JP2004061410A - Focal image synthesizing method and its program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem of false determination that a noise is detected when a maximum luminescence of a pixel corresponding to a position of a sample surface is low, for example, because of a low reflectivity of the sample surface. <P>SOLUTION: Luminance information stored in a luminance information storage means 1 is referred to for obtaining an estimated pixel height Ztemp and an estimated pixel luminance value Itemp for a pixel i subjected to processing. It is determined whether the pixel i is focused with the estimated pixel height Ztemp. If the determination result is Yes, the estimated pixel height Ztemp and the estimated pixel luminance value Itemp are set to a definite pixel height Z(i) and a definite pixel luminance value I(i), respectively. If the determination result is No, exceptional values (Zexception, Iexception) are set to the definite pixel height Z(i) and the definite pixel luminance value I(i). The above processing is repeated for all pixels corresponding to respective positions of the sample surface. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a focus image synthesizing method for acquiring an image with a deep depth of focus and a three-dimensional shape of a sample surface using luminance information obtained from a microscope having an optical system having a confocal effect, and a program therefor.
[0002]
[Prior art]
In a microscope equipped with an optical system having a confocal effect, a two-dimensional image is constructed by condensing reflected light from each position on a focal plane and detecting each as a pixel value corresponding to each position. be able to. When such a microscope is used to construct a two-dimensional image of a sample having irregularities on the surface, reflected light from the sample surface is detected when the sample surface is on the focal plane. If not, no reflected light is detected. That is, it is possible to construct a two-dimensional image brightened by the reflected light only for the pixel corresponding to the position where the sample surface and the focal plane overlap.
[0003]
Accordingly, a plurality of two-dimensional images obtained when the focal plane is displaced relative to the sample surface are obtained, and the maximum luminance of a pixel corresponding to each position on the focal plane is obtained from the plurality of two-dimensional images. When an image is constructed in which the maximum luminance is obtained and the corresponding pixel is output, the image becomes an in-focus image at all positions on the focal plane. Further, when acquiring a two-dimensional image in which the pixel corresponding to each position on the focal plane has the maximum luminance from among the acquired plural two-dimensional images, displacement information of the sample surface with respect to the focal plane is obtained from the corresponding pixel. When an output image is constructed, the image becomes an image representing the three-dimensional shape of the sample surface. However, if the sample has a steep slope or the reflectance of the sample surface is low and there is no luminance peak among the acquired two-dimensional images, the original “surface” does not appear in the pixel. Therefore, in this case, simply obtaining the maximum luminance of the corresponding pixel as described above results in noise being picked up, and the noise is included on a steep slope or a low reflectance portion.
[0004]
Therefore, in order to remove such noise, a specified value is set when the maximum luminance of the corresponding pixel is obtained from each two-dimensional image as described above, and when the maximum luminance of the relevant pixel is equal to or less than the specified value, A method has been proposed in which the output value (displacement information or luminance) is set to zero, output as an interpolated value from surrounding pixels, or is not output (for example, JP-A-6-308390, JP-A-8-308). 210819). A feature of these methods is that if the maximum luminance is equal to or less than a specified value, all of them are regarded as noise and exclusion processing and interpolation processing are performed.
[0005]
[Problems to be solved by the invention]
However, there is a problem in that if the maximum luminance is equal to or less than the specified value, it is regarded as noise. The problem is that normal reflected light from a low reflectance region of the sample surface is regarded as noise.
[0006]
FIG. 15 is a diagram illustrating an example of a change in luminance with respect to the height of each position when a sample surface is measured using a microscope having an optical system having a confocal effect. However, in the figure, the height of each position is indicated by the number of the corresponding slice image (a two-dimensional image obtained at a predetermined height).
[0007]
In the figure, (a) shows a pixel in a high reflectivity area, (b) shows a pixel in a low reflectivity area, and (c) shows a luminance change of a pixel corresponding to a flaw on the sample surface. The shape of the luminance change in (a) and (b) is a unimodal peak shape where the luminance value becomes maximum at the height where the position on the sample surface corresponding to each pixel coincides with the focal plane due to the confocal effect. have. On the other hand, the shape of the luminance change in (c) is completely different from those in (a) and (b), and the height at which the luminance is maximum is irrelevant to the sample surface.
[0008]
In such a case, only (c) should be judged as noise. However, since the maximum luminance of (b) is equal to (c), if the noise of (c) is simply removed with the specified value, the normal (b) ) Will be removed.
In view of the above circumstances, it is an object of the present invention to provide a focus image synthesis method that does not erroneously determine noise even when the maximum luminance of a pixel corresponding to a position on a sample surface becomes low due to a low reflectance on the sample surface. It is to provide a method and its program.
[0009]
[Means for Solving the Problems]
A first aspect of the present invention stores luminance at each height on the optical axis of a pixel corresponding to each position on the surface of an object to be measured, obtained using a microscope having an optical system having a confocal effect. A storage step, and referring to the luminance stored in the storage step according to processing target pixel specifying information for uniquely specifying a processing target pixel, an optical axis estimated to be focused on the processing target pixel The first acquisition step of acquiring the upper height and the luminance at that time as an estimated pixel height and an estimated pixel luminance value, and according to the processing target pixel designation information and the estimated pixel height, A query step of determining whether or not the pixel to be processed is in focus at the estimated pixel height by referring to the stored brightness, and performing the processing at the estimated pixel height in the determination step. When the target pixel is in focus When it is determined, the estimated pixel height and the estimated pixel luminance value are acquired as the determined pixel height and the determined pixel luminance value, and the pixel to be processed is focused on the estimated pixel height in the determination step. And a second acquisition step of acquiring an exceptional height and an exceptional luminance value as the confirmed pixel height and the confirmed pixel luminance value when it is determined that the focused image is not present.
[0010]
According to the above method, after the estimated pixel height and the estimated pixel luminance value are obtained, it is determined whether or not focus is achieved at the estimated pixel height. Based on the determination result, the determined pixel height is determined. The height and the determined pixel luminance value are the estimated pixel height and the estimated pixel luminance value, or are exceptional height and luminance values. Thereby, even when the maximum luminance of the pixel corresponding to the position of the sample surface is low due to the existence of a steep slope on the sample or the low reflectance of the sample surface, it is possible to eliminate the erroneous determination as noise. be able to.
[0011]
According to a second aspect of the present invention, in the first aspect, based on the determined pixel height and the determined pixel luminance value acquired in the second acquisition step, at each position on the surface of the device under test. The method further includes a step of generating surface shape information including height information of a corresponding pixel and surface luminance information including luminance information of a pixel corresponding to each position on the surface of the device under test.
[0012]
According to this method, the surface shape information and the surface luminance information are generated based on the acquired determined pixel height and the determined pixel luminance value.For example, based on the surface shape information and the surface luminance information, the display and the display are performed. Analysis and the like can be performed.
According to a third aspect of the present invention, in the first aspect, in the first acquisition step, based on the fact that the brightness at the height on the optical axis where the focus is focused on the processing target pixel is the highest value, In this method, a height on the optical axis estimated to be focused on the processing target pixel and a luminance at that time are obtained.
[0013]
According to this method, for example, the height on the optical axis at which the luminance of the processing target pixel has the highest value and the luminance at that time are acquired as the estimated pixel height and the estimated pixel luminance value. Alternatively, the predetermined height and the luminance at the predetermined height when the average of the luminance at a plurality of consecutive heights before and after the predetermined height on the optical axis including the predetermined height on the processing target pixel is the highest value Are obtained as the estimated pixel height and the estimated pixel luminance value.
[0014]
According to a fourth aspect of the present invention, in the first aspect, in the first obtaining step, the luminance change with respect to the height on the optical axis for the pixel to be processed is the height on the optical axis where the focus is on. A height on the optical axis estimated to be in focus on the pixel to be processed and a luminance at that time based on the fact that the pixel has a single peak.
[0015]
According to this method, for example, in the luminance change with respect to the height on the optical axis for the pixel to be processed, each luminance value of the height at a predetermined interval before and after that including the predetermined height on the optical axis is used. When the value of the evaluation function, which becomes larger as approaching the peak of the unimodal peak, becomes the maximum value, the predetermined height and the luminance at the predetermined height are estimated. Obtained as the pixel height and the estimated luminance luminance value. As a result, it is possible to obtain a more correct estimated pixel height and estimated pixel luminance value.
[0016]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, in the determining step, the light focused on the luminance change with respect to the height on the optical axis of the processing target pixel. Based on the difference in luminance change between the unimodal peak region having the height on the axis as the vertex and the other background region, it is determined whether or not the processing target pixel is focused at the estimated pixel height. It is a method of determining.
[0017]
According to this method, for example, the focus at the estimated pixel height is determined based on a comparison between the estimated pixel luminance value that is the highest luminance value in the unimodal peak region and the highest luminance value in the other background regions. It is determined whether or not matches. This makes it possible to accurately determine the validity of the estimated pixel height and the estimated pixel luminance value.
[0018]
According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the exceptional height and the exceptional luminance value are at least determined to be in focus in the determination step. The lowest value, the highest value, or the average value, the fixed value, or any one of the interpolated values obtained from the pixels determined to be in focus in the determination step. Is the way.
[0019]
According to this method, it is possible to set the exceptional height and the exceptional luminance value to values according to the shape of the sample surface, and to display and analyze the surface shape information and the surface luminance information. It becomes possible to set a suitable value.
According to a seventh aspect of the present invention, in any one of the first to fifth aspects, when the estimated pixel luminance value obtained in the first step is equal to or more than a predetermined value, the determination is performed. A method of acquiring the estimated pixel height and the estimated pixel luminance value as the confirmed pixel height and the confirmed pixel luminance value in the second acquisition step without performing the step.
[0020]
According to this method, the influence of noise is small and the estimated pixel height and the estimated pixel luminance value are erroneous, as in the case where light is sufficiently reflected on the sample surface and a high luminance value is obtained as the estimated pixel luminance value. When the possibility of the estimation is low, the determination step is not performed, so that the processing speed can be improved.
[0021]
An eighth aspect of the present invention is a program for causing a computer to execute the steps according to the first aspect.
By causing a computer to execute the above-described program, the same operation and effect as in the first aspect can be obtained.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a first embodiment will be described.
FIG. 1 is a diagram showing a schematic configuration for explaining a focus image synthesizing method of the present invention.
[0023]
In the figure, a luminance information storage unit 1 corresponds to each position on the surface of the measured object obtained by a measuring unit (dotted line in the figure) using a microscope or the like having an optical system having a confocal effect. The luminance information at each height on the optical axis of the pixel to be stored is stored (arrow a).
[0024]
When the processing target pixel specifying information that uniquely specifies the processing target pixel is input, the focus information output unit 2 outputs the processing target pixel specifying information to the estimated pixel information output unit 3 as a first procedure ( An arrow b) obtains an estimated pixel height and an estimated pixel luminance value from the estimated pixel information output means 3 (arrow c).
[0025]
When obtaining the target pixel designation information from the focus information output means 2 (arrow b), the estimated pixel information output means 3 refers to the luminance information stored in the luminance information storage means 1 (arrow d), and estimates the estimated pixel height. It obtains the estimated pixel luminance values and outputs them to the focus information output means 2 (arrow c).
[0026]
Further, as a second procedure, the focus information output unit 2 outputs the target pixel designation information and the estimated pixel height obtained in the first procedure to the validity determination unit 4 (arrow d), and From the sex determination means 4, a determination result as to whether or not the pixel to be processed is in focus at the estimated pixel height is obtained (arrow e).
[0027]
Upon acquiring the target pixel designation information and the estimated pixel height from the focus information output unit (arrow e), the validity determination unit 4 refers to the luminance information stored in the luminance information storage unit 1 (arrow g), It is determined whether or not the processing target pixel is in focus at the estimated pixel height, and the determination result is output to the focus information output unit 2 (arrow f).
When the focus information output unit 2 determines that the pixel to be processed is in focus at the estimated pixel height obtained in the first procedure based on the determination result obtained in the second procedure, The estimated pixel height and the estimated pixel luminance value acquired in the first procedure are output to the focus image generating unit 5 as the determined pixel height and the determined pixel luminance value, respectively (arrow h), or acquired in the second procedure. When it is determined from the result of the determination that the pixel to be processed is not focused on at the estimated pixel height obtained in the first procedure, the exceptional determined pixel height and the determined pixel luminance value are determined by the focus image generation unit. 5 (arrow h).
[0028]
When acquiring the determined pixel height and the determined pixel luminance value from the focus information output unit 2 (arrow h), the focus image generation unit 5 obtains surface shape information including height information at pixels corresponding to each position on the surface of the device under test. , And surface luminance information including luminance information at each position on the surface of the device under test.
[0029]
The surface shape information and the surface luminance information generated in this manner are thereafter output to, for example, a display unit (dotted line in the figure) (arrow i), and an image or the like corresponding to the surface shape information and the surface luminance information is output. Is displayed.
Next, the configuration of the above-described luminance information storage unit 1 will be described.
[0030]
FIG. 2A is a diagram illustrating a configuration example of the luminance information storage unit 1.
As shown in FIG. 1A, the luminance information storage means 1 sequentially stores slice images having, as pixel information, luminances corresponding to respective positions on the surface of the DUT obtained at respective heights. It is configured to include a storage list, a Z coordinate storage list (Zmatrix) that sequentially accumulates the heights at which the slice images stored in the slice image storage list are obtained, and the like. With such a configuration, the slice image (or its storage position) stored in the slice image storage list and the height (or its storage position) stored in the Z coordinate storage list are uniquely associated with each other, For example, when a predetermined slice image stored in the slice image storage list is designated, it is possible to uniquely obtain the height stored in the Z coordinate storage list associated with the slice image. Will be possible.
[0031]
FIG. 2B is a flowchart illustrating an example of a process performed by the luminance information storage unit 1. (B) The flow on the left side shows the initialization processing, and the flow on the right side shows the new data addition processing.
The initialization process is a process performed before the first slice image is obtained by a measuring unit (not shown). First, in S201, a slice image storage list is initialized as preparation for storing a slice image, and then in S202 Then, a Z coordinate storage list is initialized as preparation for storing the Z coordinate.
[0032]
The new data adding process is a process in which the slice image and its height are sequentially acquired while moving the height in a fixed direction after the above-described initialization process is completed. , The newly acquired slice image is stored at the end, and in S212, the height of the newly acquired slice image is stored at the end of the Z coordinate storage list.
[0033]
By such processing, the slice image and the height are sequentially added to the end of the slice image storage list and the end of the Z coordinate storage list, respectively. Therefore, the height of the Nth slice image stored in the slice image storage list is , And Z are stored in the N-th coordinate storage list. As a result, the two are associated with each other by the position in the storage list.
[0034]
Note that the configuration of the luminance information storage means 1 is not limited to that shown in FIG. 3A, but can be realized by other configurations.
FIG. 3C is a diagram showing another example of the configuration of the luminance information storage means 1.
As shown in FIG. 3C, the luminance at each height on the optical axis of the pixel corresponding to each position on the surface of the DUT is represented by a color component (R, G, B in FIG. 3C). It is also possible to configure to store the slice images separated for each image. Such a configuration is suitable, for example, when the measurement unit uses three lasers having different wavelengths.
[0035]
Alternatively, if the height difference between the slice images can be considered to be constant, the Z coordinate storage list is omitted from the configuration of the luminance information storage means 1, and the height Zini of the first stored slice image and each slice are replaced. By storing the height difference dZstep between the images, the height Zn of the slice image stored at the Nth position in the slice image storage list can be obtained by the following equation (1).
[0036]
Zn = Zini + N × dZstep (N = 0, 1, 2, 3,...) Equation (1)
Next, processing performed by the focus information output unit 2, the estimated pixel information output unit 3, the validity determination unit 4, the focus image generation unit 5, and the like will be described.
[0037]
FIG. 3 is a flowchart showing an example of the processing.
In the figure, the processing of S303 (dotted line part a in the figure) indicates the processing performed by the estimated pixel information output means 3, and the processing of S304 (dotted line part b in the figure) is performed by the validity determination means 4. The processing of steps S303 to S306 (dotted line c in FIG. 3) indicates processing performed by the focus information generating means 2 and the like. Further, the processing of S308 to S312 (dotted line portion d in the figure) indicates the processing performed by the focus image generating means 5.
[0038]
As shown in the figure, first, in S301, the processing target pixel i is initialized to the first pixel.
In S302, it is determined whether or not the processing performed by the focus information generation unit 2 has been completed for the pixels corresponding to all positions on the surface of the object (whether or not i> = i_max), and the determination result is obtained. Is Yes, the process proceeds to S308, and if No, the process proceeds to S303. Note that i_max indicates the total number of pixels corresponding to all positions on the surface of the device under test.
[0039]
In S303, the estimated pixel information output means 3 acquires an estimated pixel height and an estimated pixel luminance value for the processing target pixel i, and substitutes them into Ztemp and Itemp, respectively. However, Ztemp is a value indicating the position (storage position) of the slice image storage list in which the slice image obtained at the height estimated to be focused on the processing target pixel i is stored as the estimated pixel height. Is substituted. Since the height stored at the storage position of the corresponding Z coordinate storage list can be uniquely acquired from the value indicating the position of the slice image storage list, the estimated pixel height is simply added to Ztemp. It can be said that it is substituted. Further, a luminance value at a height at which it is estimated that the processing target pixel i is in focus is substituted into Itemp as the estimated pixel luminance value. The details of the process in this step will be described later with reference to FIGS.
[0040]
In S304, the validity determination unit 4 determines whether the processing target pixel i is in focus at the estimated pixel height Ztemp. If the determination result is Yes, the process proceeds to S306, and the process proceeds to S306. In this case, the process proceeds to S305. The details of the process of this step will be described later with reference to FIG.
[0041]
In S305, when it is determined in the previous step that the focus is not achieved, a predetermined exceptional value (Zexception, Iexception) is substituted for the estimated pixel height Ztemp and the estimated pixel luminance value Itemp.
In S306, the values of the estimated pixel height Ztemp and the estimated pixel luminance value Itemp of the processing target pixel i are substituted into Z (i) and I (i) as the determined pixel height and the determined pixel luminance value, respectively. However, as in the case of Ztemp described above, a value indicating the storage position of the slice image storage list for the corresponding slice image is substituted for Z (i). Can be obtained, it can be said that the determined pixel height is simply substituted for Z (i).
[0042]
In S307, the processing target pixel i is incremented, the processing target pixel is changed to the next pixel, and the process returns to S302.
As described above, when the focus information generation unit 2 acquires the determined pixel height and the determined pixel luminance value for the pixels corresponding to all positions on the surface of the measured object, the focus image generation unit 5 It shifts to the process after S308 performed.
[0043]
In S308, when it is determined in S302 that i> = i_max, an area for storing the surface shape information SG and the surface luminance information SI for pixels corresponding to all positions on the surface of the device under test is secured. You.
In S309, the processing target pixel i is initialized to the first pixel.
[0044]
In S310, it is determined whether or not the processing has been completed for the pixels corresponding to all the positions on the surface of the device under test (whether or not i> = i_max). If the determination result is Yes, this processing is performed. The process ends, and in the case of No, the process proceeds to S311.
In S311, Zmatrix (Z (i)), which is the determined pixel height of the processing target pixel i, is substituted into the surface shape information SG (i) of the processing target pixel i. Note that Zmatrix (Z (i)) obtains the height stored in the storage position of the Z coordinate storage list corresponding to the storage position of the slice image storage list indicated by the value assigned to Z (i). Shows the processing to be performed. Further, the determined pixel luminance value I (i) of the processing target pixel i is substituted for the surface luminance information SI (i) of the processing target pixel i.
[0045]
In S312, the processing target pixel i is incremented, the processing target pixel is changed to the next pixel, and the process returns to S310.
As described above, when the estimated pixel height and the estimated pixel luminance value are obtained by performing the present flow, the validity of the estimated pixel height is determined, and the determined pixel height and the determined pixel are determined based on the determination result. It is determined whether the luminance value is to be an estimated pixel height and an estimated pixel luminance value or an exceptional value. Based on the determined pixel height and the determined pixel luminance value, all positions on the surface of the measured object are determined. The surface shape information and the surface luminance information of the pixel corresponding to are obtained. Thereby, even when the maximum luminance of the corresponding pixel is low due to the low reflectance of the sample surface or the like, it is possible to eliminate erroneous determination as noise.
[0046]
Subsequently, the processing of S303 performed by the above-described estimated pixel information output means 3 will be described.
FIG. 4 is a flowchart showing an example of the processing.
First, in S401, a slice into which a value indicating the position of the processing target slice image (storage position in the slice image storage list) is substituted, and a slice image having the highest luminance value for the processing target pixel i. Slice_top into which the value indicating the position is substituted is initialized to a value indicating the head position of the slice image stored in the slice image storage list.
[0047]
In S402, the luminance value of the processing target pixel i in the slice image at the position indicated by the slice value stored in the slice image storage list is obtained (GetI (i, slice)), and the luminance value is set as i_top as the maximum luminance value. Is assigned to
In S403, the slice is incremented, and the slice image to be processed is changed to the next slice image.
[0048]
In S404, it is determined whether the processing has been completed for all slice images to be processed (whether slice> = slice_max). If the determination result is Yes, the process proceeds to S409. If No, the process proceeds to S405. Note that slice_max indicates the total number of all slice images to be processed.
[0049]
In S405, the luminance value of the processing target pixel i in the slice image (processing target slice image) at the position indicated by the slice value is obtained (GetI (i, slice)), and the luminance value is substituted into I_now.
In S406, the highest luminance value i_top thus far is compared with the I_now substituted in the previous step, that is, it is determined whether or not i_top <I_now. If the determination result is Yes, the process proceeds to S407. , No, the process proceeds to S408.
[0050]
In S407, when it is determined in the previous step that i_top <I_now, the value of I_now is substituted for I_top, and the value of slice at this time is substituted for slice_top. That is, I_top and slice_top are updated.
[0051]
In S408, the slice is incremented, the slice image to be processed is changed to the next slice image, and the process returns to S404.
In S409, if it is determined in S404 that slice> = slice_max, the value of slice_top into which the value indicating the position of the slice image having the highest luminance value for the processing target pixel i is substituted is the estimated pixel height. Is substituted into Ztemp. Also, the luminance value of the processing target pixel i in the slice image is obtained (GetI (i, slice_top)), and the luminance value is substituted into Itemp as the estimated pixel luminance value, and this processing ends. In this step, the luminance value is obtained by the processing of GetI (i, slice_top) and is substituted for Itemp. For example, the value of the maximum luminance value I_top substituted at this time is substituted for Itemp. You may do it.
[0052]
As described above, by performing the present flow, the value indicating the position of the slice image having the highest luminance value for the processing target pixel i and the highest luminance value among all the slice images stored in the slice image storage list are obtained. , Estimated pixel height Ztemp and estimated pixel luminance value Itemp.
[0053]
Note that the processing shown in this flow is to calculate the estimated pixel height and the estimated pixel luminance value by utilizing the fact that the highest luminance is obtained at a height at which the processing target pixel i is focused in principle. However, the method of obtaining the value is not limited to the processing shown in FIG. 4, and can be obtained by other methods.
[0054]
For example, the height of the processing target slice image when the average value of the luminance value of the processing target pixel i is the highest from the consecutive slice images before and after the processing target slice image including the processing target slice image is Ztemp as the estimated pixel height. , And the luminance value of the processing target pixel i in the slice image may be substituted into Itemp as the estimated pixel luminance value. The processing in this case will be described with reference to FIG.
[0055]
FIG. 5 is a flowchart illustrating another example of the process of S303 performed by the estimated pixel information output unit 3.
In the processing shown in the figure, since the processing is performed based on the continuous slice images before and after that including the processing target slice image, the processing target slice when starting the processing is different from the processing shown in FIG. The position of the image is not the first. That is, assuming that the total number of consecutive slice images before and after that including the processing target slice image is window (however, window is an odd number of 3 or more), the value indicating the position of the processing target slice image at the start of processing is: (Window-1) / 2. Similarly, the value indicating the position of the slice image to be processed when ending the processing is slice_max- (window-1) / 2. The luminance value substituted into the above-mentioned i_top and i_now is not the luminance value of the processing target pixel i of the processing target slice image, but is the average value of the luminance values of the processing target pixel i of the window slice image.
[0056]
This makes it possible to suppress the influence of noise even when the luminance value of the processing target pixel i includes noise.
Specifically, as shown in FIG. 5, first, in S501, the value of (window-1) / 2 is assigned to halfwnd. Here, a value indicating the position of the slice image to be processed at the time of starting the process is substituted into halfwnd.
Halfwnd is a value indicating the total number of consecutive slice images before or after the processing target slice image in the preceding and succeeding consecutive slice images including the processing target slice image used when processing is performed. It is also substituted.
[0057]
In S502, the slice in which the value indicating the position of the processing target slice image is substituted and the slice_top in which the value indicating the position of the slice image assumed to have the highest luminance value for the processing target pixel i are substituted are the values of halfwnd. Initialized.
In step S <b> 503, the average value of the luminance values of the processing target pixel i in the halfwnd consecutive slice images before and after including the slice image at the position indicated by the slice value stored in the slice image storage list is obtained, and the average value is obtained. Is assigned to i_top as the highest luminance value.
[0058]
In S504, the slice is incremented, and the slice image to be processed is changed to the next slice image.
In S505, it is determined whether or not the processing has been completed for all slice images to be processed (whether slice + halfwnd> = slice_max). If the result of the determination is Yes, the process proceeds to S510; If No, the process proceeds to S506.
[0059]
In S506, the average value of the luminance values of the processing target pixel i in the preceding and following halfwnd consecutive slice images including the slice image at the position indicated by the slice value stored in the slice image storage list is acquired, and the average value is obtained. Is assigned to I_now as the highest luminance value.
[0060]
In S507, the current I_top is compared with the I_now substituted in the previous step, that is, it is determined whether or not I_top <I_now. If the determination result is Yes, the process proceeds to S508, and the process proceeds to S508. In this case, the process proceeds to S509.
[0061]
In S508, if it is determined in the previous step that I_top <I_now, the value of I_now is substituted for I_top, and the value of slice at this time is substituted for slice_top. That is, I_top and slice_top are updated.
[0062]
In S509, the slice is incremented, the slice image to be processed is changed to the next slice image, and the process returns to S505.
In step S510, when it is determined in step S505 that slice + halfwnd> = slice_max, a value indicating the position of the processing target slice image when the average luminance value of the processing target pixel i is the highest is substituted. The value of slice_top is substituted into Ztemp as the estimated pixel height. Also, the luminance value of the processing target pixel i in the slice image is obtained (GetI (i, slice_top)), and the luminance value is substituted into Itemp as the estimated pixel luminance value, and this processing ends.
[0063]
As described above, by performing this flow, it is possible to obtain a more correct estimated pixel height and estimated pixel luminance value for the processing target pixel i.
Further, as another method for obtaining the estimated pixel height and the estimated pixel luminance value shown in FIG. 4 or FIG. 5, for example, in a luminance change with respect to each height of the processing target pixel i, a monomodal An evaluation function PeakRate is defined in advance such that the value becomes larger as approaching the peak apex, and the luminance value of the processing target pixel i of a predetermined number of slice images before and after the processing target slice image including the processing target slice image is used. The height of the slice image to be processed when the value of the evaluation function PeakRate becomes the maximum value is substituted into Ztemp as the estimated pixel height, and the luminance value in the slice image is substituted into Itemp as the estimated pixel luminance value. good. The processing in this case will be described with reference to FIGS.
[0064]
FIGS. 6A and 6B are flowcharts illustrating another example of the process of S303 performed by the estimated pixel information output unit 3.
In the processing shown in the figure, since the processing is performed based on a predetermined number of slice images before and after including the processing target slice image, unlike the processing shown in FIG. The position of the slice image does not become the head. That is, assuming that the total number of slice images of a predetermined number before and after the slice image including the processing target slice image is div (however, div is an odd number of 3 or more) and the above-mentioned predetermined number is step, the processing at the time of starting the processing The value indicating the position of the target slice image is (div-1) * step / 2. Similarly, the value indicating the position of the slice image to be processed when ending the processing is slice_max- (div-1) * step / 2. The luminance value substituted into the above-mentioned i_top and i_now becomes the value of the evaluation function PeakRate for the processing target pixel i of the processing target slice image.
[0065]
By doing so, it becomes possible to estimate the height when the luminance value reaches the maximum value from the luminance change of the slice image in a wider range, and it is possible to suppress the influence of local noise. Become.
Specifically, in FIG. 6A, first, in S601, the value of (div-1) * step / 2 is substituted into halfwnd. Here, a value indicating the position of the slice image to be processed at the time of starting the process is substituted into halfwnd. Further, this halfwnd is included in a slice image for each step before or after the processing target slice image in a slice image for each step before and after including the processing target slice image used when processing is performed. A value indicating the total number of slice images is also substituted.
[0066]
In S602, the slice into which the value indicating the position of the slice image to be processed is substituted and the value indicating the position of the slice image to be processed when the value of the evaluation function PeakRate reaches the maximum value for the pixel to be processed i are substituted. slice_top is initialized to the value of halfwnd.
[0067]
In step S603, the value of the evaluation function PealRate is obtained using the luminance value of the processing target pixel i in each of the preceding and following slice images including the slice image at the position indicated by the slice value stored in the slice image storage list. , Its value is assigned to i_top. The method of obtaining the value of the evaluation function PealRate will be described later with reference to FIG.
[0068]
In S604, the slice is incremented, and the slice image to be processed is changed to the next slice image.
In S605, it is determined whether or not the processing has been completed for all slice images to be processed (whether or not slice + halffwd> = slice_max). If the determination result is Yes, the process proceeds to S610. If No, the process proceeds to S606.
[0069]
In step S606, the value of the evaluation function PeakRate is calculated using the luminance value of the processing target pixel i in each of the preceding and succeeding slice images including the slice image at the position indicated by the slice value stored in the slice image storage list. , Its value is assigned to i_now.
[0070]
In S607, I_top is compared with I_now substituted in the previous step, that is, it is determined whether or not I_top <I_now. If the determination result is Yes, the process proceeds to S608, and if No, the process proceeds to S608. The process proceeds to S609.
In S608, if it is determined in the previous step that I_top <I_now, the value of I_now is substituted for I_top, and the value of slice at this time is substituted for slice_top. That is, I_top and slice_top are updated.
[0071]
In S609, the slice is incremented, the slice image to be processed is changed to the next slice image, and the process returns to S605.
In step S610, when it is determined in step S605 that slice + halfwnd> = slice_max, a value indicating the position of the processing target slice image when the value of the evaluation function PeakRate reaches the maximum value for the processing target pixel i is substituted. The value of slice_top is substituted into Ztemp as the estimated pixel height.
Also, the luminance value of the processing target pixel i in the slice image is obtained (GetI (i, slice_top)), and the luminance value is substituted into Itemp as the estimated pixel luminance value, and this processing ends.
[0072]
Next, the process of obtaining the value of the evaluation function PealRate, which is performed in S603 or S606, will be described with reference to FIG.
FIG. 7B is a flowchart showing an example of a process for obtaining the value of the evaluation function PeakRate.
[0073]
In FIG. 13B, first, in S611, the value of-(div-1) / 2 is substituted for n.
In S612, it is determined whether or not the value of n is greater than the value of (div-1) / 2 (whether or not n> = (div-1) / 2), and if the determination result is Yes. The process proceeds to S615, and in the case of No, the process proceeds to S613.
[0074]
In S613, the luminance value of the processing target pixel i in the slice image at the position indicated by the value of slice-n * step, which is stored in the slice image storage list, is obtained, and the luminance value is substituted into i_pickup (n). You.
In S614, n is incremented, and the process returns to S612.
[0075]
Through the processing of S611 to S614 described above, the luminance value of the processing target pixel i for each of the slice images in the preceding and following steps including the slice image at the position indicated by the slice value is obtained.
In S615, ret is initialized (ret = 0).
[0076]
In S616, the value of-(div-1) / 2 is substituted for n.
In S617, it is determined whether or not n <0. If the determination result is Yes, the process proceeds to S618, and if No, the process ends.
In S618, i_pickup (n) is subtracted from i_pickup (n + 1) based on the processing result in S613 described above, and the subtracted value is raised to the third power and added to the previous ret. Also, i_pickup (-n) is subtracted from i_pickup (-n-1), the resulting value is raised to the third power, and further added to the ret.
[0077]
In S619, n is incremented, and the process returns to S617.
By the above processing of S615 to S619, the value of the evaluation function PealRate is calculated using the luminance value of the processing target pixel i in each of the preceding and following slice images including the slice image (processing target slice image) at the position indicated by the slice value. (Ret) is required.
[0078]
Here, the processing shown in FIG. 6B will be described with a specific example.
FIG. 7A shows an example of a luminance change with respect to each height for the processing target pixel i.
In FIG. 6A, Z (slice) = a−2, a−1, a, a + 1, a + 2, a + 3 indicates the height for each step described above. Further, the luminance values when Z = a-2, a-1, a, a + 1, a + 2, a + 3 are set to I_a-2, I_a-1, I_a, I_a + 1, I_a + 2, I_a + 3, respectively. In this example, div = 5.
[0079]
In this case, when the process shown in FIG. 6B is performed with the slice value being a single-peaked peak position, that is, slice = a, i_pickup (−2) and i_pickup (−) are performed by the above-described S611 to S614. 1), i_pickup (0), i_pickup (1), and i_pickup (2) are obtained as I_a-2, I_a-1, I_a, I_a + 1, and I_a + 2, respectively, and by the processing of S615 to S619, ret = (I_a-1-I_a-2) ＾ 3 + (I_a + 1-I_a + 2) ＾ 3 + (I_a-I_a-1) ＾ 3 + (I_a-I_a + 1) ＾ 3 is obtained, and the value of the evaluation function PeakRate becomes maximum.
[0080]
Further, if the processing is performed in the same manner as the position where the slice value is away from the single-peak peak position, for example, slice = a + 1, i_pickup (−2), i_pickup (−1), I_a-1, I_a, I_a + 1, I_a + 2, and I_a + 3 are obtained as i_pickup (0), i_pickup (1), and i_pickup (2), respectively, and ret = (I_a−I_a−) by the above-described processing of S615 to S619. 1) 3+ (I_a + 2−I_a + 3) ＾ 3 + (I_a + 1−I_a) ＾ 3 + (I_a + 1−I_a + 2) ＾ 3 is obtained. However, since the value of (I_a + 1−I_a) ＾ 3 is negative, the evaluation function is obtained. PeakRate is at least smaller than the value when slice = a. It made.
[0081]
Similarly, when the value of the evaluation function PeakRate is obtained for each slice, a Z (slice) -PeakRate curve shown in FIG. 7B showing the change in the value of PeakRate with respect to each height is obtained.
As shown in FIG. 3B, when the value of slice is a single-peaked peak position, that is, slice = a, the value of ret (evaluation function PeakRate) is maximized, but the value of slice is monomodal. As the distance from the peak position increases, the value of ret decreases.
[0082]
As described above, by using the evaluation function PeakRate such that the closer to the peak of the unimodal peak in the luminance change with respect to each height of the processing target pixel i, the luminance of the slice image in a wider range is obtained. It is possible to estimate the height when the luminance value reaches the maximum value from the change, and it is possible to suppress the influence of local noise.
[0083]
In a slice image used to calculate the value of the evaluation function PeakRate, the range (height difference) from the slice image having the lowest height to the slice image having the highest height is a luminance change with respect to each height. By setting the value of the step so as to be substantially equal to the peak width in the above, more accurate determination can be performed. For example, if the peak width in the luminance change at each height is wide, the value of step may be increased, and if the peak width is narrow, the value of step may be decreased.
[0084]
As described above, by performing the flows shown in FIGS. 6A and 6B, it is possible to acquire a more correct estimated pixel height and estimated pixel luminance value for the processing target pixel i. .
Next, the processing of S304 performed by the validity determination unit 4 will be described in detail.
[0085]
FIG. 8A is a flowchart showing an example of the processing. The process shown in FIG. 11 uses the estimated pixel height Ztemp to divide the luminance change of each pixel to be processed i for each height into a unimodal peak region A and other background regions B1 and B2, and If the pixel luminance value (i_top) is equal to or more than k times the maximum luminance value (Imax) in the background areas B1 and B2, it is determined that the processing target pixel i is in focus at the estimated pixel height Ztemp. .
[0086]
FIG. 3B shows that the luminance change at each height of the processing target pixel i is divided into a unimodal peak region A and other background regions B1 and B2 using the estimated pixel height Ztemp. It is an example of time.
Here, the processing shown in FIG. 6A will be described with reference to FIG.
[0087]
First, in S801, the range z_range of the single-peak peak region A is acquired. The range z_range of the unimodal peak region A is uniquely determined by the optical system at the time of measurement. For example, the objective lens identifier LensID and the range z_range of the peak area A are stored in advance in association with each other, and the range z_range of the peak area A is acquired by inputting the identifier LensID of the objective lens.
In S802, 0 is substituted into num and Isum, INBALID_IMAX indicating invalid is substituted into Imax, and INBALID_IMIN indicating invalid is substituted into Imin. Thereby, variables relating to the statistical information (average, maximum value, minimum value, etc.) of the luminance change of the background regions B1 and B2 are initialized.
[0088]
In S803, 0 is substituted for z_low_low, and Ztemp- (z_range / Zstep) / 2 is substituted for z_low_high. Thereby, the range (z_low_low to z_low_high) of the background area B1 is determined. Note that Ztemp is the position of the center of Z_range, and Zstep indicates the difference in height between adjacent slice images.
[0089]
In S804, the value of z_low_low is substituted for j.
In S805, it is determined whether the processing for the entire range of the background area B1 has been completed (whether j> = z_low_low). If the determination result is Yes, the processing proceeds to S809, and the processing proceeds to No. In this case, the process proceeds to S806.
[0090]
In S806, the luminance value of the processing target pixel i of the slice image at the position indicated by the value of j is obtained, and is substituted for i_now.
In S807, num is incremented, the value of i_now substituted in the previous step is added to Isum, and max (Imax, i_now) and min (Imin, i_now) are calculated. In the case of max (Imax, i_now), the previous Imax and i_now are compared. If Imax <i_now, the value of i_now is substituted for Imax, and the other values are not substituted. In min (Imin, i_now), the current Imin and i_now are compared. If Imin> i_now, the value of i_now is substituted for Imin, and the other values are not substituted.
[0091]
In the following, in max (a, b), a and b are compared, and if a <b, a process is performed in which the value of b is substituted for a and the other values are not substituted. . Also, in min (a, b), it is assumed that processing is performed in which a and b are compared, and if a> b, the value of b is substituted for a, and the other values are not substituted.
[0092]
In S808, j is incremented, and the process returns to S805.
Through the processing of S803 to S808, statistical information of luminance change such as num, Isum, Imax, and Imin in the background area B1 is obtained.
Subsequently, the process proceeds to S809, and the process for the background area B2 is started.
[0093]
In S809, Ztemp + (z_range / Zstep) / 2 is substituted for z_high_low, and 0 is substituted for z_high_high. Thereby, the range (z_high_low to z_high_high) of the background area B2 is determined.
[0094]
In S810, the value of z_high_low is substituted for j.
In S811, it is determined whether or not the processing for the entire range of the background area B2 has been completed (whether or not j> = z_high_high). If the determination result is Yes, the process proceeds to S815, and the process proceeds to S815. In this case, the process proceeds to S812.
[0095]
In S812, the luminance value of the processing target pixel i of the slice image at the position indicated by the value of j is obtained, and is substituted for i_now.
In S813, as in S807 described above, num is incremented, the value of i_now substituted in the previous step is added to Isum, and max (Imax, i_now) and min (Imin, i_now) are calculated.
[0096]
In S814, j is incremented, and the process returns to S811.
Through the processing of S809 to S814, statistical information of luminance changes such as num, Isum, Imax, and Imin in the background areas B1 and B2 is obtained.
In S815, the luminance value of the processing target pixel i of the slice image at the position indicated by the value of Ztemp is obtained, and is substituted for i_top.
[0097]
In S816, TRUE is substituted for ret.
In S817, it is determined whether or not the value substituted for i_top is greater than the value of Imax multiplied by k (i.e., whether or not i_top> k * Imax). If the determination result is Yes, this processing is performed. Ends, and in the case of No, the process proceeds to S818.
[0098]
In S818, FALSE is substituted for ret, and this processing ends.
As described above, by performing this flow, when the luminance value of the processing target pixel i of the slice image with the estimated pixel height Ztemp is larger than the value k times the maximum luminance value Imax in the range of the background regions B1 and B2, , It is determined that the pixel i to be processed of the slice image having the estimated pixel height Ztemp is in focus (TRUE), and the other pixels are out of focus (FALSE).
[0099]
Accordingly, when the estimated pixel height is not near the peak of the unimodal peak, it is determined that focus is not achieved at that height, and focus is achieved even when the estimated pixel luminance value is low. It is possible to distinguish between pixels that are present and pixels that do not match. Therefore, even when the maximum luminance of the corresponding pixel is low due to the low reflectance of the sample surface or the like, it is possible to eliminate erroneous determination as noise.
[0100]
In the present process, when an offset is superimposed on the luminance values acquired in the background areas B1 and B2, the background areas B1 and B2 are calculated from the estimated pixel luminance value i_top and the maximum luminance value Imax in the background areas B1 and B2. It is also possible to obtain a better determination result by performing the determination after subtracting the minimum luminance value Imin in.
[0101]
In addition, other than such a determination method, for example, using the average luminance value (Isum / num) in the background areas B1 and B2, the estimated pixel luminance value i_top is calculated as the average luminance value (Isum / num) in the background areas B1 and B2. If the value is k times or more, the processing for determining that the processing target pixel i of the slice image with the estimated pixel height Ztemp is in focus may be performed.
[0102]
Alternatively, the determination may be performed using a histogram other than those determination methods. For example, as shown in FIG. 9, a histogram is created from the luminance change for each height of the processing target pixel i, and the processing target pixel i of the slice image having the estimated pixel height Ztemp is created based on the shape of the histogram and the like. A process for determining whether or not the image is in focus may be performed.
[0103]
As described above, according to the present embodiment, obtained using a microscope or the like having an optical system having a confocal effect, from the luminance change along the optical axis direction of the pixel corresponding to each position on the surface of the measured object, After estimating the height at the pixel corresponding to each position on the surface of the device to be measured as the estimated pixel height, it is possible to determine whether the estimated pixel height is in focus or not. In this determination, the luminance change of the corresponding pixel along the optical axis direction is queried, and the validity can be determined in detail in view of the characteristic of the luminance change. For example, a spike-like noise that appears on the luminance Corrects even if is incorrectly estimated as the estimated pixel height, surface shape information according to the determined pixel height and the determined pixel luminance value that is the estimated pixel height and estimated pixel luminance value determined to be valid and Generation of surface luminance information becomes possible.
[0104]
Next, a second embodiment of the present invention will be described.
FIG. 10 is a flowchart illustrating an example of processing performed by the focus information output unit 2, the estimated pixel information output unit 3, the validity determination unit 4, the focus image generation unit 5, and the like according to the present embodiment. This corresponds to the flowchart shown in FIG. 3 according to the first embodiment.
[0105]
In FIG. 10, the processing in S1004 (dotted line a in FIG. 10) indicates the processing performed by the estimated pixel information output unit 3, and the processing in S1005 (dotted line b in FIG. 10) is performed by the validity determination unit 4. The processing of steps S1004, S1005, S1007, and S1008 (dotted line portion c in the figure) indicates processing performed by the focus information generation unit 2 and the like. Further, the processing of S1010 to S1016 (dotted line portion d in the figure) indicates the processing performed by the focus image generating means 5.
[0106]
As shown in the figure, first, in S1001, the processing target pixel i is initialized to the first pixel.
In S1002, 0 is substituted for num, Zsum, and Isum, INVALID_ZMAX indicating Zmax is invalid, INVALID_ZMIN indicating Zmin is invalid, INVALID_IMAX indicating Imax is invalid, and INVALID_IMIN indicating invalid is substituted for Imin. That is, variables relating to statistical information (average value, maximum value, minimum value, and the like) of the determined pixel height and the determined pixel luminance value are initialized.
[0107]
In S1003, it is determined whether or not the processing performed by the focus information generation unit 2 has been completed for pixels corresponding to all positions on the surface of the device under test (whether or not i> = i_max), and the determination result is obtained. If Yes, the process proceeds to S1010, and if No, the process proceeds to S1004.
[0108]
In S1004, the same processing as the processing in S303 described above (for example, the processing shown in FIG. 4, FIG. 5, or FIGS. 6A and 6B) is performed.
In S1005, the validity determination unit 4 determines whether or not the processing target pixel i is in focus at the estimated pixel height Ztemp. If the determination result is Yes, the process proceeds to S1006, and the process proceeds to S1006. In this case, the process proceeds to S1007. Note that, for the determination processing in this step, for example, processing similar to the processing illustrated in FIG. 7 is performed.
[0109]
In S1006, when it is determined that the processing target pixel i is in focus at the estimated pixel height Ztemp, num is incremented, Zmatrix (Ztemp) is added to the previous Zsum, and Itemp is added to the previous Isum. Addition is performed to calculate max (Zmax, Ztemp), min (Zmin, Ztemp), max (Imax, Itemp), and min (Imin, Itemp). That is, the statistical information of the determined pixel height and the determined pixel luminance value is updated. Note that Zmatrix (Ztemp) indicates a process of acquiring the height (determined pixel height) stored in the storage position of the Z coordinate storage list corresponding to the position indicated by the value assigned to Ztemp. . The statistical information obtained in this manner is used when the value assigned to the determined pixel height Z (i) is determined to be an exceptional value in the processing of S1013 described below, and the exceptional value is determined in S1014. Is used instead of.
[0110]
In S1007, similarly to the processing of S305 described above, when it is determined that the processing target pixel i is out of focus at the estimated pixel height Ztemp, the estimated pixel height Ztemp and the estimated pixel luminance value Itemp are specified in advance. The exception value (Zexception, Iexception) thus set is substituted.
[0111]
In S1008, as in the process of S306 described above, the values of the estimated pixel height Ztemp and the estimated pixel luminance value Itemp of the processing target pixel i are set as Z (i) and I (I) as the determined pixel height and the determined pixel luminance value, respectively. (I).
In S1009, the processing target pixel i is incremented, the processing target pixel is changed to the next pixel, and the process returns to S1003.
[0112]
As described above, when the focus information generation unit 2 acquires the determined pixel height and the determined pixel luminance value for the pixels corresponding to all positions on the surface of the measured object, the focus image generation unit 5 Then, the process proceeds to S1010 and subsequent processes performed.
The processes in S1010 and S1011 are the same as the processes in S308 and S309 described above.
[0113]
In S1012, it is determined whether or not the processing has been completed for pixels corresponding to all positions on the surface of the device under test (whether or not i> = i_max). If the determination result is Yes, this processing is performed. The process ends, and in the case of No, the process proceeds to S1013.
In S1013, it is determined whether or not the value of Z (i) is an exceptional value (Zexception), that is, whether or not the estimated pixel height of the processing target pixel i is an exceptional value. If the determination result is Yes The process proceeds to S1014, and in the case of No, the process proceeds to S1015.
[0114]
In S1014, the height corresponding to the set id is substituted into the surface shape information SG (i) of the processing target pixel i, and the id set in the surface luminance information SI (i) of the processing target pixel i. Is assigned. Note that id changes a value to be substituted into SG (i) and SI (i) according to the value. For example, when id = 0, the value of Zmax is substituted for SG (i), and the value of Imax is substituted for SI (i). When id = 1, the value of Zmin is substituted for SG (i), and the value of Imin is substituted for SI (i). When id = 2, the value of Zsum / num (average of height) is substituted for SG (i), and the value of Isum / num (average of luminance value) is substituted for SI (i). When id = 3, a fixed value (such as 0) is substituted for SG (i), and a fixed value (such as 0) is substituted for SI (i). When id = 4, a height which is an interpolated value between pixels described later is substituted into SG (i), and a luminance value which is an interpolated value between pixels described later is substituted into SI (i).
[0115]
In S1015, as in S311 described above, the determined pixel height Zmatrix (Z (i)) of the processing target pixel i is substituted for the surface shape information SG (i) of the processing target pixel i, and the surface of the processing target pixel i is changed. The determined pixel luminance value I (i) of the processing target pixel i is substituted for the luminance information SI (i).
[0116]
In S1016, the processing target pixel i is incremented, the processing target pixel is changed to the next pixel, and the processing returns to S1013.
As described above, by performing this flow, the values to be substituted into SG (i) and SI (i) can be arbitrarily set by id. Therefore, the values should be set according to the shape of the sample surface. It is also possible to set values suitable for display and analysis relating to surface shape information and surface luminance information.
[0117]
For example, when the surface shape of the sample as shown in FIG. 11A is obtained, the surface shape of the linear portion 11 in FIG. 11A is changed to the linear portion 11 as shown in FIG. It is assumed that a change in height for each position is obtained.
In this case, in the change of the height shown in FIG. 6B, the height with respect to the position a is 0 (exceptional value), but in the actual sample shown in FIG. When it is clear that a surface shape such that the surface shape becomes 0 cannot be obtained, in the above-described processing of S1014, for example, an average height Zmean (Zsum / num) is substituted as SG (i), and the height relative to the position a is set. By setting the value as Zmean (point b in FIG. 3B), it becomes possible to set a value suitable for display and analysis.
[0118]
Next, a description will be given of a method of obtaining an interpolated value when an interpolated value between pixels is substituted into SG (i) and SI (i) in the process of S1014 described above.
FIG. 12A is a diagram for explaining how to obtain the interpolation value, and FIG. 12B is a flowchart showing an example of a process for obtaining the interpolation value.
[0119]
Here, the process for obtaining the interpolation value of the processing target pixel Pi will be described with reference to FIG. In FIG. 9A, the hatched area indicates a pixel to which an exceptional value is substituted as the estimated pixel height and the estimated pixel luminance value.
In FIG. 13B, first, in step S1201, a pixel P1 that is not an exceptional value and is the nearest pixel from Pi is searched.
[0120]
In step S1202, a pixel P2 which is not on the exceptional value and is the nearest pixel from Pi on a substantially straight line connecting P1 and Pi and different from P1 with respect to the position of Pi is searched for. You.
In step S1203, the distance L1 between P1 and Pi and the distance L2 between Pi and P2 are obtained, and the height Zi and the luminance value Ii of the processing target pixel Pi are calculated as the estimated pixel height (Z_P1) and the estimated pixel luminance value (P_1) of P1. The estimated pixel height (Z_P2) and the estimated pixel luminance value (I_P2) of I_P1) and P2 are calculated as points internally divided by L1 and L2.
[0121]
As described above, by performing this flow, the height Zi and the luminance value Ii of the processing target pixel Pi can be obtained by interpolation.
As described above, according to the present embodiment, when the value of the determined pixel height Z (i) is an exceptional value, the values to be substituted into SG (i) and SI (i) are adjusted according to the shape of the sample surface. It can be set arbitrarily, and can be set to a value suitable for displaying and analyzing surface shape information and surface luminance information.
[0122]
Next, a third embodiment of the present invention will be described.
FIG. 13 is a flowchart illustrating an example of processing performed by the focus information output unit 2, the estimated pixel information output unit 3, the validity determination unit 4, the focus image generation unit 5, and the like according to the present embodiment. This corresponds to the flowchart shown in FIG. 3 according to the first embodiment.
[0123]
In FIG. 13, the processing in S1303 (dotted line a in FIG. 13) indicates the processing performed by the estimated pixel information output unit 3, and the processing in S1305 (dotted line b in FIG. 13) is performed by the validity determination unit 4. The processing from S1307 to S1307 (dotted line portion c in the figure) indicates processing performed by the focus information generating means 2 and the like. Further, the processing from S1309 to S1313 (dotted line portion d in the figure) indicates the processing performed by the focus image generating means 5.
[0124]
In the figure, the processing of S1301 to S1303 is the same as the processing of S301 to S303 shown in FIG.
In S1304, it is determined whether or not the estimated pixel luminance value Itemp is equal to or larger than a preset threshold value Ith. If the determination result is Yes, the process proceeds to S1307, and if No, the process proceeds to S1305. Advances.
[0125]
In the processes of S1305 to SS1313, the same processes as those of S304 to S312 of FIG. 3 described above are performed.
As described above, by performing this flow, the validity determination is performed when the estimated pixel luminance value Itemp is less than the preset threshold value Ith, and the validity determination is not performed when the estimated pixel luminance value Itemp is equal to or greater than the threshold value Ith. The estimated pixel height Ztemp and the estimated pixel luminance value Itemp are defined as the determined pixel height and the determined pixel luminance value. As a result, the influence of noise is small and the estimated pixel height and the estimated pixel luminance value are erroneously estimated, as in the case where light is sufficiently reflected on the sample surface and a high luminance value is obtained as the estimated pixel luminance value. When the possibility is low, the determination processing is not performed, so that the processing speed can be improved.
[0126]
In the first to third embodiments described above, the processing described in the embodiment, for example, FIGS. 2B, 3, 4, 5, 6, 6A, and 6B A program for causing a computer to execute the processing shown in FIG. 8, FIG. 10, FIG. 12 (b), or FIG. 13 is stored in a recording medium or the like, and the computer reads and executes the program. The processing may be realized.
[0127]
FIG. 14 is a diagram showing an example in which the program is stored in a recording medium or the like, and the program is read and executed by an information processing device (computer).
In the example shown in the figure, the program is stored in a portable recording medium 21 such as a CD-ROM, a DVD, or a floppy (registered trademark) disk, or a storage device 22 of a program provider, and the program is processed by information processing. It is read and executed by the device 23.
[0128]
When the program is stored in a portable recording medium 21 such as a CD-ROM or a floppy (registered trademark) disk, the portable recording medium 21 is inserted into a drive device of the information processing device 23 to read the program. The program that has been output (loaded) and read out is stored in a storage device 24 such as a RAM or a hard disk, and the program is executed. When the program is provided from the program provider via the communication line, the program stored in the storage device 22 or the memory of the program provider is received by the information processing device 23 via the communication line. Then, the received program is stored in a storage device 24 such as a RAM or a hard disk and executed. Note that the program stored in the recording medium or the like may realize a part of the processing described in the above embodiment.
[0129]
As described above, the focus image synthesizing method and the program thereof according to the present invention have been described in detail. However, the present invention is not limited to the above embodiment, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.
[0130]
【The invention's effect】
As described in detail above, according to the present invention, even when the maximum luminance of the corresponding pixel is low, noise is erroneously determined due to the presence of a steep slope on the sample or the low reflectance of the sample surface. Can be eliminated.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration for explaining a focus image synthesizing method of the present invention.
2A is a flowchart illustrating an example of a configuration of a luminance information storage unit, FIG. 2B is a flowchart illustrating an example of processing performed by the luminance information storage unit, and FIG. FIG.
FIG. 3 is a flowchart illustrating an example of processing performed by a focus information output unit, an estimated pixel information output unit, a validity determination unit, a focus image generation unit, and the like according to the first embodiment.
FIG. 4 is a flowchart illustrating an example of a process of S303 performed by an estimated pixel information output unit.
FIG. 5 is a flowchart illustrating another example of the process of S303 performed by the estimated pixel information output unit.
FIGS. 6A and 6B are flowcharts illustrating another example of the process of S303 performed by the estimated pixel information output unit.
FIG. 7A shows an example of a luminance change with respect to each height of a processing target pixel i, and FIG. 7B shows an example of a Z (slice) -PeakRate curve showing a change of a PeakRate value with respect to each height. FIG.
FIG. 8A is a flowchart illustrating an example of the process of S304 performed by the validity determination unit, and FIG. 8B is a diagram illustrating an example of the process for each height of the processing target pixel i using the estimated pixel height Ztemp. This is an example when the luminance change is divided into a unimodal peak area A and other background areas B1 and B2.
FIG. 9 is an example of a histogram created based on a luminance change with respect to each height for a processing target pixel i.
FIG. 10 is a flowchart illustrating an example of processing performed by a focus information output unit, an estimated pixel information output unit, a validity determination unit, a focus image generation unit, and the like according to the second embodiment of the present invention; is there.
11A is a diagram illustrating an example of a sample, and FIG. 11B is a diagram illustrating a change in height with respect to each position of the linear portion 11 of the sample illustrated in FIG.
12A is a diagram for explaining how to obtain an interpolation value, and FIG. 12B is a flowchart showing an example of a process for obtaining the interpolation value.
FIG. 13 is a flowchart illustrating an example of processing performed by a focus information output unit, an estimated pixel information output unit, a validity determination unit, a focus image generation unit, and the like according to the third embodiment of the present invention. is there.
FIG. 14 is a diagram illustrating an example in which a program is stored in a recording medium or the like, and the program is read and executed by an information processing device (computer).
FIG. 15 is a diagram illustrating an example of a change in luminance with respect to the height of each position when a sample surface is measured using a microscope including an optical system having a confocal effect.
[Explanation of symbols]
1 brightness information storage means
2 Focus information storage means
3 Estimated pixel information output means
4 Legitimacy determination means
5 Focus image generating means
11 Straight part
21 Portable recording media
22 Storage device
23 Information processing device
24 storage devices

Claims (8)

A storing step of storing the luminance at each height on the optical axis of a pixel corresponding to each position on the surface of the measured object obtained using a microscope having an optical system having a confocal effect,
Inquiring the luminance stored in the storing step according to the processing target pixel specifying information that uniquely specifies the processing target pixel, the height on the optical axis estimated to be focused on the processing target pixel And a first acquisition step of acquiring the luminance at that time as an estimated pixel height and an estimated pixel luminance value,
Inquiring the luminance stored in the storing step according to the processing target pixel designation information and the estimated pixel height, to determine whether the processing target pixel is focused at the estimated pixel height. A determining step of determining;
When it is determined in the determination step that the pixel to be processed is in focus at the estimated pixel height, the estimated pixel height and the estimated pixel luminance value are acquired as a determined pixel height and a determined pixel luminance value. When it is determined in the determining step that the processing target pixel is not focused at the estimated pixel height, the exceptional height and the exceptional luminance value are changed to the final pixel height and the final pixel luminance. A second acquisition step to acquire as a value;
A focus image synthesizing method, comprising: Based on the determined pixel height and the determined pixel luminance value acquired in the second acquisition step, surface shape information including height information at a pixel corresponding to each position on the surface of the measured object; A generation step of generating surface luminance information composed of luminance information in a pixel corresponding to each position on the measurement object surface,
2. The focus image synthesizing method according to claim 1, further comprising: In the first obtaining step,
Based on the fact that the luminance at the height on the optical axis where the focus is focused on the processing target pixel is the highest value, the height on the optical axis estimated to be focused on the processing target pixel and the luminance at that time are calculated. Ask,
2. The focus image synthesizing method according to claim 1, wherein: In the first obtaining step,
The luminance change with respect to the height on the optical axis for the processing target pixel is estimated to be in focus on the processing target pixel based on the fact that the luminance change with respect to the height on the optical axis at which the focus is focused has a single peak. Determine the height on the optical axis and the brightness at that time,
2. The focus image synthesizing method according to claim 1, wherein: In the determining step,
In the luminance change with respect to the height on the optical axis for the processing target pixel, based on the difference between the luminance change between the unimodal peak region having the height on the focused optical axis as the apex and the other background region. Determining whether or not the processing target pixel is in focus at the estimated pixel height,
The focus image synthesizing method according to any one of claims 1 to 4, wherein: The exceptional height and exceptional brightness values are:
At least, a minimum value, a maximum value, or an average value, a fixed value, or a fixed value obtained from all the pixels determined to be in focus in the determination step, or a value determined from the pixels determined to be in focus in the determination step. Any of the interpolated values obtained,
The focus image combining method according to claim 1, wherein: When the estimated pixel luminance value acquired in the first step is equal to or more than a predetermined value, the estimation pixel height and the estimated pixel luminance value are obtained in the second acquisition step without performing the determination step. Is obtained as the determined pixel height and the determined pixel luminance value,
The focus image combining method according to claim 1, wherein: On the computer,
A storing step of storing the luminance at each height on the optical axis of a pixel corresponding to each position on the surface of the measured object obtained using a microscope having an optical system having a confocal effect,
Inquiring the luminance stored in the storing step according to the processing target pixel specifying information that uniquely specifies the processing target pixel, the height on the optical axis estimated to be focused on the processing target pixel And a first acquisition step of acquiring the luminance at that time as an estimated pixel height and an estimated pixel luminance value,
Inquiring the luminance stored in the storing step according to the processing target pixel designation information and the estimated pixel height, to determine whether the processing target pixel is focused at the estimated pixel height. A determining step of determining;
When it is determined in the determination step that the pixel to be processed is in focus at the estimated pixel height, the estimated pixel height and the estimated pixel luminance value are acquired as a determined pixel height and a determined pixel luminance value. When it is determined in the determining step that the processing target pixel is not focused at the estimated pixel height, the exceptional height and the exceptional luminance value are changed to the final pixel height and the final pixel luminance. A second acquisition step to acquire as a value;
Focus image composition program for executing

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