KR100906508B1 - 3d measurement apparatus using digital holography - Google Patents

Abstract

A 3D measurement system using digital holography is provided to improve measuring speed and lateral resolution and to minimize the test space for reflective sample. A 3D measurement system using digital holography comprises a first wave plate(30) which performs right-hand circular polarization of the beam linearly polarized by 45°, a beam separation/composition unit(20) dividing the polarized beam into a reference beam and a measurement beam, a second wave plate(31) making the reference beam of P-type waveform and the reference beam of S-type waveform with a phase difference of 90° incident to the beam separation/composition unit, a first polarizer(32) making the measurement beam of P-type waveform and the measurement beam of S-type waveform with a phase difference of 0° incident to the beam separation/composition unit, and interference beam separation units(40) separating an interference beam from the beam separation/composition unit into first and second interference beam.

Description

3D measuring device using digital holography {3D MEASUREMENT APPARATUS USING DIGITAL HOLOGRAPHY}

The present invention relates to a 3D measuring apparatus using digital holography, and more particularly, to compensate for the disadvantages in terms of the measurement speed of the conventional on-axis method and the disadvantages of the lateral resolution of the off-axis method. And it relates to a 3D measuring apparatus using digital holography that can satisfy both the lateral resolution.

Digital holography is one of the optical-based three-dimensional (3D) measurement technology because of its ease of high-speed measurement is important. 1 is a view for explaining the concept of 3D measurement technology using digital holography.

FIG. 1 is a diagram illustrating a state in which measurement light reflected from a measurement object, which is a three-dimensional object, is captured by a CCD camera. Since the measurement object is imaged without using an imaging lens in front of the CCD camera, the conventional 3D measurement is performed. It's a big difference from the way it works.

That is, the image picked up by the CCD camera is an encrypted signal represented by a digital hologram as shown in FIG. 2, and the image information on the measurement target is measured through Fresnel transform of the information included in the digital hologram. We calculate the value numerically to obtain the image.

Since the 3D measurement method using digital holography does not use an imaging lens, it is also called lensless imaging. Since the 3D information of the measurement object is stored in the digital hologram, the conventional vision optical system is used. In addition to the two-dimensional information has a variety of three-dimensional information can be extracted in recent years has been spotlighted as a 3D measurement technology.

As the 3D measurement technology using the digital holography as described above, there is an On-axis method and an Off-axis method, and FIG. 3 is a diagram illustrating the configuration of a 3D measuring device using digital holography of the on-axis method.

The on-axis method captures with a CCD camera while the light reflected from the measurement object (hereinafter referred to as 'measured light') and the light reflected from the reference plane (hereinafter referred to as 'reference light') are parallel to each other. This is how interference occurs.

When the digital hologram is reconstructed, the on-axis method blurs a zero order and a measurement object with DC information represented by a white square as shown in FIG. 4. Since the conjugate image, which is an image (Twin image), is simultaneously reproduced on the same axis, there is a disadvantage in that information of only a desired measurement object cannot be obtained accurately.

For this reason, a 3D measuring device using on-axis digital holography cannot reproduce information on an accurate measurement object using a single hologram.

[Equation 1]

In more detail with reference to [Equation 1], it can be seen that the information stored in the hologram value H (x, y) in the on-axis method is composed of four terms. I _ref represents the intensity of the reference light, and I _obj is a DC term representing the intensity of the measurement light. If the desired term is OR ^* term, O ^* R represents a conjugate image of the measurement object, which is a blurred image.

In general, it can be assumed that the I _ref term among the DC terms can be measured in advance because there is no change, and the entire spatially averaged value of the new hologram obtained by the equation H (x, y) -I _ref is obtained. I _obj terms can be easily removed numerically as 뺌 in Hol (x, y).

When the DC term is removed using this technique, as shown in FIG. 5, a result of mixing the measurement object and the conjugate image may be obtained. That is, the reproduction result of the equation O ^* R + OR ^* as shown in FIG. 5 can be obtained using one hologram. This may be expressed as in [Equation 2].

[Equation 2]

In other words, in the on-axis method, only one hologram cannot separate the image of the measurement object. For this reason, two pieces of hologram information having a phase value of 90 ° must exist to reproduce information on the desired measurement object. Will be.

As described above, the 3D measuring apparatus using the on-axis digital holography has a problem in that the measuring speed is lowered due to a plurality of shots for acquiring a plurality of holograms. For this purpose, as illustrated in FIGS. 6 and 7, An off-axis method for acquiring holograms in a state in which the directions of the measurement light and the reference light are not parallel to each other but have a constant angle has been proposed.

In the method using off-axis digital holography, the DC term and the conjugation are reproduced by using a single hologram I _H (x, y) obtained from a CCD camera to reproduce an image of a measurement object through a Fresnel transform. Since the gate image term is spatially separated from the image portion of the measurement object, three-dimensional information can be obtained from a single hologram.

However, in the off-axis method, as shown in FIG. 7, since only a part of the space is used, a CCD camera having the same pixel number and pixel size is implemented as compared to the on-axis method. There is a disadvantage in that the lateral resolution may be lowered.

The technical problem to be solved by the present invention is to solve the disadvantages in terms of the measurement speed of the conventional on-axis method and the disadvantages of the lateral resolution of the off-axis method as described above to improve the measurement speed and lateral resolution It is to provide a 3D measuring device using digital holography that can satisfy all.

According to the present invention, there is provided a 3D measuring apparatus using digital holography, comprising: a first imaging unit and a second imaging unit, a light source unit emitting 45 ° linearly polarized light, and the 45 ° linear emitted from the light source unit A light splitting / synthesizing splits the polarized light into a first wave plate for circularly polarizing the light, and the light circularly polarized by the first wave plate into a right circularly polarized reference light and a right circularly polarized measurement light, and emits the light to the reference plane and the measurement object, respectively. And the right circularly polarized reference light emitted from the light splitting / compositing part through -45 ° linearly polarized light, and disposed on an optical path between the reference plane and the light splitting / compositing part, and reflected from the reference plane. The -45 ° linearly polarized reference light is circularly polarized to form a P-wave reference light having a phase difference of 90 ° and an S-wave reference light so as to be incident to the light splitter / composite unit. Is arranged on a light path between the second wavelength plate and the measurement object and the light splitter / synthesized part, and passes the right circularly polarized measurement light emitted from the light splitter / combined part by 45 ° linearly polarized light, The 45 ° linearly polarized measurement light reflected from the measurement object is -45 ° linearly polarized to form P-wave measurement light having a phase difference of 0 ° and S-wave measurement light and enter the light split / composite portion. And a first polarizing plate disposed on the optical path of the interference light emitted from the light splitter / compositing unit, and the interference light separated into a first interference light and a second interference light having a phase difference of 90 ° to each other. An interference light splitter directed to an image pickup section and the second image pickup section, respectively; Any one of the first interference light and the second interference light is incident by the P-wave reference light and the P-wave measurement light into the light splitter / synthesis unit and formed by mutual interference; The other one of the first interference light and the second interference light is digital holography, characterized in that the S-wave-shaped reference light and the S-wave-shaped measurement light is incident to the light splitter / synthesis unit is formed by mutual interference It is achieved by a 3D measuring device using.

The interference light splitter may include: a light splitter configured to split the interference light emitted from the light splitter / combiner into the first and second imaging units, respectively; A second polarizing plate disposed between the light splitting unit and the first imaging unit to allow the first interference light to pass through the first interference light so that the first interference light is directed to the first imaging unit; A third polarizer may be disposed between the light splitter and the second imaging unit to pass the second interference light among the interference light so that the second interference light is directed toward the second imaging unit.

The second polarizer may be aligned parallel to the optical plane, and the third polarizer may be aligned perpendicular to the optical plane.

The interference light splitter may be provided in the form of a Wallaston prism in which the interference light is separated into the first interference light and the second interference light so as to be incident to the first imaging unit and the second imaging unit, respectively. Can be.

Here, the first wave plate may be provided in the form of a λ / 4 wave plate (QWP).

The second wave plate may be provided in the form of a λ / 4 wave plate (QWP) aligned with the same axis of rotation as the first wave plate.

The 45 ° linearly polarized measurement light disposed between the first polarizing plate and the measurement object and directed toward the measurement object from the first polarizing plate is focused on the measurement object, and the 45 ° linear reflection from the measurement object is performed. The display device may further include an object lens configured to enlarge the polarized measurement light to be directed toward the first polarizing plate.

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According to the present invention, by using the digital holography that can satisfy both the measurement speed and the lateral resolution by complementing the disadvantages in terms of the measurement speed of the conventional on-axis method and the disadvantages of the lateral resolution of the off-axis method A 3D measuring device is provided.

In addition, since the Michelson-type optical interference system is applied to the 3D measuring apparatus using the digital holography according to the present invention, it is simpler than the Mach-gender type optical interference system to measure the reflective sample, and space can be minimized.

Hereinafter, with reference to the accompanying drawings will be described in detail embodiments according to the present invention. Here, in describing the embodiments according to the present invention, the same reference numerals are used for components corresponding to each other, and description thereof may be omitted as necessary.

First embodiment

3D measuring apparatus using digital holography according to the first embodiment of the present invention, as shown in Figure 8, the first imaging unit 52, the second imaging unit 53, the light source unit 10, the light split / The synthesizer 20 includes a first wave plate 30, a second wave plate 31, a first polarizer 32, and an interference light separation unit 40.

The light source unit 10 emits light toward the light splitting / combining unit 20. Here, the light source unit 10 according to the present invention may include a light source 11, a fixing member 13, and a light source polarizing plate 12. The light source 11 emits short-wavelength laser light. In the present invention, a He-Ne laser is used as the light source 11 as an example. Here, as the light source 11, other types of lasers can be applied as long as the short wavelength laser light can be emitted.

The short wavelength laser light emitted from the light source 11 passes through the light source polarizing plate 12. The light source polarizing plate 12 linearly polarizes the short wavelength laser light emitted from the light source 11 by 45 °. Here, the light source polarizing plate 12 is adjusted to be 45 degrees to the optical plane, thereby linearly polarizing 45 degrees laser light. Accordingly, the light passing through the light source polarizing plate 12 has two waveforms in which the mutual polarization directions are orthogonal to each other, that is, a linearly polarized form of P wave form and S wave form.

Then, the light emitted from the light source 11 and passed through the light source polarizing plate 12 extends around the pinhole of the fixing member 13. The light passing through the pinhole forms parallel light while passing through the convex lens 14 disposed between the fixing member 13 and the light splitting / compositing unit 20.

The first wave plate 30 is disposed on an optical path between the light source unit 10 and the light splitting / compositing unit 20. The first wave plate 30 circularly polarizes light emitted from the light source unit 10, that is, light linearly polarized by 45 ° by the light source polarizing plate 12 of the light source unit 10. Here, for example, the first wave plate 30 may be provided in the form of a λ / 4 wave plate (QWP) that performs right-circular polarization of light in a 45 ° linearly polarized state emitted from the light source unit 10.

Light passing through the first wave plate 30 is incident to the light splitter / combiner 20. Here, the light incident on the light splitter / synthesizer 20 is light in a right circularly polarized state by the first wave plate 30, and the light splitter / combiner 20 splits the right circularly polarized light and respectively reference planes. It is emitted to the 200 and the measurement object (100). The light emitted from the light splitter / composite 20 and directed toward the reference plane 200 becomes a reference beam, and the light emitted from the light splitter / composite 20 and directed toward the measurement object 100 is measured. It becomes an object beam.

The second wave plate 31 is disposed on the optical path between the reference plane 200 and the light splitter / combiner 20. The second wave plate 31 is incident from the light splitter / combiner 20 so that the reference light reflected from the reference plane 200 is incident to the light splitter / composite 20 in a circularly polarized state.

More specifically, the second wave plate 31 is provided in the form of a λ / 4 wave plate (QWP) aligned with the same axis of rotation as the first wave plate 30, and includes a light split / composite unit ( When the reference light in the circularly polarized state, which is emitted from the light source 20 and is incident on the second wave plate 31, passes through the second wave plate 31, -45 ° linearly polarizes.

When the -45 ° linearly polarized reference light is reflected from the reference plane 200 and passes through the second wavelength plate 31 again, the left circularly polarized light is again reflected from the reference plane 200 to the second wavelength plate 31. The incident -45 ° linearly polarized reference light is circularly polarized to form a P-wave reference light having a phase difference of 90 ° and an S-wave reference light while passing through the second wave plate 31, and then split into light. Incident on (20).

Here, FIG. 9A illustrates that the light emitted from the light source unit 10 passes through the first wave plate 30-> light splitting / compositing unit 20-> second wave plate 31-> reference plane 200. -> FIG. 2 shows a polarization change when passing through the first wave plate 30 and the second wave plate 31 in the course of passing through the light splitter / composite unit 20.

On the other hand, the measurement light emitted from the light splitter / combiner 20 passes through the first polarizing plate 32 disposed on the optical path between the measurement object 100 and the light splitter / composite 20. Here, the first polarizing plate 32 is emitted from the light splitting / synthesizing unit 20 so that the measurement light reflected from the measurement object 100 is incident on the light splitting / synthesizing unit 20 in a linearly polarized state.

More specifically, the measurement light emitted from the light splitting / compositing unit 20 is in a right circularly polarized state, and the measured light in the right circularly polarized state is 45 ° linearly polarized while passing through the first polarizing plate 32. In addition, the measurement light that is linearly polarized by 45 ° while passing through the first polarizing plate 32 is reflected from the measurement object 100 to pass through the first polarizing plate 32 again, wherein the first polarizing plate 32 is incident 45 ° linearly polarized measurement light is -45 ° linearly polarized.

By disposing the first polarizing plate 32 on the optical path between the light splitting / compositing unit 20 and the measuring object 100 as described above, the light is reflected from the measuring object 100 to the light splitting / compositing unit 20. The incident measurement light has a linearly polarized form that forms a P-wave measurement light having an orthogonal polarization direction and a S-wave measurement light, wherein the P-wave incident on the light splitting / compositing unit 20 is formed. The phase difference between the measurement light of the form and the measurement light of the S wave form is 0 °.

Here, FIG. 9B illustrates that light emitted from the light source unit 10 passes through the first wave plate 30-> light splitting / compositing unit 20-> first polarizing plate 32-> measurement object 100. The polarization change when passing through the first wavelength plate 30 and the first polarizing plate 32 in the course of passing through the first polarizing plate 32 and the light splitter / compositing unit 20.

In addition, the measurement object 100 measured by the 3D measuring apparatus according to the first embodiment of the present invention has a macro size, and as shown in FIG. 8, light splitting / synthesizing is performed on the optical path of the measurement light. The part 20, the first polarizing plate 32, and the measurement object 100 are disposed.

Through the above process, the reference light reflected from the reference plane 200 and the measurement light reflected from the measurement target 100 are incident on the light splitter / combiner 20. At this time, the reference light and the measurement light incident on the light splitter / combining unit 20 are interfering with each other to form interference light, and the formed interference light includes the first imaging unit 52 and the second imaging unit 53. It is emitted to one area.

Here, in the light splitting / compositing unit 20, interference occurs between light having the same polarization direction among the reference light and the measurement light. That is, the P-wave reference light and the P-wave measurement light interfere with each other to form one interference light (hereinafter referred to as 'first interference light'), and the S-wave reference light and the S-wave measurement light This other interference light (hereinafter referred to as 'second interference light') is formed. Here, since the P-wave reference light and the S-wave reference light have a phase difference of 90 °, the first interference light and the second interference light also have a phase difference of 90 °.

As described above, the first interference light and the second interference light synthesized and output through the interference in the light splitter / combiner 20 are separated by the interference light splitter 40 to respectively separate the first imaging unit 52 and the first image. 2, the imaging section 53 is directed.

Here, the interference light splitter 40 of the 3D measuring apparatus using the digital holography according to the first embodiment of the present invention, as shown in FIG. 8, the light splitter 41, the second polarizing plate 42 and The third polarizer 43 may be included.

The light splitter 41 splits the interference light emitted from the light splitter / combiner 20 to emit light in both directions of the first and second imaging units 52 and 53. Here, in the present invention, for example, the light splitter 41 is provided in the form of a beam splitter.

The second polarizing plate 42 is disposed on the optical path between the light splitting portion 41 and the first imaging portion 52. Here, the second polarizing plate 42 passes only the first interfering light such that only the first interfering light is directed toward the first imaging unit 52. The third polarizer 43 is disposed on the optical path between the light splitter 41 and the second imaging unit 53 so that only the second interference light is directed to the second imaging unit 53. 2 Pass only interfering light.

In this case, since the polarization directions of the first interference light and the second interference light are orthogonal to each other, one of the first interference light and the second interference light is disposed parallel to the optical plane, and the other is arranged perpendicular to the optical plane. And selectively pass the first and second interfering light, respectively.

Through the above configuration, two images having a phase difference of 90 °, that is, two image information for acquiring 3D images, are simultaneously applied to the first and second imaging units 52 and 53 at one time. By imaging, two image information can be obtained simultaneously. Accordingly, while solving the problem of the measurement speed by the conventional on-axis method that requires a plurality of holograms, it is possible to have a high-speed measurement capability of off-axis.

In addition, the conventional off-axis method can prevent the disadvantage of not using the entire area of the CCD camera generated by having a constant angle between the reference light and the measurement light, that is, lowering of the lateral resolution.

Here, the first imaging unit 52 and the second imaging unit 53 according to the present invention are provided in the form of a charge-coupled device (CCD) camera, and the first imaging unit 52 and the second imaging unit 53 are provided. The first interference light and the second interference light acquired by are used to acquire a 3D image of the measurement object 100 by a control unit such as a computer (not shown), and the Fresnel transform (used in the conventional digital holography method) Fresnel transform is applied to acquire 3D image using digital holography.

Second embodiment

In the 3D measuring apparatus using the digital holography according to the second embodiment of the present invention, as shown in FIG. 10, the first imaging unit 52, the second imaging unit 53, the light source unit 10, and the light splitting / The synthesizer 20, the first wave plate 30, the second wave plate 31, the first polarizer 32, and the interference light separation unit 40a are included.

Here, in the second embodiment of the present invention, as in the first embodiment, the 3D measuring apparatus measures the measurement object 100 having a macro size, and a description of the configuration different from that of the first embodiment will be given below. In addition, the description about the same structure can be abbreviate | omitted.

For example, the interference light splitter 40a of the 3D measuring apparatus according to the second exemplary embodiment of the present invention may be provided in the form of a wallaston prism. Here, the first interference light and the second interference light have a phase difference of 90 °, which is the same as the first embodiment described above, and the Wallaston Prism is the interference light emitted from the light splitter / composite 20. That is, the first interference light and the second interference light are split and directed to the first imaging unit 52 and the second imaging unit 53, respectively. That is, by arranging the polarization directions of the first and second interfering light, which are spatially separated from the Wallaston Prism, and the slow axis and the fast axis of the second wave plate 31 to be coincident with each other, 90 °. Phase difference is achieved.

As described above, the first imaging unit 52 picks up the first intermittent light by the Wollaston Prism, and the second imaging unit 53 is the second interference whose polarization direction is orthogonal to the first interference light. In this case, since the first interference light and the second interference light have a phase difference of 90 °, two image information for acquiring a 3D image can be obtained at the same time. The same effects as in the first embodiment of can be obtained.

Third Embodiment and Fourth Embodiment

3D measuring apparatus using digital holography according to the third embodiment of the present invention is a modified embodiment of the 3D measuring apparatus according to the first embodiment of the present invention, as shown in FIG. It has a structure for measuring the measurement object 100a of size.

Thus, the 3D measuring apparatus according to the third exemplary embodiment of the present invention may further include an object lens 60 disposed between the first polarizing plate 32 and the measurement target 100a.

Here, the object lens 60 condenses the measurement light emitted from the light splitting / compositing unit 20 and passed through the first polarizing plate 32 to the measurement object 100a. In addition, the object lens 60 magnifies the measurement light reflected from the measurement object 100a again to face the first polarizing plate 32.

Through such a configuration, the 3D measuring apparatus using digital holography according to the third exemplary embodiment of the present invention can measure the measurement target 100a having a micro size. Here, the operating principle of the 3D measuring apparatus according to the third embodiment of the present invention shown in Figure 11 corresponds to the first embodiment described above, the detailed description thereof will be omitted.

12 is a diagram illustrating a configuration of a 3D measuring apparatus using digital holography according to a fourth exemplary embodiment of the present invention. As shown in FIG. It has a configuration for measuring (100a), it can be seen that the interference light separation unit 40a is provided in the form of Wallaston Prism (Wollaston Prism) as in the second embodiment.

Here, the operating principle of the 3D measuring apparatus according to the fourth embodiment of the present invention corresponds to the above-described second and third embodiments, and a detailed description thereof will be omitted.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

1 is a view for explaining the concept of 3D measurement technology using digital holography,

2 is a diagram illustrating an example of an encrypted signal represented by a digital hologram,

3 is a view showing the configuration of a 3D measurement apparatus using a conventional on-axis digital holography,

4 and 5 are diagrams for explaining a process of reproducing a digital hologram in the conventional On-axis method,

6 and 7 are views for explaining a 3D measurement apparatus using a conventional off-axis digital holography,

8 is a diagram illustrating a configuration of a 3D measuring apparatus using digital holography according to a first embodiment of the present invention,

FIG. 9 is a view for explaining a polarization direction that changes according to an optical path of light emitted from a light source unit in the 3D measuring apparatus using digital holography according to the first embodiment of the present invention.

10 is a diagram showing the configuration of a 3D measuring apparatus using digital holography according to a second embodiment of the present invention,

FIG. 11 is a diagram illustrating a configuration of a 3D measuring apparatus using digital holography according to a third exemplary embodiment of the present invention.

12 is a diagram illustrating a configuration of a 3D measuring apparatus using digital holography according to a fourth embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: light source part 20: light splitting / synthesis part

30: first wave plate 31: second wave plate

32: first polarizing plate 40: reference plane

40, 40a: interference light separating unit 52: first imaging unit

53: second imaging unit 60: object lens

Claims (8)

In the 3D measuring device using digital holography, A first imaging unit and a second imaging unit, A light source unit emitting 45 ° linearly polarized light, A first wave plate for circularly polarizing the 45 ° linearly polarized light emitted from the light source unit; A light splitting / compositing unit for dividing the right circularly polarized light by the first wave plate into a right circularly polarized reference light and a right circularly polarized measurement light, and emitting them to a reference plane and a measurement object, respectively; The -45 disposed on an optical path between the reference plane and the light splitter / synthesizer, and linearly polarizes the right circularly polarized reference light emitted from the light splitter / composite by -45 °, and is reflected from the reference plane. A second wave plate for circularly polarizing the linearly polarized reference light to form a P-wave reference light having a phase difference of 90 ° and an S-wave reference light to be incident on the light splitting / synthesizing part; The right circularly polarized measurement light, which is disposed on an optical path between the measurement object and the light splitter / composite, and passes through the circularly polarized measurement light emitted from the light splitter / composite by 45 °, and is reflected from the measurement target. A first polarizing plate having a 45 ° linearly polarized measurement light to -45 ° linearly polarized light to form a P-wave measurement light having a phase difference of 0 ° and an S-wave measurement light to be incident to the light splitter / composite unit; The first imaging unit and the second imaging unit are disposed on the optical path of the interference light emitted from the light splitter / compositing unit so that the interference light is separated into a first interference light and a second interference light having a phase difference of 90 °. An interference light splitting portion directed toward the negative portion; Any one of the first interference light and the second interference light is incident by the P-wave reference light and the P-wave measurement light into the light splitter / synthesis unit and formed by mutual interference; The other one of the first interference light and the second interference light is digital holography, characterized in that the S-wave-shaped reference light and the S-wave-shaped measurement light is incident to the light splitter / synthesis unit is formed by mutual interference 3D measuring device using. The method of claim 1, The interference light separation unit, A light splitting unit dividing the interference light emitted from the light splitting / combining unit to direct the first and second imaging units, respectively; A second polarizing plate disposed between the light splitting unit and the first imaging unit to allow the first interference light to pass through the first interference light so that the first interference light is directed to the first imaging unit; And a third polarizing plate disposed between the light splitting unit and the second imaging unit to pass the second interference light among the interference light so that the second interference light is directed to the second imaging unit. 3D measuring device using holography. The method of claim 2, And the second polarizer is aligned parallel to the optical plane, and the third polarizer is aligned perpendicular to the optical plane. The method of claim 1, The interference light splitter may be provided in the form of a Wallaston Prism which separates the interference light into the first interference light and the second interference light so that the interference light is incident on the first imaging unit and the second imaging unit, respectively. 3D measuring device using a digital holography characterized in that. The method according to any one of claims 2 to 4, The first wave plate is a λ / 4 wave plate (Quarter Wave Plate: QWP) 3D measurement apparatus using digital holography, characterized in that provided in the form. The method of claim 5, The second wave plate is a 3D measurement device using a digital holography, characterized in that provided in the form of a λ / 4 wave plate (QWP) aligned with the same axis of rotation as the first wave plate. delete The method according to any one of claims 2 to 4, The 45 ° linearly polarized measurement light disposed between the first polarizing plate and the measurement object and directed toward the measurement object from the first polarizing plate is focused on the measurement object, and the 45 ° linearly polarized light reflected from the measurement object. 3D measuring apparatus using digital holography, characterized in that it further comprises an object lens for enlarging the measurement light to the first polarizing plate.

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