CN108279069B - A kind of optical phase difference demodulation method based on spiral shape interference image Feature Extraction Technology - Google Patents
A kind of optical phase difference demodulation method based on spiral shape interference image Feature Extraction Technology Download PDFInfo
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Abstract
The present invention provides a kind of optical phase difference demodulation method based on spiral shape interference image Feature Extraction Technology, and this method can demodulate the optical phase difference between two light beams.It include: to obtain orbital angular momentum light beam to interfere the spiral shape interference image to be formed with Gaussian beam；Common trait image is extracted, is analyzed for the spiral shape interference image to a series of different optical phase differences of correspondences, obtains its common trait image；Feature demodulation, spiral shape interference image is mapped to using common trait image as the two-dimensional space of base vector, finds out coordinate value of the spiral shape interference image in two-dimensional space, realizes the Data Dimensionality Reduction of spiral shape interference image；Optical phase difference calculates, and utilizes the coordinate value calculating optical phase difference in two-dimensional space.Spiral shape interference image of the invention is convenient for feature extraction, carries out dimensionality reduction by the data to spiral shape interference image, improves the efficiency of signal demodulation, it is possible to prevente effectively from light beam power fluctuation impacts optical phase difference demodulation result.
Description
Technical field
The present invention relates to Application Optics field more particularly to a kind of light based on spiral shape interference image Feature Extraction Technology
Learn phase difference demodulation method.
Background technique
As people are to the growing of information requirement, optical detective technology is due to its high-acruracy survey performance, by people
Extensive concern.Optical interdferometer is a kind of optical detector that physical quantity to be measured is obtained using the interference effect of light
Device, optical interdferometer is in many precisions such as astronomy, optics, engineering survey, oceanography, seismology, Spectrum Analysis, quantum physics
Fields of measurement is all widely used.The common signal demodulating method of optical interdferometer includes intensity demodulation and Wavelength demodulation.It compares
Compared with for, intensity demodulation method is more intuitive, and structure is simple and cost is relatively low, but intensity demodulation is easy by light source power
Influence of fluctuations and so that measurement result is caused a deviation.Wavelength demodulation is realized by the change in location of characteristic wavelength in reflection or transmission spectrum
The demodulation of transducing signal, characteristic wavelength position depends on parameter to be measured to the modulating action of sensing arrangement characteristic, and light source function
Rate fluctuation only influences spectrum absolute intensity, without influencing relative intensity distribution.This method can exclude the influence of light source power fluctuation.
But in spectral measurement, spectroanalysis instrument be it is indispensable, spectrometer volume is larger at present, and expensive.
Summary of the invention
According to technical problem set forth above, and provide that a kind of structure is simple, demodulation is high-efficient and convenient for feature extraction
Optical interdferometer optical phase difference demodulation method.The present invention mainly utilizes image feature extraction techniques, by a series of spirals
Shape interference image carries out processing and extracts common trait image, and the spiral shape that the extraction common trait image utilized analyzes needs is dry
It relates to image to be converted, spiral shape interference image is mapped to using common trait image as the two-dimensional space of base vector, utilization is low
Coordinate value calculating optical phase difference in dimension space realizes optical phase difference demodulation.
The technological means that the present invention uses is as follows:
A kind of optical phase difference demodulation method based on spiral shape interference image Feature Extraction Technology, comprising: obtain spiral
The step of the step of shape interference image and extraction spiral shape interference image feature,
The step of acquisition spiral shape interference image refers to: spiral shape interference image is by orbital angular momentum light beam and Gauss
Beam interference is formed, and has spiral-shaped interference fringe in the spiral shape interference pattern, wherein
The spiral shape interference image changes with the optical phase difference between two light beams, and the optical phase difference is
Optical phase difference between the orbital angular momentum light beam and Gaussian beam；
The step of extraction spiral shape interference image feature, refers to: extracting common trait image, feature demodulation optics
The step of phase difference calculating；
The step of described extraction common trait image is the spiral shape interference to a series of different optical phase differences of correspondences
The common trait image of image extracts；
The step of feature demodulates is that spiral shape interference image is mapped to using common trait image as base vector
Two-dimensional space finds out coordinate value of the spiral shape interference image in two-dimensional space, for indicating the feature of spiral shape interference image；
The step of optical phase difference calculates is to realize light using the coordinate value calculating optical phase difference in two-dimensional space
Learn the demodulation of phase difference.
Further, the orbital angular momentum light beam topological charge number is+1 or -1.
Further, the Gaussian beam topological charge number is 0, and the Gaussian beam radially light distribution meets high
This function.
The extraction common trait image the following steps are included:
S401: spiral shape interference image matrix is rearranged as column vector, the spiral shape interference image matrix
Having a size of N × N, and form can be expressed as:
Wherein, in matrix each element representation correspondence image pixel gray value,
The column vector is having a size of N2× 1, and form can be expressed as:
ΨmWhat is indicated is the corresponding dimensional vector of a pair interference image；
S402: the spiral shape interference image that M width corresponds to different optical phase differences is rearranged into M by the method in S401
An a dimensional vector, is expressed as Ψ1,Ψ2,…ΨM, it is calculated by the following formula the average vector of a M dimensional vectors:
Data matrix Φ is calculated by following formula:
S403: the covariance matrix C=Φ of data matrix described in S402 is calculatedTΦ；
S404: the characteristic value of covariance matrix and the feature vector of covariance matrix described in S403 are calculated；
S405: two maximum associations are chosen in the characteristic value of the covariance matrix and the feature vector of covariance matrix
The feature vector V of the characteristic value of variance matrix and its corresponding two covariance matrixes1,V2；
S406: by the feature vector V of two covariance matrixes described in S4051,V2And data square described in S402
Battle array Φ calculates common trait image U by following formula1And U2:
[U1 U2]=Φ × [V1 V2]。
Further, the characteristic solution tune the following steps are included:
S501: it will need to carry out a secondary spiral shape interference image of optical phase difference demodulation according to the method in S401 again
It is arranged as column vector, and described rearranging is expressed as Ψ as column vectori, described needs to carry out optical phase difference
The secondary spiral shape interference image of the one of demodulation can be the spiral shape interference pattern that M width described in S402 corresponds to different optical phase differences
A width spiral shape interference image as among, is also possible to the other width spiral shapes of same size obtained under the same conditions
The size of interference image, spiral shape interference image matrix is N × N, is rearranged as column vector ΨiHaving a size of N2×1；
S502: by the ΨiAverage vector described in S402 is subtracted, and obtained result is expressed as Φi, therefore
Described
S503: the ΦiIt is mapped to common trait image U1And U2For the two-dimensional space of base vector, pass through following public affairs
Formula calculates ΦiCoordinate value Ω in two-dimensional spacei, Ωi=[ω1 ω2]T:
Further, the optical phase difference calculate the following steps are included:
S601: by following formula by the coordinate value Ω in S503iCoordinate value [the ω being converted into cylindrical coordinater ωθ]:
Wherein, ωrFor coordinate value ΩiRadial coordinate value, ωθFor coordinate value ΩiAngular coordinate value.
S602: the optical phase difference φ being calculated by the following formula between orbital angular momentum light beam and Gaussian beam:
φ=pi/2-ωθ。
The invention has the following advantages that
1, interfere present invention introduces orbital angular momentum light beam and by it with Gaussian beam, obtain the apparent spiral of feature
Shape interference image is convenient for feature extraction.
2, the Feature Extraction Technology that uses of the present invention can by the feature 2-d spatial coordinate of spiral shape interference image into
Row indicates, carries out dimensionality reduction by the data to spiral shape interference image, improves the efficiency of signal demodulation.
3, the present invention is it is possible to prevente effectively from light beam power fluctuation impacts optical phase difference demodulation result.
The present invention can be widely popularized in optical field based on the above reasons.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to do simply to introduce, it should be apparent that, the accompanying drawings in the following description is this hair
Bright some embodiments for those of ordinary skill in the art without any creative labor, can be with
It obtains other drawings based on these drawings.
Fig. 1 is Gaussian beam (a) of the present invention, orbital angular momentum light beam (b) and spiral shape interference image (c).
Fig. 2 is that spiral shape interference pattern of the present invention becomes with the optical phase difference between orbital angular momentum light beam and Gaussian beam
Change, optical phase difference is respectively 0 degree (a), 45 degree (b), 90 degree (c), 135 degree (d), 180 degree (e), 225 degree (f), 270 degree
(g), 315 degree (h) and 360 degree (a).
Fig. 3 is two that the present invention is extracted by the spiral shape interference image of (a) (b) 2 secondary corresponding different optical phase differences
Width common trait image.
Fig. 4 is that the optical phase difference φ between the orbital angular momentum light beam and Gaussian beam is 0 degree to 360 degree Shi Bianhua
When, corresponding spiral shape interference image is mapped in coordinate value [ω in two-dimensional space1,ω2] change in location schematic diagram.
Fig. 5 is the angular coordinate value ω that spiral shape interference image is mapped in coordinate value in two-dimensional spaceθWith optical phase difference
Correspondence diagram between φ.
Specific embodiment
In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention
In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is
A part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, those of ordinary skill in the art
Every other embodiment obtained without making creative work, shall fall within the protection scope of the present invention.
Embodiment 1
As shown in Figure 1, spiral shape interference image (Fig. 1 c) is by Gaussian beam (Fig. 1 a) and orbital angular momentum light beam (Fig. 1 b)
Interference is formed.The size of spiral shape interference image is 500 × 500 in the present embodiment, in the spiral shape interference image (Fig. 1 c)
In have spiral-shaped striped.
Orbital angular momentum light beam topological charge number is+1.(Fig. 1 b).
Gaussian beam topological charge number is 0, and the Gaussian beam radially light distribution meets Gaussian function (figure
1a)。
As shown in Fig. 2, 32 width are shared for extracting the spiral shape interference image of common trait image in the present embodiment, it is corresponding
Optical phase difference variation range is 0 degree to 360 degree, and the interval of optical phase difference variation is 11.25 degree, is given in Fig. 2 (a-h)
8 width spiral shape interference images in 32 width spiral shape interference images, the size of all spiral shape interference images are 500 × 500.
Extract common trait image specifically includes the following steps:
S401: the spiral shape interference image matrix is rearranged as column vector, the spiral shape interference image
The size of matrix is 500 × 500, and can be expressed as form:
Wherein N=500
The column vector can be expressed as form having a size of 250000 × 1, wherein N=500:
S402: the spiral shape interference image that 32 width correspond to different optical phase differences is rearranged by the method in S401
A M dimensional vectors, are expressed as Ψ1,Ψ2,…Ψ32, calculate the average vector of this 32 dimensional vectors
Then, data matrix Φ is calculated by following formula:
S403: the covariance matrix C=Φ of data matrix described in S402 is calculatedTΦ。
S404: the characteristic value of covariance matrix and the feature vector of covariance matrix described in S403 are calculated.
S405: two maximum associations are taken out in the characteristic value of the covariance matrix and the feature vector of covariance matrix
The feature vector V of the characteristic value of variance matrix and its corresponding two covariance matrixes1,V2。
S406: the feature vector V of two covariance matrixes described in S4051,V2And data square described in S402
Battle array Φ calculates common trait image U1And U2, calculation formula is as follows:
[U1 U2]=Φ × [V1 V2]
As shown in figure 3, by U1And U2The two dimension of 500 × 500 sizes is transformed into according to the alignment processes opposite with step S401
Matrix can more clearly from see the distribution characteristics (Fig. 3 a, Fig. 3 b) of common trait image.
Feature demodulation specifically includes the following steps:
S501: it will need to carry out a secondary spiral shape interference image of optical phase difference demodulation according to the method in S401 again
It is arranged as column vector, and described rearranging is expressed as Ψ as column vectori, described needs to carry out optical phase difference
The secondary spiral shape interference image of the one of demodulation can be the spiral shape interference pattern that M width described in S402 corresponds to different optical phase differences
A width spiral shape interference image as among, is also possible to the other width spiral shapes of same size obtained under the same conditions
Interference image, the size of the spiral shape interference image matrix are 500 × 500, are rearranged as column vector ΨiHaving a size of
250000×1.
S502: by the ΨiSubtract average vector described in S402And obtained result is expressed as Φi, because
Described in this
S503: by the ΦiIt is mapped to common trait image U1And U2For the two-dimensional space of base vector, ΦiIn two dimension
Coordinate value in space is Ωi=[ω1 ω2]T, it is as follows which obtains calculation formula:
When optical phase difference φ between orbital angular momentum light beam and Gaussian beam changes when being 0 degree to 360 degree, corresponding spiral shell
Rotation shape interference image is mapped in coordinate value [ω in two-dimensional space1,ω2] change in location as shown in figure 4, the coordinate value
[ω1,ω2] be distributed in using 2-d spatial coordinate origin as on the circumference in the center of circle, the coordinate value [ω1,ω2] as φ is from 0
Variation is along rotation counterclockwise when spending to 360 degree.
Optical phase difference calculate specifically includes the following steps:
S601: by coordinate value Ω described in S503iCoordinate value [the ω being converted into cylindrical coordinater ωθ], wherein ωr
For coordinate value ΩiRadial coordinate value, ωθFor coordinate value ΩiAngular coordinate value, calculated using following formula:
S602: the optical phase difference φ between orbital angular momentum light beam and Gaussian beam can use coordinate value ΩiAngle
To coordinate value ωθIt is calculated:
φ=pi/2-ωθ
When changing when as shown in figure 5, be φ being 0 degree to 360 degree using optical phase difference, every 5 degree of one width spirals of acquisition
Shape interference image, and calculate corresponding coordinate value ΩiAngular coordinate value ωθ, two-dimentional sky is mapped in using spiral shape interference image
Between middle coordinate value angular coordinate value ωθCorresponding relationship (Fig. 5) between optical phase difference φ, meets the optics phase in S602
The calculation formula of potential difference φ can prove the validity of this method in the present embodiment.
Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention., rather than its limitations；To the greatest extent
Pipe present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that: its according to
So be possible to modify the technical solutions described in the foregoing embodiments, or to some or all of the technical features into
Row equivalent replacement；And these are modified or replaceed, various embodiments of the present invention technology that it does not separate the essence of the corresponding technical solution
The range of scheme.
Claims (6)
1. a kind of optical phase difference demodulation method based on spiral shape interference image Feature Extraction Technology characterized by comprising
The step of the step of obtaining spiral shape interference image and extraction spiral shape interference image feature,
The step of acquisition spiral shape interference image refers to: spiral shape interference image is by orbital angular momentum light beam and Gaussian beam
Interference is formed, and has spiral-shaped interference fringe in the spiral shape interference pattern, wherein
The spiral shape interference image changes with the optical phase difference between two light beams, and the optical phase difference is described
Optical phase difference between orbital angular momentum light beam and Gaussian beam；
The step of extraction spiral shape interference image feature, refers to: extracting common trait image, feature demodulation optical phase
The step of difference calculates；
The step of described extraction common trait image is the spiral shape interference image to a series of different optical phase differences of correspondences
Common trait image extract；
The step of feature demodulates is mapped to spiral shape interference image using common trait image as the two dimension of base vector
Space finds out coordinate value of the spiral shape interference image in two-dimensional space, for indicating the feature of spiral shape interference image；
The step of optical phase difference calculates is to utilize the coordinate value calculating optical phase difference in two-dimensional space.
2. the optical phase difference demodulation method of spiral shape interference image Feature Extraction Technology according to claim 1, special
Sign is that the orbital angular momentum light beam topological charge number is+1 or -1.
3. the optical phase difference demodulation method of spiral shape interference image Feature Extraction Technology according to claim 1, special
Sign is that the Gaussian beam topological charge number is 0, and radially light distribution meets Gaussian function to the Gaussian beam.
4. the optical phase difference demodulation method of spiral shape interference image Feature Extraction Technology according to claim 1, special
Sign is, the extraction common trait image the following steps are included:
S401: spiral shape interference image matrix is rearranged as column vector, the size of the spiral shape interference image matrix
For N × N, and form can be expressed as:
Wherein, in matrix each element representation correspondence image pixel gray value,
The column vector is having a size of N2× 1, and form can be expressed as:
ΨmWhat is indicated is the corresponding dimensional vector of a pair interference image；
S402: the spiral shape interference image that M width corresponds to different optical phase differences is rearranged into M one by the method in S401
Dimensional vector is expressed as Ψ1,Ψ2,…ΨM, it is calculated by the following formula the average vector of a M dimensional vectors
Data matrix Φ is calculated by following formula:
S403: the covariance matrix C:C=Φ of data matrix described in S402 is calculatedTΦ；
S404: the characteristic value of covariance matrix and the feature vector of covariance matrix described in S403 are calculated；
S405: two maximum covariances are chosen in the characteristic value of the covariance matrix and the feature vector of covariance matrix
The feature vector V of the characteristic value of matrix and its corresponding two covariance matrixes1,V2；
S406: by the feature vector V of two covariance matrixes described in S4051,V2And data matrix Φ described in S402
Common trait image U is calculated by following formula1And U2:
[U1 U2]=Φ × [V1 V2]。
5. the optical phase difference demodulation method of spiral shape interference image Feature Extraction Technology according to claim 4, special
Sign is, the characteristic solution tune the following steps are included:
S501: the secondary spiral shape interference image for needing to carry out optical phase difference demodulation is rearranged according to the method in S401
Ψ is expressed as column vector as column vector, and by described rearrangingi, described needs to carry out optical phase difference demodulation
A secondary spiral shape interference image can be M width described in S402 correspond to different optical phase differences spiral shape interference image it
In a width spiral shape interference image, be also possible to same size obtain under the same conditions an other width spiral shapes interference
The size of image, spiral shape interference image matrix is N × N, is rearranged as column vector ΨiHaving a size of N2×1；
S502: by the ΨiAverage vector described in S402 is subtracted, and obtained result is expressed as Φi, described
S503: the ΦiIt is mapped to common trait image U1And U2For the two-dimensional space of base vector, pass through following formula meter
Calculate ΦiCoordinate value Ω in two-dimensional spacei, Ωi=[ω1ω2]T:
6. the optical phase difference demodulation method of spiral shape interference image Feature Extraction Technology according to claim 5, special
Sign is, the optical phase difference calculate the following steps are included:
S601: by following formula by the coordinate value Ω in S503iCoordinate value [the ω being converted into cylindrical coordinater ωθ]:
Wherein, ωrFor coordinate value ΩiRadial coordinate value, ωθFor coordinate value ΩiAngular coordinate value.
S602: the optical phase difference φ being calculated by the following formula between orbital angular momentum light beam and Gaussian beam:
φ=pi/2-ωθ。
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