JP2856067B2 - Dimension measurement method using images - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring an inclination angle and a width of an image having a shape close to a rectangular shape in which each side is wavy (hereinafter simply referred to as a rectangular shape). The present invention relates to a method for performing measurement by image processing so as not to be significantly different from measurement by visual observation.

[0002]

2. Description of the Related Art Television shadow masks and ICs
When a hole is formed in a substrate of an (integrated circuit), exposure etching is performed. This is a processing method that enlarges the pattern to be processed, draws it on a transparent film, projects it on the target surface coated with a photosensitizer, forms an image, and obtains a reduced image, and then etches this to obtain the target pattern. It is.
When a rectangular small hole is formed by such exposure etching, the smaller the hole, the more the laser light used for exposure exudes due to refraction by diffraction, and when a rectangular shape on the film is projected, the center tends to be dented in a cocoon shape. On the other hand, shadow mask is CRT
In order to convert the scan image of the (cathode ray tube) into an electric signal, a barrel-shaped shape having a bulge at the center is preferable, and a barrel-shaped rectangle is used. Since each side of the rectangle is a particle of the photosensitive agent itself and the etching proceeds like rust, it is not a straight line but a curve of irregularities. In addition, in many cases, those irregularities having a narrow width but a large peak are randomly mixed.

FIG. 8 shows the shape of a rectangular small hole obtained by exposure etching. (A) shows a barrel-shaped rectangle,
(B) shows a cocoon-shaped rectangle. Each side is composed of an uneven curve, and the unevenness has a narrow width but a large peak. To show an example of the size of a rectangle, the rectangular side (width) is 8
The wave height from peak to peak is 4 to 10 μm, and the suddenly generated large wave height is about 2 to 3 times that of most other wave heights. When this rectangle is imaged by a television camera connected to a microscope and displayed on a CRT, since the size of one pixel is about 2 μm, the width of the rectangle is 40 to 100 pixels, and the regular peak to peak of unevenness is used. Is represented by 2 to 5 pixels. The period of the irregularities is 3 to 8 pixels.

For a rectangle having such a shape and dimensions, the inclination θ and the width of the rectangle are measured. At the same time, the relative positions and intervals of the rectangles in the vicinity are measured. Conventionally, the measurement was performed by moving the crosshair and the image relative to each other visually in the visual field of the microscope.
When this is automatically measured by image analysis, the inclination θ is defined by the inclination of the center line S passing through the rectangular center of gravity G and indicating the direction of the long side as shown in FIG. 9 and the line Q perpendicular to the scanning line P on the CRT screen. It is represented by the angle θ. The angle θ is determined by determining the center of gravity G of the rectangle, passing through the center of gravity G, and finding the line segment L1 having the largest length between intersections at the line segment intersecting the rectangle and the next largest line segment L2, that is, a virtual diagonal line, The bisector of L1 and L2 is set as the center line S, and θ is determined as an angle with a vertical line Q perpendicular to the scanning line P.

When a person measures the width of a rectangle using a crosshair of a microscope, a good resolution and reproducibility can be obtained by drawing an average line as shown in FIG. On the other hand, FIG.
0 indicates an automatic measurement method by image analysis of a rectangular width.
(A) is a dimension determined from a line segment parallel to the width, and the angle θ of the center line S with respect to the vertical line Q perpendicular to the scanning line P is determined by the above-described method. , Draw several lines before and after in parallel with this line, find the intersection of each line and the rectangle, find the length between the intersections for each line, and calculate the average of this length as the width of the rectangle I do. Note that the interval between the parallel lines was set at a distance of about several pixels. (B) is a method of calculating from the area, which is drawn at an interval h between two parallel lines H1 and H2 orthogonal to the center line S across the center of gravity G and surrounded by these two line segments H1 and H2 and the long side of the rectangle. In this method, the area indicated by the oblique lines is obtained, and the value obtained by dividing the area by h is used as the width.

[0006]

In order for a person to measure visually using a crosshair, human power is required, and fatigue takes a long time. When the angle θ is measured by the method based on the image analysis shown in FIG. 9, the line segments L1 and L2 are determined by the shapes of the four corners of the rectangle, but the shapes of the four corners are often distorted and greatly affected by deformation due to unevenness. As a result, a large error occurs in the determination of the line segments L1 and L2, and the error of the angle θ of the center line obtained by the bisector is large.

In the method shown in FIG. 10A, the pitch of the parallel lines coincides with the pitch of the irregularities on the long side of the rectangle, and the parallel lines come only at the positions of the concave portions on both sides, or only at the positions of the convex portions. Such measurement data often differs from the case where the rectangular shape is linearized visually and the distance between the long sides is measured. When linearizing uneven sides by visual observation, the data of the maximum and minimum values are often unintentionally removed and linearized.
Not performing such processing is another cause.

In the method shown in FIG. 10 (B), when h is increased, if the rectangle is barrel-shaped, it includes a portion with a small distance between opposite sides deviating from the central bulge, and the measured value is smaller than the visually measured value. It will be a small value. When h is reduced, the area indicated by oblique lines changes depending on how the pixels representing the parallel lines H1 and H2 are taken. FIG. 11 shows parallel lines H1 and H2 when calculating the area.
This is a diagram for explaining how to represent a pixel representing a pixel, and the size of the area differs between a case where a pixel represented by a solid line is taken and a case where a pixel represented by a broken line is taken. Note that straight lines L 3 and L 4 drawn along the long sides in FIG. 11 represent average lines drawn by a person when viewed visually.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has a method of calculating the inclination of a substantially rectangular shape with an image processing apparatus and a method of measuring the width of a substantially rectangular shape with the same degree of accuracy as a visual measurement. The purpose is to provide.

[0010]

In order to achieve the above object, the center of gravity of a substantially rectangular image is obtained, a vertical line passing through the center of gravity and perpendicular to the scanning line is set, and the vertical line is perpendicular to the vertical line and at intervals h. A first line and a second line are drawn, and the intersection of the first line and the substantially rectangle is A and B, the intersection of the second line and the substantially rectangle is C and D, and the quadrilateral A
The area A1 of the BCD is obtained, a perpendicular line is drawn from each of the intersections A, B, C, and D to the opposing first and second lines, and the area surrounded by the perpendicular lines at both ends and the first and second lines is A0, θ = tan ⁻¹ (A0−A1) / h ² (1) The angle between the center line and the vertical line passing through the substantially rectangular center of gravity and indicating the direction of the long side of θ represented by the equation (1) I do.

Further, the center of gravity of the substantially rectangular image is determined, and the angle θ between a vertical line passing through the center of gravity and orthogonal to the scanning line and a center line passing through the center of gravity of the substantially rectangle and indicating the direction of the long side is determined by a predetermined method. Draw each line that passes through the center of gravity and forms an angle θ ± mΔθ (m is an integer) with the scanning line, finds the intersection of each line and a substantially rectangle, finds the length of the line segment between the intersections of each line, and finds the maximum and minimum values Is a method of calculating an average value M of the remaining length excluding the above, wherein Δθ is an estimated value of the average value M, and Δθ · M ′ / 2 is near an intersection of a substantially rectangular and a line segment. The size of the pixel is set to be about one pixel, and the above-mentioned m is determined so as to include at least one set of unevenness representing a wave of a substantially rectangular side in an intersection range of 2m + 1 lines.

The center of gravity of the substantially rectangular image is determined, and the angle θ between a vertical line passing through the center of gravity and perpendicular to the scanning line and a center line passing through the center of gravity of the substantially rectangular shape and indicating the direction of the long side is determined by a predetermined method. Then, a reference line that passes through the center of gravity and forms an angle θ with the scanning line is obtained, and a total of n lines including this reference line are drawn in parallel with this reference line at a pitch δ, and between the intersections of these lines and the sides of the substantially rectangle Is a method of calculating the length of the line segment and calculating the average value N excluding the maximum value and the minimum value, wherein the pitch δ is about the size of one pixel, and the n is It is determined that at least one set of irregularities representing the waving is included in the intersection range of the n lines.

The coordinate point of a line segment intersecting with the above-mentioned substantially rectangular shape uses the center of a pixel or the center point of four pixels arranged in a square, and if there is no intersection at this coordinate point position, The length of the line segment is calculated with the line passing through the center of gravity and forming an angle θ with the scanning line as the inside, and the center of the nearest pixel or the center point of the four pixels outside the corresponding line segment as the intersection.

[0014]

FIG. 2 is a diagram for explaining a method of calculating the inclination θ of a substantially rectangle. An image captured by a television camera attached to a microscope is displayed in pixels. When an image is displayed on a display device, a line perpendicular to the scanning line P is defined as a vertical line Q, and a rectangular center of gravity G
, A line along the long side is defined as a center line S, and the center line S
And the angle θ between the vertical line Q and the vertical line Q is a substantially rectangular inclination. The value obtained by subtracting the area A1 of a substantially rectangular shape represented by oblique lines from the area A0 of the quadrilaterals A, E, D, and F is a triangle AEC, a triangle BD
F indicates the area, and a value obtained by dividing this area by h (A0-A
1) / h represents the average value of the straight line CE and the straight line BF. Angle C
Assuming that AE is θa, angle BDF is θb, and the average angle between θa and θb is θ, h · tan θ = (A0−A1) / h holds. From this expression, Expression (1) is derived, and this θ is approximately Let it be the inclination of the rectangle.

FIG. 4 is a diagram showing a method of calculating a width M near the center of gravity of a substantially rectangular shape in which the angle between the center line S and the vertical line Q is θ. A reference line T, which is an inclined straight line, is drawn. This reference line T is orthogonal to the center line S. Draw a straight line radially at an angle of Δθ with the angle of Δθ centering on the reference line T, find the intersection with the approximate rectangle, find the length of the line segment between these intersections, and remove the maximum and minimum values. An average value M is obtained. This average value M is set as a substantially rectangular width. By removing the maximum value and the minimum value, a sudden peak value can be removed and a proper average value can be obtained. The value of Δθ is Δθ · M ′ / 2 representing the pitch of a radial straight line near the intersection, which is about the size of one pixel. And the probability of passing only through the position of the convex portion is reduced. Also, 1
By providing a radial line in a range including a set of irregularities or more, the average position of the substantially rectangular sides is represented. In summary, a result close to the measurement by visual observation is obtained. By averaging the length between the intersections of a plurality of straight lines, a resolution exceeding the resolution of the size of each pixel (for example, 2 μm) can be obtained. In the example, 1μ
A reproducible measurement result of about m is obtained.

FIG. 6 is a view showing another method of calculating the width N near the center of gravity of a substantially rectangular shape in which the angle between the center line S and the vertical line Q is θ. The n lines including the reference line T are drawn at intervals of about one pixel, and an intersection with a substantially rectangular shape is obtained. Next, the length of the line segment between the intersections is obtained, and the average value N is obtained except for the maximum value and the minimum value. Compared with the conventional method of measuring width using parallel lines, the pitch is as small as about 1 pixel,
By setting the range of the parallel lines to a range including a set of irregularities or more, the probability that each parallel line passes only at the positions of the concave portions on both sides of the substantially rectangular shape and at the position of the convex portions is reduced. In almost the same manner as in the method shown in FIG. 4, a result close to measurement by visual observation is obtained.

The length between the intersections of the line segments intersecting the substantially rectangle is calculated as the length between the coordinate points representing the pixels. The coordinates representing the pixels are the pixels arranged in a square as shown in FIG. , Or the center of the pixel (B), and one of them is used so as not to mix them. Both sides of the substantially rectangular shape and the radial lines shown in FIG. 4,
When the parallel line shown in FIG. 6 intersects and the position of the intersection does not coincide with the center of the pixel or the center of the four pixels, that is, the coordinates representing the pixel on the intersection with the corresponding radial line or parallel line When there is no, the coordinates representing the closest pixel outside the radial line or the parallel line with the reference line T shown in FIGS. 4 and 6 inside are used. By doing so, the positions of radial lines and parallel lines can be displayed by pixels at a pitch of one pixel or less.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an apparatus for realizing this embodiment. The microscope 1 is provided with an imaging lens attached to an eyepiece and an imaging device 16 for taking an image through the imaging lens. The position of the stage 17 on which the measurement sample is placed is adjusted by a plane moving mechanism 18 that moves back and forth and right and left by a pulse motor provided on the stand by a signal from the auto stage driver 10,
Vertical movement mechanism 19 by auto focus driver 11
Is operated to move the stage 17 in the up-down direction to focus. In the inspection of the shadow mask of a television, the shadow mask is rotated on the auto stage by a certain angle to put the inspection point in the field of view, and the direction of the hole is appropriately inclined with respect to the scanning line to increase the measurement accuracy. There is a mechanism.

The A / D converter 2 converts input data from the imaging device 16 from analog to digital, and the input buffer 3 temporarily stores the digital data. The bus 4 transmits signals, the program memory 5 stores a program that defines the operation of the apparatus, and the CPU 6 controls the entire apparatus according to the program.

An image processor 7 performs density processing, binarization processing, image analysis and the like of the input image data. A density image memory 8 stores density image data,
Stores binary image data. The auto stage driver 10 controls the plane moving mechanism 18 to move the stage 17 on which the measurement sample is placed in the X and Y directions in accordance with an instruction from the CPU, and sets the measurement position and area of the measurement sample. The auto focus driver 11 receives a control command from the CPU 6 to the vertical movement mechanism 19, controls the vertical movement mechanism 19,
Focus automatically. The output buffer 12 temporarily stores the output data, the D / A converter 13 converts the output data from digital to analog, and the CRT 14 displays the output data on the screen. An operator inputs instructions and data from the keyboard 15.

Next, as a first embodiment, a method of calculating the inclination .theta. Of a rectangle will be described with reference to flowcharts shown in FIGS. First, a rectangular image is captured to obtain image data (ST1). Next, the center of gravity G of the rectangle is obtained from the image data (ST2). A vertical line Q orthogonal to the scanning line P for displaying an image through the center of gravity G is set (ST3), and a first line L1 and a second line L2 orthogonal to the vertical line Q are set at an interval h.
And intersections A and B between the first line L1 and the rectangle, and the second line L2
Intersection of the rectangular C, obtaining the D (ST4). Next, a perpendicular line is drawn from the intersection to the line on the other side, and the area A0 of the square AFDE surrounded by the outermost perpendicular line and the first line L1 and the second line L2 is obtained (ST5). The area A1 of each of the quadrilaterals A, B, C, and D is obtained, and h, A0, and A1 are substituted into the equation (1) to obtain θ (ST6). A line passing through the center of gravity G and inclined by θ with respect to the vertical line Q is defined as a rectangular center line S.

Next, a method for measuring the width of a rectangle will be described as a second embodiment. FIG. 4 is a diagram showing a method of measuring the shape and the width M near the center of gravity of a barrel-shaped rectangle, and FIG. 5 is a flowchart of the second embodiment. In FIG. 4, a vertical line Q is a line perpendicular to the scanning line P, and a center line S is a straight line passing through the center of gravity G and inclined by the vertical line Q and θ obtained in the first embodiment. Note that θ can be a value obtained by a method other than the first embodiment, for example, an angle obtained by the conventional example shown in FIG. The reference line T is a straight line that passes through the center of gravity G, is inclined by θ with respect to the scanning line P, and is orthogonal to the center line S. The shape of the long side near the center of gravity G of the rectangle is shown by left and right stepped solid lines, and as shown in detail in a part, the hatched pixel is a square, and the outer shape of the pixel is represented.
The straight lines L3 and L4 are imaginary lines drawn in parallel to the center line S left and right after the rectangular width M is obtained, in order to easily show M.

In this method, m lines are drawn radially at an angle Δθ to the left and right through the center of gravity G with respect to the reference line T as a center, an intersection with the left and right long sides is obtained, and the length between the intersections of each line is calculated. An average value M is obtained, and this is set as the width near the center of gravity G of the rectangle. In calculating the average value, the maximum value and the minimum value are excluded as abnormal values, and the remaining values are averaged. Further, Δθ is set so that the value of Δθ · M ′ / 2 is about the size of one pixel (preferably about 0.3 to 1.5 times the size of one pixel, assuming that the expected value of the width is M ′). Set. The value of Δθ · M ′ / 2 corresponds to the pitch of the intersection of the line drawn for each angle Δθ with the straight lines L3 and L4. The value of m is assumed to be straight lines L3 and L4.
The number is set so that it can be covered by 2 m + 1 radial lines or more (preferably about 2 sets). FIG. 4 shows a case of one set.

A radial line drawn m lines to the left and right of the reference line T every Δθ is such that m = 1, 2,
3,... And clockwise m = -1, -2, -3,.
Is displayed. The intersection of the reference line T, each radial line m, and the long side of the rectangle often does not coincide with the center point of the four pixels representing the coordinates of the pixel shown in FIG. 7 or the center of the pixel. In this case, The reference line T takes the coordinate point of the pixel closest to this intersection, and the intersection with each radial line m takes the coordinate point of the nearest pixel outside each radial line m with the reference line T inside. The distance between the intersections of the line segments is calculated from the distance between the coordinate points. A method of shifting the intersection of the radial line m = -5 and the long side to the coordinate point -5p as shown by the arrow is shown in a part of FIG. In this case, although the center point of the four pixels shown in FIG. 7A is used as the coordinate point, it may be the center of the pixel shown in FIG. However, unify either. The coordinates of the pixel at each intersection are indicated by mp and mq, where mp is the coordinates of the intersection with the long side on the right and mq is the coordinates of the intersection with the long side on the left.
Find the distance between the intersection points mp and mq. When the average value M obtained as described above and the estimated value M 'are significantly different, M may be used as M' and the average value M may be obtained again.

Next, a method of measuring the width of a rectangle will be described with reference to the flowchart of the second embodiment shown in FIG. This embodiment is to be performed following the operation shown in the flowchart of the first embodiment,
It is assumed that the rectangular image data, the center of gravity G, the center line S, and the inclination θ of the center line S are already stored in the image processing apparatus shown in FIG. First, Δθ, m is input from the keyboard 15 (ST11). The value of Δθ is obtained by calculating an estimated value M ′ of the width,
θ · M ′ / 2 is determined to be about the size of one pixel. However, when the size of the rectangle is substantially determined, the value of Δθ is also constant. In this embodiment, the size of one pixel is 2
It is about μm. M to determine the number of radial lines 2m + 1
Is determined so as to cover one or two sets of irregularities on the long side of the rectangle. However, since one concave or convex is often composed of 3 to 5 pixels, m = 5 in the case of one set. For two sets, m =
It can be set to 10 in advance.

Next, a reference line T passing through the center of gravity G and orthogonal to the center line S is obtained (ST12). With respect to this reference line T, m radial lines and 2m + 1 radial lines including the reference line T are drawn on the left and right at an angle Δθ pitch passing through the center of gravity G to obtain the intersection with the left and right long sides of the rectangle (ST13). ). When the intersection is not at the coordinate point of the pixel of the image, the reference line T is set inside and the coordinate point of the nearest pixel outside the corresponding radial line m is set as the intersection (ST14). The distance between the intersections is calculated for the reference line T and each radial line m, and the remaining average value M is calculated except for the maximum value and the minimum value (ST15).

Next, another method for measuring the width of a rectangle will be described as a third embodiment. While the second embodiment calculates the width from the intersection of a radial line segment passing through the center of gravity G and the long side of the rectangle, the second embodiment is parallel to the reference line T and has a pitch of about one pixel size. A parallel line is drawn, and a width is obtained from an intersection between the n parallel lines including the reference line T and the rectangle. FIG.
Since the pitch is smaller than that of the conventional example shown in FIG. 1A and the average value is excluded when the maximum value and the minimum value are obtained, a value close to a visually measured value can be obtained.

FIG. 6 is a diagram showing a method of measuring the shape and width N near the center of gravity of the same barrel-shaped rectangle as in FIG. 6, the scanning line P, the vertical line Q, the center line S, the angle θ between the vertical line Q and the center line S, the reference line T, and the straight lines L3 and L4 are the same as those in FIG. This method draws n parallel lines including the reference line T at a constant pitch δ in parallel with the reference line T, finds intersections with the long sides of the right and left rectangles, and calculates the length between the intersections of the respective line segments. An average value N is obtained, and this is set as the width near the center of gravity G of the rectangle. In calculating the average value, the average is calculated using the remaining values excluding the maximum value and the minimum value. The pitch δ is about the size of one pixel (1
The value of n is assumed to be straight lines L3 and L4, and one or more sets of irregularities with L3 and L4 as the center, and preferably about two sets Is determined so as to be covered by n parallel lines. When the intersection between the parallel line and the long side of the left and right rectangles is not on the coordinate point of the pixel described in FIG. 7, the coordinate point of the nearest pixel is used for the reference line T, and the reference point is used for other parallel lines. With the line T inside, the coordinate point of the nearest pixel outside the corresponding parallel line is assumed. In this embodiment, the number of the n parallel lines is the same as the number of the upper and lower lines around the reference line T. However, the number of the parallel lines does not necessarily have to be the same number. In FIG. 6, the numbers attached to the parallel lines indicate the numbers of the respective parallel lines, and n
p indicates the coordinate point of the pixel at the intersection on the right side of the parallel line n, and nq
Indicates the coordinate point of the pixel at the left intersection.

The flow chart of the present embodiment is almost the same as the flow chart of the second embodiment of FIG. 5, in which the pitch δ is set to about the size of one pixel, and the value of n is from 10 (in the case of one set of irregularities). It is set to a value of 20 (about two sets of irregularities).

Although the rectangular shape has been described as a barrel shape, the measurement is not unique to the barrel shape.
The method of each embodiment can also be applied to the measurement of the inclination θ of the center line and the width M (or N) of a normal rectangle whose opposite sides are parallel. Also, the distance between rectangles can be measured.

[0031]

As is clear from the above description, according to the present invention, the inclination angle .theta. Of the center line of the rectangle is calculated by measuring the area. In addition, a radial line is drawn by m lines to the left and right at a Δθ pitch around the reference line T through the width near the center of gravity of the rectangle through the center of gravity, and the distance between the intersections with the long sides of the rectangle is determined for each line segment. And the average value excluding the minimum value as the width,
The pitch of Δθ is set to be about one pixel in the vicinity of the intersection, and the value of m is determined so that 2m + 1 radial lines cover one or more sets of irregularities on the sides of the rectangle. Approximately the same range of accuracy can be obtained. In addition, n parallel lines including the reference line T are drawn at a pitch of about one pixel in parallel with the reference line T, passing through the center of gravity of the rectangle, the intersection with the rectangle is determined, and the distance between the intersections of the parallel lines is determined. The average value of the values excluding the maximum value and the minimum value is defined as the width, and the value of n is determined by visual observation by determining that n parallel lines cover at least one set of irregularities on the sides of the rectangle. Approximately the same range of precision is obtained. By obtaining the average value, a resolution exceeding the resolution depending on the size of the pixel can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image processing apparatus that implements an embodiment.

FIG. 2 is a diagram illustrating a method of calculating a rectangular inclination θ according to the first embodiment.

FIG. 3 is an operation flowchart of the first embodiment.

FIG. 4 is a diagram illustrating a method for measuring the width of a rectangle according to a second embodiment.

FIG. 5 is an operation flowchart of the second embodiment.

FIG. 6 is a diagram illustrating a method of measuring the width of a rectangle according to a third embodiment.

FIG. 7 is a diagram showing coordinate points representing pixels.

FIG. 8 is a view showing a rectangular shape processed by exposure etching and width measurement by visual observation.

FIG. 9 is a diagram illustrating a conventional method for measuring the inclination θ of a rectangle.

FIG. 10 is a diagram illustrating a conventional method for measuring the width of a rectangle.

FIG. 11 is a diagram illustrating a conventional method for measuring the width of a rectangle using an area.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01B 11/00 G06T 1/00 G06T 7/60

Claims (4)

(57) [Claims] 1. A center of gravity of a substantially rectangular image is obtained, a vertical line passing through the center of gravity and orthogonal to a scanning line is set, and a first line and a second line are drawn orthogonally to the vertical line and at an interval h. The intersections of the first line and the substantially rectangle are A and B, and the intersections of the second line and the substantially rectangle are C and D,
The area A1 of the quadrilateral ABCD is determined, and each intersection A, B, C,
A perpendicular line is drawn from D to the opposing first and second lines, and the area surrounded by the perpendicular lines at both ends and the first and second lines is A0, and θ = tan ⁻¹ (A0−A1) / h ^2. (1) A dimension measurement method using an image, wherein θ represented by the expression (1) is an angle between a center line passing through a substantially rectangular center of gravity and indicating a direction of a long side and a vertical line. 2. A center of gravity of a substantially rectangular image is obtained, and an angle θ between a vertical line passing through the center of gravity and a scanning line and a center line passing through the center of gravity of the substantially rectangle and indicating a direction of a long side is determined by a predetermined method. Asked,
Draw each line that passes through the center of gravity and forms an angle θ ± mΔθ (m is an integer) with the scanning line, finds the intersection of each line and a substantially rectangle, finds the length of the line segment between the intersections of each line, and excludes the maximum and minimum values And calculating an average value M of the remaining lengths, wherein Δθ is an estimated value of the average value M, and Δθ · M ′ / 2 is one pixel near the intersection of a substantially rectangular and a line segment. About the size of
The above-mentioned m is represented by two or more sets of irregularities representing the wavy shape of a substantially rectangular side.
A dimension measuring method based on an image, wherein the dimension is determined so as to be included in an intersection range of m + 1 lines. 3. A center of gravity of a substantially rectangular image is obtained, and an angle θ between a vertical line passing through the center of gravity and orthogonal to a scanning line and a center line passing through the center of gravity of the substantially rectangle and indicating a direction of a long side is determined by a predetermined method. Asked,
A reference line passing through the center of gravity and forming an angle θ with the scanning line is determined, and a total of n lines including this reference line are drawn in parallel with this reference line at a pitch δ, and a line between the intersections of these lines and the sides of the substantially rectangle A method of calculating the length of a minute, and calculating the average value N excluding the maximum value and the minimum value, wherein the pitch δ is set to about the size of one pixel, and A dimension measuring method based on an image, characterized in that at least one set of unevenness representing the following is defined so as to be included in the intersection range of n lines. 4. A coordinate point of a line segment that intersects the substantially rectangular shape uses a center of a pixel or a center point of four pixels arranged in a square. If there is no intersection at this coordinate point position, A line passing through the center of gravity and forming an angle θ with the scanning line as an inner side, and calculating the length of the line segment with the center of the nearest pixel or the center point of four pixels outside the corresponding line segment as an intersection. 4. The method for measuring dimensions using images according to claim 2 or 3.