TW200527907A - Autofocus control method, autofocus controller, and image processor - Google Patents

Abstract

An autofocus control method, an autofocus controller, and an image processor capable of eliminating influence originated from an optical system, realizing a stable autofocus function. In calculating a focus evaluation value of each sample image obtained at plural focus positions, dark and light patterns of brightness originated from the optical system is reduced by applying smoothing processing to the obtained sample image, and the focus evaluation value is calculated based on the smoothed sample image. Further, the focus evaluation value is standardized by average display brightness of the smoothed sample image to obtain an optimal evaluation value.

Description

200527907 (1) IX. Description of the invention [Technical field to which the invention belongs] The present invention relates to a control method and an automatic focus control device for realizing a stable automatic focusing operation, such as a device suitable for observation and inspection. [Prior Art] , Control the image to automatically gather (workpiece) image data to evaluate and evaluate. That is, the lens material is changed, and the focal position is calculated for each of the materials. Fig. 21 shows an example of the relationship between the lens workpiece (vertical axis). This is to access the image and calculate the focus evaluation (maximum) focus position in each image graph. Hereinafter, the drawing of this through-hole is referred to as a "focus curve". In the conventional technique, the focus of the chart is evaluated 値 or the focus before and after the maximum 値. As the focus evaluation 値, high-dispersion, high-differential imaging cameras are used to take photographic samples, and in particular, auto-focus control methods, auto-focus settings, and image processing devices are excluded from the influence of the optical system. "Focus" is to collect the image of the sample by using the distance between the focal points and the number of focusing points of the photographic sample to calculate the value of the image. To retrieve the appropriate focus distance (horizontal axis) and focus evaluation, change at regular intervals. Focus evaluation of the distance between lens workpieces and plotting. Is the focus position, that is, the focus evaluation of the most appropriate focusing distance between the workpieces. The search range changes the maximum distance between the lens workpieces. As the most suitable focusing position evaluation, the maximum brightness of the most suitable focusing position is calculated. Scattering of tadpoles, etc. 200527907 (2) As the arithmetic to obtain the most appropriate focus position from the focus evaluation 200527907, there is a mountain climbing method, etc. In addition, in order to shorten the search time, a method of dividing the search operation into several stages has been put into practical use (Japanese Patent Application Laid-Open No. 6 -2 1 7 1 8 0, JP 2 0 2-3 3 5 7 1 and Patent No. 2 9 7 1 8 92). With the miniaturization of the target workpiece, an inspector to which this focusing technique is applied is required to increase the decomposition energy. In order to increase the decomposition energy, a short wavelength and a single wavelength of the illumination light source can be coped with. The use of shorter wavelengths can improve the optical resolution, and the use of single wavelengths can avoid the effects of chromatic aberrations. However, the use of shorter wavelengths of illumination light sources will limit the use of optical materials such as lenses used in the optical path. The single-wavelength problem has the effect of streaks. The term "streak" as used herein refers to a state where the brightness of the screen is distributed in a speckled pattern ', which uses a unique pattern of intensity distribution based on the wavelength of the light source or the configuration of the optical system. With these effects, as shown in FIG. 22, the above-mentioned focus curve is a case where the influence of the optical system is larger than the focus evaluation value of the most appropriate focus position. The shape or number range of the focus curve cannot be determined uniformly by using the surface state of the object such as the reflectance of the object. Therefore, in this state of the art, "the focus position is to be obtained from the maximum of the focus evaluation unit", The most appropriate focus position cannot be obtained stably. The present invention has been made by the creator in view of the above-mentioned disadvantages, and an object thereof is to provide an automatic focus control method, an automatic focus control device, and an image processing device that eliminate a stable automatic focus operation due to the influence of an optical system. -6- 200527907 (3) [Summary of the Invention] In order to solve the above problems, the automatic focus control method of the present invention includes: an image acquisition process for acquiring image data of a photographic body at a plurality of focal positions with different distances between a lens and a photographic body; Based on the acquired image data, the plural focus positions are used to separately calculate the focus evaluation 値 evaluation and calculation process, and the focus position where the focus evaluation 値 becomes the largest focus position is calculated as the focus position calculation process. The focal position of the lens is relative to the movement process of the relative movement of the photographic body; the image data obtained in the image obtaining process is smoothed, and the focus evaluation is calculated based on the smoothed image data. That is, the gradation distribution of the speckle brightness is caused by a speckle of a single wavelength. As described above, in order to reduce the gradation distribution pattern, a smoothing process for an image is performed in the present invention. With this smoothing process, the focus evaluation image can be appropriately calculated while capturing the characteristics of the target sample (photograph body) while reducing the shading distribution pattern. For image smoothing processing, the number of processing target pixels (unit processing range), processing conditions such as filter coefficients, number of processing times, and whether or not weighting is set are set according to the type of optical system to be used or the sample of the photographic sample. ® Properties can be set appropriately. On the other hand, in order to calculate the focus evaluation 値, it is desirable to detect the difference in brightness data between adjacent pixels of the acquired image data. For example, it can be calculated by using an edge emphasis process that extracts changes in brightness data between pixels in a feature portion and a contour portion. Focus evaluation: If there is uneven brightness using the focus position 200527907 (4) in the same target area, the insulation value of the brightness data difference between adjacent pixels will change. 'Focus evaluation cannot be calculated properly. In order to avoid such shortcomings, the standardization of the average brightness of the screen according to the focus evaluation is performed by dividing the calculated evaluation 値 by the average brightness of the screen as a whole. It is also attached to the autofocus. The control operation can evaluate the focus of each sample image obtained at a plurality of focus positions, and a function of synthesizing a full-focus image or a three-dimensional image of a photographic body can be added. These processes are performed by dividing the acquired image of each focus position into a plurality of areas in the plane, and at the same time based on the focus evaluation information or focus position information obtained elsewhere in the divided area. At this time, it becomes possible to inspect or observe the surface of a three-dimensionally structured photographic body with excellent resolution, excluding the influence of the optical system. Furthermore, the 'autofocus control device of the present invention has: each of the image data obtained based on the plural focus positions having different distances between the lens and the photographic body, and' the focus and evaluation methods for calculating the focus evaluation and calculation methods separately 'and the basis; Calculated focus evaluation (maximum), focus position calculation means for calculating focus position, and image smoothing means for image data obtained by smoothing processing; calculated based on image data subjected to smoothing processing by the image smoothing method Focus evaluation of each portrait data 値. The autofocus control device of the present invention is combined with an image acquisition means for acquiring image data of a photographic body at a plurality of focus positions, a driving means for adjusting the distance between a lens and a photographic body, and the like, and can be configured as an image processing device. These image acquisition means and driving means can constitute another independent body. -8-200527907 (5) According to the present invention, it is possible to observe a sample using a short-wavelength / single-wavelength light source, for example, because high-precision autofocus control can be stably performed due to the influence of the optical system, for example, with high resolution Semiconductor wafers and the like that have been improved in microfabrication can be observed. [Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the drawings. (First Embodiment) Fig. 1 is a schematic configuration diagram of an image processing device showing an automatic focus control method and an automatic focus control device according to an embodiment of the present invention. The image processing apparatus 1 is used to observe the surface of a photographic sample (workpiece). In particular, the image processing apparatus 1 is a microscope for detecting defects such as a device structure that is formed by performing microfabrication on a surface of a semiconductor wafer or the like. The image processing apparatus 1 includes a measuring table 2, an objective lens 3, a lens driving unit 4, a lens barrel 5, a CCD (Charge Coupled Device) camera 6, a controller 7, a driver 8, a monitor 9, and an illumination light source. The measurement table 2 supports a photographic sample (for example, a semiconductor wafer) w, and is configured to move freely in the X-Y direction (the left-right direction in the figure and the vertical direction on the paper surface). The lens driving unit 4 moves the objective lens 3 relative to the focus axis direction (up and down direction in the figure) at a predetermined focus position for the photographic sample W on the measurement table 2 and searches the entire axis range at a predetermined focus position. distance. The lens driving unit 4 corresponds to "driving means". 200527907 (6) In this embodiment, the lens driving unit 4 is made of a piezoelectric element, but other than that, a precision transfer mechanism such as a pulse motor may be used. In addition, the objective lens is moved in the direction of the focus axis while adjusting the distance between the lens and the workpiece, but instead of this, the measurement stage 2 may be moved in the direction of the focus axis. The C C D camera 6 outputs the acquired image data to the controller 7 through an objective lens 3 that moves within the search range of the focus position, and a video camera that functions as a surface of the photographic sample w on the photographic measurement table 2. The CCD camera 6 constitutes the "image acquisition means" of the present invention together with the objective lens 3, the lens driving section 4, and the lens barrel 5. In addition to C C D, other solid-state imaging devices such as CMOS image devices can be applied. The controller 7 is an automatic focus (AF) control unit 11 which is provided with a computer and controls the overall operation of the image processing device 1 and detects an optimum focus position (focus position) of a specific area on the surface of the photographic sample W at the same time. The autofocus control unit 11 corresponds to the "autofocus control device" according to the present invention. The driver 8 receives a control signal from the autofocus control section and generates a driving signal for driving the lens driving section 4. In this embodiment, the driver 8 is a piezoelectric driver having a hysteresis compensation function. The driver 8 may be incorporated in the autofocus control unit n. The autofocus control unit 11 drives the lens drive unit 4 via a driver 8 to change the distance between the objective lens 3 and the photographic sample W (the distance between the lens and the workpiece) at a fixed interval by a CCD camera. 6 Obtain the image data of the photographic sample w separately and perform various processes as described below to detect the most appropriate focus position in the photographic field of the photographic sample w '-10- 200527907 (7), that is, the focus position. The monitor 9 displays, according to the processing content of the controller 7, the portrait of the photographic sample W taken by the CC camera 6 and the like. As the illumination light source 10, an example is used in this embodiment; a continuous laser or pulsed laser light source of ηm. In addition, the illumination light source region is not limited to the above-mentioned ultraviolet light field, and other ultraviolet or visible light collars having different wavelength ranges can be used depending on the application. FIG. 2 is a block diagram showing the configuration of the image processing device 1 from a CCD camera The analog picture signal output by 6 is converted into a digital picture signal by the borrower 1 3. The A / D converter 1 3 is supplied to the memory 14 and stored. The custom section 11 of the controller 7 reads the digital image data converted from the memory 14 and performs the following autofocus control. The driver 8 generates a driving signal for the counter section 4 based on a control signal from the controller 7 supplied from the inverter 17. The autofocus control unit 11 is provided with a smoothing processing circuit 1, a brightness calculation circuit 1 1 B, an evaluation threshold calculation circuit 1 1 C, and a focus circuit 1 1 D. The smoothing processing circuit 1 1 A is a circuit for flattening the automatic area (the entire screen or a part of the screen) of each of the image signals (sample images) of the specimen W photographed at the plural focus positions, and corresponds to this Invention of "Image Smoothing Means". The control unit 1] uses this image smoothing processing circuit 1 1 A to display the wavelength collar of the wavelength 1 196 in a time-decreasing manner: such as the light source in the field. Of course, the focus control is changed by changing the output signal from A / D. No., -11-200527907 obtained by taking the focus of the subject and smoothing it through the lens drive 1 A and calculating the average position through D / A (-11) The speckle distribution (speckle) of the brightness of each sample image. An example of the smoothing process is shown in [Number 1]. [Number 1]

—— Ί6 Also, the processing conditions of image smoothing (the number of pixels to be processed (3 X 3 in the above example), filter coefficients, processing coefficients, the presence or absence of weighting, and the use of coefficients, etc.) It can be set arbitrarily within the range of the original features and contours of the surface of the sample W taken by the CCD camera 6, and these processing conditions are set by, for example, an input device 16 such as a keyboard, a mouse, and a touchpad. The average brightness calculation circuit 11B is a circuit that calculates the average brightness of the screen in the autofocus target area of each sample image, and corresponds to the "average brightness calculation means" of the present invention. The average screen brightness at each focus position obtained by the average luminance calculation circuit 11B is used to calculate the focus evaluation 値 PV of the calculation circuit 1 1 C described below. The evaluation / calculation circuit 1 1 C is a circuit for calculating the focal evaluation value 値 P V of each sample portrait, and corresponds to the “evaluation / calculation means” of the present invention. In this embodiment, the evaluation / calculation circuit 1 1 C is configured to include an edge enhancement processing circuit. In the present embodiment, the focus evaluation means an index that can be used to evaluate the state where the characteristic part and the contour part can be clearly seen. The change in the brightness data between the pixels of the characteristic part and the contour part is a drastic change in the unfavorable image -12-200527907 (9), and a mild change in the unfavorable image. As described above, in this embodiment, an edge emphasis process is used to evaluate the brightness data difference between adjacent pixels, and a focus evaluation 値 P v is performed. In addition, the focus evaluation 値 may be calculated based on the differential 値 of the brightness, the dispersion of the brightness, and the like.

In the actual processing example, a calculation shown in [Equation 2] is performed on all the pixels in the captured image, and the luminance data from the surrounding pixels is obtained. In this formula, the former term is to detect the vertical direction, and the latter term is to detect the brightness change in the horizontal direction. Therefore, it is only possible to extract the evaluation as the luminance change component between the evaluation point and its surroundings without depending on the processing pixel brightness. 〔Number 2〕 Γ 12 1 -10 1 0 0 0 + -2 0 2 > -1 -2 -Ί -1 0 1 i

In this example, the processing target pixel area is 3 X 3, but 5 X 5 or 7 X 7 may be used. In addition, the coefficients are weighted, but the method of setting the coefficients is arbitrary, and the processing may be performed without weighting. In order to calculate the focus evaluation 値 Pv, the calculation is performed according to the above-mentioned edge emphasis processing formula, and then the division processing is performed using the screen average brightness corresponding to the focused position calculated by the average brightness calculation circuit 1 1B. That is, as shown in [Equation 3], the focus evaluation 値 Pv of each sample portrait is the focus evaluation obtained by the edge enhancement processing circuit 値 Pvo divided by the average screen brightness Pave of the focus position 値. -13- 200527907 (ίο) 〔Number 3〕

Pv (i)-

Pvo (i) Pave ⑴ In [Equation 3], pv (i) is the focus evaluation of the i-th focus position normalization 値; P v 〇 (i) is the i-th focus evaluation price 値; Pave (i ) Is the screen at the i-th focus position. As shown in [Equation 4], it is possible to calculate the focus evaluation by calculating the maximum screen average brightness 値 Pavemax obtained in [Equation 3]. As a result, the focus evaluation type reduction points divided by the average brightness are compensated, and it is easy to see the focus evaluation type transition after referring to the focus curve. The multiplied average screen brightness is not limited to 値, for example, minimum 値 may be used. [Number 4] D Pvo (i)

Pv (l) = d-Γ: X Pavemax Pave (i) In this way, as the focus evaluation 値 Pv, the division of the average screen brightness of the evaluation 値 calculated by the edges is used, and the focus evaluation point (pixel) and its surrounding There are many differences in the brightness of the pixels, so there is uneven brightness between the acquired images, and the degree of brightness (the brightness of the sum of the brightness of the pixels constituting the image divided by the number of pixels) varies. In order to avoid changing the absolute value of the calculated index. The calculation of the focal average brightness via the brightness position (multiplying the price Pv is also the amount of the price 値 is equal to its maximum strength si! Processing evaluation 値 is the total brightness of the average bright picture of the relevant party is less here -14 > 200527907 (11 ) For example, the brightness difference from the surrounding is 20%. At an average brightness of 50, the 20% brightness difference becomes 10, and at an average brightness of 100, it becomes 20. In this way, even for the same rate of change, the average density of the original picture makes the insulation 値 very different. An optical system such as a visible light microscope is rarely a problem, and an optical system such as an ultraviolet microscope is a problem. Thus, in this embodiment, it corresponds to such a change in the brightness of the screen. Therefore, the focus evaluation calculated at the edge emphasis processing and the average screen brightness Pave are used to standardize the focus evaluation based on the change in screen brightness. The impact of cricket. That is, as the focus evaluation (by using the division of the average brightness of the screen), the focus evaluation when the screen has an average brightness of 50 and a brightness difference of 20% becomes 0.2 (1 0/50); the screen average brightness of 1 0, The focus evaluation 时 at a brightness difference of 20% becomes 0 2 (20/100), which is consistent with each other, and the influence of the focus evaluation 値 caused by uneven brightness depending on the focus position is excluded. The focus position calculation circuit n 0 is a circuit that calculates the focus position based on the maximum value of the focus evaluation 算 calculated by the evaluation calculation circuit 1 1 C, and corresponds to the "focus calculation means" of the present invention. In general, the image autofocus control obtains a sample image at a plurality of focal positions with different distances between a lens and a workpiece, and determines the focus position by detecting the focus position of the sample image from which the largest focus evaluation is obtained. Therefore, the more images of the sample (the narrower the amount of focus movement between samples), the more accurate automatic focus control can be achieved. On the other hand, if the number of samples is increased, the processing time becomes longer, and it becomes impossible to ensure the high-speed performance of -15-200527907 (12). As shown in FIG. 6, in the present embodiment, based on the calculated maximum focus evaluation 値 Pv (m) and the complex focus evaluations 値 Pv (m-1) and Pv (m + 1) near it. 'Pv (m-2) > P v (m + 2),

Pv (m-3) and Pv (ni + 3) to detect the most appropriate focus position (focus position). As shown in Fig. 6, the quadratic curve near the focal position is convex near the top. Here, the approximate quadratic curve is calculated by using the least square method near the focal position, and the vertex is obtained, and this vertex is used as the focal position. The solid line in the figure is 3 points by Pv (m), Pv (m-1), pv (m + i), and the dotted line is by 5 points Pv (mv), Pv (m-1), and Pv (m + l). , P v (m-2), P v (m + 2), a one-point chain line consists of 7 points P v (m),

Pv (m-1), Pv (m + l), pv (m-2), Pv (m + 2),

Focus evaluation of Pv (m-3) and Pv (m + 3) 値 Approximately calculated curve. The degree of opening of the graph is different, but the positions of the vertices are approximately the same. It can be seen that although it is a simple process, it is an effective approximation method. Moreover, it is not limited to the above-mentioned curve approximation method. For example, a straight line passing through two points of P v (m) and P v (m + 1), and a line passing through pv (guai 1) and P v (m — 2) are used. The intersection points of the other two straight lines are calculated, and the focus position may be detected by a method (linear approximation method) or an approximate method such as a normal distribution curve approximation that uses this as the focus position. Referring to FIG. 2 'Memory' 5, various calculations used by the CPU of the controller 7 are performed. In particular, in the memory space of 'Memory 5', the first memory unit for various calculations of the autofocus control unit 1 1] 5 A and the second -16-200527907 (13) Memory unit 1 5 B. In this embodiment, in order to obtain the high-speed performance of the automatic focus control, while continuously changing the distance between the lens and the workpiece, sample images are obtained at a plurality of focus positions. As a result, compared with a case where the lens is stopped at each focus position to obtain an image, the speed of the autofocus control can be increased. The relationship between the instruction voltage of the driver 8 for the lens driving section 4 and the actual moving voltage of the lens driving section 4 is shown in Fig. 7. The lens driving unit 4 made of a piezoelectric element is provided with a position detection movement detection sensor. The real moving voltage in Figure 7 is the sensing monitor signal. The instruction voltage is determined by changing the frame of the video signal of the CC camera 6 after the lens is moved to the start position of the autofocus control. Comparing the indication voltage with the real moving voltage, although the response is delayed, the movement is smooth, and the slope of the two graphs in the increasing field is approximately the same while destroying the step difference of the indication voltage. From this, it can be seen that the lens operates at a constant speed and at a constant speed corresponding to the indicated voltage. Therefore, when the sample image is acquired in synchronization with the image synchronization signal, it can be calculated at a fixed interval of the focus axis coordinates, and the focus evaluation is obtained. In addition, in this embodiment, in order to increase the speed of the autofocus operation, the process of obtaining the sample image and the process of calculating the focus evaluation frame can be performed in parallel. This is how the second memory section is processed while fetching image data from the first memory section 5a as shown in FIG. 8! 5 B has already taken in the image data, and calculated the focus evaluation 缓冲 pv by double buffering. In the case of this example, the image data retrieved in even frames is processed in the first memory section 15A, and the image data retrieved in odd frames is processed in the second memory section 15B. -17- 200527907 (14) Hereinafter, the operation of the image processing apparatus 1 of this embodiment configured as described above will be described with reference to FIG. 3. Fig. 3 is a flowchart showing the process of the autofocus control section. First, input the autofocus processing area of the photographic sample W, the search range of the focus position S ', and obtain the initial setting of the focus movement amount (focus axis step length) between image samples, image smoothing processing conditions, and edge emphasis processing conditions ( In step S1), automatic focus control is performed. The objective lens 3 is driven in the direction of the focus axis from the start position of the autofocus control by the driving of the lens drive unit 4 (close to the direction of the photographing / photographing sample W in this embodiment), and the photograph is obtained by synchronizing with the image synchronization signal. Sample portrait of the sample W (steps S2 and S3). Then, a focus axis coordinate (a lens-workpiece distance coordinate) of the obtained sample image is obtained (step S 4). Thereafter, a focus evaluation process is performed by the screen average brightness calculation process, the image smoothing process, the edge enhancement process, and the brightness normalization process for the acquired sample portrait (steps S5 to S8). In the screen average brightness calculation process (step S5), the average brightness calculation circuit 1 1 B is calculated. The calculated average screen brightness is used as a calculation for subsequent focus evaluation. The screen average brightness calculation process may be performed after the smoothing process process (step S6). The image smoothing process (step S 6) is processed in the smoothing processing circuit Π A. In this image smoothing process, for example, an image smoothing process is performed using a calculation formula represented by [Equation 1]. Therefore, in the sample image obtained, the effect of the single-wavelength speckle caused by the light source can be excluded -18- 200527907 (15). The edge enhancement process (step S 7) is performed in the evaluation / calculation circuit 1 1 C. In this process, based on the image of the sample that has been smoothed in the previous smoothing process (step S 6), the features of the feature parts and the contour parts are calculated by the edge enhancement processing formula shown in the above [Equation 2]. The brightness data difference between pixels is used as the basic data for focus evaluation. Thereafter, a brightness normalization process is performed by normalizing the screen average brightness to the focus evaluation frame calculated in step S7 (step S8). This process is performed in the evaluation / calculation circuit i 1 C. In the example shown in FIG. 3, the focus evaluation 値 P v 〇 (i) obtained by the previous edge enhancement processing process (step S 7) is obtained by calculating the process using the average brightness on the screen (step s 5). Divide the average screen brightness Paveci) to calculate the focus normalized focus evaluation 値 Pv (i) of [Equation 3]. The above-mentioned steps S 2 to S 8 constitute an auto-focus circuit (AF circuit). In this circuit, the same processing as described above is performed for each of the acquired sample images of each focus position. In the present embodiment, as described above, the lens driving unit 4 is in a state where the objective lens 3 is continuously moved, and the CCD camera 6 photographs a photographic sample W at a predetermined sampling period, and obtains an image (step s 3) and focus with the image. The evaluation / calculation process (step S 8) is processed in parallel (FIGS. 6 and 7). Therefore, "in addition to calculating the focus evaluation 値 of the previously taken sample portrait", the next sample portrait can also be obtained. As a result, the focus evaluation 値 can be calculated with one frame period of the video signal, and the autofocus operation can be accelerated. . When the total movement length of the objective lens 3 reaches the full search range, the AF return is ended-19- 200527907 (16). For the focus evaluation of the obtained sample portraits, the maximum average multiplying degree of the drawing surface, pavemax, is implemented. Processing (step, s) 〇). As a result, the focus evaluation of each sample portrait has the same meaning as that obtained by the calculation formula shown in the above-mentioned [Equation 4]. Also, as in the engineering process shown in FIG. 4, the a F loop is completed according to the calculation of the focal point s, which is the edge emphasis processing, as in step s 丨 〇A in the same figure, after the AF loop is terminated. The normalized processing of the average brightness of the screen based on the focus evaluation is performed using the calculation processing shown in [Equation 4] for each sample portrait. The result is the same as the example shown in FIG. . In FIG. 5, the focus curve FC 1 obtained by performing the smoothing processing (step S 6 in FIG. 3) and the normalization processing (step s 8 in FIG. 3) is shown by a solid line, and is shown by a one-point key line. The focus curve FC2 obtained by performing only the smoothing process without normalizing the screen average brightness is not performed. Also for comparison ', the conventional focus curve F C 3 shown in Fig. 22 is shown with a dotted line. As can be seen from Fig. 5, according to this embodiment, the influence portion 'of the optical system can be greatly changed, and the peak value of the focus evaluation frame to be detected as the most appropriate focus position (focus position) can be displayed. This makes it possible to achieve stable and accurate autofocus operation even in a short-wavelength, single-wavelength optical system. Also, although only the smoothing process of the sample image is performed, the effect of the optical system can be improved, so the brightness normalization process can be omitted if necessary (at step S 8 in FIG. 3), but by performing the brightness The normalization process can further improve the optical system influence section, and can more accurately detect the focus position. Then, a focus position calculation process is performed (step S 1 1). This focus bit -20- 200527907 (17) The setting calculation process is performed in the focus position calculation circuit U D. To calculate the position of the focal point, as described with reference to FIG. 6, an approximate curve of each point passing the maximum value 焦点 of the focus evaluation 値 and the complex focus evaluation 附近 near it is obtained, and its vertex is detected as the focus position. Therefore, compared with the conventional mountaineering method widely used, the focus position can be detected efficiently and with high accuracy, and thus it greatly contributes to the acceleration of the autofocus operation. On the other hand, in Fig. 6, if the distance between the lens and the workpiece on the horizontal axis is used as the total search range, and it can be determined that the focus position is passed during the operation, image acquisition after Pv (m + 3) becomes unnecessary. As a result, the operation time of the tiller can be reduced, so that a higher speed of the autofocus operation can be realized. In addition, as a method of judging the passing of the focus position, there is a method of approximately obtaining a required number of samples by surpassing a certain focus evaluation 値 (given as a parameter or learned from the focus operation results so far). Wait. Finally, the movement process of moving the objective lens 3 toward the focus position (step S 1 2) 'ends the autofocus control of this embodiment. As described above, according to this embodiment, a high-precision autofocus control can be performed stably, excluding the influence of the short-wavelength, single-wavelength optical system, thereby making it possible to observe and inspect a semiconductor device with high resolution. Fine structures on the surface of wafers, etc. (Second Embodiment) Hereinafter, a second embodiment of the present invention will be described. -21-200527907 (18) In recent years, semiconductor wafers have been miniaturized to minimize the pattern width (rule of processing) 'and have a more three-dimensional structure in the height direction. The lightness becomes shorter as the focal point is shortened. The lower the focus on the target in a low-level object, the more disadvantageous it becomes. If there is a height difference in the screen and the focus-focused surfaces are different, it is necessary to obtain the active focus action of "focusing there", such as using the surface of the sample as a reference. However, in the conventional automatic focus control method that obtains the most appropriate focus position from the focus evaluation, it is inconvenient that the place to be seen cannot be focused. As described below, the method of applying the autofocus control method of the present invention to a method for aligning a point on either side of a sample having a step difference in the screen memory will be described below. In the first embodiment described above, an example has been described in which the focus evaluation frame is calculated for the entire (or a part of the target area) sample screen obtained. However, in this embodiment, as shown in FIG. 9, the obtained The sample screen of is divided into a plurality of areas, and each of the divided areas Wij (i, j 2 1 to 3) calculates a focus evaluation 値 separately, and calculates a focus position. To calculate the focus evaluation value of each segmented area Wij, the image smoothing process and the normalization process of the screen average brightness are performed in the same manner as in the first embodiment. As a result, the 'optical system' can detect the focus position with high accuracy without being affected. As a result of the above processing, it is possible to obtain a focus curve in which the segmented area Wij otherwise corresponds to the segmented area. At this time, 'compared with any segmented domain and other segmented domains, the situation is different at no point position'. It can be seen that the height difference between the two exists on the focal plane. Therefore, any priority is given by specifying the parameter. The focus position can become an active focus action. -22- 200527907 (19) Examples of parameters are as follows. 1. The lens-sample distance is the shortest (the highest part of the sample) 2. The lens-sample distance is the longest (the lowest part of the sample) 3. The specific position of the screen 4. The most appropriate focus position (more Characteristic parts) and so on. Fig. 9 illustrates an example in which the number of screen divisions is 9 divisions of 3 x 3. However, the number of screen divisions is not limited to this. The more you divide the screen or the more detailed you get. In addition, it is also possible to divide and overlap each other's picture ’The number of screen divisions may be changed dynamically according to the use state. As described above, according to this embodiment, it is possible to fully correspond to the active focus operation of "focus there" by designating the most appropriate focus position for the target sample as a priority. (Third Embodiment) A third embodiment of the present invention will be described below. In the embodiment, a method for synthesizing an all-focus image of a photographic sample from the acquired image data will be described by applying the autofocus control method of the present invention. In the ordinary optical system, if you want to see the depth of focus beyond the optical system, you cannot see the overall focused image, which cannot meet the purpose of inspection and observation. Special optical systems, such as confocal optics, are used to obtain overall focused images, or methods based on triangulation to obtain all-focus portraits from different angles. However, these methods use special optical systems. Therefore, it cannot be realized at low cost. > 23- 200527907 (20) On the other hand, a method of obtaining an image of an object hierarchically and then synthesizing it is also proposed (Japanese Patent Laid-Open Nos. 2 0 3-2 8 1 50 1). However, there are shortcomings such as the capacity of only the image information used for synthesis, and the synthesis processing time. In this way, in this embodiment, the process of implementing the automatic focus control method described in the first embodiment described above can obtain a full-focus image of a photographic sample. This control flow is shown in FIG. 10. After the process of normalizing the focus of the obtained image (sample point) by the screen average brightness (step S 8), a process of synthesizing the image (step S 8 M) is added. The other processes are the same as the process flow (Fig. 3) described in the first embodiment, and therefore the same reference numerals are assigned to the corresponding processes, and descriptions thereof are omitted. Also when "combining portraits", as described in the first embodiment, the sample screen obtained is divided into a plurality of fields (Figure 9), and the images in each of the divided fields are used as a unit to synthesize portraits. . In addition, the number of divisions of a screen is not particularly limited, and the more the number of divisions, the finer it can be processed, until the division area can be refined by one pixel unit. The shape of the divided area is not limited to the square, and may be changed to a circular shape or the like. In addition, as the recording body 15 (Figure 2), in addition to the first memory portion 15 A that processes the portrait data acquired in the even frames and the second memory that processes the portrait data acquired in the odd frames In addition to the section 15B, as shown in FIG. 11, a third memory section 15C for all-focus processing is prepared. The third memory section 15C is provided with a synthetic image data storage area 15C1 'and the height of each of the segmented areas Wij constituting the composite image (distance between the lens and the work -24- 200527907 (21)) information storage area 1 5 C2, and the focus evaluation of these divided areas Wij 値 information storage area 1 C3. To synthesize all-focus artifacts of a photographic sample, obtain specimen vibration images at a plurality of focal positions with different distances between the lens and the workpiece. For each sample image, calculate the focus evaluation score separately for each segmented area Wij, and extract the segmented area After Wi ij is independent of each other and the focus evaluation image is the highest, the image synthesis process is performed as a whole. As described above, the "all-focus image synthesis means" of the present invention is constituted. The process flow chart shown in FIG. 10 will be described. For the sample portraits obtained in the same manner as in the first embodiment in the processes of steps S 1 to S 8, the segmented fields W ij are executed separately and then moved. Proceed to step s 8 M for image synthesis. Fig. 12 shows step S8M in detail. After the autofocus operation is started, the third image body 15C is initialized using the image taken first (steps a and b). That is, in step b, the first image is copied to the synthetic image data storage area 1 5 C 1, and the first data is used to supplement the height information storage area 1 5 C, and the focus evaluation image is copied to each of the segmented areas Wij. Focus evaluation of the information storage area 1 5 C 3 and initialisation. After the second time, the focal evaluation value 取得 of the acquired image and the focus evaluation 合成 of the synthesized image are compared in each of the divided areas Wij (step c). If the focus evaluation image of the obtained image is large, the image is copied, and the height information and focus evaluation image information corresponding to this are updated (step d). Conversely, if the focus evaluation value of the acquired image is small, no processing is performed. This repeated division is divided into components (step e). This completes the processing of one frame (3 3.3 m s e c). -25- 200527907 (22) In a series of automatic focus control operation flow, the above processing is, for example, taking the even-frame image data in the first memory 1 5 A and taking it into the second memory The process of copying or updating the required data and information in the storage area corresponding to the third memory section 1 5 C in the divided areas Wij of the odd-numbered frame image data before one frame of 1 5 B. In the present embodiment, the above-mentioned processing is performed in conjunction with the autofocus control of the photographic sample W described in the first embodiment, and it is needless to say that this processing may be performed separately. The above processing is performed on all the portraits required for the auto-focusing ', so that at the end of the auto-focusing operation, the area W ij is divided, and the most in-focus portion can be obtained, its height data and focus evaluation 値. As a result, not only the coordinates of the focal position of the photographic sample w, but also the segmented area Wij can be obtained online and in real time. The full-focus image and shape of the photographic sample w can also be obtained. In particular, by displaying the composite image copied in the composite image data storage area 1 5 C 1 on the monitor 9 (Fig. 1), all movement processes in the full search range of the objective lens 3 become separately visible in the segmented area. When the camera is in focus, the height distribution of the displayed photographic sample W can be easily grasped during the autofocus operation. Furthermore, the autofocus control method of the present invention is used to synthesize an all-focus day image of a photographic sample, thereby ensuring high-precision autofocus control capable of excluding the influence of a short-wavelength, single-wavelength optical system. As a result, it is possible to obtain a full-focus image of the surface of a structure that is spread out hierarchically, such as a semiconductor wafer, with high resolution. -26- 200527907 (23) (Fourth embodiment) Hereinafter, as a fourth embodiment of the present invention, a method for synthesizing a three-dimensional portrait of a photographic sample from image data obtained by an autofocus operation will be described. The focus operation is to perform focus evaluation after obtaining a portrait image at a plurality of focus positions. As described above, in this embodiment, a focus portion is extracted from the obtained sample image, and a three-dimensional image can be synthesized by combining this with the information in the height direction. For example, as shown in FIG. 13, focus evaluation is performed on each sample image Ra, Rb, Rc, and Rd obtained during the autofocus operation. After detection, the focus portion is extracted and the height direction (focus axis direction) is drawn ） Combination 'can be combined to form a three-dimensional portrait of the structure R. An example of a method for synthesizing a three-dimensional image according to this embodiment is shown in the flowchart in FIG. 14. In the figure, steps corresponding to the above-mentioned first embodiment (FIG. 3) are given the same reference numerals, and detailed descriptions thereof are omitted. In this embodiment, after the initial setting (step S1), there is a stereo screen buffer erasure process (step S) A). In this process, the memory area is initialized to memorize the three-dimensional images obtained in the past. Then, as in the first embodiment described above, sample images of the photographic sample are obtained at a plurality of focus positions, and each of them is subjected to a smoothing process, a focus evaluation process for edge enhancement processing, and a calculated focus. The normalized process of evaluating the average screen brightness (step S2 to step S8). After calculating the focus evaluation 値, the data at each point in the screen so far is compared with the data obtained from -27- 200527907 (24) to compare which side has focus. If the side that has acquired data has focus, update the data (steps) S 8 A). In this process, a day image of each sample is separately performed. As described above, the "stereoscopic image synthesis means" of the present invention is constituted. In this example, the screen is divided into a plurality of fields W ij as in the second embodiment, and the above-mentioned processing is performed for each divided field. However, the number of divisions is not particularly limited, and the unit is one pixel. Processing is also possible. Therefore, according to this embodiment, after the auto-focus control is completed, not only the most appropriate focus position information of the photographic sample W, but also the plurality of focused sample images are combined in a high direction, so that the surface of the photographic sample can be easily obtained. Three-dimensional portrait. Furthermore, the autofocus control method of the present invention is used to synthesize the three-dimensional portrait of the photographic g-type material, thereby ensuring high-precision autofocus control that can eliminate the influence of the optical system of short wavelength and single wavelength. In this way, it is possible to obtain a full three-dimensional image of the surface of a structure that is spread out hierarchically, such as a semiconductor wafer. (Fifth Embodiment) A fifth embodiment of the present invention will be described below. In each of the above-mentioned embodiments, the image processing device using a computer as the core has been described. The method for realizing the automatic focus control of the present invention is described. This configuration is a case where it is slightly more complicated and cannot be adapted to the need to focus only. That is, in order that the processing after focusing does not require time, simple arithmetic can be used to implement -28- 200527907 (25) The arithmetic of the automatic focus control method of the present invention can expand the scope of application and have advantages in industrial automation. Great contribution. In this embodiment, the configuration of an autofocus control device that can implement the above-described autofocus control method of the present invention without using a computer will be described. As described below, the autofocus control device is constituted by using a computing element represented by a video signal encoder or FPGA (Field Programmable Gate Array), a memory for setting storage, and the CPU (Central Processing Unit) if necessary. Or PMC (Pulse Motor

Controller), integrated circuits such as external memory. These component groups are used as a single substrate unit by mounting on a common wiring substrate, or as a packaging member that houses them. (First configuration example) Fig. 15 shows a functional block diagram of a first configuration example of the autofocus control device according to the present invention. The autofocus control device 31 shown in the figure is composed of a video signal decoder 41, an FPGA 42, a field memory 43, a CPU 44, a ROM / RAM 45, a PMC 46, and an I / F circuit 47. The video signal used for the focusing action is an NTSC-encoded analog image signal. This is converted into a horizontal / vertical sync signal by the video signal decoder 41, EVEN (even) ODD (odd) field information, and brightness information. Digital portrait signal. The FPGA 42 is composed of a calculation element that performs a calculation process of a predetermined calculation process in the autofocus control flow (FIG. 3) of the present invention described in the first embodiment, and corresponds to the "image smoothing hand -29- 200527907 (26) paragraph "," Edge emphasis processing method "and" Evaluation / calculation method ". The FPGA 42 extracts the information of the effective part in the picture from the synchronization signal and field information digitally signaled by the video signal decoder 41, and stores its brightness information in the field memory 43. In addition, data is sequentially read out from the field memory 43 in sequence, and a so-called filtering (image smoothing process) 'average brightness calculation and focus evaluation / calculation calculation process are performed. In addition, the functions of the field memory 43 CPU 44 and PMC 46 can be assembled in the FPGA 42 by the integration degree of the FPGA 42. The field recorder 43 is output through an interface and is used for the purpose of temporarily storing the above-mentioned field information in order to process a video signal that constitutes a frame of an even field and an odd field. CPU 4 4 is the image of each sample calculated from FPGA 42 by moving the worktable that supports the sample of the camera and changing the lens-workpiece distance through the PC Μ46 and I / F circuit 4 at the same time. Focus evaluation: Calculate the most appropriate focus position (focus position), etc. to manage the overall system. In this example, C P U 4 4 is a "focus position calculating means" corresponding to the present invention. The ROM / RAM 45 is a memory for using parameters necessary for calculation of the operation software (program) of the CPU 44 and the focus position. The ROM / RAM 45 can be built into the CPU. P M C 4 6 is a driving control element for a pulse motor (not shown) that drives the table, and controls the table via an interface circuit (! / F circuit) 47. The output of the sensor that detects the position of the table is supplied to P C M 46 through the I / F circuit 47. -30- 200527907 (27) In the autofocus control device 31 configured as described above, a video signal of a sample image is supplied from a CCD camera not shown. The video signal is input to the FPGA 42 via the video signal decoder 41, and the FPGA is subjected to a smoothing process of the input image, an average brightness calculation, and a calculation of focus evaluation. FPG A 42 is the timing of the end-of-field synchronization signal, and transfers focus evaluation data to CPU 44. The CPU 44 acquires the coordinates of the focusing stage at the end of the field, and uses the coordinates as the distance between the lens and the workpiece. After repeating the above processing as many times as necessary for the autofocus operation of the present invention, C P U 4 4 performs the calculation of the focus position. After that, move the table to the most appropriate focus position to end the focus operation. In addition, if necessary, a screen division function is performed, and an all-focus image synthesis process of a photographic sample and / or a stereo image synthesis process are performed. The organic focus control device of the present invention configured as described above is organically connected to a focus axis movement means such as an existing CCD camera, monitor, pulse motor, etc., so that the same functions as those of the image processing device can be achieved. Therefore, the autofocus control method of the present invention can be implemented using a simple and simple structure, which is extremely advantageous in terms of cost, installation space, and the like. (Second configuration example) Fig. 16 is a functional block diagram showing a second configuration example of the autofocus control device according to this embodiment. The same reference numerals are given to portions corresponding to the first configuration example (Fig. 5), and detailed descriptions thereof are omitted. The autofocus control device 3 2 of this configuration example is composed of a video signal decoder 41, F P G A 4 2, -31-200527907 (28) CPU 44, 11〇] ^ / 11 八 1 ^ 45 ,? 1 ^ 匸 46 and 1 /? Circuit 47. In the autofocus control device 31 of the first configuration example described above, the field memory 43 is used to control the image processing on the interface as the same image as the television set, and control is performed from the frame information. However, considering only the auto-focusing action, there is no need to use frame information, and there are cases where processing in field units is sufficient, and this also becomes an advantage. As described above, the autofocus control device 32 of this configuration example is a configuration in which the field memory 43 is removed from the first configuration example. With this configuration, since the transfer timing processing of information to the field memory is unnecessary, it is also simpler physically or logically than the first configuration example described above. In addition, since the focus evaluation process is performed on a field unit basis, compared with the first configuration example processed on a frame unit basis, there are advantages such that the sampling interval of the focus evaluation unit is shorter. (Third configuration example) Fig. 17 is a functional block diagram showing a third configuration example of the autofocus control device according to this embodiment. The same reference numerals are given to portions corresponding to the first configuration example (Fig. 15), and detailed descriptions thereof are omitted. The autofocus control device 33 of this configuration example is composed of a video signal decoder 41, an FPGA 42, a CPU 44, a ROM / RAM 45, a PMC 46, and an I / F circuit 47. The autofocus control device 33 of this configuration example is a configuration in which the logic block of PMC 46 is built in the FPG A 42 and the second configuration example described above does not require a separate logic circuit for the PMC 46. With this configuration, the 1C chip for the independent PMC 46 is unnecessary, and the substrate size and the mounting cost can be reduced by -32-200527907 (29). (Fourth configuration example) Fig. 18 is a functional block diagram showing a fourth configuration example of the autofocus control device according to this embodiment. The same reference numerals are given to portions corresponding to the first configuration example (Fig. 15), and detailed descriptions thereof are omitted. The autofocus control device 34 of this configuration example includes a video signal decoder 41, FPGA 4, 2, CPU 44, ROM / RAM 45, AD (Analog to Digtal) / DA (Digital to Analog) circuit 48, and I / F circuit 47. The autofocus device 34 of this configuration example is an example in which a drive source for a focus table is configured from a piezoelectric table controlled by an analog signal from a pulse motor. Instead of the PMC 46 of the second configuration example described above, an AD / DA circuit 48 is used. . In addition, the AD / DA circuit 48 can be incorporated in cPU4, for example. In this case, it is not necessary to make the AD / DA circuit 48 as a peripheral circuit. In the AD / DA circuit 48, the DA circuit part is a circuit for converting an instruction voltage from the CPU 44 to an analog signal; the AD circuit part is used for converting a sense from a moving position of the piezoelectric table. The signal of the tester (not shown) is converted into a digital signal and fed back to the circuit of the CPU 4 4. When this feedback control is not performed, the AD circuit portion can be omitted. (Fifth configuration example) Fig. 19 shows a specific configuration example of the autofocus control device 33 as the third configuration example (Fig. 17) described above as the fifth configuration example of this embodiment. In the figure, the same symbols are given to the corresponding parts, and detailed descriptions are omitted -33- 200527907 (30). The autofocus control device 35 of this configuration example is equipped with a video signal decoder 41, an FPGA 42, a CPU 44, a flash memory 45A, a SRAM (Static Random Access Memory) 45B, and an RS driver on a common wildcard substrate 50. 47A, a power supply monitoring circuit 51, an FPGA initialization ROM 52, and a plurality of connectors 53A, 53B, 53C, and 53D. The flash memory 45A and the SRAM 45B correspond to the ROM / RAM 45 described above. In one of the flash memories 45A, an operation program of the CPU 44 or initial setting information of an autofocus operation (focus moving speed, smoothing processing) are stored. Conditions, etc.); the other SRAM 45B is used to temporarily store various parameters necessary for calculating the focus position of the CPU 44. RS driver 4 7 A is an interface circuit necessary for communication with external devices connected via connectors 5 3 A to 5 3 D. Here, a CD camera is connected to the connector 5 3 A, and a host controller or CPU is connected to the connector 53B. A power supply circuit is connected to the connector 53C, and a focusing stage is connected to the connector 53D. The focus stage is equipped with a pulse motor as a drive source, and the PMC of the controller is incorporated in the FPG A 42. As described above, according to the autofocus control device 35 of this configuration example, the external dimensions of various components on which a wiring substrate 50 can be mounted to implement the algorithm implemented by the autofocus control method of the present invention are as follows] 00 mm square board mount. This can reduce the cost of the device and simplify the device configuration. In addition, since the degree of freedom in setting the machine can be increased, the industrial field that has not been used so far has become a site that can be responded to by the autofocus operation required by the field. -34-200527907 (31) In the above, the embodiments of the present invention have been described. Of course, the present invention is not limited to these. Various changes can be made according to the technical idea of the present invention, such as the first embodiment described above. In order to make the distance between the lens and the sample different, a configuration in which the objective lens 3 side is moved in the direction of the focus axis has been described. Instead of this configuration, a table 2 that can move and support the sample may be used. In the first embodiment described above, the driving system for changing the distance between the lens and the sample is constituted by the lens driving unit 4 and the driver 6 made of piezoelectric elements. However, it is not limited to this. It is also possible to apply other driving systems to those who change the distance between lens samples smoothly. For example, FIG. 20A shows an example in which a pulse motor 2 0 is used as a drive source. At this time, the driver 21 generates a driving signal for the pulse motor 2 according to a control signal supplied from the pulse motor controller 22, and the lens driving unit 4 and the above-mentioned pulse motor 20 perform so-called field forward control. For driving, a sensor for detecting the lens position or the position of the table is provided, and a configuration of a feedback control driving source can also be used. Fig. 20B shows an example of a configuration of a drive system in which a drive source is controlled by field feedback control. The driver 24 generates a drive signal for the drive system 23 according to a control signal supplied from the output instruction circuit 25. At this time, a cylinder device, a motor, or the like can be applied as the drive train 23. The position sensor 26 can be configured by a strain gauge, a potentiometer, or the like, and supplies its output to the coupling circuit 27. The coupling circuit 27 supplies a position compensation signal to the output instruction circuit 25 based on the output of the position sensor 26, and corrects the position of the drive system 23. -35- 200527907 (32) In each of the above embodiments, the NTSC method is used to describe the video signal supplied from the CCD camera, but it is not limited to this. For example, the PAL (Phase Alter nation by Line) method can be used for processing. . In addition, if the video signal decoder unit is replaced, it can correspond to other formats such as the IEEE 1 3 94 'camera chain. At this time, the function of the video signal decoder circuit can also be integrated into the FPGA 42. In addition, the focus evaluation frame or focus position of each object material image obtained by performing the autofocus control of the present invention may be displayed on the monitor 9 together with the sample image (Fig. 1). At this time, it can be set to convert this information into NTSC, etc. and display the encoder circuit used. This encoder circuit is one of the board mounting components of the autofocus control device having the configuration described in the fifth embodiment. [Brief Description of the Drawings] Fig. 1 is a schematic configuration diagram showing an image processing apparatus 1 according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of the controller 7. FIG. 3 is a flowchart illustrating the operation of the image processing device 1. Fig. 4 is a flowchart showing another example of the operation of the image processing apparatus 1. Fig. 5 shows an example of a focus curve explaining a function of the present invention; FC 1 shows an example when performing image smoothing processing and highly normalized processing of focus evaluation; FC 2 shows only image smoothing processing Example; FC3 is a conventional example. • 36- 200527907 (33) Fig. 6 is a diagram illustrating a method of calculating a focus position by making a close curve in the vicinity of the focus evaluation 値 maximum 値. Fig. 7 is a diagram showing the relationship between the instruction voltage to the lens driving unit 4 and the real movement voltage of the lens. Fig. 8 is a diagram illustrating a method of combining day images of processing samples in parallel and a method of calculating a focal evaluation value. Fig. 9 is a diagram showing a second embodiment of the present invention; a diagram explaining a method of dividing a screen into a plurality of numbers and detecting a focus position in each of the divided areas. Fig. 10 is a flowchart showing a process according to a third embodiment of the present invention. Fig. 11 is a diagram showing a memory structure applicable to the third embodiment of the present invention. Fig. 12 is a flowchart illustrating an all-focus image acquisition process. Fig. 13 is a diagram showing a fourth embodiment of the present invention; and a diagram explaining a method of obtaining a three-dimensional picture by combining the focal positions of the sample picture toward the focus axis direction. Fig. 14 is a flowchart showing a method for synthesizing the above-mentioned three-dimensional portrait. Fig. 15 is a functional block diagram showing a first configuration example of an autofocus control device according to a fifth embodiment of the present invention. Fig. 6 is a functional block diagram showing a second configuration example of an autofocus control device according to a fifth embodiment of the present invention. Fig. 17 is a functional block diagram showing a third configuration example of the automatic focus control -37-200527907 (34) manufacturing apparatus according to the fifth embodiment of the present invention. Fig. 18 is a functional block diagram showing a fourth configuration example of an autofocus control device according to a fifth embodiment of the present invention. Fig. 19 is a functional block diagram showing a fifth configuration example of the autofocus control device according to the fifth embodiment of the present invention. 20A to 20B are block diagrams showing modifications of the configuration of the drive system of the image processing apparatus 1. Fig. 21 is an example of a focus curve showing the relationship between the lens-workpiece distance (focus position) and the focus evaluation angle. Fig. 22 is a diagram illustrating a disadvantage of the prior art. [Description of main component symbols] 1 Image processing device 2 Measuring table 3 Objective lens 4 Lens driving unit 5 Lens barrel 6 CCD camera 7 Controller 8 Driver 9 Monitor 10 Illumination light source 1 1 Focus (AF) control unit Π A smoothing processing circuit -38- 200527907 (35) 11B average brightness calculation circuit 1 1 C evaluation / calculation circuit 1 1 D focus position calculation circuit 13 A / D converter 14 memory 1 5 A first memory section 1 5 B second memory Part 16 Input device 17 D / A converter 20 Pulse motor 2 1 Driver 22 Pulse motor controller (PMC) 2 3 Drive system 2 4 Driver 25 Output indicating circuit 2 6 Position sensor 2 7 Combination circuit 3 1, 3 2 3 3 3 4 3 5 Focus control device 4 1 Video signal decoder

42 FPGA 43 Field Memory

44 CPU

4 5 ROM / RAM 46 PMC -39- 200527907 (36) 47 I / F circuit 48 AD / DA circuit 5 〇 Wiring board 51 Power monitor circuit 5 2 FPGA initializing ROM. 53A, 53B, 53C, 53D connector

-40-

Claims (1)

200527907 (1) X. Application for patent scope 1. An automatic focus control method, comprising: a daylight image acquisition project for obtaining image data of the above-mentioned photographic body at plural focusing positions with different distances between the lens and the photographic body; For each of the image data, the above-mentioned plural focus positions separately calculate the evaluation of the focus evaluation 値, and the calculation process of the focus; the calculation of the focus position which is the focus position where the focus evaluation 値 becomes the largest; and the calculation of the focus position as the focus position; and The method for the automatic focus control of the lens with respect to the movement process of the relative movement of the illuminating body is characterized in that: between the image acquisition process and the evaluation / calculation process, there is a smoothing process for smoothing the image of the acquired day image data. Engineering; calculating the focus evaluation value based on the smoothed image data. 2 · The automatic focus control method according to item 1 of the scope of patent application, wherein before or after the image smoothing process, there is an average brightness calculation process for calculating the average brightness of the screen of the acquired image data; as the focus The evaluation 値 uses the division of the average screen brightness calculated as described above. 3. The automatic focus control method according to item 1 of the scope of patent application, wherein in the above-mentioned evaluation process, the focus evaluation process is calculated based on the brightness data difference between adjacent pixels of the obtained image data. 4. The automatic focus control method described in item 1 of the scope of the patent application, -41-200527907 (2) wherein the calculation of the focus position at the focus position is based on the calculated focus evaluation 値 maximum 値 and the complex focus evaluation near it 値To calculate the focus position. 5. The automatic focus control method according to item 1 of the scope of patent application, wherein in the image acquisition process, the image data is obtained at the multiple focus positions while continuously changing the lens and the distance between photographic objects'. 6. The automatic focus control method according to item 1 of the scope of patent application, wherein the image acquisition process and the evaluation / calculation process are performed in parallel. 7 The automatic focus control method according to item 1 of the scope of patent application, wherein the illumination light source of the photographic body uses ultraviolet rays. 8. The automatic focus control method according to item 1 of the scope of patent application, wherein the acquired image data is divided into a plurality of fields; and each of the divided fields separately calculates the focus position. 9 · The automatic focus control method according to item 8 of the scope of the patent application, wherein the images of the focus positions of the divided fields are synthesized between the fields to obtain a full-focus image of the photographed body. 10. The automatic focus control method according to item 8 of the application 5P3 patent, wherein 'combining the image of the focus position of each of the divided fields between the multiple focus positions to obtain a three-dimensional image of the photographic body. Π. An automatic focus control method comprising: an image obtaining process for obtaining the image data of the above-mentioned photographic body at plural focusing positions with different distances between the lens and the photographic body; -42- 200527907 (3) According to each of the above obtained For the image data, the above-mentioned plural focus positions are separately calculated for the focus evaluation 値 evaluation and calculation process; the focus position where the focus evaluation 値 becomes the largest is calculated as the focus position calculation position for the focal black position; and the above-mentioned calculated focus position is calculated for the above-mentioned focus position An automatic focus control method of the lens for the above-mentioned finger-relative movement mobile project is characterized by having an image smoothing process for 'smoothing' the image data obtained above, and calculating an average screen height of the image data obtained above The average brightness calculation process is calculated; the focus evaluation value is calculated based on the smoothed image data; at the same time, as the focus evaluation value, a division value of the average screen brightness calculated according to the above is used. 1 2 · The automatic focus control method according to item 11 of the scope of patent application ′, wherein in the above-mentioned evaluation process, the focus evaluation process is calculated based on the brightness data difference between adjacent pixels of the obtained image data. 13. The automatic focus control method according to item 11 of the scope of patent application, wherein the focus position calculation process calculates the focus position based on the maximum value of the focus evaluation value 算出 calculated above and the complex focus evaluation 近 near it. 1 4. The automatic focus control method according to item 11 of the scope of the patent application, wherein in the image acquisition process, the distance between the lens and the photographic body is continuously changed, and the images are obtained at the multiple focus positions. data. -43- 200527907 (4) 1 5 · The automatic focus control method according to item 11 of the scope of patent application, wherein the image acquisition process and the evaluation / calculation process are performed in parallel. 16 · The automatic focus control method according to item 11 of the scope of patent application, wherein ultraviolet light is used as an illumination light source of the photographic body. 17. The automatic focus control method according to item 11 of the scope of patent application, wherein 'the image data obtained above is divided into a plurality of fields; the above-mentioned focus positions are calculated separately for each of the above-mentioned respective fields. 18 · The automatic focus control method according to item 17 of the scope of patent application, wherein the images of the focal position of each of the divided areas are synthesized between the areas to obtain a full-focus portrait of the photographic body. 19 · The automatic focus control method according to item 17 of the scope of the patent application, wherein the three-dimensional image of the photographic body is obtained by synthesizing the images of the focus positions in the divided fields in the above-mentioned multiple focus positions. 20 · An automatic focus control device comprising: each of the image data obtained at a plurality of focus positions having different distances between a lens and a photographic body, and the plurality of focus positions separately calculate focus evaluation (evaluation) calculation means; and An autofocus control device that calculates a focus position based on the calculated maximum focus evaluation value 値 is provided with an image smoothing means for smoothing the acquired image data; and based on the smoothing. The processed image data is used to calculate the above-mentioned focus evaluation 値 0 -44-200527907 (5) 21. The autofocus control device according to item 20 of the patent application scope, wherein it has an average brightness of the screen for calculating the acquired image data Means for calculating the average brightness, as the focus evaluation, use the division of the average brightness of the screen calculated as described above. 2 2. The automatic focus control device according to item 20 of the scope of the patent application, wherein the evaluation and calculation means is an edge emphasis processing means for calculating a difference in luminance data between adjacent pixels of the acquired image data. 23. The automatic focus control device according to item 20 of the scope of patent application, wherein the focus position calculation means is to calculate the focus position based on the calculated maximum value of the focus evaluation 値 and the complex focus evaluation 近 near it. 24. The autofocus control device as described in item 20 of the patent claim, which includes an all-focus image synthesis means for synthesizing an all-focus image of the photographic object using each of the acquired image data. 25. The autofocus control device according to item 20 of the scope of patent application, wherein '' is provided with a means for synthesizing a three-dimensional image of the three-dimensional image of the photographic body using each of the acquired image data. 26. The automatic focus control device according to item 20 of the scope of patent application, wherein the automatic focus control device is the above-mentioned evaluation / calculation means, the above-mentioned focus position calculation means, and the above-mentioned image smoothing means, and calculates The average brightness calculation means for the average brightness of the screen of the above-mentioned image data is formed as a single or plural element mounted on a substrate mounting body on the same substrate. 0 2 7 .Autofocus control as described in item 26 of the patent application scope Device -45- 200527907 (6), wherein a drive control element for controlling a drive means for adjusting a distance between a lens and a photographic body is mounted on the substrate. 2 8 · The automatic focus control device according to item 26 of the scope of patent application, wherein the above-mentioned evaluation / calculation means, the above-mentioned image smoothing means, and the above-mentioned average brightness calculation means are based on a single FPGA (Field Programmable Gate Array) Structure 〇29 · —A kind of image processing device, including: an image obtaining means for obtaining the image data of the above-mentioned photographic body at a plurality of focusing positions with different distances between the lens and the photo-taking body, and the image data obtained based on the above-mentioned ' The plural focus positions separately calculate focus evaluation 焦点 evaluation 値 calculation means, and focus position calculation means to calculate a focus position based on the calculated focus evaluation 値 maximum 値, and the lens is aligned with the lens toward the calculated focus position. The automatic focus control device that is a driving means for the relative movement of the photographic body is characterized by having image smoothing means for smoothing the acquired image data; and calculating the focus evaluation value based on the smoothed image data. 30. The automatic focus control device according to item 29 of the scope of patent application, further comprising an average brightness calculation means for calculating the average brightness of the screen of the acquired image data, as the focus evaluation, using the calculated value as described above. Divide the average screen brightness. 31. The automatic focus control device according to item 9 of the scope of patent application 2, wherein the evaluation / calculation means is an edge emphasis processing means for calculating a luminance data difference between adjacent pixels of the acquired image data. -46- 200527907 (7) 32. The automatic focus control device according to item 29 of the scope of patent application, wherein the focus position calculation means is based on the calculated maximum focus value 値 and the multiple focus evaluations near it.値 to calculate the focus position. 33. The autofocus control device according to item 29 of the scope of patent application, further comprising an all-focus image synthesis means for synthesizing an all-focus image of the photographic object using each of the acquired image data. 34. The autofocus control device according to item 29 of the scope of patent application, further comprising a method for synthesizing a three-dimensional image of the three-dimensional image of the photographed body using the acquired image data. -47-