets values in the register memories of the change point setting unit 45a, the tilt setting unit 43a, and the tilt offset setting unit 44a of the contrast calculation unit 4a. Set.

  FIG. 4 is an example of a diagram illustrating a parameter adjustment GUI screen displayed on the screen display unit 151 of the PC 15 in the present embodiment.

  The horizontal axis 021 indicates the input pixel value X, and the vertical axis 022 indicates the output pixel value Y. When the input pixel value X is an 8-bit image, the pixel values of the input pixel value X and the output pixel value Y are in the range of 0 to 255, respectively.

The vertex 023 of the polygonal line 024 in FIG. 4 is input to the change point setting unit 45a of the contrast calculation unit 4a in FIG. 2, and the following two linear equations for linear approximation are obtained.
Y = 3X 0 ≦ X ≦ 55
Y = 0.45X + 140.25 55 ≦ X ≦ 255
The horizontal axis coordinate (X = 55) of the vertex (change point) H023 of the broken line 024 in FIG. 4 is set in the change point setting unit 45a in FIG.

  The inclination (3 and 0.45) of the broken line 024 in FIG. 4 is set in the inclination setting unit 43a in FIG.

  The slope offset (140.25) of the polygonal line 024 in FIG. 4 is set in the offset setting unit 44a in FIG.

  The contrast calculation unit 4a in FIG. 2 calculates an output pixel value from an input pixel value by a linear approximation calculation. Hereinafter, details of calculation contents of the contrast calculation unit 4a will be described.

  The gradient calculation unit 4a1 of the contrast calculation unit 4a multiplies the input pixel value 40a and the register memory value set by the gradient setting unit 43a.

  The change point comparison unit 46a of the contrast calculation unit 4a compares the input pixel value with the value of the register memory set by the change point setting unit 45a. If the input pixel value is large, the value is “1”, and if the input pixel value is small. '0' is output.

  The gradient offset calculation unit 42a of the contrast calculation unit 4a inputs the result calculated by the gradient calculation unit 41a, the value set by the offset setting unit 44a, and the result compared by the change point comparison unit 46a. When the comparison result at the comparison unit is “1”, the result calculated by the slope calculation unit 41a is output. When the comparison result at the change point comparison unit 46a is “0”, the calculation is performed by the slope calculation unit 41a. The value set by the offset setting unit 44a is added to the result and output.

  The contrast calculation unit 4a calculates the contrast of the input pixel value as described above.

  Taking the GUI screen of FIG. 4 as an example, the range of input pixel values 0 to 55 is converted to output pixel values of 0 to 165 in the contrast calculation unit 4a. As a result, the range of pixel values was expanded and the contrast was enhanced.

  FIG. 5 is an example of a contrast adjustment flowchart in this embodiment.

  First, contrast adjustment is started (S501), a change point is set in the change point setting unit 45a of FIG. 2 (S502), an inclination is set in the inclination setting unit 43a of FIG. 2 (S503), and further, FIG. An inclination offset is set in the offset setting unit 44a (S504). Next, the inclination calculation unit 41a in FIG. 2 calculates the inclination, and using the result, the inclination offset calculation unit 42a calculates the inclination offset (S505), and the contrast adjustment is completed (S506).

  In the example of the GUI screen of FIG. 4, a two-stage broken line 024 having one vertex (change point) and two slopes is displayed, and there are three parameters. In addition to this example, it is possible to set a fine enhancement range by increasing the number of change points and increasing the number of steps of the straight line.

  FIG. 6 is an example of a GUI showing the relationship between input and output pixel values when the number of change points is four.

  In FIG. 6, the change point is indicated by coordinates a: 0301, b: 0302, c: 0303, d: 0304 on the horizontal axis X. In addition, the inclination is indicated by A: 0305, B: 0306, C: 0307, D: 0308, E: 0309. Further, the inclination offset is indicated by coordinates B of the vertical axis Y B: 0310, bias C: 0311, bias D: 0312, bias E: 0313.

  FIG. 7 shows an example of the circuit of the contrast calculation unit 4a ′ when the number of change points is four as in the case of FIG.

  7 includes registers a: 451a, b: 452a, c: 453a, d: 454a constituting the change point setting unit 45a ′, and a register A: 431 constituting the inclination setting unit 43a ′. B: 432, C: 433, D: 434, E: 435, registers bias B: 441, bias C: 442, bias D: 443, bias E: 444, inclination calculator 41a ', calculators 411a-415a, calculators 421a-424a corresponding to the slope offset calculator 42a', comparators 461a-464a corresponding to the change point comparator 46a ', and a selector 47a.

  From the registers a: 451, b: 452, c: 453, and d: 454 of the change point setting unit 45a ′, the horizontal axis coordinates a: 00301, b: 0302, c: 0303 of the change point having the parameters of the linear interpolation method. , D: 0304 is determined.

  The slope setting unit registers A: 431, B: 432, C: 433, D: 434, and E: 435 of the contrast calculation unit 4a ′ in FIG. 7 are the slopes A: 0305, B: 0306 between the change points in FIG. It corresponds to C: 0307, D: 0308, and E: 0309.

  The offset setting unit registers bias B: 441a, bias C: 442a, bias D: 443a, bias E: 444a of the contrast calculation unit 4a ′ in FIG. 7 are the slope offset bias B: 0310, bias C: 0311, bias in FIG. D: 0312, bias E: 0313.

  8A and 8B show a comparative example of circuit resources in the prior art using the LUT and the present embodiment. FIG. 8A shows a comparison of RAM (Random Access Memory) usage charges, and FIG. A comparison of device usage was given. In the SEM apparatus 100 according to the present embodiment, the conversion characteristic is linearly approximated at n points to eliminate the need for an LUT, thereby reducing the circuit scale and setting time, and realizing a real-time contrast enhancement function at a low cost. An image processing apparatus system and an SEM apparatus using the image processing apparatus system can be realized. As a result, when the image processing apparatus system is configured with six 16-bit image channels (using six detectors 104), the RAM usage amount 081 is eliminated by not using a look-up table as shown in FIG. 8A. 6M, and the usage amount of the logic device (Logic) can be reduced from 600 slices to 428 slices as shown in FIG. 8B.

  As described above, the contrast calculation units 4a to 4n according to the present embodiment can significantly reduce the circuit scale as compared with the contrast enhancement method configured using the conventional LUT.

  In the case of a conventional SEM apparatus using a LUT, it is necessary to multiply the look-up table by n for the number of channels for the correspondence to multi-channel image input, and when the number of image bits increases as the resolution improves, Although the usability decreases due to an increase in the circuit scale of the look-up table, an increase in cost, and an increase in the set time of conversion data, the scanning electron microscope (SEM) apparatus 100 using the image processing system according to the present embodiment. Is a memory-less configuration by linearly calculating the conversion characteristics at n points, and can support multi-channel image input at low cost, so that the cost of the apparatus can be reduced without reducing usability. And an excellent image processing system and SEM apparatus can be provided.

  In the present embodiment, an example of an SEM apparatus using an image processing system that determines linear interpolation parameters using a histogram and the effect thereof will be described.

  FIG. 9 shows an example of the configuration of an SEM apparatus 900 using the image processing system according to this embodiment. A scanning electron microscope (SEM) device 900 includes a personal computer 150 (hereinafter abbreviated as a PC) having an SEM 1, image generation units 2a to 2n, an electron beam control unit 12, an image processing system 140, and a display 152 as a display unit. I have. The image processing system 140 includes AD converters 3 a to 3 n, a scan / image capturing unit 130, and a histogram calculation unit 9. The scan / image capturing unit 130 includes contrast calculation units 410a to 410n, an image transfer unit 510, image processing units 610a to 610n, and a scan control unit 7.

  The SEM apparatus 900 using the image processing system according to the present embodiment is obtained by adding a histogram calculation unit 9 to the configuration of the SEM apparatus 100 using the image processing system described with reference to FIG. . The same components as those shown in FIG. 1 described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the configuration shown in FIG. 9, the image data 40 a to 40 n output from the AD converters 3 a to 3 n are input to the scan / image capturing unit 130 and the histogram calculation unit 9.

  FIG. 17 is a diagram illustrating the configuration of the histogram calculation unit 9.

  The histogram calculation unit 9 includes a pixel value counter unit 93 and a setting data calculation unit 94.

  The pixel value counter unit 93 counts the number of generated pixel values of the image data 40a to 40n input from the AD converters 3a to 3n, and obtains a histogram calculation result 95.

  The histogram calculation unit 9 transmits the histogram calculation result 95 to the PC 150.

  The PC 150 transmits the parameter adjustment information 92 created using the histogram calculation result 95 to the setting data calculation unit 94 of the histogram calculation unit 9.

  The setting data calculation unit 94 uses the parameter adjustment information 92 input from the PC 150 to calculate the tilt, change point, and offset parameter, and outputs setting data 96a to 96n.

  The parameter setting information 96a to 96n output from the histogram calculation unit 9 is input to the contrast calculation units 410a to 410n.

  FIG. 10 illustrates the principle of setting a linear interpolation parameter on the parameter adjustment GUI screen displayed on the display screen 152 of the PC 150 from the histogram of the pixel values of the image data 40a to 40n obtained by the histogram calculation unit 9 in this embodiment. It is an example of the figure to do.

  (A) of FIG. 10 shows the input pixel values counted by the pixel value counter unit 93 when the image data 40a to 40n are input from the AD converters 3a to 3n to the pixel value counter unit 93 of the histogram calculation unit 9. The histogram is displayed on the parameter adjustment GUI screen displayed on the display screen 152 of the PC 150.

  In FIG. 10A, the horizontal axis 021 is the input pixel value X, and the vertical axis 1101 is the number of the same pixel value of the image (the number of pixel values as the count result).

  In the vertical axis 1101 in FIG. 10A, there is a peak 1102 where the number of data is large.

  The emphasis section 1103 is displayed for the purpose of emphasizing a portion of the image where the peak 1102 in FIG.

  FIG. 10B is a diagram showing the input / output relationship of pixel values, and is an example of a parameter adjustment GUI screen displayed on the display screen 152 of the PC 150. The range of this emphasis section 1103 is displayed on the input / output relationship diagram of FIG. 10 (b), and the user selects the shape of the line graph 1104 (on each part of the continuous line graph) so as to emphasize the contrast of this emphasis section on the screen. Set (Tilt).

  The method of selecting the peak of the input pixel value histogram in FIG. 10A and determining the emphasis section of the input image in FIG. 10B according to the present embodiment increases the accuracy of the range setting of the emphasis section. Therefore, it is easy to use even for users who have no experience in contrast correction, and usability can be improved.

  As shown in FIGS. 10A and 10B, the information of the range of the emphasis section 1103 set on the parameter adjustment GUI screen displayed on the display screen 152 of the PC 150 is the scan / image capture unit. It is input to 130 contrast calculation sections 410a to 410n. The configuration of the contrast calculation units 410a to 410n is basically the same as the configuration shown in FIG. 2 described in the first embodiment, and the input parameter information 48a is the setting data output from the setting data calculation unit 94 in FIG. The difference is that 96a is replaced.

  The results processed by the contrast calculation units 410a to 410n are sent to the image processing units 610a to 610n as described in the first embodiment, and the image processing units 610a to 610n perform frame integration, two-dimensional conversion, and the like. Image processing is performed, and the result of the image processing is transferred to the image transfer unit 510. The image transfer unit 510 collects the image processing results of the image processing units 610 a to 610 n and transfers them to the PC 150.

  FIG. 11 is a flowchart of contrast adjustment executed by the contrast calculation units 410a to 410n in the second embodiment. The internal configuration of the contrast calculation units 410a to 410n will be described by substituting the configuration of the contrast calculation unit 4a shown in FIG.

  First, image data obtained by imaging the sample 110 with the SEM 1 is input to the histogram calculation unit 9 and the contrast calculation units 410a to 410n (S1101), and the pixel value of the image input in the pixel value counter 93 of the histogram calculation unit 9 is input. The histogram is created and displayed on the display screen 152 of the PC 150 (S1102). For example, the user selects (designates) the peak 1302 on the histogram 1301 displayed on the histogram display screen 1201 as shown in FIG. 12A, and shows the relationship between the input pixel value and the output pixel value as shown in FIG. 12B. On the graph 1202, adjustment is performed by inputting each parameter such as adjusting each parameter of the magnification, range, and center point displayed on the parameter adjustment unit 1203 (S1103). Next, information of each parameter set on the screen in S1103 is input to the setting data calculation unit 94 of the histogram calculation unit 9, and the slope, change point, and offset parameter are processed in steps S1301 to S1319 as shown in FIG. (S1104). Next, the changing point is set in the changing point setting unit 45a (S1105), the inclination is set in the inclination setting unit 43a (S1106), and the inclination offset is set in the offset setting unit 44a (S1107). Next, an inclination is calculated by the inclination calculating unit 41a, and an inclination offset is calculated by the inclination offset calculating unit 42a using the result (S1108), and the pixel values of the image based on the calculation result are calculated from the image processing units 610a to 610a. 610n is output (S1109), and contrast adjustment is completed.

  The user selects a region 1302 including a peak to be corrected from the input pixel value histogram display 1301 on the histogram display screen 1201 displaying the pixel value histogram in this embodiment shown in FIG. 12A. Also, each parameter is input to the parameter adjustment unit 1203 displaying the magnification, range, and center point parameters shown in FIG. 12B, and is checked and adjusted with a graph 1202 showing the relationship between the input pixel value and the output pixel value. To do. For each parameter of the straight line of the graph 1202, the details of correction are set by sliding the button 1309 displayed on the parameter adjustment unit 1203.

  The parameters set by the parameter adjustment unit 1203 in FIG. 12B are correction magnifications 1303 and 1306 corresponding to each peak, correction ranges 1304 and 1307, and correction center points 1305 and 1308.

  Based on the parameters set by the parameter adjustment unit 1203, the histogram calculation unit 9 calculates the slope, change point, and offset parameter for each channel.

  The image processing system according to the present embodiment and the scanning electron microscope (SEM) apparatus using the image processing system set the change point and tilt from the histogram created from the SEM image data of the sample obtained by imaging with the SEM in the histogram calculation unit 9. Since setting and offset are set, it is possible to optimally set the contrast adjustment parameter and improve the adjustment accuracy. Thereby, since it is easy to use even for a person who has no experience of contrast correction, it is possible to provide an image processing system excellent in terms of improvement in usability and an SEM apparatus using the image processing system.

  In the present embodiment, an example of an image processing apparatus that determines a linear interpolation parameter by luminance value display and an SEM apparatus using the image processing apparatus will be described.

  An example of the configuration of the image processing system according to the present embodiment and the SEM apparatus using the image processing system is the same as the configuration described in FIG. 1 and FIG. 2 described in the first embodiment, and thus the description of the entire configuration is omitted.

  FIG. 14 shows an example of a GUI screen displayed according to the present embodiment.

  An image 1401 in FIG. 14 is acquired by imaging the sample 110 with the SEM 1. The user does.

  An image 1402 in FIG. 14 shows an example of a GUI screen that displays the luminance value of the image in the area 1411 designated on the image 1401 for each pixel.

  In the image 1403 in FIG. 14, the enhancement range (the luminance value minimum 1412 and the maximum value 1413) is displayed by the user in the image in which the luminance value for each pixel of the image in the designated area 1411 displayed in the image 1402 is displayed. It is an example of a GUI screen on which a user selects and sets a magnification.

  FIG. 15 is an example of a flowchart for determining the linear interpolation parameter from the luminance value display and performing contrast adjustment according to this embodiment.

  First, image data obtained by imaging the sample 110 with the SEM 1 is input to the contrast calculation units 4a to 4n (S1501), and the input image is displayed on the display screen 151 of the PC 15 as shown in an image 1401 in FIG. Specify the area to be emphasized on the screen. (S1502). Next, as in the image 1402 in FIG. 14, the luminance value of the designated area is displayed for each pixel (S1503), and the luminance value is displayed for each pixel as shown in the image 1403 in FIG. The enhancement range (luminance value minimum and maximum value) is selected and the magnification is set (S1504). Next, the inclination, change point, and offset parameter are calculated by the PC 15 as shown in FIG. 16 based on the highlight range information and magnification information selected on this screen (S1505). Next, based on the calculated result, a changing point is set in the changing point setting unit 45a (S1506), an inclination is set in the inclination setting unit 43a (S1507), and an inclination offset is set in the offset setting unit 44a ( S1508). Next, an inclination is calculated by the inclination calculating unit 41a, and an inclination offset is calculated by the inclination offset calculating unit 42a using the result (S1509), and the pixel values of the image based on the calculation result are calculated by the image processing units 610a to 610a. 610n is output (S1510), and contrast adjustment is completed.

  FIG. 16 shows the enhancement range (luminance value minimum 1412 and luminance value maximum 1413) selected on the image 1403 displayed on the screen 151 of the PC 15 shown in FIG. Based on the magnification setting, an example of calculating along processing procedures S1601 to S1611 is shown.

  The image processing system and scanning electron microscope (SEM) apparatus according to the present embodiment performs contrast adjustment accuracy by setting change point parameters, tilt parameters, and offset parameters while displaying the pixel display of these luminance values on the GUI. Can be improved. Thereby, since it is easy to use even for a person who has no experience of contrast correction, it is possible to provide an image processing system excellent in terms of improvement in usability and an SEM apparatus using the image processing system.

  In this embodiment, an example of an image processing apparatus for correcting a display image with reference to a histogram and an SEM apparatus using the image processing apparatus will be described. The configuration of the image processing apparatus and the SEM apparatus using the same in this embodiment is the same as that described in Embodiment 2 with reference to FIGS.

  FIG. 18 is an example of a diagram showing a GUI screen displayed on the display screen 152 of the PC 150 when the display image is corrected according to the present embodiment.

  The GUI 1800 displayed on the display screen 152 of the PC 150 includes a display image area 1801, a correction image display area 1803, a correction histogram display area 1805, and a γ correction display button 1802 is displayed.

In the display image area 1801, an image 1820 acquired by imaging the sample 110 with the SEM 1 is displayed. When the γ correction button 1802 is pressed in this state, an image 1811 subjected to γ correction is displayed in the corrected image display area 1803.
In the corrected image display area 1803, a correction method selection button 1804 is displayed. The correction method selection button 1804 can select, for example, “entire”, “area”, or “point”.

  When “all” is selected with the correction method selection button 1804, a correction histogram is displayed in the correction histogram display area 1805.

  In the correction histogram display area 1805, a correction option button display unit 1806, an apply button 1807, and a histogram contrast adjustment screen display unit 1808 are displayed. The correction option button display unit 1806 displays, for example, a correction effective selection button 1812 and a correction adjustable point selection button 1813, and enables ON / OFF of correction correction and selection of the correction adjustable point.

  As an example, when ON is selected by the correction effective selection button 1812 of the correction option button display unit 1806 and two points are selected by the correction adjustment possible point selection button 1813, the histogram contrast adjustment screen display unit 1808 is shown in FIG. A GUI screen of such a two-point correction histogram is displayed.

  In the two-point correction histogram 1900 in FIG. 19, the X-axis represents the pixel value: 1904. The Y axis represents the number of pixels: 1903. Histogram (1): 1909 corresponds to image (1): 1809 of display image 1801, and histogram (2): 1910 corresponds to image (2): 1810 of display image 1801.

  The user changes the magnification M: 1906 and the range H: 1905 while operating the positions of the two-point correction adjustment points 1907 and 1908 on the screen on which the two-point correction histogram 1900 is displayed. The image corrected by reflecting the result of the above change is displayed on an image 1811 in the corrected image display area 1803 of the GUI shown in FIG.

  After the adjustment of the magnification M: 1906 and the range H: 1905 is completed, an apply button 1807 of the GUI correction histogram display area 1805 shown in FIG. 18 is pressed (a cursor (not shown) displayed on the screen is applied) The correction image is reflected on the image displayed in the display image area 1801 by clicking on the image 1807.

  As another example, in the GUI shown in FIG. 18, when the correction option selection display 1818 of the correction option button display unit 1806 is turned ON and four points are selected using the correction adjustable point selection button 1813, the histogram contrast is selected. An example of the four-point correction histogram 2000 displayed on the adjustment screen display unit 1808 is shown in FIG.

  On the screen on which the four-point correction histogram 2000 of FIG. 20 is displayed, the user operates the positions of the adjustment points 2005, 2006, 2007, and 2008 for four-point correction while scaling M1: 2003 and magnification M2: 2004, range H1: 2001, H2: 2002 are changed. The image corrected by reflecting the result of the above change is reflected in the image 1811 in the corrected image display area 1803 of the GUI shown in FIG.

  After completing the adjustment of the magnification and the range, the application button 1807 in the correction histogram display area 1805 of the GUI 1800 shown in FIG. 18 is pressed to reflect the correction image on the image displayed in the display image area 1801.

FIG. 21 is a diagram illustrating an example in which “area” of the correction selection button 1804 displayed in the correction image display area 1803 of the GUI 1800 is selected.
When “area” of the correction selection button 1804 is selected and a place (area) 2101 to be corrected is designated on the image 1820 displayed in the display image area 1801, the correction histogram display area 1805 relates to the designated area. A two-point correction histogram 1900 as shown in FIG. 19 or a four-point correction histogram 2000 as shown in FIG. 20 is displayed.
On the screen on which the two-point correction histogram 1900 or the four-point correction histogram 2000 is displayed, the user can position the two-point corrections 1907 and 1908 as shown in FIG. 19 or as shown in FIG. While manipulating the positions of the adjustment points 2005, 2006, 2007, 2008 for four-point correction, the magnification M: 1906 and the range H: 1905 are adjusted, or the magnification M1: 2003, the magnification M2: 2004, the range H1: 2001. , H2: 2002 is adjusted. After the adjustment is completed, the image corrected by reflecting the result of the above adjustment is reflected in the image 1811 in the corrected image display area 1803 of the GUI shown in FIG.

  After completing the adjustment of the magnification and the range, the application button 1807 in the correction histogram display area 1805 of the GUI 1800 shown in FIG. 21 is pressed to reflect the correction image on the image displayed in the display image area 1801.

  Heretofore, an example in which the display image is corrected with reference to the histogram has been described.

  Next, FIG. 22 shows an example in which “point” of the correction selection button 1804 displayed in the correction image display area 1803 of the GUI 1800 is selected.

  When the user selects “Point” on the correction selection button 1804, a correction luminance value display screen 2201 and an application button 2207 are displayed on the GUI 1800.

  After selecting “Point” of the correction selection button 1804, the pointer is moved to an arbitrary point 2206 to be viewed on the image 1820 displayed in the display image area 1801 and clicked. The example shown in FIG. 22 shows a case where four points are designated.

  On the correction brightness value display screen 2201, a brightness value table 2202 for 25 pixels centering on the point clicked by the user is displayed for each designated location.

  The user confirms the brightness value table 2202 and inputs the values of the magnification 2203, the start pixel value 2204, and the end pixel value 2205. After the user inputs, the application button 2207 is pressed to reflect the corrected content in the image 1829 displayed in the display image area 1801.

  The image processing system according to this embodiment and the scanning electron microscope (SEM) apparatus using the image processing system can correct the contrast while referring to the histogram on the GUI. For example, it is easy to use even for beginners who have little experience in contrast correction. An image processing system and an SEM apparatus that are excellent in terms of improvement in usability are provided.

  As described above, the example in which the display image is corrected with reference to the luminance value has been described.

  In the present invention, as described in the above-described embodiments, the image processing system is configured to input an image obtained by imaging a sample with a scanning electron microscope and to correct the contrast of the image input to the input unit. A contrast calculation unit for obtaining the correction formula, an image processing unit for processing an image input to the input unit using a correction formula for correcting the contrast of the image obtained by the contrast calculation unit, an image input from the input unit, A display unit that displays an image processed by the image processing unit, and the image processing unit displays an image displayed based on a condition set on the display unit on which the image input from the input unit is displayed The correction formula for correcting the contrast of the image is determined, the contrast of the image input from the input unit is corrected using the determined correction formula, and the display unit corrects the contrast by the image processing unit. And in which an image of the sample was set to be displayed on the display screen.

  In addition, as described in the above embodiments, the present invention inputs an image obtained by imaging a sample with a scanning electron microscope, and corrects the contrast of the image obtained by imaging the sample with the input scanning electron microscope. An image processing method for obtaining a corrected image by processing an image obtained by imaging a sample with a scanning electron microscope using a correction formula for correcting the contrast of the obtained image In the above, a correction formula for correcting the contrast of the displayed image is determined based on the conditions set on the display screen on which the image obtained by imaging the sample with the input scanning electron microscope is displayed, and this determination is performed. The contrast of the image obtained by imaging the sample with the scanning electron microscope is corrected using the corrected equation, and the image of the sample with the corrected contrast is displayed on the display screen. .

  Furthermore, as described in the above-described embodiments, the present invention provides a scanning electron microscope and an image processing unit that processes an image obtained by imaging a sample with the scanning electron microscope. And a display unit having a display screen for displaying an image obtained by imaging the sample with a scanning electron microscope and a result processed by the image processing unit, and the image processing unit is configured to scan the image displayed on the display unit. Contrast of the image obtained by imaging the sample with the scanning electron microscope displayed on the display screen based on the conditions set on the display screen of the display unit where the image obtained by imaging the sample with the electron microscope is displayed The correction formula for correcting the image is determined, the contrast of the image obtained by imaging the sample with the scanning electron microscope is corrected using the determined correction formula, and the display unit is an image of the sample whose contrast is corrected by the image processing unit. Display screen In which it was to be displayed on.

  The image processing system and scanning electron microscope (SEM) apparatus according to the present embodiment can correct the contrast while referring to the luminance value in the SEM image of the sample displayed on the GUI. Provided is an image processing system that is easy to use for scholars and is excellent in terms of improvement in usability, and an SEM apparatus using the image processing system.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  Each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function can be stored in a recording device such as a memory, a hard disk, an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

  Further, the control lines and information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

  DESCRIPTION OF SYMBOLS 1 ... SEM 2a, 2n ... Image generation part 3a, 3n ... A / D converter 4a, 4n ... Contrast calculation part 5 ... Image transfer part 6a, 6n ... Image processing part 7: Scan control unit 41 ... Inclination calculation unit 42 ... Offset calculation unit 43 ... Inclination setting unit 44 ... Offset setting unit 45 ... Change point setting unit 46 ... Change point comparison Units 461, 462, 463, 464, 465 ... comparator 47 ... selector 93 ... pixel value counter unit 94 ... setting data calculation unit 100 ... scanning electron microscope apparatus 1800 ... GUI .

Claims (15)

An input unit for inputting an image obtained by imaging a sample with a scanning electron microscope;
A contrast calculation unit for obtaining a correction formula for correcting the contrast of the image input to the input unit;
An image processing unit that processes the image input to the input unit using a correction formula for correcting the contrast of the image obtained by the contrast calculation unit;
An image processing system comprising a display unit that displays an image input from the input unit and an image processed by the image processing unit,
The image processing unit determines a correction formula for correcting the contrast of the displayed image based on conditions set on the display unit on which the image input from the input unit is displayed, and the determined correction The image processing is characterized in that the contrast of the image input from the input unit is corrected using an equation, and the display unit displays the image of the sample whose contrast is corrected by the image processing unit on the display screen. system.   The image processing system according to claim 1, wherein the input unit simultaneously inputs a plurality of images obtained by imaging a sample with the scanning electron microscope, and the image processing unit inputs simultaneously to the input unit. An image processing system for processing a plurality of images simultaneously and outputting the plurality of images processed simultaneously.   The image processing system according to claim 1, wherein the image processing unit calculates a contrast of the input image based on a condition set on a display unit on which the image input from the input unit is displayed. An image processing system, wherein a plurality of conversion expressions for performing primary conversion on the brightness of the input image are determined as correction expressions for correction in accordance with the brightness of the input image.   The image processing system according to claim 1, wherein the image processing unit calculates a contrast of the input image based on a condition set on a display unit on which the image input from the input unit is displayed. An image processing system, wherein a plurality of conversion formulas for linearly converting the brightness of the input image are determined as correction formulas for correction in accordance with the brightness distribution of the input image.   5. The image processing system according to claim 3, wherein the image processing unit is an area designated by the display unit of the input image for a conversion expression for performing a primary conversion on the brightness of the input image. Or an image processing system characterized in that a plurality is determined according to the brightness of the part. Input the image obtained by imaging the sample with a scanning electron microscope,
Obtaining a correction formula for correcting the contrast of an image obtained by imaging the sample with the input scanning electron microscope,
Using the correction formula for correcting the contrast of the obtained image, an image obtained by imaging the sample with the scanning electron microscope is processed to obtain an image with corrected contrast.
An image processing method comprising:
Determining a correction formula for correcting the contrast of the displayed image based on conditions set on a display screen on which an image obtained by imaging the sample with the input scanning electron microscope is displayed; An image processing characterized by correcting the contrast of an image obtained by imaging a sample with the scanning electron microscope using the determined correction formula, and displaying the image of the sample with the contrast corrected on the display screen Method.   7. The image processing method according to claim 6, wherein inputting the image includes simultaneously inputting a plurality of images obtained by imaging a sample with the scanning electron microscope and obtaining a contrast-corrected image of the image. In other words, the image processing system is characterized in that the plurality of images input simultaneously are processed simultaneously to obtain a plurality of contrast-corrected images.   8. The image processing method according to claim 6 or 7, wherein the input image is based on a condition set on a display screen on which an image obtained by imaging the sample with the input scanning electron microscope is displayed. An image processing method comprising: determining, as a correction formula for correcting the contrast, a plurality of conversion formulas for linearly converting the brightness of the input image according to the brightness of the input image.   8. The image processing method according to claim 6 or 7, wherein the input image is based on a condition set on a display screen on which an image obtained by imaging the sample with the input scanning electron microscope is displayed. An image processing method comprising: determining, as a correction formula for correcting a contrast, a plurality of conversion formulas for linearly converting the brightness of the input image in accordance with the brightness distribution of the input image .   10. The image processing method according to claim 8 or 9, wherein a conversion expression for performing a primary conversion on the brightness of the input image is a brightness of an area or a location designated on the display screen of the input image. An image processing method characterized in that a plurality of determinations are made according to the method. A scanning electron microscope,
An image processing unit for processing an image obtained by imaging a sample with the scanning electron microscope;
An apparatus comprising a display unit having a display screen for displaying an image obtained by imaging a sample with the scanning electron microscope and a result processed by the image processing unit,
The image processing unit is displayed on a display screen based on conditions set on the display screen of the display unit on which an image obtained by imaging a sample with the scanning electron microscope displayed on the display unit is displayed. A correction formula for correcting the contrast of an image obtained by imaging the sample with the scanning electron microscope is determined, and the contrast of the image obtained by imaging the sample with the scanning electron microscope is determined using the determined correction formula. An SEM apparatus using an image processing system, wherein the display unit displays the image of the sample corrected and contrast-corrected by the image processing unit on the display screen.   The SEM apparatus using the image processing system according to claim 11, wherein the scanning electron microscope images the sample and simultaneously acquires a plurality of images, and the image processing unit acquires simultaneously with the scanning electron microscope. An SEM apparatus using an image processing system, wherein the plurality of images processed simultaneously and the plurality of images processed simultaneously are integrated and output.   The SEM device using the image processing system according to claim 11 or 12, wherein the image processing unit is set on the display unit on which an image obtained by imaging a sample with the scanning electron microscope is displayed. As a correction formula for correcting the contrast of the image obtained by imaging the sample with the scanning electron microscope based on the above conditions, the brightness of the image obtained by imaging the sample with the scanning electron microscope is subjected to primary conversion An SEM apparatus using an image processing system, wherein a plurality of conversion formulas are determined according to the brightness of an image obtained by imaging a sample with the scanning electron microscope.   The SEM apparatus using the image processing system according to claim 11 or 12, wherein the image processing unit is set on a display unit on which an image obtained by imaging a sample with the scanning electron microscope is displayed. Conversion that linearly converts the brightness of the image obtained by imaging the sample with the scanning electron microscope as a correction formula for correcting the contrast of the image obtained by imaging the sample with the scanning electron microscope based on conditions An image processing system, wherein a plurality of equations are determined according to a brightness distribution of an image obtained by imaging a sample with the scanning electron microscope.   The SEM apparatus using the image processing system according to claim 13 or 14, wherein the image processing unit has a conversion equation for linearly converting the brightness of an image obtained by imaging a sample with the scanning electron microscope. An image processing system, wherein a plurality of images are determined in accordance with the brightness of an area or location designated by the display unit of an image obtained by imaging a sample with the scanning electron microscope.

Images