KR101955295B1 - Apparatus for detecting hologram using optical scanning and method thereof - Google Patents

Abstract

The present invention relates to a device and a method for detecting a hologram using optical scanning. According to the present invention, the method for detecting a hologram using optical scanning includes: a step of scanning a subject in an X-Y direction by a scan beam in which a spherical wave and a plane wave are overlapped; a step of generating an electric signal proportional to the intensity of light collected by using an optical detector collecting the scan beam reflected from the subject in accordance with a scanning position in a time-axis direction; a step of transmitting the electric signal to a data collecting unit by a single channel and storing a digital signal by changing the electric signal which is input to the digital signal; a step of generating a three-dimensional array by aligning a beating signal generated as the stored electric signal is cut in accordance with a beating period, in order; a step of generating a reference signal by adding the value of each matrix corresponding to the time axis in the three-dimensional array; and a step of obtaining a real number unit and an imaginary number unit of the hologram using the reference signal and detecting a complex number hologram about the subject by using the real number unit and the imaginary number unit of the hologram. According to the present invention, the device for detecting a hologram using optical scanning generates the reference signal by obtaining the electric signal about the subject detected by the optical scanning and performs digital heterodyne detection by a numerical method using the reference signal. So, the device for detecting a hologram using optical scanning can obtain a hologram signal of high reliability and also enables high-speed optical detection.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical scanning hologram detecting apparatus and an optical scanning hologram detecting apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning hologram detecting apparatus and method, and more particularly, to an optical scanning hologram detecting apparatus and method which can detect a hologram of an object at a high speed using optical scanning.

A holography capable of three-dimensionally recording and reproducing an object can extract a large amount of information stored in the hologram by reproducing information in various ways after recording information on the measurement volume. Digital holography, which is rapidly replacing existing optical holography, is widely used in various fields due to its merits that it is possible to simplify the system without the need of chemical processing of the hologram and real time analysis, , Holographic cameras and so on.

In particular, optical scanning holography is useful because it can extract hologram information of a phosphor as well as actual reflection objects without speckle noise speckle noise, bilinear noise, and background noise.

That is, the optical scanning holography has an advantage of detecting a highly reliable signal using heterodyne optical detection.

However, according to the related art, if a vibration is generated in the interferometer, the beating signal is distorted by the vibration, so that the reference signal is transmitted to the data collecting unit through the two channels to minimize the distortion of the beating signal.

Therefore, according to the prior art, for the purpose of heterodyne detection, the reference signal must be input to the data collecting unit via a separate channel from the photodetector and the beam spreader, respectively. In the case of detecting a signal using two channels, there is a problem in that it is difficult to detect ultra-high-speed light because a speed limit is generated in collecting data by the data collecting unit.

The background art of the present invention is disclosed in Korean Patent Laid-Open No. 10-2013-0081127 (published on 10.17.07.16).

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical scanning hologram detecting apparatus and method which can detect a hologram of an object at a high speed using optical scanning.

According to an aspect of the present invention, there is provided a method of detecting a hologram using an optical scanning hologram detecting apparatus, comprising: scanning an object in an XY direction with a scan beam superimposed on a spherical wave and a plane wave; Generating an electric signal proportional to the intensity of the focused light in a time axis direction in accordance with a scanning position using a photodetector for collecting a scan beam, transmitting the electric signal to a data collector through a single channel, Dimensional array by sequentially arranging the beating signals generated by cutting the stored electric signals according to a beating cycle to generate a three-dimensional array, wherein each matrix corresponding to the corresponding time axis in the three- And generating a reference signal by summing the reference signal < RTI ID = 0.0 > By using a step of obtaining a real part and an imaginary part of the holograms, and by using of the holographic real and imaginary parts of the complex detected hologram for the object.

The starting point of the beating cycle is a point that is larger than the beating signal value of the immediately preceding beating signal and is larger than the beating signal value of the position immediately after the beating signal, It may be a point corresponding to a peak in the signal.

Dimensional array (i (n, m, l)) by arranging the beating signals on the XY plane in the cut order, the beating signals being arranged in the Z axis direction, Lt; / RTI >

)와 사분위상(quadrature-phase) 기준 신호(

)를 생성할 수 있다. The step of generating the reference signal may comprise generating an in-phase reference signal (< RTI ID = 0.0 >

) And a quadrature-phase reference signal (

Can be generated.

Here, P is the beating period.

Detecting the complex hologram is, by applying the in-phase reference signal and the four minutes the phase reference signal to the following equation: the real part _{(H Re (n, m)} ) and the imaginary part (H _Im (n, m) Can be obtained.

According to another aspect of the present invention, there is provided an apparatus for detecting an optical scanning hologram, comprising: an XY scanner for scanning an object in a XY direction with a scan beam superimposed on a spherical wave and a plane wave; a condenser for condensing the scanned beam reflected from the object, A data collector for receiving the electrical signal on a single channel, converting the received electrical signal to a digital signal, and storing the converted electrical signal in a storage unit, A signal processor for generating a reference signal by summing the values of the matrices corresponding to the time axis in the three-dimensional array, sequentially generating the beating signals by cutting the electric signals according to the beating cycle, And acquiring a real part and an imaginary part of the hologram using the reference signal, And a hologram detector for detecting a complex hologram of the object using an imaginary part.

According to the present invention, an electrical signal for an object detected through optical scanning is acquired on a single channel to generate a reference signal, and digital heterodyne detection is performed by a numerical method using a reference signal, Thereby obtaining a highly reliable hologram signal.

1 is a configuration diagram of an optical scanning hologram detecting apparatus according to an embodiment of the present invention.
2 is a view for explaining an optical scanning hologram detecting apparatus according to an embodiment of the present invention.
3 is a flowchart of a hologram detection method using optical scanning according to an embodiment of the present invention.
4 is a view for explaining a process of scanning an object by the XY scanner according to FIG.
5 is an exemplary view showing an electric signal generated from the photodetector of FIG.
FIG. 6 is a diagram for explaining a method of setting a beating cycle according to an embodiment of the present invention.
FIGS. 7A and 7B are diagrams for explaining a process of generating a three-dimensional array for a beating signal according to an embodiment of the present invention.
8 is a diagram for explaining a process of generating a reference signal according to the signal processing unit of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

Hereinafter, an optical scanning hologram detecting apparatus according to an embodiment of the present invention will be described in detail with reference to FIG.

1 is a configuration diagram of an optical scanning hologram detecting apparatus according to an embodiment of the present invention.

1, the optical scanning hologram detecting apparatus 100 includes an XY scanner 110, a photodetector 120, a data collecting unit 130, a storage unit 140, a signal processing unit 150, (160).

First, the X-Y scanner 110 scans an object in the X-Y direction with a scan beam superposed with a spherical wave and a plane wave.

Next, the photodetector 120 condenses the scan beam reflected from the object, and generates an electric signal proportional to the intensity of the focused light in the time axis direction according to the scanning position.

Next, the data collecting unit 130 receives the electric signal in a single channel, converts the input electric signal into a digital signal, and stores the converted electric signal in the storage unit 140.

The signal processor 150 generates a three-dimensional array i (n, m, l) by sequentially arranging the beating signals generated by cutting the electric signals stored in the storage unit 140 according to a beating cycle . The signal processor 150 generates a reference signal by summing the values of the matrices corresponding to the time axis in the three-dimensional array.

Finally, the hologram detecting unit 160 acquires the real part and the imaginary part of the hologram using the reference signal, and detects the complex hologram for the object using the real part and the imaginary part of the hologram.

Hereinafter, a complex hologram detection method using optical scanning according to an embodiment of the present invention will be described with reference to FIG. 2 through FIG.

FIG. 2 is a view for explaining an optical scanning hologram detecting apparatus according to an embodiment of the present invention, and FIG. 3 is a flowchart of a hologram detecting method using optical scanning according to an embodiment of the present invention.

2, when the laser emitting means 101 transmits a laser signal, the laser signal is divided through the reflecting mirror M1 and the first interfering means 102 (beam splitter), and the divided first laser signal is divided into And outputs a spherical wave through a first beam expander 104 (Beam Expander) through a first acoustooptic modulator 103 (AOM, acousto-optic modulator) and a reflector M3. The second laser signal divided through the first interferometer 102 passes through the second acoustooptic modulator 105 and the reflector M2 and then outputs a plane wave through a second beam expander 106 do.

Then, the spherical wave passes through the focus lens L1 and is incident on the second interfering means 107. The plane wave is also incident on the second interfering means 107, and the incident spherical wave and the plane wave form a superimposed scan beam (S310).

Next, as shown in FIG. 2, the X-Y scanner 110 scans an object with the superimposed scan beam in the X-axis and Y-axis directions (S320).

FIG. 4 is a view for explaining a process of scanning an object by the X-Y scanner according to FIG. 1;

As shown in FIG. 4, the X-Y scanner 110 includes (1, 1), (1,2), ..., , (1, m), and then (2, 1), (2, 2), , And (2, m), respectively. In this way, the X-Y scanner 110 generates (n, 1), (n, 2), ... , and (n, m), respectively.

At this time, the XY scanner 110 modulates the scan beam according to time by deflecting the frequencies of the two overlapping beams to extract the complex hologram of the object 200 from which the pair image and background noise are removed, ).

The scan beam reflected from the object 200 is focused on the photodetector 120 through the third interferometer 108 and the focus lens L2.

At this time, the photodetector 120 generates an electric signal proportional to the intensity of the focused light in the direction of the time axis according to the scanning coordinates, and simultaneously generates the hologram information I ₀ (x, y, z) of the object S330).

5 is an exemplary view showing an electric signal generated from the photodetector of FIG.

As shown in Fig. 5, the photodetector 120 generates the electric signal detected in accordance with each scanning position in the direction of the time axis t.

Here, since the hologram information of the object 200 is contained in the envelope of the electric signal (i _seq (k)), the hologram of the object can be generated later through the envelope of the electric signal.

Next, the photodetector 120 transmits an electric signal proportional to the intensity of the condensed light to the data acquisition unit 130 (DAQ) in a single channel (S340).

The data collector 130 converts the input electrical signal into a digital signal through sampling and quantization, and sequentially stores the digital signal in the storage unit 140 (S350).

Then, the signal processing unit 150 reads the sequentially stored electric signals i _seq (k) from the storage unit 140 and divides the electric signals i _seq (k) according to the beating cycle to generate the beating signal (S360).

FIG. 6 is a diagram for explaining a method of setting a beating cycle according to an embodiment of the present invention.

6, the signal processing unit 150 calculates the difference value i _seq (k) between the electric signal i _seq (k) at the specific point k and the electric signal i _seq (k-1) -i _seq (k-1).

In addition, the signal processor 150 is the difference value _(seq i (k) of the electrical signal _(seq i (k + 1)) immediately after the position and the electrical signal _seq i (k) at a particular point (k) -i _seq ( k + 1).

Then, the signal processing unit 150 selects the point (k) where the two difference values are both positive as the starting point of the beating signal.

That is, as shown in FIG. 6, the point corresponding to the peak in the i _seq (k) signal is the starting point of the beating signal.

The signal processing unit 150 calculates the difference between the immediately preceding position value i _seq (k-1) and the immediately following position value i _seq (k + 1) at the next specific point k from the starting point of the beating signal, And selects the point where both of the difference values are positive as the end point of the beating signal.

That is, as shown in FIG. 6, the point corresponding to the peak of the signal after the start point of the beating signal is the end point of the beating signal.

Here, the end point of the beating signal is not necessarily limited to the next peak signal after the start point, but may be the next or subsequent peak signal.

Therefore, the time difference from the starting point to the ending point of the beating signal becomes the beating cycle, and the distance from the starting point to the ending point of the beating signal becomes the length of the beating signal.

Since the signal processor 150 cuts the input electrical signal at the same beating cycle, the lengths of all the beating signals are set to be the same.

Next, the signal processing unit 150 sequentially arranges the beating signals that are cut according to the beating cycle to generate a three-dimensional array (S370).

FIGS. 7A and 7B are diagrams for explaining a process of generating a three-dimensional array for a beating signal according to an embodiment of the present invention.

The signal processing unit 150 arranges the beating signals on the XY plane in the order of the cut corresponding to the scan positions (n, m) according to the instantaneous movement of the XY scanner 110, and the beating signals are arrayed Dimensional array (i (n, m, l)).

That is, if the beating signal cut in the beating cycle is arranged in the first row on the XY plane as shown in FIG. 7A, the signal processing unit 150 arranges the beating signal in the second row in the next beating cycle, .

In this way, the signal processing unit 150 rearranges the beating signals to the last row of the three-dimensional array as shown in FIG. 7B.

Here, the three-dimensional array generated by the rearranged beating signal as shown in FIGS. 7A and 7B can be represented by i (n, m, l).

Therefore, the beating signal having the same l value is a beating signal generated on the same time axis with respect to each starting point of the beating cycle.

Next, the signal processing unit 150 generates a reference signal by summing the values of the matrices corresponding to the time axis in the three-dimensional array (S380).

8 is a diagram for explaining a process of generating a reference signal according to the signal processing unit of FIG.

8, the signal processing unit 150 includes i (n, m, 1) included in the two-dimensional matrix i (n, m, l) arranged along the time axis , i (n, m, 2), ... , and i (n, m, l).

Then, the signal processor 150 can generate a reference signal of the corresponding time axis as shown in the following Equation (1).

는 수치적 디지털 헤테로다인 검출을 위한 동위상(in-phase) 기준신호가 된다. here,

Is an in-phase reference signal for numerical digital heterodyne detection.

The signal processor 150 may generate a quadrature-phase reference signal as shown in Equation (2) by delaying the in-phase reference signal shown in Equation (1) by half a period.

 Here, P is the beating cycle.

)와 수학식 2에서 획득한 q-phase 기준신호(

)를 3차원 어레이의 비팅 시간축(Z축) 방향으로 곱하여 누적하면 수학식 3 및 수학식 4와 같이 각각의 스캔 위치에 대한 홀로그램의 실수부(H_Re(n,m))와 허수부(H_Im(n,m))를 획득할 수 있다(S390). Next, the hologram detecting unit 160 obtains the in-phase reference signal (

) And the q-phase reference signal (

) A three-dimensional beating time axis (Z axis) when stacked multiply in the direction of the hologram for each scan position as shown in equations (3) and (4) a real part (H _Re (n, m) of the array) and the imaginary part (H _Im (n, m) (S390).

Next, the hologram detecting unit 160 may detect complex holograms of the object as shown in Equation (5) by combining Equations (3) and (4) (S400).

As described above, according to the embodiment of the present invention, the electric signal for the object detected through the optical scanning is acquired in one channel to generate the reference signal, and the digital heterodyne detection is performed numerically using the reference signal High-speed optical detection is possible, and a highly reliable hologram signal can be obtained.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: Optical scanning hologram detecting device 101: Laser emitting means
102: first interfering means 103: first acoustic optical modulator
104: first beam spreader 105: second acoustic optical modulator
106: second beam spreader 107: second interference means
108: third interference means 110: XY scanner
120: photodetector 130: data collecting unit
140: storage unit 150: signal processor
160: Hologram detector

Claims (10)

A hologram detecting method using an optical scanning hologram detecting apparatus,
Scanning the object in the X and Y directions with a scanning beam superimposed on the spherical wave and the plane wave,
Generating an electric signal proportional to the intensity of the focused light in a time axis direction according to a scanning position using a photodetector that condenses a scan beam reflected from the object;
Transferring the electrical signal to a data collecting unit through a single channel, converting the input electrical signal into a digital signal and storing the digital signal,
Dimensional array (i (n, m, l)) by arranging the beating signals generated by cutting the stored electric signals according to a beating cycle on the XY plane in the order of cut, , ≪ / RTI >
Generating a reference signal by summing the values of the respective matrices corresponding to the time axis in the three-dimensional array, and
Obtaining a real part and an imaginary part of a hologram using the reference signal and detecting a complex number hologram for the object using a real part and an imaginary part of the hologram,
Wherein the step of generating the reference signal comprises:
The in-phase reference signal (< RTI ID = 0.0 >

) And a quadrature-phase reference signal (

) ≪ / RTI >

Here, P is the beating period. The method according to claim 1,
The starting point of the beating cycle is a point which is larger than the beating signal value of the immediately preceding beating signal and corresponds to a peak that is larger than the beating signal value of the position immediately after the beating signal,
Wherein an end point of the beating cycle is a point corresponding to a peak in an electric signal after a start point of the beating cycle. delete delete The method according to claim 1,
The step of detecting the complex number hologram includes:
And obtaining the real part (H _Re (n, m)) and the imaginary part (H _Im (n, m)) by applying the in-phase reference signal and the quadrature reference signal to the following equation.

An XY scanner that scans an object in the X and Y directions with a scan beam superposed with a spherical wave and a plane wave,
A photodetector for condensing the scan beam reflected from the object and generating an electric signal proportional to intensity of the focused light in a time axis direction according to the scanning position,
A data collecting unit for receiving the electrical signal through a single channel, converting the input electrical signal into a digital signal and storing the digital signal in a storage unit,
Dimensional array (i (n, m, l)) by arranging the beating signals generated by cutting the stored electric signals according to a beating cycle on the XY plane in the order of cut, A signal processor for generating a reference signal by summing the values of the matrices corresponding to the time axis in the three-dimensional array, and
And a hologram detecting unit that obtains a real part and an imaginary part of a hologram using the reference signal and detects a complex number hologram for the object using a real part and an imaginary part of the hologram,
The signal processing unit,
The in-phase reference signal (< RTI ID = 0.0 >

) And a quadrature-phase reference signal (

The optical scanning hologram detecting apparatus according to claim 1,

Here, P is the beating period. The method according to claim 6,
The starting point of the beating cycle is a point which is larger than the beating signal value of the immediately preceding beating signal and corresponds to a peak that is larger than the beating signal value of the position immediately after the beating signal,
Wherein an end point of the beating cycle is a point corresponding to a peak in an electric signal after a start point of the beating cycle. delete delete The method according to claim 6,
Wherein the hologram detecting unit comprises:
The optical scanning hologram detecting apparatus according to claim 1, wherein the in-phase reference signal and the quadrature phase reference signal are applied to the following equation to obtain a real part (H _Re (n, m)) and an imaginary part (H _Im .

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