HOLOGRAPHIC RECONSTRUCTION DEVICE AND METHOD

Abstract

The present disclosure relates to improved holographic reconstruction device and a method. In one aspect, the present disclosure relates to improved holographic reconstruction device and method that can measure a digital hologram regardless of optical characteristics of an object to be measured, by an all-in-one type system integrating a transmissive system that measures an object transmitting light and a reflective system that measures an object reflecting light.

Claims

1. A holographic reconstruction device comprising: a first beam splitter configured to split single wavelength light into a first transmitted beam and a second transmitted beam; a plurality of optical mirrors configured to reflect the first transmitted beam toward an object to be measured; a second beam splitter configured to split the second transmitted beam into a first reflected beam and a second reflected beam; an object beam objective lens configured to allow the first transmitted beam to pass through the object or the first reflected beam to pass therethrough; a reference beam objective lens configured to allow the second reflected beam to pass therethrough; a position adjustment mirror configured to transmit the second reflected beam passing through the reference beam objective lens; a recording medium configured to record an interference pattern formed based on two or more of the first transmitted beam, the second transmitted beam, the first reflected beam, or the second reflected beam, entering the second beam splitter; and a processor configured to receive and store an image file generated by converting the interference pattern transmitted from the recording medium, wherein the processor is configured to selectively acquire a beam transmitting object hologram for the object and a beam reflecting object hologram for the object according to a transmissive mode and a reflective mode.

2. The holographic reconstruction device of claim 1, wherein the beam transmitting object hologram is expressed as a complex conjugated hologram corresponding to an interference pattern for a beam transmitting part of the object as in Equation 1 below:
|U.sub.T(x,y,0)|.sup.2=|O.sub.T(x,y)|.sup.2+|R.sub.T(x,y)|.sup.2+O*.sub.T(x,y)R.sub.T(x,y)+O.sub.T(x,y)R*.sub.T(x,y)  (1) wherein x and y denote spatial coordinates, U.sub.T(x,y,0) denotes the acquired beam transmitting object hologram, O.sub.T(x,y), R.sub.T(x,y) denote an object beam and a reference beam of the beam transmitting object hologram, and O*.sub.T(x,y), R*.sub.T(x,y) denote complex conjugates of the object beam and the reference beam of the beam transmitting object hologram.

3. The holographic reconstruction device of claim 1, wherein the beam reflecting object hologram is expressed as a complex conjugated hologram corresponding to an interference pattern for a beam reflecting part of the object as in Equation 2 below:
|U.sub.R(x,y,0)|.sup.2=|O.sub.R(x,y)|.sup.2+|R.sub.R(x,y)|.sup.2+O*.sub.R(x,y)R.sub.R(x,y)+O.sub.R(x,y)R*.sub.R(x,y)  (2) wherein x and y denote spatial coordinates, U.sub.R(x,y,0) denotes the acquired beam reflecting object hologram, O.sub.R(x,y), R.sub.R(x,y) denote an object beam and a reference beam of the beam reflecting object hologram, and O*.sub.R(x,y), R*.sub.R(x,y) denote complex conjugates of the object beam and the reference beam of the beam reflecting object hologram.

4. The holographic reconstruction device of claim 2, wherein the beam transmitting object hologram is the interference pattern formed for the beam transmitting part of the object, by the first transmitted beam and the second transmitted beam.

5. The holographic reconstruction device of claim 3, wherein the beam reflecting object hologram is the interference pattern formed for the beam reflecting part of the object to be measured, by the first reflected beam and the second reflected beam.

6. The holographic reconstruction device of claim 1, wherein: the processor is configured to correct a difference in an optical path of light in the transmissive mode and the reflective mode by adjusting a position of the position adjustment mirror, and the beam transmitting object hologram and the beam reflecting object hologram are configured to be transmitted from the recording medium to the processor to be acquired in the form of an image file.

7. The holographic reconstruction device of claim 1, further comprising a light source unit configured to emit the single wavelength light.

8. The holographic reconstruction device of claim 1, wherein the first and second transmitted beams are configured to meet at the second beam splitter to form the beam transmitting object hologram.

9. The holographic reconstruction device of claim 8, wherein the first transmitted beam corresponds to an object beam of the beam transmitting object hologram, and wherein the second transmitted beam corresponds to a reference beam of the beam transmitting object hologram.

10. The holographic reconstruction device of claim 1, wherein the first and second reflected beams are configured to meet at the second beam splitter to form the beam reflecting object hologram.

11. The holographic reconstruction device of claim 10, wherein the first reflected beam corresponds to an object beam of the beam reflecting object hologram, and wherein the second reflected beam corresponds to a reference beam of the beam reflecting object hologram.

12. The holographic reconstruction device of claim 1, wherein the interference pattern is configured to be formed when 1) the first transmitted beam transmitted through the object or the first reflected beam reflected from a surface of the object and 2) the second reflected beam passing through the reference beam objective lens and reflected from the position adjustment mirror respectively pass through the object beam objective lens and the reference beam objective lens and are subsequently transmitted to the second beam splitter.

13. A holographic reconstruction device comprising: a first beam splitter configured to split single wavelength light into a first transmitted beam and a second transmitted beam; a plurality of optical mirrors configured to reflect the first transmitted beam toward an object to be measured; a second beam splitter configured to split the second transmitted beam into a first reflected beam and a second reflected beam; an object beam objective lens configured to allow the first transmitted beam to pass through the object or the first reflected beam to pass therethrough; a reference beam objective lens configured to allow the second reflected beam to pass therethrough; a position adjustment mirror configured to transmit the second reflected beam passing through the reference beam objective lens; and a recording medium configured to record an interference pattern formed based on two or more of the first transmitted beam, the second transmitted beam, the first reflected beam, or the second reflected beam, entering the second beam splitter.

14. The holographic reconstruction device of claim 13, further comprising a light source unit configured to emit the single wavelength light.

15. The holographic reconstruction device of claim 13, further comprising: a processor configured to receive and store an image file generated by converting the interference pattern.

16. The holographic reconstruction device of claim 15, wherein the processor is further configured to selectively acquire a beam transmitting object hologram for the object and a beam reflecting object hologram for the object according to a transmissive mode and a reflective mode.

17. The holographic reconstruction device of claim 16, wherein the first and second transmitted beams are configured to meet at the second beam splitter to form the beam transmitting object hologram for a beam transmitting part of the object, wherein the first transmitted beam corresponds to an object beam of the beam transmitting object hologram, and wherein the second transmitted beam corresponds to a reference beam of the beam transmitting object hologram.

18. The holographic reconstruction device of claim 16, wherein the first and second reflected beams are configured to meet at the second beam splitter to form the beam reflecting object hologram for a beam reflecting part of the object, wherein the first reflected beam corresponds to an object beam of the beam reflecting object hologram, and wherein the second reflected beam corresponds to a reference beam of the beam reflecting object hologram.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0051] FIG. 1 is a block diagram illustrating in detail a two-wavelength digital holography microscope device according to the disclosed related art.

[0052] FIG. 2 is a schematic block diagram illustrating an improved holographic reconstruction device according to an exemplary embodiment of the present disclosure.

[0053] FIG. 3 is a flowchart illustrating an improved holographic reconstruction method according to an embodiment of the present disclosure.

[0054] FIG. 4 is a flowchart illustrating in detail a detailed embodiment operation of operation S3 of the improved holographic reconstruction method of FIG. 3.

DETAILED DESCRIPTION

[0055] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Here, like reference numerals denote like elements in the accompanying drawings. Also, in describing the present disclosure, when detailed descriptions of associated elements or functions are determined as being unneeded, the detailed descriptions thereof may be omitted.

[0056] Referring to FIG. 2 illustrating an improved holographic reconstruction device according to an embodiment of the present disclosure, an improved holographic reconstruction device 1 according to an embodiment of the present disclosure may be an all-in-one type digital holographic microscope that selectively executes a transmissive mode for measuring an object transmitting light and a reflective mode for measuring an object reflecting light.

[0057] The improved holographic reconstruction device 1 according to an embodiment of the present disclosure may include: a light source unit 10 that emits single wavelength light; a first beam splitter 20 that splits the single wavelength light emitted from the light source unit 10 into a first transmitted split beam T1 and a second transmitted split beam T2; a plurality of optical mirrors 30 and 31 that reflect the first transmitted split beam T1 split by the first beam splitter 20; a second beam splitter 60 that splits the second transmitted split beam T2 split by the first beam splitter 20 into a first reflected split beam R1 and a second reflected split beam R2; an object beam objective lens 50 that allows the first transmitted split beam T1 reflected from the plurality of optical mirrors 30 and 31 and transmitted through an object 40 to be measured or the first reflected split beam R1 split by the second beam splitter 60 to pass therethrough; a reference beam objective lens 51 that allows the second reflected split beam R2 split by the second beam splitter 60 to pass therethrough; a position adjustment mirror 70 to which the second reflected split beam R2 passing through the reference beam objective lens 51 is transmitted; a recording medium 80 that records an interference pattern formed when the first transmitted split beam T1 transmitted through the object 40 to be measured or the first reflected split beam R1 reflected from a surface of the object 40 to be measured and the second reflected split beam R2 passing through the reference beam objective lens 51 and reflected from the position adjustment mirror 70 respectively pass through the object beam objective lens 50 and the reference beam objective lens 51 and are transmitted to the second beam splitter 60; and a processor 90 that receives and stores an image file generated by converting the interference pattern transmitted from the recording medium 80.

[0058] The processor 90 of the improved holographic reconstruction device 1 according to an embodiment of the present disclosure described above may be embodied as a device capable of performing an arithmetic operation, such as a microprocessor, a personal computer (PC), or the like, and the recording medium 80 may be embodied as an image sensor, such as a charge coupled device (CCD), complementary metal-Oxide semiconductor (CMOS), or the like.

[0059] The improved holographic reconstruction device 1 according to an embodiment of the present disclosure may selectively acquire a beam transmitting object hologram and a beam reflecting object hologram by the processor 90 thereof according to a transmissive mode and a reflective mode. In other words, the processor 90 of the improved holographic reconstruction device 1 as an all-in-one type according to an embodiment of the present disclosure corrects a difference in an optical path of a beam in the transmissive mode and the reflective mode by variably adjusting a position of the position adjustment mirror 70. Therefore, the beam transmitting object hologram or the beam reflecting object hologram may be transmitted to the processor 90 through the recording medium 80 (e.g., a CCD) to be acquired in the form of an image file.

[0060] In more detail, the improved holographic reconstruction device 1 according to an embodiment of the present disclosure splits the light emitted from a laser, which is the light source unit 10, into the first transmitted split beam T1 and the second transmitted split beam T2 through the first beam splitter 20 in the transmissive mode for measuring an object transmitting light.

[0061] The first transmitted split beam T1 is reflected respectively from the plurality of optical mirrors 30 and 31 to be transmitted to the object 40 to be measured, passes through the object 40 to be measured, and passes through the object beam objective lens 50 to the second beam splitter 60. In an embodiment of the present disclosure, although the plurality of optical mirrors 30 and 31 are illustrated as being embodied as two optical mirrors, those skilled in the art fully understand that the plurality of optical mirrors 30 and 31 may be embodied as three or more optical mirrors. The second transmitted split beam T2 passes through the second beam splitter 60 and the reference beam objective lens 51, is reflected from the position adjustment mirror 70, and then passes through the reference beam objective lens 51 to the second beam splitter 60.

[0062] The first and second transmitted split beams T1 and T2 that meet at the second beam splitter 60 form an interference pattern (the beam transmitting object hologram) for a beam transmitting part of the object 40 to be measured. Here, the first transmitted split beam T1 corresponds to an object beam of the beam transmitting object hologram, and the second transmitted split beam T2 corresponds to a reference beam of the beam transmitting object hologram.

[0063] In the reflective mode for measuring an object reflecting light, the light emitted from the laser, which is the light source unit 10, is split into the first transmitted split beam T1 and the second transmitted split beam T2 through the first beam splitter 20.

[0064] The second transmitted split beam T2 is split into the first reflected split beam R1 and the second reflected split beam R2 by the second beam splitter 60. The first reflected split beam R1 passes through the object beam objective lens 50, is reflected from the object 40 to be measured, and then repasses through the object beam objective lens 50 to the second beam splitter 60. The second reflected split beam R2 passes through the reference beam objective lens 51, is reflected from the position adjustment mirror 70, and then repasses through the reference beam objective lens 51 to the second beam splitter 60.

[0065] The first reflected split beam R1 and the second reflected split beam R2 that meet at the second beam splitter 60 form an interference pattern (the beam reflecting object hologram) for a beam reflecting part of the object 40 to be measured. Here, the first reflected split beam R1 corresponds to an object beam of the beam reflecting object hologram, and the second reflected split beam R2 corresponds to a reference beam of the beam reflecting object hologram.

[0066] Here, the difference in the optical path of the beam occurring in the transmissive mode and the reflective mode is corrected by adjusting the position of the position adjustment mirror 70, for example, by the processor 90 that is embodied as a PC. The beam transmitting object hologram and the beam reflecting object hologram are respectively transmitted to the PC, which is the processor 90, through the CCD, which is the recording medium 80, to be acquired in the form of the image file.

[0067] If a measurement is performed by selecting the transmissive mode by the improved holographic reconstruction device 1 according to an embodiment of the present disclosure described above, the acquired beam transmitting object hologram is the interference pattern for the beam transmitting part of the object 40 to be measured. The beam transmitting object hologram acquired as described above may be expressed as a complex conjugated hologram as in Equation 1 below:

|U.sub.T(x,y,0)|.sup.2=|O.sub.T(x,y)|.sup.2+|R.sub.T(x,y)|.sup.2+O*.sub.T(x,y)R.sub.T(x,y)+O.sub.T(x,y)R*.sub.T(x,y)  (1)

[0068] wherein x and y denote spatial coordinates, U.sub.T(x,y,0) denotes the acquired beam transmitting object hologram, O.sub.T(x,y), R.sub.T(x,y) denote the object beam and the reference beam of the beam transmitting object hologram, and O*.sub.T(x,y), R*.sub.T(x,y) denote complex conjugates of the object beam and the reference beam of the beam transmitting object hologram.

[0069] In contrast, if a measurement is performed by selecting the reflective mode, the acquired beam reflecting object hologram is the interference pattern for the beam reflecting part of the object 40 to be measured. The beam reflecting object hologram acquired as described above may be expressed as a complex conjugated hologram as in Equation 2 below:

|U.sub.R(x,y,0)|.sup.2=|O.sub.R(x,y)|.sup.2+|R.sub.R(x,y)|.sup.2+O*.sub.R(x,y)R.sub.R(x,y)+O.sub.R(x,y)R*.sub.R(x,y)  (2)

[0070] wherein x and y denote spatial coordinates, U.sub.R(x,y,0) denotes the acquired beam reflecting object hologram, O.sub.R(x,y), R.sub.R(x,y) denote the O*.sub.R(x,y), R*.sub.R(x,y) object beam and the reference beam of the beam reflecting object hologram, and denote complex conjugates of the object beam and the reference beam of the beam reflecting object hologram.

[0071] Hereinafter, a detailed method of reconstructing a three-dimensional shape of an object from two types of object holograms acquired above will be described.

[0072] In detail, referring to FIGS. 2 through 4 again, as described above, 2D Fourier Transform is performed to remove direct current and imaginary image information from the beam transmitting object hologram (S21 of FIG. 3) acquired by selecting the transmissive mode by the processor 90 (S3 of FIG. 3).

[0073] In the case of the transmissive mode, a frequency spectrum of the beam transmitting object hologram acquired by 2D Fourier Transform appears to be divided into real image, imaginary image, and direct current (DC) information of the beam transmitting object hologram (S31 of FIG. 4). To remove the divided imaginary image and DC information of the beam transmitting object hologram, for example, an automatic real image spot-position extraction algorithm is applied to extract phase information from a real image spot-position (S3 of FIG. 3 and S32 of FIG. 4).

[0074] Thereafter, reference beam information of the beam transmitting object hologram is extracted by using a frequency filtering algorithm (S33 of FIG. 4).

[0075] A wavenumber vector constant of the extracted reference beam information is calculated to calculate a compensation term of the extracted reference beam information (S34 of FIG. 4). The compensation term of the extracted reference beam information is calculated by using the calculated wavenumber vector constant (S35 of FIG. 4). In this case, the compensation term of the extracted reference beam information is a conjugate term of the beam transmitting object hologram.

[0076] Thereafter, curvature information is extracted from the beam transmitting object hologram to compensate for a curvature aberration of the object beam objective lens 51 used when measuring a hologram (S36 of FIG. 4). For this, for example, a curvature information compensation term is generated by using an automatic frequency curvature compensation algorithm.

[0077] The compensated beam transmitting object hologram is acquired by multiplying the beam transmitting object hologram by the compensation term of the extracted reference beam information and the curvature information compensation term (S5 of FIG. 3 and S37 of FIG. 4).

[0078] Meanwhile, even in the case of the reflective mode, the same method as in the transmissive mode described above is also applied to the beam reflecting object hologram acquired by 2D Fourier Transform to acquire the compensated beam reflecting object hologram. The compensated beam transmitting object hologram and the compensated beam reflecting object hologram acquired in this manner may be respectively expressed as in Equations 3 and 4 below:

|U.sub.CT(f.sub.x,f.sub.y,0)|.sup.2=F{O.sub.T(x,y)R*.sub.T(x,y)R.sub.CT(x,y)R.sub.CAT(x,y)}  (3)

|U.sub.CR(f.sub.x,f.sub.y,0)|.sup.2=F{O.sub.R(x,y)R*.sub.R(x,y)R.sub.CR(x,y)R.sub.CAR(x,y)}  (4)

[0079] wherein U.sub.CT(f.sub.x,f.sub.y,0) and U.sub.CR(f.sub.x,f.sub.y,0) respectively denote the compensated beam transmitting object hologram and the compensated beam reflecting object hologram, O.sub.T(x,y), R*.sub.T(x,y) denote the object beam and the reference beam of the beam transmitting object hologram, O.sub.R(x,y), R*.sub.R(x,y) denote the object beam and the reference beam of the beam reflecting hologram, R.sub.CT(x,y) denotes the compensation term of the reference beam information of the beam transmitting object hologram, R.sub.CAT(x,y) denotes the curvature information compensation term of the beam transmitting object hologram, R.sub.CR(x,y), denotes a compensation term of reference beam information of the beam reflecting object hologram, and R.sub.CAR(x,y) denotes a curvature information compensation term of the beam reflecting object hologram.

[0080] The compensated beam transmitting object hologram expressed as in Equation 3 above is converted into information of a reconstruction image plane by using an angular spectrum propagation algorithm.

[0081] Phase information is extracted from the converted compensated object hologram through inverse 2D Fourier Transform. Here, the acquired phase information includes only phase information of the beam transmitting part of the object 40 to be measured, in the form of removing remaining information (i.e., information about light and curvature information of the object beam objective lens 50) except for the phase information of the beam transmitting part of the object 40 that the acquired beam transmitting object hologram has.

[0082] The same method is applied to the compensated beam reflecting object hologram to extract phase information. Here, the acquired phase information includes only phase information of the beam reflecting part of the object 40 to be measured, in the form of removing remaining information (i.e., information about light and the curvature information of the object beam objective lens 50) except for the phase information of the beam reflecting part of the object 40 that the acquired beam reflecting object hologram has.

[0083] The extracted phase information of the beam transmitting part of the object 40 to be measured and the extracted phase information of the beam reflecting part of the object 40 to be measured are respectively compensated for distorted phase information by using a 2D phase unwrapping algorithm, and quantitative thickness information of the object 40 to be measured is calculated by using the same (S5 of FIG. 3). The quantitative thickness information may be expressed as in Equation 5 below:

[00001]$\begin{array}{cc}\Delta L=\frac{\lambda \left({\mathrm{\Delta \varnothing }}_T\left(x,y\right)+\Delta {\varnothing }_T\left(x,y\right)\right)}{2\pi \Delta n\left(x,y\right)}& \left(5\right)\end{array}$

[0084] Wherein ΔL denotes the quantitative thickness information of the object 40 to be measured, λ denotes a wavelength of a light source used when acquiring the object hologram, ΔΦ.sub.T(x,y) denotes the phase information of the beam transmitting part of the object 40 to be measured, ΔΦ.sub.R(x,y) denotes the phase information of the beam reflecting part of the object 40 to be measured, and Δn(x,y) denotes a difference between refractive indexes of the object 40 to be measured and air. A 3D shape of an object is reconstructed by using calculated quantitative thickness information of the object.

[0085] FIG. 3 is a flowchart illustrating an improved holographic reconstruction method according to an embodiment of the present disclosure.

[0086] Referring to FIGS. 2 and 3, the improved holographic reconstruction method according to an embodiment of the present disclosure includes: a) selecting two types of measurement modes of an object hologram of the object 40 to be measured (S1); b) measuring the object hologram according to the selected measurement mode (S2); c) removing direct current, imaginary image, and curvature information of the measured object hologram (S3); d) extracting phase information of the object hologram (S4); and e) reconstructing 3D shape information and quantitative size (thickness) information of the object 40 to be measured (S5).

[0087] In the improved holographic reconstruction method according to an embodiment of the present disclosure described above, operation b) may include operation S21 measuring the object hologram in a transmissive mode or operation S22 measuring the object hologram in a reflective mode.

[0088] Also, a beam transmitting object hologram acquired in operation S21 may be expressed as a complex conjugated hologram corresponding to an interference pattern for a beam transmitting part of the object 40 to be measured as in Equation 1 below:

|U.sub.T(x,y,0)|.sup.2=|O.sub.T(x,y)|.sup.2+|R.sub.T(x,y)|.sup.2+O*.sub.T(x,y)R.sub.T(x,y)+O.sub.T(x,y)R*.sub.T(x,y)  (1)

[0089] wherein x and y denote spatial coordinates, U.sub.T(x,y,0) denotes the acquired beam transmitting object hologram, O.sub.T(x,y), R.sub.T(x,y) denote an object beam and a reference beam of the beam transmitting object hologram, and O*.sub.T(x,y), R*.sub.T(x,y) denote complex conjugates of the object beam and the reference beam of the beam transmitting object hologram.

[0090] In contrast, a beam reflecting object hologram acquired in operation S22 may be expressed as a complex conjugated hologram corresponding to an interference pattern for a beam reflecting part of the object 40 to be measured as in Equation 2 below:

|U.sub.R(x,y,0)|.sup.2=|O.sub.R(x,y)|.sup.2+|R.sub.R(x,y)|.sup.2+O*.sub.R(x,y)R.sub.R(x,y)+O.sub.R(x,y)R*.sub.R(x,y)  (2)

[0091] wherein x and y denote spatial coordinates, U.sub.R(x,y,0) denotes the acquired beam reflecting object hologram, O.sub.R(x,y), R.sub.R(x,y) denote an object beam and a reference beam of the beam reflecting object hologram, and O*.sub.R(x,y), R*.sub.R(x,y) denote complex conjugates of the object beam and the reference beam of the beam reflecting object hologram.

[0092] In the improved holographic reconstruction method according to an embodiment of the present disclosure described above, if the measured object hologram is the beam transmitting object hologram, operation c) may include: c1) dividing a frequency spectrum of the beam transmitting object hologram, which is acquired by performing 2D Fourier Transform, into real image, imaginary image, and direct current information of the beam transmitting object hologram to remove the direct current and imaginary image information from the beam transmitting object hologram; c2) extracting a real image spot-position by applying an automatic real image spot-position extraction algorithm to remove the divided imaginary image and DC information of the beam transmitting object hologram; c3) extracting reference beam information of the beam transmitting object hologram by using a frequency filtering algorithm; c4) calculating a wavenumber vector constant of the extracted reference beam information; c5) calculating a compensation term of the extracted reference beam information by using the calculated wavenumber vector constant; c6) extracting curvature information from the beam transmitting object hologram to compensate for a curvature aberration of the object beam objective lens 50 used when measuring the object hologram; and c7) converting the beam transmitting object hologram having the compensated compensation term and the compensated curvature information into information of a reconstruction image plane by using an angular spectrum propagation algorithm.

[0093] Here, operation c6) may include: generating a curvature information compensation term by using an automatic frequency curvature compensation algorithm; and acquiring the compensated beam transmitting object hologram by multiplying the beam transmitting object hologram by the compensation term of the extracted reference beam information and the curvature information compensation term.

[0094] Even in the case of the reflective mode, the same method as in the transmissive mode described above is also applied to the beam reflecting object hologram acquired by 2D Fourier Transform to acquire a compensated beam reflecting object hologram.

[0095] In the improved holographic reconstruction method according to an embodiment of the present disclosure, the compensated beam transmitting object hologram or the compensated beam reflecting object hologram may be expressed as in Equation 3 or 4:

|U.sub.CT(f.sub.x,f.sub.y,0)|.sup.2=F{O.sub.T(x,y)R*.sub.T(x,y)R.sub.CT(x,y)R.sub.CAT(x,y)}  (3)

|U.sub.CR(f.sub.x,f.sub.y,0)|.sup.2=F{O.sub.R(x,y)R*.sub.R(x,y)R.sub.CR(x,y)R.sub.CAR(x,y)}  (4)

[0096] wherein U.sub.CT(f.sub.x,f.sub.y,0) denotes the compensated beam transmitting object hologram, U.sub.CT(f.sub.x,f.sub.y,0) denotes the compensated beam reflecting object hologram, O.sub.T(x,y), R*.sub.T(x,y) denote the object beam and the reference beam of the beam transmitting object hologram, O.sub.R(x,y), R*.sub.R(x,y) denote the object beam and the reference beam of the beam reflecting hologram, R.sub.CT(x,y) denotes the compensation term of the reference beam information of the beam transmitting object hologram, R.sub.CAT(x,y) denotes the curvature information compensation term of the beam transmitting object hologram, R.sub.CR(x,y) denotes a compensation term of reference beam information of the beam reflecting object hologram, and R.sub.CAR(x,y) denotes a curvature information compensation term of the beam reflecting object hologram.

[0097] In the improved holographic reconstruction method according to an embodiment of the present disclosure described above, operation d) may be embodied as operation extracting phase information of the converted compensated object hologram through inverse 2D Fourier Transform, wherein the acquired phase information includes only phase information of the beam transmitting or reflecting part of the object 40 to be measured, in the form of removing remaining information (i.e., information about light and curvature information of the object beam objective lens 50) except for the phase information of the beam transmitting or reflecting part of the object 40 that the acquired beam transmitting object hologram or the acquired beam reflecting object hologram has.

[0098] In the improved holographic reconstruction method according to an embodiment of the present disclosure described above, operation e) may include: respectively compensating the extracted phase information of the beam transmitting part of the object 40 to be measured or the extracted phase information of the beam reflecting part of the object 40 to be measured for distorted phase information by using a 2D phase unwrapping algorithm; calculating quantitative thickness information of the object 40 to be measured, by using the compensated phase information; and reconstructing a 3D shape of the object 40 to be measured, by using the calculated quantitative thickness information of the object 40.

[0099] The calculated thickness information may be expressed as in Equation 5 below:

[00002]$\begin{array}{cc}\Delta L=\frac{\lambda \left({\mathrm{\Delta \varnothing }}_T\left(x,y\right)+\Delta {\varnothing }_T\left(x,y\right)\right)}{2\pi \Delta n\left(x,y\right)}& \left(5\right)\end{array}$

[0100] wherein ΔL denotes the quantitative thickness information of the object 40 to be measured, λ denotes a wavelength of a light source used when acquiring the object hologram, ΔΦ.sub.T(x,y) denotes the phase information of the beam transmitting part of the object 40, ΔΦ.sub.R(x,y) denotes the phase information of the beam reflecting part of the object 40, and Δn(x,y) denotes a difference between refractive indexes of the object 40 and air.

[0101] As described above, in the improved holographic reconstruction device 1 and method according to the present disclosure, 3D information of the object 40 to be measured may be reconstructed by directly generating a calculated digital reference hologram from the object hologram by using the processor 90, thereby solving a complicated optical device structure and consequent considerable cost that are needed for a one-shot digital holography reconstruction using a single object hologram image, according to the related art.

[0102] Also, according to the improved holographic reconstruction device 1 and method according to the present disclosure, the improved holographic reconstruction device 1 additionally uses only the processor 90, and thus an entire construction thereof may be greatly simplified, and a holographic reconstruction may be achieved at low cost.

[0103] In addition, in the improved holographic reconstruction device 1 and method according to the present disclosure, the other elements other than the processor 90 and the position adjustment mirror 70 have the substantially same constructions as reflective and transmissive holographic reconstruction devices of the related art and thus have versatility of being easily applicable to all the reflective and transmissive holographic reconstruction devices of the related art.

[0104] Moreover, in the improved holographic reconstruction device 1 and method according to the present disclosure, in particular, unlike the related art, a reference beam does not need to be used for a hologram reconstruction, and a quantitative 3D image reconstruction of the object 40 to be measured may be achieved in real time.

[0105] Furthermore, the improved holographic reconstruction device 1 and method according to the present disclosure, as described above, may achieve the quantitative 3D image reconstruction of the object 40 to be measured in real time without using the reference beam, and thus may be applied to devices used for detecting defects of ultrafine structures such as TFTs and semiconductors, medical devices needing displaying precise three-dimensional images, and devices used for detecting, verifying, or displaying various fields including refractive index error detections of transparent objects such as other lens, and the like.

[0106] Besides, in the improved holographic reconstruction device 1 and method according to the present disclosure, a digital hologram may be measured regardless of optical characteristics of an object to be measured by selectively selecting a transmissive mode and a reflective mode by an all-in-one type system integrating the reflective and transmissive holographic reconstruction devices of the related art, and thus additional cost may be solved.

[0107] While the present disclosure has been particularly shown and described with reference to embodiments thereof, various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure.