KR101447645B1 - Method for measuring three dimensional shape - Google Patents

Abstract

A three-dimensional shape measuring method capable of measuring a three-dimensional shape of an object to be measured by using an N-bucket algorithm, wherein each of the grating light beams applied from a plurality of directions is irradiated with N measurement objects And then sequentially detects the grid pattern light reflected from the measurement object to acquire N pattern images of the measurement object in each direction. Next, the phase and brightness in each direction corresponding to each position of the X-Y coordinate system are extracted from the pattern images, and the height weight is calculated from the brightness of the initial height from the phase. Next, the initial height is multiplied by the height weight to calculate the weight height in each direction, and the final height is calculated by summing the weight weights in all directions. Thus, by calculating the final height using the height weight according to the brightness in each direction, the three-dimensional shape of the measurement object can be more accurately measured.

Description

[0001] METHOD FOR MEASURING THREE DIMENSIONAL SHAPE [0002]

The present invention relates to a three-dimensional shape measuring method, and more particularly, to a three-dimensional shape measuring method capable of measuring a three-dimensional shape of a measurement object using grating light.

Generally, a three-dimensional shape measuring apparatus is composed of a stage, a camera, a lighting unit, and a central processing unit. Here, a general method of measuring the three-dimensional shape of the measurement object using the three-dimensional shape measuring apparatus will be briefly described as follows.

First, the grating pattern light emitted from the illumination unit is irradiated onto a measurement object disposed on the stage. At this time, the grid pattern light is irradiated to the measurement object while moving to the side N times. Then, the camera detects the grid pattern light reflected from the measurement object to acquire N pattern images of the measurement object. Then, the central processing unit calculates the height of each measurement object from the N pattern images using an N-bucket algorithm. When the height according to each of the positions thus calculated is integrated, the three-dimensional shape of the measurement object can be measured.

On the other hand, the grating light generated in the illumination unit and irradiated to the measurement object forms a saturated region having a relatively high luminance in a portion of the measurement object adjacent to the illumination unit, A shadow region having a relatively low luminance can be formed. Alternatively, a shadow or a saturation region may be generated depending on the shape of the measurement object. However, the saturation region and the shadow region may decrease the reliability of the calculated height when the height according to each position of the measurement object is calculated through the N-bucket algorithm. That is, when the height according to each position of the measurement object is calculated using the N-bucket algorithm, the central processing unit can calculate an inaccurate height in the saturation region and the shadow region.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above problems, and it is an object of the present invention to provide a three-dimensional shape measuring method capable of accurately measuring a three-dimensional shape of a measurement object in all areas.

A three-dimensional shape measuring method according to an exemplary embodiment of the present invention relates to a measuring method for measuring a three-dimensional shape of an object to be measured using an N-bucket algorithm, And sequentially grasping the grid pattern light reflected from the measurement object and irradiating the measurement object with N pattern images of the measurement object in each direction do. Then, a phase {P _i (x, y)} and a brightness {A _i (x, y)} in each direction corresponding to each position {i (x, y)} of the XY coordinate system are obtained from the pattern images after extraction, the initial height of the in each direction from the phase _{{H i (x, y)} } a calculation, and increases in each direction by using a weighting function to the average brightness as a parameter weights {W _i ( x, y)}. Then, the initial heights are multiplied by the height weights to calculate weight weights {W _i (x, y) H _i (x, y)} in the respective directions and summing the weights in all directions calculate the final height {ΣW _i (x, y) and _{H i (x, y) /} ΣW i (x, y)} in position. Here, the brightness may be an average brightness obtained by averaging the detected grid pattern light. In addition, the sum of the height weights in all directions may be '1' {ΣW _i (x, y) = 1}.

In the step of extracting the phase and the average brightness, a visibility or a signal-to-noise ratio (SNR) corresponding to each position may be further extracted from the pattern images, And may be a function having the average brightness and the visibility or the SNR as parameters.

Also, in the step of extracting the phase and the average brightness, a measurement range (lambda), which is a lattice pitch in each of the grid pattern lights, can be further extracted from the pattern images, And may be a function having the visibility or the SNR and the measurement range as parameters. Here, the measurement ranges of the grating light may differ by at least two or more.

The weight function may decrease the height weight when the average brightness increases or decreases from a median or a preset reference value, and may increase the height weight when the visibility or the SNR is increased , The height weight can be reduced when the measurement range is increased. At this time, the preset reference value may be set when determining the three-dimensional measurement condition using a specimen, or may be arbitrarily set by a user.

The step of dividing the pattern images into a shadow region, a saturated region, and a non-saturated region may further include dividing the pattern image into a shadow region, a shadow region, Wherein the saturation region is an area in which the average brightness is equal to or greater than a maximum brightness value and the visibility or the SNR is equal to or less than a minimum reference value, This is the remaining area.

The weight function in the shadow region and the saturation region may calculate the height weight as '0'. On the other hand, the weight function in the non-saturated region may calculate the height weight as the same value in all the non-saturated regions. Alternatively, the weight function in the non-saturating region reduces the height weight when the average brightness increases or decreases from the median, increases the height weight when the visibility or the SNR is increased, The height weight can be reduced when the measurement range is increased.

If the average brightness is equal to or greater than a specific value, the brightness is determined as a saturation region and the height weight is set to '0'. If the average brightness is less than a specific value, the shadow region is determined and the height weight is set to '0' . The one specific value and the other specific value may be arbitrarily set by the user in consideration of the measurement environment such as the color of the measurement substrate.

A three-dimensional shape measuring method according to an exemplary embodiment of the present invention relates to a measuring method for measuring a three-dimensional shape of an object to be measured using an N-bucket algorithm, And sequentially grasping the grid pattern light reflected from the measurement object and irradiating the measurement object with N pattern images of the measurement object in each direction do. Then, from the pattern images, a phase {P _i (x, y)} and a visibility {V _i (x, y) in each direction corresponding to each position { (x, y)} in the respective directions from the phase, and calculates a height value {H _i (x, y)} in each direction using a weight function having the visibility as a parameter {W _i (x, y)}. Then, the initial heights are multiplied by the height weights to calculate weight weights {W _i (x, y) H _i (x, y)} in the respective directions and summing the weights in all directions calculate the final height {ΣW _i (x, y) and _{H i (x, y) /} ΣW i (x, y)} in position.

According to the present invention, the average brightness, the visibility or the SNR, and the measurement range are extracted from the pattern images photographed in each direction, and the height weight is determined according to the extracted result. Thus, all the regions including the shadow region and the saturation region The height according to each position of the measurement object can be measured more precisely than in the prior art.

1 is a conceptual diagram showing an exemplary three-dimensional shape measuring apparatus used in a three-dimensional shape measuring method according to an embodiment of the present invention.
FIG. 2 is a plan view showing a grid pattern image by grid pattern light irradiated to the measurement object in FIG. 1. FIG.
3 is a plan view of an image measured by the camera when the grating light is irradiated to the measurement object in the right direction.
4 is a plan view of the image measured by the camera when the grid pattern light is irradiated to the measurement object in the left direction.
5 is a graph showing the relationship between the average brightness and the basic weight in the pattern images measured by the camera.
6 is a graph showing the relationship between the visibility or the SNR and the basic weight in the pattern images measured by the camera.
7 is a graph showing a relationship between a measurement range and a basic weight in pattern images measured by a camera.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprising" or "having ", and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, parts, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted as ideal or overly formal in meaning unless explicitly defined in the present application Do not.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

1 is a conceptual diagram showing an exemplary three-dimensional shape measuring apparatus used in a three-dimensional shape measuring method according to an embodiment of the present invention.

1, the three-dimensional shape measuring apparatus used in the three-dimensional shape measuring method according to the present embodiment includes a measurement stage unit 100, an image capturing unit 200, first and second illumination units 300 and 400 An image acquisition unit 500, a module control unit 600, and a central control unit 700. [

The measurement stage unit 100 may include a stage 110 for supporting the measurement object 10 and a stage transfer unit 120 for transferring the stage 110. [ In this embodiment, as the measurement object 10 is moved by the stage 110 relative to the image capturing unit 200 and the first and second illumination units 300 and 400, the measurement object 10 10 can be changed.

The image capturing unit 200 is disposed at an upper portion of the stage 110 and receives light reflected from the measurement object 10 to measure an image of the measurement object 10. That is, the image capturing unit 200 receives the light emitted from the first and second illumination units 300 and 400 and reflected by the measurement object 10, and outputs a plane image of the measurement object 10 I shoot.

The image capturing unit 200 may include a camera 210, an image forming lens 220, a filter 230, and a circular lamp 240. The camera 210 receives the light reflected from the measurement object 10 and captures a plane image of the measurement object 10. For example, either a CCD camera or a CMOS camera can be applied. The image-forming lens 220 is disposed below the camera 210 to image the light reflected from the measurement object 10 at the camera 210. The filter 230 is disposed at a lower portion of the image forming lens 220 to filter the light reflected from the measurement object 10 and provide the image to the image forming lens 220. For example, And an intensity adjustment filter. The circular lamp 240 may be disposed below the filter 230 to provide light to the measurement object 10 in order to capture a specific image such as a two-dimensional shape of the measurement object 10.

The first illumination unit 300 may be disposed at an angle to the stage 110 supporting the measurement object 10 on the right side of the image sensing unit 200. The first illumination unit 300 may include a first illumination unit 310, a first grating unit 320, a first grating transfer unit 330, and a first condenser lens 340. The first illumination unit 310 is composed of an illumination source and at least one lens to generate light, and the first grating unit 320 is disposed below the first illumination unit 310, Unit 310 to the first lattice pattern light having a lattice pattern. The first grating transfer unit 330 is connected to the first grating unit 320 and transfers the first grating unit 320. For example, the first grating transfer unit 330 may be a PZT (Piezoelectric) transfer unit or a fine linear transfer unit . The first condensing lens 340 is disposed below the first grating unit 320 to condense the first grating pattern light emitted from the first grating unit 320 into the measurement object 10.

The second illumination unit 400 may be disposed at an angle to the stage 110 supporting the measurement object 10 on the left side of the image sensing unit 200. The second illumination unit 400 may include a second illumination unit 410, a second grating unit 420, a second grating transfer unit 430, and a second condenser lens 440. Here, the second illuminating unit 400 is substantially the same as the first illuminating unit 300 described above, and thus a detailed description thereof will be omitted.

The first illumination unit 300 irradiates N first grid pattern lights with the measurement object 10 while the first grid transfer unit 330 sequentially moves the first grid unit 320 N times, The image capturing unit 200 may sequentially acquire N first pattern images by sequentially receiving the N first pattern light beams reflected from the measurement object 10. [ The second illuminating unit 400 may be configured such that the second grating transfer unit 430 sequentially moves the second grating unit 420 N times, The image capturing unit 200 may sequentially receive the N second grid pattern lights reflected from the measurement object 10 and take N second pattern images. Here, N is a natural number, for example, 3 or 4.

In the present embodiment, only the first and second illumination units 300 and 400 are described as an illumination device for generating the first and second grid-patterned lights, but the number of the illumination units may be three or more . That is, the grid pattern light irradiated to the measurement object 10 is irradiated in various directions, and various types of pattern images can be photographed. For example, when three illumination units are arranged in an equilateral triangle shape around the image capturing unit 200, three grid pattern lights can be applied to the measurement object 10 in different directions, The four grid-patterned lights can be applied to the measurement object 10 in different directions when the image pickup unit 200 is arranged in a square shape with the center of the image pickup unit 200 as a center.

The image acquisition unit 500 is electrically connected to the camera 210 of the image capturing unit 200 and acquires and stores the pattern images from the camera 210. For example, the image acquisition unit 500 includes an image system for receiving and storing the N first pattern images and the N second pattern images captured by the camera 210.

The module control unit 600 is electrically connected to the measurement stage unit 100, the image capturing unit 200, the first illuminating unit 300, and the second illuminating unit 400 to control the module. The module control unit 600 includes, for example, a lighting controller, a lattice controller, and a stage controller. The illumination controller controls the first and second illumination units 310 and 410 to generate light, and the lattice controller controls the first and second lattice transfer units 330 and 430, respectively, Thereby moving the first and second grating units 320 and 420. The stage controller may control the stage transfer unit 120 to move the stage 110 vertically and horizontally.

The central control unit 700 is electrically connected to the image acquisition unit 500 and the module control unit 600 to control the respective units. Specifically, the central control unit 700 receives the N first pattern images and the N second pattern images from the image system of the image obtaining unit 500, processes the received N first pattern images and the N second pattern images, The shape can be measured. In addition, the central control unit 700 may control the illumination controller, the lattice controller, and the stage controller of the module control unit 600, respectively. As such, the central control unit may include an image processing board, a control board, and an interface board.

FIG. 2 is a plan view showing a grid pattern image by grid pattern light irradiated to the measurement object in FIG. 1. FIG.

1 and 2, a lattice pattern image is formed on the measurement object 10 when the lattice pattern light emitted from any one of the plurality of illumination units is irradiated onto the measurement object 10 . At this time, the grid pattern image includes a plurality of grid patterns. In this embodiment, the interval between the grid patterns, that is, the grid pitch is defined as a measurement range (?).

Meanwhile, the measurement range (?) May have the same value regardless of the type of the grating light, but may have a different value depending on the type of the grating light. At this time, it is preferable that at least two or more of the measurement range (λ) are different from each other depending on the type of the grid pattern light. For example, the grid pattern image of the first grid pattern light generated in the first illumination unit 300 has a grid pattern of a first measurement range, and the grid pattern image of the second grid pattern light generated by the second illumination unit 400 The grid pattern image by the grid pattern light may have a grid pattern of a second measurement range different from the first measurement range.

FIG. 3 is a plan view of the image measured by the camera when the grid pattern light is irradiated to the measurement object in the right direction, FIG. 4 is a plan view of the image measured by the camera when the grid pattern light is irradiated as the measurement object in the left direction, to be. 3 and FIG. 4 illustrate an image expressing only the relative amount to the brightness (brightness) in which the grid pattern is omitted.

1, 3, and 4, when the grid pattern light emitted from any one of the plurality of illumination units is irradiated to the measurement object 10, the image captured by the camera 210 is relatively A dark shadow region and a relatively bright saturation region may be formed.

For example, when the grid pattern light is applied to the measurement object 10 in the right direction as shown in Fig. 3, generally, the saturation region is mainly formed in the right portion of the measurement object, As shown in FIG. On the other hand, as shown in FIG. 4, when the arbitrary light is applied to the measurement object 10 in the right direction from the grid pattern light in the left direction, the saturation region is generally formed mainly in the right portion of the measurement object, The region may be formed mainly in the left portion of the measurement object.

Hereinafter, a method for measuring a three-dimensional shape according to the present embodiment will be described based on the above description with reference to FIGS. 1 to 3 again.

First, grid pattern light generated in a plurality of directions is sequentially irradiated onto the measurement object 10 disposed on the stage 110, and the grid pattern light reflected from the measurement object 10 Are sequentially detected by the camera 210 to acquire a plurality of pattern images.

Specifically, each of the grid pattern light beams is irradiated to the measurement object 10 while moving N times, for example, 3 or 4 times to obtain N pattern images for the measurement object in each of the directions do. For example, as shown in FIG. 1, when the first and second grid-shaped lights generated in the first and second illumination units 300 and 400 are irradiated to the measurement object 10, Pattern images and N second pattern images can be obtained.

Next, N brightness levels {I ⁱ ₁ , I ⁱ ₂ , ..., I ⁱ _N } at each position {i (x, y)} of the XY coordinate system from N pattern images in the above- and, the phase of the {P in each direction is also extracted from the measurement range (λ), as in 2, and the N light levels of these _{^{{I i 1, I i 2}} , ..., I i N} _i (x, y)}, recall calculated brightness _{{a i (x, y)} } and visibility _{{V i (x, y)} }. At this time, the phase {P _i (x, y)}, the brightness {A _i (x, y)}, and the visibility {V _i (x, y)} in the respective directions are calculated using an N-bucket algorithm ). ≪ / RTI > Also, the brightness {A _i (x, y)} is preferably an average brightness obtained by averaging the detected grid pattern light. Therefore, the brightness {A _i (x, y)} will be hereinafter referred to as an average brightness {A _i (x, y)}.

For example, if N is 3, three degrees of brightness {I ⁱ ₁ , I ⁱ ₂ , I ⁱ ₃ } are extracted from the three pattern images in each direction, and through the 3-bucket algorithm It is possible to calculate the phase {P _i (x, y)}, the average brightness {A _i (x, y)} and the visibility {V _i (x, y)}. In the following expression, B _i (x, y) denotes the amplitude of the image signal (brightness signal) in the three pattern images in each direction. In this case, I ⁱ ₁ is a + b cos (Φ), I ⁱ ₂ is a + b cos (φ + 2π / 3), and I ⁱ ₃ is a + b cos (φ + 4π / 3).

If N is 4, four brightness levels {I ⁱ ₁ , I ⁱ ₂ , I ⁱ ₃ , I ⁱ ₄ } are extracted from the four pattern images in each direction, through it can calculate a phase _{{P i (x, y)} }, the average brightness _{{a i (x, y)} } and visibility _{{V i (x, y)} } , such as the following equation. In the following expression, B _i (x, y) denotes the amplitude of the image signal (brightness signal) in the four pattern images in each direction. At this time, I ⁱ ₁ is a + b cos (Φ) and, I ⁱ ₂ is a + b, and cos (φ + π / 2) , I i 3 is a + b cos (φ + π /) and, I ⁱ ₃ is a + b cos (? + 3? / 2).

In the present embodiment, the signal-to-noise ratio, that is, the signal-to-noise ratio (SNR) may be calculated and used instead of the visibility V _i (x, y). In this case, the SNR represents the ratio {S / N} of the image signal S to the noise signal N in the N pattern images in the respective directions.

Next, the initial height {H _i (x, y)} in each direction from the phase {P _i (x, y)} in each direction is calculated as follows. Here, k _i (x, y) in the following equation means a phase-to-height conversion scale indicating a conversion ratio between phase and height.

On the other hand, by using at least one of the average brightness {A _i (x, y)}, the visibility {V _i (x, y)} and the measurement range _i (x, y)}. The high weight _{{W i (x, y)} } in each direction, for example, the average brightness _{{A i (x, y)} }, the visibility _{{V i (x, y)} } , and the measurement range can be derived as follows by a weight function {f (A _i , V _i , λ)} having a parameter λ as a parameter. At this time, it is preferable that the sum of the height weights in all directions is '1' (ΣW _i (x, y) = 1}.

Then, the first height _{{H i (x, y)} } in each direction high weights of the in each direction on the {W _i (x, y)} weight Height {W of the in each direction is multiplied by _i (x, y) and H _i (x, y)} and the calculation, the weight of the combined height of the sum of the height weight {ΣW _i in all directions (x, y)} by dividing the final height at each position {Σ W _i (x, y) · H _i (x, y) / ΣW _i (x, y)}.

Thereafter, the three-dimensional shape of the measurement object 10 can be accurately measured by integrating the height according to each of the positions thus calculated.

Hereinafter, the characteristics of the weight function {f (A _i , V _i , λ)}, ie, the average brightness {A _i (x, y)}, the visibility {V _i And the height weight {W _i (x, y)} in the respective directions will be described in more detail.

5 is a graph showing the relationship between the average brightness and the basic weight in the pattern images measured by the camera.

At first, 5, the weight function _{{f (A i, V i} , λ)} is to increase or decrease the starting point to a certain value is set to the average brightness _{{A i (x, y)} } is pre , And to reduce the height weight {W _i (x, y)}. That is, the average brightness _{{A i (x, y)} } is the time a specific value, the height weight _{{W i (x, y)} } has a relatively highest value and the average brightness {A _i (x, the value of the height weight {W _i (x, y)} may gradually decrease as the distance from the specific value increases. Here, the specific value may be set when determining the three-dimensional measurement condition using a specimen, or may be arbitrarily set by a user. However, it is preferable that the specific value is a median value of the average value, that is, the average brightness {V _i (x, y)}.

6 is a graph showing the relationship between the visibility or the SNR and the basic weight in the pattern images measured by the camera.

6, the weight function {f (A _i , V _i , λ)} increases the height weight when the visibility {V _i (x, y)} or the SNR is increased Lt; / RTI > That is, the value of the height weight {W _i (x, y)} can also be gradually increased when the visibility {V _i (x, y)} or the value of the SNR is gradually increased.

7 is a graph showing a relationship between a measurement range and a basic weight in pattern images measured by a camera.

Referring now to FIG. 7, the weight function {f (A _i , V _i , λ)} is calculated to decrease the height weight {W _i (x, y)} as the measurement range λ is increased Lt; / RTI > That is, when the value of the measurement range (?) Is gradually increased, the value of the height weight {W _i (x, y)} may gradually decrease.

Referring again to FIGS. 2, 5 and 6, the N pattern images in the respective directions are divided into a shadow region, a saturated region, and a non-saturated region, and different height weights {W _i x, y)} can be given. Here, the shaded areas are the average brightness _{{A i (x, y)} } that is not more than the minimum luminance value (A1), the visibility _{{V i (x, y)} } or less than or equal to the SNR to a minimum threshold (Vmin) Area. The saturation region is an area in which the average brightness _Ai (x, y) is equal to or greater than a maximum brightness value A2 and the visibility or SNR is equal to or less than a minimum reference value Vmin. The non-saturation region is a region other than the shadow region and the saturation region.

First, the weight function {f (A _i , V _i , λ)} in the shadow region and the saturation region calculates the height weight {W _i (x, y)} as '0'. That is, the height weight {W _i (x, y)} in the shadow region and the saturation region is determined as '0'.

The weight function {f (A _i , V _i , λ)} in the non-saturation region is obtained by increasing the average brightness {A _i (x, y) (X, y)} or increase the height weight {W _i (x, y)} as the visibility {V _i (x, y)} or the SNR is increased, the height weight {W _i (x, y)} can be reduced when the wavelength λ is increased.

On the other hand, the weight function {f (A _i , V _i , λ)} in the non-saturation region may calculate the height weight {W _i (x, y)} as the same value in all the non-saturated areas. For example, when height heights in four directions located in the non-saturation region are respectively referred to as first to fourth height weights W ₁ , W ₂ , W ₃ and W ₄ , All the values of the four height weights W ₁ , W ₂ , W ₃ and W ₄ can be determined as '1/4'.

As described above, according to the present embodiment, the average brightness {A _i (x, y)}, the visibility {V _i (x, y)} or SNR, extracting a measurement range (λ), said high weight according to the extracted result {W _i (x, y)} to measure accurately than the conventional height for each location of the object to be measured 10 in the by determining, every area can do.

Specifically, by dividing N pattern images in each direction into shadow regions, saturated regions, and non-saturated regions and assigning different height weights {W _i (x, y)} to the regions, And the reliability of the height value in the saturation region is reduced. That is, by assigning the height weight {W _i (x, y)} to a relatively low value, for example, '0' in the shadow region and the saturation region, and giving a relatively high value in the non- , It is possible to more accurately measure the three-dimensional shape of the measurement object by compensating for the adverse effects caused by the shadow region and the saturation region.

While the present invention has been described in connection with what is presently considered to be practical and exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Accordingly, the foregoing description and drawings are to be regarded in an illustrative rather than a restrictive sense of the invention.

10: Measurement object 100: Measurement stage
200: image capturing unit 300: first illuminating unit
400: second illuminating unit 500: image acquiring unit
600: module control unit 700: central control unit

Claims (20)

Obtaining N pattern images reflected from the measurement object by irradiating the measurement object with the grid pattern light N times in a plurality of directions;
Extracting phase and brightness in each direction corresponding to each position of the measurement object from the obtained pattern images;
Extracting a height weight in each of the directions using a weight function having the brightness as a parameter; And
And calculating a weight height of the measurement object in each of the directions using the height of the measurement object based on the phase and the height weight. The method according to claim 1,
Wherein the grid pattern lights irradiated N times include pattern light having different patterns. The method according to claim 1,
And calculating a height at each of the positions using the weight heights in the respective directions. The method of claim 3,
And measuring the three-dimensional shape of the measurement object by integrating the heights at the respective positions. 2. The method according to claim 1, wherein the brightness is an average brightness obtained by averaging the grid pattern light. 2. The method of claim 1,
Further comprising at least one of visibility and signal-to-noise ratio (SNR) in each direction extracted from the pattern images in the respective directions. 7. The method of claim 6,
And a measurement range (lambda), which is a lattice pitch in each of the grid pattern lights extracted from the pattern images in the respective directions. 8. The method according to claim 7, wherein the measurement ranges of the grating light are different by two or more. The method according to claim 6,
Wherein the brightness is an average brightness obtained by averaging the grating light,
Wherein the weight function reduces the height weight when the average brightness increases or decreases from a specific value. 10. The method according to claim 9, wherein the specific value is a median of the average brightness. 7. The method of claim 6,
Wherein the height weight is increased when the visibility or the SNR is increased. 8. The method of claim 7,
And decreasing the height weight when the measurement range is increased. The method according to claim 6,
Wherein the brightness is an average brightness obtained by averaging the grating light,
The step of extracting the height weights may comprise:
Dividing the pattern images into a shadow region, a saturated region, and a non-saturated region,
Wherein the shadow region is an area in which the average brightness is less than a minimum brightness value and the visibility or SNR is less than a minimum reference value,
Wherein the saturation region is an area in which the average brightness is greater than or equal to a maximum brightness value and the visibility or SNR is less than or equal to a minimum reference value,
And the non-saturation region is a region other than the shadow region and the saturation region. 14. The apparatus of claim 13, wherein the weight function in the shadow region and the saturation region comprises:
And the height weight is calculated as " 0 ". 15. The method of claim 14, wherein the weight function in the non-
Decreasing the height weight when the average brightness increases or decreases from a median,
Wherein the height weight is increased when the visibility or the SNR is increased. The method according to claim 1,
Wherein the sum of the height weights in all directions is one. Obtaining N pattern images reflected from the measurement object by irradiating the measurement object N times with the grid pattern light in a plurality of directions;
Extracting a phase and a visibility in each direction corresponding to each position of the measurement object from the obtained pattern images;
Extracting a height weight in each of the directions using a weight function having the visibility as a parameter; And
And multiplying the height of the measurement object based on the phase by the height weight to calculate a weight height of the measurement object in each of the directions. 17. The method of claim 16,
And calculating a height at each of the positions using the weight heights in the respective directions. 16. The method of claim 15,
And measuring the three-dimensional shape of the measurement object by integrating the heights at the respective positions. 18. The method of claim 17,
Wherein the sum of the height weights in the respective directions is one.

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