CN106643477A - Polarization multiplexing phase modulation type laser self-mixing two-dimensional interferometer and measuring method thereof - Google Patents
Polarization multiplexing phase modulation type laser self-mixing two-dimensional interferometer and measuring method thereof Download PDFInfo
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
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- 239000000395 magnesium oxide Substances 0.000 description 1
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Abstract
The invention discloses a polarization multiplexing phase modulation type laser self-mixing two-dimensional interferometer and a measuring method thereof. The two-dimensional interferometer comprises a double-frequency laser used for emitting a circularly polarized light; a polarization beam splitting prism; a common beam splitting prism, an electro-optic crystal modulator, a light density filter, and a to-be-measured object, which are disposed on an o polarization optical axis; the electro-optic crystal modulator, the light density filter, and another to-be-measured object, which are disposed on an e polarization optical axis; a signal acquisition and phase calculation system, which is used for harmonic analysis and phase demodulation of acquired light intensity signals to acquire the phases and the displacements of the measured objects. The two electro-optic phase modulation frequencies are completely different, and therefore a frequency spectrum aliasing phenomenon is effectively prevented. Because the two polarization lights are linearly polarized lights, and laser speckle effect is small, and by adopting a phase shift technology, resolution of a demodulation result can reach a nanometer level.
Description
Technical field
The present invention relates to a kind of two dimension based on double-longitudinal-mode laser, optical interference, electrooptic effect and polarization multiplexing
Non-contact laser self-mixed interference instrument and its measuring method, belong to the knot of Application Optics, nonlinear electrooptical crystal, laser technique
Conjunction field.Suitable for optical metrology, pick up calibration, micro-nano observing and controlling, micromorphology scanning, it is particularly suitable in two-dimensional measurement to light
The high research of journey sensitivity requirement or engineering field.
Background technology
The accurate measurement method of optics two-dimension displacement has great research meaning to the micro-nano technology such as photoetching, integrated circuit field
Pattern magnitude, microelectronics original paper play critical effect in the positioning of printed circuit board (PCB) in justice, such as mask；Same industry
Environment also has larger demand to independent Bi-objective or two-parameter synchronizing detection, such as the preserving jar for preserving dangerous materials is generally required
Synchronous detecting deformation and temperature, machine vibration is often two dimension, scanning micro-mirror in advanced MEMS (MEMS), super
The harmonic motion of the devices such as sound and vibration is also two dimension；In topography measurement, Workpiece structure detection flaw detection, two or more sensing points
Also using value is had more than single-point detection.Therefore research possesses the non-contact optical survey that Bi-objective is detected simultaneously and sensitivity is high
Amount system is significant.
Existing optical detective technology is relied on reaches two-dimentional inspection by increasing the method for laser instrument and detection channels quantity
Effect is surveyed, such as Laser Doppler Velocimeter is detected respectively with two shift lasers in two-dimensional measurement in different directions, into
This raising, operation is more complicated, and requires more signal acquisition process data；For another example double-frequency interference instrument often cannot be individually complete
Into two-dimensional detection, it is necessary to constitute two-dimensional detection effect with two interferometers；When carrying out two-dimensional detection using single laser instrument at present
Cannot meet requirement due to crosstalk between optical signal, certainty of measurement and range etc. cannot be eradicated.
To solve the problems, such as instrument cost, the quantity of increase laser instrument and collection signal is both avoided, while and elimination two dimension survey
The problem of light path crosstalk in amount, the present invention combines existing palarization multiplexing and phase modulation technique, realizes without crosstalk, Dan Ji
Light device, the high performance-price ratio two dimension self-mixed interference instrument of forms data passage.
The content of the invention
Goal of the invention：It is contemplated that announce a kind of palarization multiplexing that combines mixes dry certainly with the two-dimensional laser of phase-modulation
Interferometer and its measuring method, only using single laser tube and detector in the interferometer optics structure, using the original of palarization multiplexing
Reason produces the independent optical path without optical crosstalk, and Electro-optical Modulation effect and laser self-mixing effect are produced in double-longitudinal-mode laser
Raw light-intensity variation, by analyzing the real-time detection that the harmonic amplitude of light intensity signal is realized to two optical paths target to be measured.
Technical scheme：For achieving the above object, the present invention is adopted the following technical scheme that：
Palarization multiplexing phase modulation-type laser mixes two-dimentional interferometer certainly, including：The double longitudinal mode laser of output circularly polarized light
Device, circularly polarized light is decomposed into the polarization splitting prism of the line polarized light of two cross-polarization, be placed in the first light path
One electro-optic phase modulator, the first ray density wave filter and the first target to be measured, the second electric light being placed in the second light path
Phase-modulator, the second ray density wave filter and the second target to be measured, common point in the first light path or the second light path
Light prism, and the photodetection for detecting the common Amici prism light intensity signal for reflecting and export detected signal waveform
Device；The modulating frequency of first electro-optic phase modulator and the second electro-optic phase modulator is different；The photodetector with
Signals collecting and phase calculation system are electrically connected, and the signals collecting and phase calculation system are used for according to the light intensity signal for gathering
Carry out frequency analyses and phase demodulating draws measured target phase place, and then obtain displacement.
Further, the signals collecting and phase calculation system include：Low-pass filtering amplifying circuit, with photodetector
It is connected, carries out signal filtering and amplify；Data collecting card, for gathering filter and amplification after signal realize analog digital conversion；And
Computer module, for the first harmonic component and second harmonic point of two light paths in the collected light intensity signal of extraction
Amount, based on harmonic component phase demodulating is realized.
Further, the computer module includes：Band filter group unit, including four band filters, respectively
Export the first harmonic component I of the first light patho1With second harmonic component Io2, and the first harmonic component I of the second light pathe1With
Second harmonic component Ie2；Divider, for according to formula Ao/e1(t)=Io/e1/cos(ωo/eAnd A t)o/e2(t)=Io/e2/
cos(2ωo/eT) amplitude curve of two kinds of harmonic components, wherein ω are calculatedo/eFor the phase shift angular frequency of two light paths, ωo
≠ωe；Arctangent unit, for according to formulaIt is calculated the phase place of two light paths；And,
Displacement computing unit, for according to formulaIt is calculated two light paths
Measurement displacement.
The palarization multiplexing phase modulation-type laser comprises the steps from the measuring method for mixing two-dimentional interferometer：
(1) 5mA electric currents are stably supplied to double-longitudinal-mode laser so as to export visible red circularly polarized light, rotary laser
Pipe causes two polarization states of output to be located at respectively both horizontally and vertically；
(2) polarization splitting prism is adjusted so that incident illumination there are 45 ° of angles with the intermediate layer of prism, and o light is worn in the horizontal direction
Cross the first electro-optic phase modulator that polarization state is all horizontal direction, e light is in vertical direction through vertical second electric of polarization state
Light phase modulation；
(3) o light reaches the first target to be measured through the first optical filter, and by former road laser tube is reflected back；E light is through the
Two optical filters reach the second target to be measured, along backtracking laser instrument；Common Amici prism in o light paths or e light paths
Light intensity signal is refracted to into photodetector；
(4) the light intensity signal input signal collection of photodetector output and phase calculation system are processed, filtered
Amplification, analog digital conversion, harmonic amplitude extraction, arctangent cp cp operation and unpacking obtain measured object phase place and displacement.
Beneficial effect：Circular polarization light source, polarization multiplexing are introduced phase modulation-type laser self-mixing interference by the present invention
In instrument, the self-mixed interference instrument of double optical paths is produced.Main technical characterstic is as follows：
Double-longitudinal-mode laser：Double-bus network light frequency difference is about 40MHz, and wavelength is 632.8nm, exports milliwatt power.Should
Class laser linewidth is narrow, is affected low by temperature change.He-Ne mixed gas as laser working medium, by two exocoels
The light intensity change of microwave section is produced after feedback light, in the response range of common photodetector, the photoelectric current of generation be easy to into
Row analog digital conversion and signal analysis.
Sinusoidal phase modulation technology：Combined with line polarized light, the phase-modulation of generation possesses high efficiency, and broadband is unglazed
The characteristics of strong disturbance.Sine wave possesses very sharp frequency domain distribution, therefore introduces after phase-modulation equivalent to will believe from mixing
Number carry out redistribution in frequency domain, produce center frequency and the accurate adjustable harmonic component of adjacent spaces, and the filtering skill of maturation
Art is combined, and harmonic component is easy to be extracted.
Laser self-mixing effect：The narrow linewidth of laser instrument causes phase response that the system feeds back to comparable optical less than partly leading
Body class laser instrument, appropriate decay can eliminate the slant characteristic of striped.Laser self-mixing effect possesses with traditional two-beam interference
Similar phase sensitive degree, linear from mixing striped and tested light path, wavelength the first day of the lunar month characteristic in source ensure that the system tool
There is nano-precision.
Polarization Optical multiplexing technology：In polarization optics, the light beam of two orthogonal polarization states along same optical axis propagate when and circle
Polarized light is equivalent.Using polarization splitting prism, circularly polarized light and two crossed polarized lights can realize from mixed optical path it is reversible
Exchange, thus circularly polarized light laser instrument can possess two independent polarizations from mixed optical path, this improves from mixing and surveys
The destination number of amount, and crosstalk can not possibly be produced between feedback light.
Compared with prior art, the invention has the advantages that：
1) it is cross structure to design light path, and two optical paths are operated in orthogonal polarisation state, without optical crosstalk, not shape
Into referring-to relation；Two optical paths can simultaneously work or work independently.
2) two-frequency laser short-term wavelength uncertainty is better than 10e-6, and to the sensitivity of temperature semiconductor laser is less than,
By DC driven (5mA), without the need for extra pump and accurate temperature control system.
3) single-pass data for collecting is extracted the phase place change on o roads and e roads by the method for frequency analyses.
4) the light feedback intensity that laser instrument is received is necessary for weak feedback, and feedback light intensity is controlled by two optical filters,
So that the striped for producing does not possess obvious tilt phenomenon.
5) system allows two measured objects to be subjected to displacement simultaneously, its amplitude, phase place, frequency can with it is identical can not also
Together；Only one of which measured object is allowed to move another measured object static.Photoetching, micro-nano structure, microcircuit printing can be realized
Etc. the two-dimentional precision positioning that industry needs, it is also possible to two-dimension displacement in industrial environment, vibration, warped, deformation, surface profile
Measure.
Description of the drawings
Fig. 1 is the schematic device of the embodiment of the present invention；
In figure, 1- double-longitudinal-mode lasers；2- polarization splitting prisms；3- first phase manipulators；4- second phase manipulators；
The common Amici prisms of 5-；6- the first ray density wave filter；7- the second ray density wave filter；The targets to be measured of 8- first；9-
Two targets to be measured；10- photodetectors；11- low-pass filtering amplifying circuits；12- data collecting cards；13- computer modules.
Fig. 2 is the frequency domain character schematic diagram of the light intensity signal gathered in the embodiment of the present invention；
Fig. 3 is from the harmonic wave demodulation method flow chart for mixing light intensity signal in the embodiment of the present invention.
Specific embodiment
With reference to specific embodiment, the present invention is further elucidated, it should be understood that these embodiments are merely to illustrate the present invention
Rather than the scope of the present invention is limited, and after the present invention has been read, various equivalences of the those skilled in the art to the present invention
The modification of form falls within the application claims limited range.
As shown in figure 1, a kind of palarization multiplexing phase modulation-type laser disclosed in the embodiment of the present invention is interfered from two dimension is mixed
Instrument mainly includes double-longitudinal-mode laser 1, and polarization splitting prism 2, first phase manipulator 3, first phase manipulator 4 is common to divide
Light prism 5, the first ray density wave filter 6, the second ray density wave filter 7, the first target to be measured 8, the second target to be measured 9,
Photodetector 10, and adopted by the signal of low-pass filtering amplifying circuit 11, data collecting card 12 and the composition of computer module 13
Collection and phase calculation system.Wherein：
Double-longitudinal-mode laser 1, typical atomic gas He-Ne laser instrument exports double-bus network, circular polarization state light, and wavelength is
632.8nm, feedback-less output is 5mW.
Polarization splitting prism 2, possesses fast axle, slow axis, and the line that incident circularly polarized light can be decomposed into into two cross-polarizations is inclined
Shake light (o light and e light).
First electro-optic phase modulator 3, positioned at the first light path (o light paths), encapsulates the lithium columbate crystal mixed with magnesium oxide,
By additional low-frequency high-voltage (<Signal of telecommunication 0.25GHz) changes refractive index, and to the laser beam by crystal phase-modulation is carried out.
Second electro-optic phase modulator 4, is the electric light with the same specification of phase-modulator 3 positioned at the second light path (e light paths)
Phase-modulator, is placed in the optical path with vertical direction, therefore its polarization state is entirely different with the polarization state of phase-modulator 3.
Common Amici prism 5, positioned at arbitrary light path, by the light intensity signal in a light path photodetector is refracted to, and is used
Waveform is detected in producing.
First ray density wave filter 6, it is seen that light intensity wave filter, for controlling the light intensity of o light paths.
Second ray density wave filter 7, be and the same specification device of wave filter 6, for controlling the light intensity of e light paths.
First target to be measured 8, the measured object axially vertical with o light paths can be precision displacement platform, piezoelectric ceramics, swash
Shake device etc..
Second target to be measured 9, the measured object axially vertical with e light paths.
Photodetector 10, the broadband photodetector of silicon substrate, it is necessary to cover 632.8nm optical maser wavelengths, must in use
Must connect with adjustable resistance.
Low-pass filtering amplifying circuit 11, Pre-processing hardware circuit, filter cutoff frequency is adjustable, and possesses amplification signal amplitude
Function.
Data collecting card 12, NI series or same type data collecting card, differential mode collection voltages signal.
Computer module 13, computer is equipped with software environment and realizes that solution mutually shows with result.
In order to realize above-mentioned palarization multiplexing phase modulation-type laser from mixing two-dimentional interferometer to two pinpoint targets or
The real-time measurement of two-dimension displacement/vibration, the measuring method of the present invention is mainly included the following steps that：
1. stably supply 5mA electric currents to double-bus network gas laser 1 so as to export visible red circularly polarized light, rotate
Laser tube causes two polarization states for exporting to be located at respectively both horizontally and vertically.
2. adjustment is placed on the polarization splitting prism 2 of laser instrument leading portion so that incident illumination has 45 ° of folders with the intermediate layer of prism
Angle.O light is all in the horizontal direction the electro-optic phase modulator 3 of horizontal direction through polarization state；E light is in vertical direction through polarization
The vertical electro-optic phase modulator 4 of state.
3.o light reaches target to be measured 8 through optical filter 6, and by former road laser tube is reflected back；E light passes through optically filtering
Device 7 reaches target to be measured 9, along backtracking laser instrument.Common Amici prism 5 can be placed on any one of o or e light paths, will
Photodetector 10 is refracted to from mixed signal.
4. the photoelectricity of the output of photodetector 10 flows through adjustable resistance and is converted to voltage, and voltage signal is put by low-pass filtering
Big device 11 removes high-frequency noise, and the voltage of output completes analog digital conversion by data collecting card 12, then by USB data line transmit to
Demodulation computer 13.Signal processing is completed under the software environment (Labview or Matlab) of computer 13, specially when
Two kinds of harmonic components are extracted in domain, and (mid frequency that the classification of harmonic wave has harmonic wave determines that mid frequency is o roads electric light phase-modulation
Integral multiple be the harmonic wave of o classes, equally, another kind of is the harmonic wave of e classes).With in rahmonic comprising single order and the second harmonic, because
This total of four harmonic wave needs to extract.When the phase shift depth that two modulation are introduced is 1.22rad, measured object phase place is by anyway
Cut computing and unpacking recovers.
Based on frequency analyses and the measurement ultimate principle of phase demodulating：There is the double-longitudinal-mode laser light intensity of self-mixing effect
Model is：
Subscript o/e represents two light paths, Po/eIt is two longitudinal mode light intensity, letter e and F are the weight coefficients of two light intensity, Co
And CeIt is two equivalent reflection coefficient, for describing the intensity of reflected light, two light path cross-polarizations all the time, so mathematics fork
Take advantage of identically vanishing.In the present invention using after ray density wave filter, two reflection coefficient are much smaller than 1, therefore Co≈Ce＜ ＜
1, formula (1) is represented by：
Apply the driving voltage of different frequency same depth, activation to two electro-optic crystals by high-voltage alternating amplifying circuit
Electro-optic phase modulator introduces phase-modulation, and phase place is phase-shifted in formula (3)：
Wherein αo/eExpression is phase-modulated the depth that device introduces phase shift, and phase shift angular frequency can be determined by phase shifting frequencies：ωo/e
=2 π fo/e.Light intensity signal all the way is only needed during demodulation, by taking the light intensity signal of o roads as an example, light intensity presses table after Bessel function launches
Show as follows：
Once can be expressed as follows with second harmonic with regard to o roads phase place in formula (5)：
Once can be expressed as follows with second harmonic with regard to e roads phase place in formula (5)：
For dynamic change is presented in formula (6a)-(7b) medium wave amplitude measurement, it is represented by：
For guarantee two kinds of harmonic components in frequency domain without aliasing, therefore the angular frequency of two phase-modulations must difference ωo≠
ωeDimension, by the division arithmetic of formula (9) amplitude curve (8a) and (8b) is extracted：
Phase place is obtained by following relational expression：
When the modulation depth of two electric light phase-modulations is set to αo/eDuring=1.22rad, then with regard to αo/eSingle order and two
Rank Bessel function is equal, i.e. J1(αo/e)=J2(αo/e), the coefficient of sinusoidal phase and cosine phase in this pattern (8a) and (8b)
It is equal to eliminate, corresponding two-dimension displacement curve is obtained by following relational expression after the Phase- un- wrapping for solving：
Equally two-way phase place and displacement curve can be obtained according to formula (5)-(11) to e roads light intensity.
The frequency domain character from mixed signal of o light paths or the collection of e light paths is further illustrated with reference to Fig. 2：
1) do after FFT from mixed signal be a multi resonant wave component microwave segment signal.
As shown in the figure (two phase modulation frequencies are respectively 39KHz and 98KHz), 2) center of two kinds of harmonic waves and modulation frequency
Rate is consistent, and the adjacent spaces of harmonic wave of the same race are equal to modulating frequency.
3) spectrum width of two kinds of harmonic waves be equal to institute in the optical path measured object introducing laser Doppler frequencies.
4) necessary interval is kept between harmonic wave, therefore each harmonic wave is not in aliasing when being extracted.
The signal processing unit and handling process of computer module of the present invention are illustrated with reference to Fig. 3.Software section is main
Including band filter group unit, including four band filters, two kinds of harmonic components I of o light paths are exported respectivelyo1And Io2, with
And two kinds of harmonic components I of e light pathse1And Ie2；Divider, according to formula Ao/e1(t)=Io/e1/cos(ωo/eAnd A t)o/e2
(t)=Io/e2/cos(2ωo/eT) it is calculated the amplitude curve of two kinds of harmonic components；Arctangent unit, according to formulaIt is calculated the phase place of two light paths；Displacement computing unit, according to formulaIt is calculated the measurement displacement of two light paths.
Handling process is under Labview environment：
1) configure A/D cards to gather in a differential manner and data storage, its parameter input data demodulation flow process, appropriate regulation is put
Big multiple.
2) arranging the cut-off frequency of four band filters guarantees：1. four bandwidth do not repeat；2. mid frequency size
Respectively two phase modulation frequency fo/eWith double 2fo/e。
3)foAnd 2foThe output of two wave filter and the cos (ω for generating at centeroT) with cos (2 ωoT) array is divided by, so
After be input into arctangent cp cp operation, another two wave filter does same operation.
4) by gained Phase- un- wrapping and plot and display.
The estimated displacement that can be measured of single light path or speed limit such as table 1：
The palarization multiplexing phase modulation-type laser of table 1 is from any single channel measurement range of the two-dimentional interferometer of mixing
Note:During two-dimensional measurement, two Measurement channels are simultaneously operable or work independently.
The present invention detects the displacement of two self-movement objects using single laser tube and single detector, and palarization multiplexing is produced
The polarization state of raw light path is orthogonal, does not introduce optical crosstalk；Two longitudinal modes of double-bus network gas laser are from mixed process phase
Interaction, the light intensity change of single longitudinal mode is presented as that the cosine function of two phase places is poor；Phase modulation technique only brings pure phase position
Change, does not bring extra light intensity to change；Because phase-modulation frequency difference causes the frequency domain distribution interval of two kinds of harmonic waves big, it is easy to carry
Take；Data processing takes short, the high precision of acquisition；Synchronous detecting two-dimension displacement/vibration can be widely applied to contactless light
Quarter machine/circuit printing processes accurate real-time positioning.Comparatively speaking, two-dimentional accurate displacement in current Scientific Engineering and industrial circle
The mode of measurement is mostly to use at least 2 interferometers or two-frequency laser, and system complex is relatively costly, and is operated and inconvenient.
The present invention proposes to adopt palarization multiplexing phase modulating structure, by two modulates informations to be measured to different harmonic components, signal
The distribution character according to harmonic wave is processed, phase information is extracted from harmonic amplitude, relative accuracy is better than 10e-3, anti-speckle noise
Ability is strong.Meanwhile, the present invention can flexibly select in modulating frequency, therefore two optical paths that precision dynamic is adjustable, compare list
Light path self-mixed interference instrument improves more preferable motility, and application prospect is fine.
Claims (4)
1. palarization multiplexing phase modulation-type laser is from the two-dimentional interferometer of mixing, it is characterised in that include：
The double-longitudinal-mode laser of output circularly polarized light, circularly polarized light is decomposed into the polarization point of the line polarized light of two cross-polarization
Light prism, is placed on the first electro-optic phase modulator in the first light path, the first ray density wave filter and the first target to be measured,
The second electro-optic phase modulator in the second light path, the second ray density wave filter and the second target to be measured are placed on, positioned at
Common Amici prism in one light path or the second light path, and for detecting light intensity signal that common Amici prism reflects and defeated
Go out the photodetector of detected signal waveform；The modulation of first electro-optic phase modulator and the second electro-optic phase modulator
Frequency is different；The photodetector is electrically connected with signals collecting and phase calculation system, the signals collecting and phase calculation
System is used to carry out frequency analyses according to the light intensity signal of collection and phase demodulating draws measured target phase place, and then obtains in place
Move.
2. palarization multiplexing phase modulation-type laser according to claim 1 is from the two-dimentional interferometer of mixing, it is characterised in that institute
Stating signals collecting and phase calculation system includes：
Low-pass filtering amplifying circuit, is connected with photodetector, carries out signal filtering and amplifies；
Data collecting card, for gathering filter and amplification after signal realize analog digital conversion；
And computer module, for extracting collected light intensity signal in the first harmonic component of two light paths and secondary
Harmonic component, based on harmonic component phase demodulating is realized.
3. palarization multiplexing phase modulation-type laser according to claim 2 is from the two-dimentional interferometer of mixing, it is characterised in that institute
Stating computer module includes：
Band filter group unit, including four band filters, export respectively the first harmonic component I of the first light patho1With two
Order harmonic components Io2, and the first harmonic component I of the second light pathe1With second harmonic component Ie2；
Divider, for according to formula Ao/e1(t)=Io/e1/cos(ωo/eAnd A t)o/e2(t)=Io/e2/cos(2ωo/eT) count
Calculation obtains the amplitude curve of two kinds of harmonic components, wherein ωo/eFor the phase shift angular frequency of two light paths, ωo≠ωe；
Arctangent unit, for according to formulaIt is calculated the phase place of two light paths；
And, displacement computing unit, for according to formulaIt is calculated two
The measurement displacement of individual light path.
4. the palarization multiplexing phase modulation-type laser according to any one of claim 1-3 is from the measurement for mixing two-dimentional interferometer
Method, it is characterised in that comprise the steps：
(1) 5mA electric currents are stably supplied to double-longitudinal-mode laser so as to export visible red circularly polarized light, rotary laser pipe makes
Two polarization states that must be exported are located at respectively both horizontally and vertically；
(2) polarization splitting prism is adjusted so that incident illumination there are 45 ° of angles with the intermediate layer of prism, and o light is in the horizontal direction through partially
Polarization state is all the first electro-optic phase modulator of horizontal direction, and e light is in vertical direction through the second vertical electric light phase of polarization state
Position modulation；
(3) o light reaches the first target to be measured through the first optical filter, and by former road laser tube is reflected back；E light passes through the second light
Learn wave filter and reach the second target to be measured, along backtracking laser instrument；Common Amici prism in o light paths or e light paths is by light
Strong signal refracts to photodetector；
(4) the light intensity signal input signal collection of photodetector output and phase calculation system are processed, filtered amplification,
Analog digital conversion, harmonic amplitude are extracted, arctangent cp cp operation and unpacking obtain measured object phase place and displacement.
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