阅读说明：本技术 Ss-oct间距测量中利用伺服系统谐振消镜像的方法及其系统 (Disappeared the method and its system of mirror image in SS-OCT distance measurement using servo-system resonance ) 是由 史国华 王俊翔 冯长有 邢利娜 王冬月 潘道伟 樊金宇 于 2019-07-17 设计创作，主要内容包括：本发明公开了一种SS-OCT间距测量中利用伺服系统谐振消镜像的方法及其系统,本发明的方法利用伺服电机引起的谐振产生相位的正弦振动,并结合一种任意相位的消镜像算法实现了镜像消除。本发明的系统包括扫频光源、环形器、波分复用器、光纤耦合器、参考臂、样品臂、光电探测器、数据采集设备及电子计算机；所述光纤耦合器为50/50耦合器。所述参考臂包括第一准直器、平面镜及伺服电机系统,伺服电机系统包括伺服电机和传动装置,所述伺服电机通过所述传动装置带动所述平面镜移动及产生相位振荡。本发明不需要在系统中引入额外的PZT,大幅度减少了系统的成本和复杂度,且消镜像结果稳定,成倍增加了系统单次测量量程。(The invention discloses disappeared the method and its system of mirror image in a kind of SS-OCT distance measurement using servo-system resonance, method of the invention utilizes resonance caused by servo motor to generate the sinusoidal vibration of phase, and a kind of mirror algorithm that disappears of arbitrary phase is combined to realize image cancellation.System of the invention includes swept light source, circulator, wavelength division multiplexer, fiber coupler, reference arm, sample arm, photodetector, data acquisition equipment and electronic computer；The fiber coupler is 50/50 coupler.The reference arm includes first collimator, plane mirror and servo electrical machinery system, and servo electrical machinery system includes servo motor and transmission device, and the servo motor drives the plane mirror mobile and generates phase oscillation by the transmission device.The present invention does not need to introduce additional PZT in systems, drastically reduces the cost and complexity of system, and the mirror image result that disappears is stablized, the system that has been multiplied single measurement range.)

1. being disappeared the method for mirror image in a kind of SS-OCT distance measurement using servo electrical machinery system resonance characterized by comprising

1) the mirror algorithm formula that disappears is constructed:

1-1) the signal description for detecting the photodetector in SS-OCT distance measurement system are as follows:

Wherein, k is wave number, and S (k) is the broadband light that the k that light source issues is encoded at any time, R_R、R_SnIt is plane mirror on reference arm The reflectivity of reflectivity and the face sample arm loading position n mirror, N are total face number of sample, z_RIt is to reference arm plane mirror institute The light path walked, z_SnIt is the light path walked to the face sample arm loading position n mirror；

Fourier transformation 1-2) is done to formula (1), and omits the coefficient before each, is obtained:

(2) first, second, third in formula corresponds respectively to first, second, third of (1) formula, respectively DC terms, Sample from coherent term and the mirror surface spacing item of needs, A is DC terms, be constant；δ is Dirac function, and z is sample mirror surface Spacing；

1-3) (2) formula is symmetrical about coordinate origin, added a phase in (1) formula Section 3So (2) formula is rewritten Are as follows:

1-4) (3) formula is multiplied by phase factorAnd subtract each other with (2) formula, it obtains:

Phase 1-5) is added to (1) formulaIt carries out adding phase with above-mentionedIdentical operation obtains:

1-6) (4) formula multiplied bySubtract again (5) formula withProduct obtain:

(6) formula can be arbitrarySelection is lower to eliminate mirror image；

2) plane mirror in the reference arm in SS-OCT distance measurement system is driven to generate oscillation by servo electrical machinery system；

3) data that the photodetector in n SS-OCT distance measurement system obtains are recorded, the data volume of every data is m, It is denoted as I (m, n) and is Fourier transform FFTFT^-1(I (m, n)) obtains the position k where the maximum value in every data, meter Calculate the corresponding phase in the position:

4) InIn appoint and take 3 frames, obtain 3 phase points, carrying out ascending order arrangement postscript is A₀、A₁、A₂, selection target phase isWherein, meet:E₀、E₁Indicate error；

5) rememberIt willIt is updated to and disappears in mirror algorithm formula (6), obtain the mirror image result that disappears.

2. disappeared the method for mirror image in SS-OCT distance measurement according to claim 1 using servo electrical machinery system resonance, It is characterized in that, further includes first carrying out SS-OCT distance measurement system initialization, and adjust sample arm and reference in the step 2 Arm keeps the signal-to-noise ratio of SS-OCT distance measurement system maximum.

3. disappeared the method for mirror image in SS-OCT distance measurement according to claim 2 using servo electrical machinery system resonance, It is characterized in that, step 4) the selection target phase

4. disappeared the method for mirror image in SS-OCT distance measurement according to claim 2 using servo electrical machinery system resonance, It is characterized in that, step 4) the selection target phase

5. a kind of SS-OCT distance measurement system, which is characterized in that it uses the side as described in any one of claim 1-4 Method eliminates mirror image, which includes swept light source, circulator, wavelength division multiplexer, fiber coupler, reference arm, sample arm, photoelectricity Detector, data acquisition equipment and electronic computer；The fiber coupler is 50/50 coupler.

6. SS-OCT distance measurement system according to claim 5, which is characterized in that the reference arm includes the first collimation Device, plane mirror and servo electrical machinery system, servo electrical machinery system include servo motor and transmission device, and the servo motor passes through institute Transmission device is stated to drive the plane mirror mobile and generate phase oscillation.

7. SS-OCT distance measurement system according to claim 6, which is characterized in that the transmission device is screw rod.

8. SS-OCT distance measurement system according to claim 7, which is characterized in that the sample arm includes the second collimation Device and sample to be tested.

9. SS-OCT distance measurement system according to claim 8, which is characterized in that the circulator includes 3 ends Mouthful: first port, second port and third port；And it can only be defeated from the second port from the light that the first port enters Out, can only export from the light that the second port enters from the third port, it can only be from from the light of third port entrance The first port output.

10. SS-OCT distance measurement system according to claim 9, which is characterized in that the light that the swept light source issues Enter the circulator from the first port, then exported from the second port and enter the fiber coupler, is divided into 2 Shu Guang respectively enters the reference arm and sample arm；Wherein, into the light of the reference arm by being shone after first collimating mirror It penetrates on the plane mirror, the mechanical resonant of the servo motor drives screw rod to generate oscillation together with the plane mirror, drives light The change of journey causes the fluctuating of phase, the light backtracking that the carrying light path of plane mirror reflection converts to the fiber coupler； The light of the sample arm section is got on the sample to be tested by second collimating mirror, the carrying of the sample to be tested reflection The light backtracking of sample mirror surface information is equal again after being interfered with the light that the reference arm returns to the fiber coupler It is divided into 2 tunnels；The photoelectricity is output to through the third port after wherein entering the circulator from the second port all the way to visit Device is surveyed, another way is also output to the photodetector after the wavelength division multiplexer, and two-way light is through the photodetector It is recorded and is saved the data in the electronic computer by the data acquisition equipment after switching to electric signal.

Technical field

It is the present invention relates to field of optical measuring technologies, in particular to humorous using servo-system in a kind of SS-OCT distance measurement Vibration disappears the method and its system of mirror image.

Background technique

Optical coherent chromatographic imaging (Optical Coherence Tomography, OCT) is a kind of non-intruding, non-contact Imaging technique, can apply in optical surface non-contact measurement.But due to the characteristic of Fourier transformation, reality Measurement is influenced by mirror image, and range is reduced to half, so if mirror image can be eliminated, can range be expanded at double.

The mirror image that disappears is M.Wojtkowski earliest in article " Full range complex spectral optical Five step phase-shifting methods of coherence tomography technique in eye imaging " report calculate five interference letters Number amplitude and phase information reconstruct multiple interference spectrum；Have later by Y.Yasuno in article " Simultaneous B-M- mode scanning method for real-time full-range Fourier domain optical The linear B-M method that coherence tomography " is proposed introduces carrier frequency using PZT to eliminate complex conjugate picture.For application On distance measurement, phase-shifting method is simpler method.It is eliminated based on phase-shifting method multiple caused by optical coherence tomography (OCT) The device of conjugate image as shown in Figure 1, the light that laser issues enters fiber coupler through port 1 or optical splitter is divided into two-way, by Port 2,3 has respectively entered reference arm and sample arm, and introduces lead titanate piezoelectric ceramics (hereinafter referred to as in reference arm position PZT), be displaced using PZT nanoscale and change optical path difference, last two-beam interferes after backtracking, interference information via Port 4 switchs to electric signal by photodetector, finally by capture card and computer through row acquisition and data processing.Detector detection The signal arrived utilizes the phase reconstruction light of change so causing the change of phase by nanoscale optical path difference for real number signal Plural form, to eliminate complex conjugate picture.But PZT is as nanoscale high precision instrument, it is easy to damage and it is at high cost be very Big disadvantage.

Summary of the invention

In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is that between providing a kind of SS-OCT Away from being disappeared the method and its system of mirror image in measurement using servo-system resonance.

In order to solve the above technical problems, the technical solution adopted by the present invention is that: using watching in a kind of SS-OCT distance measurement Electric system resonance is taken to disappear the method for mirror image, comprising:

1) the mirror algorithm formula that disappears is constructed:

1-1) the signal description for detecting the photodetector in SS-OCT distance measurement system are as follows:

Wherein, k is wave number, and S (k) is the broadband light that the k that light source issues is encoded at any time, R_R、R_SnIt is plane on reference arm The reflectivity of mirror and the reflectivity of the face sample arm loading position n mirror, N is total face number of sample, z_RIt is to reference arm plane The light path that mirror is walked, z_SnIt is the light path walked to the face sample arm loading position n mirror；

Fourier transformation 1-2) is done to formula (1), and omits the coefficient before each, is obtained:

(2) first, second, third in formula corresponds respectively to first, second, third of (1) formula, respectively direct current , sample from coherent term and the mirror surface spacing item of needs, A is DC terms, be constant；δ is Dirac function, and z is sample Mirror surface spacing；

1-3) (2) formula is symmetrical about coordinate origin, added a phase in (1) formula Section 3So (2) formula changes It is written as:

1-4) (3) formula is multiplied by phase factorAnd subtract each other with (2) formula, it obtains:

Phase 1-5) is added to (1) formulaIt carries out adding phase with above-mentionedIdentical operation obtains:

1-6) (4) formula multiplied bySubtract again (5) formula withProduct obtain:

(6) formula can be arbitrarySelection is lower to eliminate mirror image；

6) plane mirror in the reference arm in SS-OCT distance measurement system is driven to generate oscillation by servo electrical machinery system；

7) data that the photodetector in n SS-OCT distance measurement system obtains, the data volume of every data are recorded For m, it is denoted as I (m, n) and is Fourier transform FFTFT^-1(I (m, n)), obtains the position where the maximum value in every data K calculates the corresponding phase in the position:

8) InIn appoint and take 3 frames, obtain 3 phase points, carrying out ascending order arrangement postscript is A₀、A₁、A₂, selection target phase Position isWherein, meet:E₀、E₁Indicate error；

9) rememberIt willIt is updated to and disappears in mirror algorithm formula (6), obtain the mirror image knot that disappears Fruit.

It preferably, further include first carrying out SS-OCT distance measurement system initialization, and adjust sample arm in the step 2 And reference arm, keep the signal-to-noise ratio of SS-OCT distance measurement system maximum.

Preferably, step 4) the selection target phase

Preferably, step 4) the selection target phase

A kind of SS-OCT distance measurement system uses method as described above to eliminate mirror image, which includes sweep light Source, circulator, wavelength division multiplexer, fiber coupler, reference arm, sample arm, photodetector, data acquisition equipment and electrometer Calculation machine；The fiber coupler is 50/50 coupler.

Preferably, the reference arm includes first collimator, plane mirror and servo electrical machinery system, servo electrical machinery system packet Servo motor and transmission device are included, the servo motor drives the plane mirror mobile and generates phase by the transmission device Oscillation.

Preferably, the transmission device is screw rod.

Preferably, the sample arm includes the second collimator and sample to be tested.

Preferably, the circulator includes 3 ports: first port, second port and third port；And from described The light that first port enters can only be exported from the second port, and the light entered from the second port can only be from the third end Mouth output, the light entered from the third port can only be exported from the first port.

Preferably, the light that the swept light source issues enters the circulator from the first port, then from described the Two-port netwerk output enters the fiber coupler, is divided into 2 beam light and respectively enters the reference arm and sample arm；Wherein, into Enter the light of the reference arm by being radiated on the plane mirror after first collimating mirror, the mechanical resonant of the servo motor It drives screw rod to generate oscillation together with the plane mirror, the change of light path is driven to cause the fluctuating of phase, the carrying of plane mirror reflection The light backtracking of light path transformation is to the fiber coupler；The light of the sample arm section is got to by second collimating mirror On the sample to be tested, the light backtracking of the carrying sample mirror surface information of sample to be tested reflection to the fiber coupling Device, the light returned with the reference arm are divided into 2 tunnels after being interfered again；Wherein all the way from described in second port entrance It is output to the photodetector through the third port after circulator, another way is also output to after the wavelength division multiplexer The photodetector, two-way light are recorded simultaneously after the photodetector switchs to electric signal by the data acquisition equipment It saves the data in the electronic computer.

The beneficial effects of the present invention are: the present invention generates the sinusoidal vibration of phase using resonance caused by servo motor, and Image cancellation is realized in conjunction with a kind of mirror algorithm that disappears of arbitrary phase, does not need to introduce additional PZT in systems, significantly Reduce the cost and complexity of system, and the mirror image result that disappears is stablized, the system that has been multiplied single measurement range.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of SS-OCT distance measurement system of the invention；

Fig. 2 is the mirror effect figure that disappears in a kind of embodiment of the invention.

Description of symbols:

1-swept light source；2-circulators；3-wavelength division multiplexers；4-fiber couplers；5-first collimators；6-the Two collimators；7-plane mirrors；8-servo motors；9-transmission devices；10-samples to be tested；11-photodetectors；12-numbers According to acquisition equipment；13-electronic computers；14-reference arms；15-sample arms.

Specific embodiment

The present invention will be further described in detail below with reference to the embodiments, to enable those skilled in the art referring to specification Text can be implemented accordingly.

It should be appreciated that such as " having ", "comprising" and " comprising " term used herein are not precluded one or more The presence or addition of a other elements or combinations thereof.

Disappeared the method for mirror image in a kind of SS-OCT distance measurement of the present embodiment using 8 system resonance of servo motor, comprising:

1) the mirror algorithm formula that disappears is constructed:

1-1) the signal description for detecting the photodetector 11 in SS-OCT distance measurement system are as follows:

Wherein, k is wave number, and S (k) is the broadband light that the k that light source issues is encoded at any time, R_R、R_SnIt is to be put down on reference arm 14 The reflectivity of 15 face the loading position n mirror of reflectivity and sample arm of face mirror 7, N is total face number of sample, z_RIt is to reference arm The light path that 14 plane mirrors 7 are walked, z_SnIt is the light path walked to 15 face loading position n mirror of sample arm；

Fourier transformation 1-2) is done to formula (1), and omits the coefficient before each, is obtained:

(2) first, second, third in formula corresponds respectively to first, second, third of (1) formula, respectively direct current , sample from coherent term and the mirror surface spacing item of needs, A is DC terms, be constant；δ is Dirac function, and z is sample Mirror surface spacing；

1-3) it can be seen that (2) formula is symmetrical about coordinate origin, if increasing or reducing nanometer in (1) formula Section 3 The light path of grade, is equivalent to and added a phaseSo (2) formula is rewritten are as follows:

1-4) (3) formula is multiplied by phase factorAnd subtract each other with (2) formula, it obtains:

The formula eliminates complex conjugate item but remains DC terms and from coherent term；

Phase 1-5) is added to (1) formulaIt carries out adding phase with above-mentionedIdentical operation obtains:

1-6) (4) formula multiplied bySubtract again (5) formula withProduct obtain:

(6) formula formula has eliminated complex conjugate mirror image, DC terms and from coherent term.It finally can be arbitraryDisappear under selection Except mirror image；Selection influence the intensity of last signal, be preferablySignal is strong at this time.

2) SS-OCT distance measurement system initialization is first carried out, and adjusts sample arm 15 and reference arm 14, is made between SS-OCT Signal-to-noise ratio away from measuring system is maximum；

Servo motor 8 is opened, automatic tuning response coefficient is adjusted and carrys out regulating system response speed, generate a faint vibration It swings, the plane mirror 7 in the reference arm 14 in SS-OCT distance measurement system is driven to generate oscillation by 8 system of servo motor；

3) data that the photodetector 11 in n SS-OCT distance measurement system obtains, the data of every data are recorded Amount is m, is denoted as I (m, n) and is Fourier transform FFTFT^-1(I (m, n)), obtains the position where the maximum value in every data K is set, the corresponding phase in the position is calculated:

4) InIn appoint and take 3 frames, obtain 3 phase points, carrying out ascending order arrangement postscript is A₀、A₁、A₂, selection target phase Position isWherein, meet:E₀、E₁Indicate error；

5) rememberIt willIt is updated to and disappears in mirror algorithm formula (6), obtain the mirror image knot that disappears Fruit.

In one embodiment, step 4) selection target phase

In another embodiment, step 4) selection target phase

The introducing of servo motor 8 SS-OCT distance measurement system is done the measurement of more microscope groups simultaneously as transmission device 9 by us For non-ideal rigidity, high performance servo-system is easy to happen resonance in high speed positive and negative rotation and quick Positioning Process, draws Play the concussion of phase.Using this concussion, three phases are intercepted in the concussion of caused phase, then according to a kind of arbitrary phase The mirror algorithm that disappears can realize elimination mirror image.The mirror algorithm that disappears of formula (1)-(6) is used in the present embodiment.

As servo motor 8 drive screw rod caused by vibrate when phase choose and using the algorithm disappear mirror image as a result, As shown in Figure 2.Wherein, the target phase of selectionFig. 2 (A) is phse conversion figure caused by 8 resonance of servo motor, Fig. 2 (B) it is the image before disappearing mirror image on, therefore, is not being needed with PZT's using the mirror effect that disappears after this patent under Fig. 2 (B) Under the premise of, the method according to the invention uses 8 system of servo motor, can also obtain the relatively good mirror effect that disappears.

The present invention utilizes resonance caused by servo motor 8 to generate the sinusoidal vibration of phase, and combines a kind of arbitrary phase The mirror algorithm that disappears realizes image cancellation, does not need to introduce additional PZT in systems, drastically reduce system cost and Complexity, and the mirror image result that disappears is stablized, the system that has been multiplied single measurement range.

The invention also discloses a kind of SS-OCT distance measurement systems, and method as above is used to eliminate mirror image, referring to figure 1, which includes swept light source 1, circulator 2, wavelength division multiplexer 3, fiber coupler 4, reference arm 14, sample arm 15, photoelectricity Detector 11, data acquisition equipment 12 and electronic computer 13；Fiber coupler 4 is 50/50 coupler.

Wherein, reference arm 14 includes 8 system of first collimator 5, plane mirror 7 and servo motor, and 8 system of servo motor includes Servo motor 8 and transmission device 9, servo motor 8 drive plane mirror 7 mobile and generate phase oscillation by transmission device 9.Servo Motor 8 is used to drive plane mirror 7 mobile by transmission device 9, compensates optical path difference, and generate phase oscillation.Preferably implementing In example, transmission device 9 is screw rod.Sample arm 15 includes the second collimator 6 and sample to be tested 10.Collimator is used for will be in optical fiber Light is converted into the spatial light of equivalent width.Circulator 2 includes 3 ports: first port, second port and third port；And The light entered from first port can only be exported from second port, and the light entered from second port can only be exported from third port, from The light that third port enters can only be exported from first port.

Optical path trend: the light that swept light source 1 issues enters circulator 2 from first port, then exports and enter from second port Fiber coupler 4 is divided into 2 beam light and respectively enters reference arm 14 and sample arm 15；Wherein, pass through into the light of reference arm 14 It is radiated at after first collimating mirror on plane mirror 7, the mechanical resonant of servo motor 8 drives screw rod to generate oscillation, band together with plane mirror 7 The change of dynamic light path causes the fluctuating of phase, the light backtracking that the carrying light path that plane mirror 7 reflects converts to fiber coupler 4；The light of 15 part of sample arm is got on sample to be tested 10 by the second collimating mirror, the carrying sample mirror surface that sample to be tested 10 reflects For the light backtracking of information to fiber coupler 4, the light returned with reference arm 14 is divided into 2 tunnels after being interfered again；Wherein Through third port photodetector 11 is output to after entering circulator 2 from second port all the way, and another way passes through wavelength division multiplexer 3 It is also output to photodetector 11 afterwards, two-way light is remembered after photodetector 11 switchs to electric signal by data acquisition equipment 12 It records and saves the data in electronic computer 13.

Although the embodiments of the present invention have been disclosed as above, but its is not only in the description and the implementation listed With it can be fully applied to various fields suitable for the present invention, for those skilled in the art, can be easily Realize other modification, therefore without departing from the general concept defined in the claims and the equivalent scope, the present invention is simultaneously unlimited In specific details.