CN216483548U - Non-interference phase detection device based on embedded data - Google Patents

Abstract

The utility model belongs to the technical field of holographic data storage, and discloses a non-interference phase detection device based on embedded data, which comprises an object plane, an optical system, a lens, a Fourier transform plane and an iterative computation processor which are sequentially arranged; the object plane is used for uploading original phase data; the optical system is used for recording original phase data on the holographic material and reading information to obtain phase data to be detected; the lens is used for generating the frequency spectrum intensity distribution of the Fourier transform of the phase data to be detected; the Fourier transform surface is used for receiving and obtaining the frequency spectrum intensity distribution of the Fourier transform of the phase data to be detected; the iterative computation processor is used for performing iterative computation on the frequency spectrum intensity distribution of the Fourier transform of the phase data to be detected to obtain detected phase data; the method can shorten the iteration times, improve the phase detection precision, adjust the proportion of embedded data and control the iteration times; the method can ensure that iteration is quickly converged to an optimal solution, shorten the required iteration times and improve the data conversion speed.

Description

Non-interference phase detection device based on embedded data

Technical Field

The utility model belongs to the technical field of holographic data storage, and particularly relates to a non-interference phase detection device based on embedded data.

Background

The holographic data storage technology is a very potential mass data long-term storage technology, and has dimensionality improvement compared with the existing storage mode because a three-dimensional storage information recording mode and a two-dimensional data page data transmission mode are adopted. However, the existing holographic data storage recording density is far from the theoretical value because it uses only amplitude encoding, ignoring other characteristics of the light, such as phase. In fact, compared with amplitude coding, the phase coding and the amplitude coding are greatly improved in coding rate and signal to noise ratio, and the data recording density and the data conversion speed can be obviously improved.

But the phase information cannot be directly acquired by the photodetector, which becomes a key factor limiting the development of the phase-type holographic data storage technology. Detection of phase information typically requires iterative methods of computation using interferometry or non-interferometry. However, holographic storage has high requirements on stability, and the interference method is not suitable for practical application due to large environmental influence and insufficient stability. Although the traditional non-interference calculation iteration method can stably acquire images and perform iteration phase detection, hundreds of iterations are often needed to obtain acceptable phase detection precision, so that the data conversion speed is greatly reduced.

SUMMERY OF THE UTILITY MODEL

The utility model provides a non-interference phase detection device based on embedded data, which provides a powerful constraint condition for iterative computation by using the embedded data, shortens the iteration times which originally need hundreds of times by about two orders of magnitude, improves the phase detection precision, and can control the iteration times by adjusting the proportion of the embedded data so as to meet the requirements of different applications.

The technical scheme of the utility model is as follows:

the utility model relates to a non-interference phase detection device based on embedded data, which comprises an object plane, an optical system, a lens, a Fourier transform plane and an iterative computation processor which are sequentially arranged; the object plane is used for uploading the original phase data; the optical system is used for recording the original phase data on a holographic material and reading information to obtain the phase data to be detected; the lens is used for generating the frequency spectrum intensity distribution of the Fourier transform of the phase data to be detected; the Fourier transform surface is used for receiving and obtaining the frequency spectrum intensity distribution of the phase data to be detected through Fourier transform; the iterative computation processor is used for performing iterative computation on the frequency spectrum intensity distribution subjected to Fourier transform on the phase data to be detected so as to obtain the detected phase data.

Preferably, the object plane is a phase-modulated spatial light modulator.

Preferably, the optical system includes a first objective lens, a holographic material, and a second objective lens arranged in this order along the light propagation direction.

Preferably, the lens is a fourier transform lens.

Preferably, the fourier transform plane is a photodetector.

Preferably, the phase data to be detected and the original phase data are in a 4f system. I.e. the distance between the object plane and the fourier transform plane is four times the focal length of the lens.

Preferably, a laser, a pinhole filter, a collimating lens, a shutter, a holographic diaphragm set, a first relay lens, a second relay lens, a first unpolarized stereo beam splitter and a half-wave plate are sequentially arranged in front of the modulation spatial light modulator along the light beam propagation direction, and the half-wave plate is arranged in the transmission light propagation direction of the first unpolarized stereo beam splitter.

Preferably, the first objective lens is disposed in a reflected light propagation direction of the first non-polarizing solid beam splitter.

Preferably, the first relay lens and the second relay lens constitute a 4f system.

Preferably, the phase modulating spatial light modulator is a reflective spatial light modulator.

Preferably, the first objective lens and the second objective lens are lenses with the same parameters.

Preferably, the holographic diaphragm group is a first coaxial holographic diaphragm group, the center of the first coaxial holographic diaphragm group is an information light portion, the periphery of the information light portion is a reference light portion, and the information light portion and the reference light portion form a coaxial structure.

Preferably, a second coaxial holographic diaphragm group is arranged between the second objective lens and the fourier transform lens, an information light portion is arranged at the center of the second coaxial holographic diaphragm group, a reference light portion is arranged at the periphery of the information light portion, and the information light portion and the reference light portion form a coaxial structure.

Preferably, the shape of the second coaxial holographic diaphragm group is the same as that of the first coaxial holographic diaphragm group.

Preferably, the light intensity transmittance of the reference light portion of the second coaxial holographic diaphragm group is smaller than that of the reference light portion of the first coaxial holographic diaphragm group.

Preferably, the reference light part of the second coaxial holographic diaphragm group is plated with a reference light intensity transmittance attenuation film layer.

Preferably, the holographic diaphragm group is an off-axis holographic diaphragm group, and an information light transmission part is arranged on the off-axis holographic diaphragm group; a second non-polarized stereo beam splitter is arranged between the shutter and the off-axis holographic diaphragm group; the off-axis holographic diaphragm group is arranged on a transmission light path of the second non-polarization stereo beam splitter; the first plane reflector is arranged on a reflection light path of the second non-polarized three-dimensional beam splitter, the second plane reflector is arranged on a reflection light path of the first plane reflector, and the holographic material is arranged on a reflection light path of the second plane reflector.

The utility model has the following beneficial effects:

the non-interference phase detection method and the detection device based on the embedded data, disclosed by the utility model, have the advantages that the embedded data is utilized to provide a powerful constraint condition for iterative computation, so that the iteration frequency which originally needs hundreds of times is shortened by about two orders of magnitude, the phase detection precision is improved, and the iteration frequency can be controlled by adjusting the proportion of the embedded data so as to meet the requirements of different applications; the embedded data can provide strong constraint force in the iterative process of phase detection, so that the iteration is ensured to be quickly converged to the optimal solution, the required iteration times are greatly shortened, and the data conversion speed is improved.

Drawings

FIG. 1 is a schematic diagram of a non-interference phase detection method and a detection device based on embedded data according to the present invention.

FIG. 2 is a flow chart of a non-interference phase detection method based on embedded data according to the present invention.

FIG. 3 is a graph of Fourier face intensity error rate versus iteration number for different ratios of embedded data.

FIG. 4 is a graph comparing a regular location distribution and a random location distribution of embedded data. In fig. 4, the left side is a regular position distribution and the right side is a random position distribution.

Fig. 5 is a graph comparing the distribution of regular phase encoding and the distribution of random phase encoding for embedded data. In fig. 5, the left side shows a regular phase code distribution and the right side shows a random phase code distribution.

Fig. 6 is a graph comparing the regular and random spectral distributions of fig. 5 on the fourier plane. In fig. 6, the left side shows a regular spectral distribution and the right side shows a random spectral distribution.

FIG. 7 is a diagram of embedded data and unknown phase data having different spatial frequencies.

FIG. 8 is a diagram illustrating the difference between the light intensity of the embedded data unit and the unknown phase data unit.

Fig. 9 is a graph of light intensity observed in fig. 8.

FIG. 10 is a schematic diagram of an unknown phase data location not adjacent to an embedded data location. The unknown phase data position is on the left side of fig. 10 and the embedded data position is on the right side.

Fig. 11 is a schematic structural diagram of a non-interference phase detection device based on embedded data, which is a coaxial holographic storage non-interference phase detection system.

FIG. 12 is a schematic structural diagram of a first holographic diaphragm set of the coaxial holographic storage non-interference phase detection system.

FIG. 13 is a schematic structural diagram of a second holographic diaphragm set of the coaxial holographic storage non-interference phase detection system.

FIG. 14 is a schematic structural diagram of an off-axis holographic storage non-interference phase detection system as a non-interference phase detection device based on embedded data.

FIG. 15 is a schematic diagram of an off-axis holographic diaphragm set of an off-axis holographic storage non-interference phase detection system.

In the figure, 101 is an object plane, 102 is a lens, 103 is a fourier transform plane, 104 is an observation line, 105 is embedded data, 106 is unknown phase data, 107 is original phase data, 108 is spectral intensity distribution of fourier transform of phase data to be detected, 109 is detected phase data, 110 is an iterative calculation processor, 1 is a laser, 2 is a pinhole filter, 3 is a collimating lens, 4 is a shutter, 5 is a holographic diaphragm set, 6 is a first relay lens, 7 is a second relay lens, 8 is a first non-polarizing stereo beam splitter, 9 is a half wave plate, 10 is a phase modulation spatial light modulator, 11 is a first objective lens, 12 is a holographic material, 13 is a second objective lens, 14 is a fourier transform lens, 15 is a photodetector, 161 is a second coaxial holographic diaphragm set, 162 is a second non-polarizing stereo beam splitter, 17 is a first plane mirror, and 18 is a second plane mirror.

Detailed Description

The following description of the embodiments of the present invention refers to the accompanying drawings and examples:

example 1:

as shown in fig. 1, the non-interference phase detection apparatus based on embedded data, for implementing the non-interference phase detection method based on embedded data, includes an object plane 101, an optical system, a lens 102, a fourier transform plane 103 and an iterative computation processor 110, which are sequentially arranged; the object plane 101 is used for uploading the raw phase data 107; the optical system is used for recording the original phase data 107 on the holographic material 12 and reading information to obtain the phase data to be detected; the lens 102 is used for generating a spectral intensity distribution 108 of the Fourier transform of the phase data to be detected; the fourier transform plane 103 is configured to receive the spectrum intensity distribution obtained by fourier transform of the phase data to be detected; the iterative computation processor 110 is configured to perform iterative computation on the spectral intensity distribution of the fourier transform of the phase data to be detected to obtain the detected phase data 109. The iterative computation processor 110 may be a computer.

Example 2:

as shown in fig. 11 and 14, the non-interference phase detection device based on embedded data according to embodiment 1 may be more specifically, the object plane 101 is a phase modulation spatial light modulator 10. The optical system comprises a first objective lens 11, a holographic material 12 and a second objective lens 13 arranged in sequence along the direction of propagation of the light. Lens 102 is a fourier transform lens 14. The fourier transform plane 103 is the photodetector 15.

Further, the phase data to be detected and the original phase data 107 are in a 4f system. I.e. the distance between the object plane 101 and the fourier transform plane 103 is four times the focal length of the lens 102.

As shown in fig. 11 and 14, further, the laser 1, the pinhole filter 2, the collimator lens 3, the shutter 4, the holographic diaphragm group 5, the first relay lens 6, the second relay lens 7, the first non-polarizing stereo beam splitter 8, and the half wave plate 9 are sequentially arranged in front of the modulation spatial light modulator 10 along the light beam propagation direction, and the half wave plate 9 is arranged in the transmission light propagation direction of the first non-polarizing stereo beam splitter 8.

Further, as shown in fig. 11 and 14, the first objective lens 11 is disposed in the reflected light traveling direction of the first non-polarizing solid beam splitter 8.

Further, the first relay lens 6 and the second relay lens 7 constitute a 4f system.

As shown in fig. 11 and 14, the phase modulation spatial light modulator 10 is further a reflective spatial light modulator.

Further, the first objective lens 11 and the second objective lens 13 are lenses having the same parameters.

Example 3:

as shown in fig. 11 and 12, the embedded data-based non-interference phase detection apparatus according to embodiment 2 may be more specifically configured as a coaxial holographic storage non-interference phase detection system, where the holographic aperture group 5 is a first coaxial holographic aperture group, a center of the first coaxial holographic aperture group is an information light portion, a periphery of the information light portion is a reference light portion, and the information light portion and the reference light portion form a coaxial structure.

As shown in fig. 13, further, a second coaxial holographic aperture group 161 is disposed between the second objective lens 13 and the fourier transform lens 14, a center of the second coaxial holographic aperture group 161 is an information light portion, a periphery of the information light portion is a reference light portion, and the information light portion and the reference light portion form a coaxial structure.

As shown in fig. 12 and 13, further, the second coaxial holographic aperture set 161 has the same shape as the first coaxial holographic aperture set.

As shown in fig. 13, further, the light intensity transmittance of the reference light portion of the second coaxial holographic diaphragm set 161 is smaller than that of the reference light portion of the first coaxial holographic diaphragm set.

As shown in fig. 13, further, the reference light portion of the second coaxial holographic aperture set 161 is coated with a reference light intensity transmittance attenuation film layer.

As shown in fig. 11 to 13, the non-interference phase detection device based on embedded data and the coaxial holographic storage non-interference phase detection system of the present embodiment may be configured such that a laser 1 emits a laser beam, for example, a green laser beam with a wavelength of 532nm, which is converted into a parallel beam with good beam quality through a pinhole filter 2 and a collimating lens 3, and then passes through a shutter 4 and a holographic diaphragm 5 set, where the holographic diaphragm 5 is a first coaxial holographic diaphragm set, and a circular beam is converted into a beam with a shape in the first coaxial holographic diaphragm set. The first relay lens 6 and the second relay lens 7 form a 4f system, that is, the focal lengths of the first relay lens 6 and the second relay lens 7 are equal, and the distance between the first relay lens 6 and the second relay lens 7 is four times of the focal length, so that the first coaxial holographic diaphragm group and the phase modulation spatial light modulator 10 have the same surface position, that is, the surfaces of the first coaxial holographic diaphragm group and the phase modulation spatial light modulator 10 are both the object surface 101. The light beam continuously passes through the first non-polarization stereo beam splitter 8 and the half wave plate 9, the first non-polarization stereo beam splitter 8 is used for reflecting the light reflected by the phase modulation spatial light modulator 10 to the other direction, and the half wave plate 9 is used for adjusting the polarization state of the light beam, so that the light beam has accurate phase information after being incident on the phase modulation spatial light modulator 10. The phase modulation spatial light modulator 10 is used for uploading a designed phase diagram, and the phase diagram information is carried after the phase modulation spatial light modulator 10 is irradiated by a light beam. Since the phase modulating spatial light modulator 10 is reflective, the light is returned and reflected in the other direction when passing through the first non-polarizing solid beam splitter 8 again. The first objective lens 11 and the second objective lens 13 are a pair of objective lenses of the same parameters for recording and reproducing object plane information. The holographic material 12 is responsive to the light field and produces a refractive index difference by a change in the material structure, and phase pattern information carried on the phase modulation spatial light modulator 10 is recorded on the holographic material 12. The second coaxial holographic diaphragm set 161 has the same diaphragm shape as the first coaxial holographic diaphragm set, except that the second coaxial holographic diaphragm set 161 is partially coated with a film at the reference light to properly attenuate the energy of the reference light. The fourier transform lens 14 performs optical fourier transform on the image after the second coaxial hologram aperture group 161, and the spectral intensity after the transform is received by the photodetector 15.

As shown in fig. 12 and 13, the centers of the first coaxial holographic aperture group and the second coaxial holographic aperture group 161 are information light portions, and the outer circles are reference light portions. The information light portion may be square, but is not limited to square, and the reference light portion may be annular, but is not limited to annular, for example, the reference light portion may be circular, but is not limited to circular. And the reference light of the second coaxial holographic diaphragm set 161 is partially coated to reduce the light intensity transmittance of the reference light.

Example 4:

as shown in fig. 14 and 15, the non-interference phase detection device based on embedded data according to embodiment 3 may be more specifically configured to form an off-axis holographic storage non-interference phase detection system, where the holographic diaphragm set 5 is an off-axis holographic diaphragm set, and the off-axis holographic diaphragm set is provided with an information light transmission part; a second non-polarized stereo beam splitter 162 is arranged between the shutter 4 and the off-axis holographic diaphragm group; the off-axis holographic diaphragm group is arranged on a transmission light path of the second non-polarization stereo beam splitter 162; the first plane mirror 17 is disposed on the reflection light path of the second non-polarization stereo beam splitter 162, the second plane mirror 18 is disposed on the reflection light path of the first plane mirror 17, and the holographic material 12 is disposed on the reflection light path of the second plane mirror 18.

In the non-interference phase detection device based on embedded data of the present embodiment, the off-axis holographic storage non-interference phase detection system may be as shown in fig. 14 and fig. 15, a laser 1 emits laser light, for example, green laser light with a wavelength of 532nm, the laser light passes through a pinhole filter 2 and a collimating lens 3 to become parallel light with good beam quality, passes through a shutter 4, passes through a holographic diaphragm group 5 serving as an off-axis holographic diaphragm group, and then a circular beam becomes a beam in a shape in the holographic diaphragm group 5. The first relay lens 6 and the second relay lens 7 form a 4f system, that is, the focal lengths of the first relay lens 6 and the second relay lens 7 are equal, and the distance between the first relay lens 6 and the second relay lens 7 is four times of the focal length, so that the first coaxial holographic diaphragm group and the phase modulation spatial light modulator 10 have the same surface position, that is, the surfaces of the first coaxial holographic diaphragm group and the phase modulation spatial light modulator 10 are both the object surface 101. The light beam continues to pass through the first non-polarization stereo beam splitter 8 and the half wave plate 9, and the first non-polarization stereo beam splitter 8 is used for reflecting the light reflected by the phase modulation spatial light modulator 10 to the other direction; the half-wave plate 9 is used for adjusting the polarization state of the light beam, so that the light beam is provided with accurate phase information after being incident on the phase modulation spatial light modulator 10. The phase modulation spatial light modulator 10 is used for uploading a designed phase diagram, and a light beam irradiates the phase modulation spatial light modulator 10 to carry phase diagram information; since the phase modulating spatial light modulator 10 is reflective, the light is returned and reflected in the other direction when passing through the first non-polarizing solid beam splitter 8 again. The first objective lens 11 and the second objective lens 13 are a pair of objective lenses of the same parameters for recording and reproducing object plane information. The holographic material 12 responds to the light field and creates a refractive index difference through a change in the material structure to record the phase pattern information carried on the phase modulated spatial light modulator 10. In the off-axis holographic storage non-interference phase detection system, when the holographic material 12 records information, a beam of reference light is required to interfere with the information light of the phase modulation spatial light modulator 10, so that the reference light comes from the light beam passing through the second non-polarizing stereo beam splitter 162 and the plane mirrors of the first plane mirror 17 and the second plane mirror 18 and irradiates the holographic material 12; the fourier transform lens 14 optically fourier-transforms the reconstructed light image after the second objective lens 13, and the spectral intensity after the transformation is received by the photodetector 15.

As shown in fig. 15, the center of the hologram diaphragm group 5 as the off-axis hologram diaphragm group is an information light transmitting portion, which may be a square, but is not limited to a square.

Referring to fig. 1 and 2, the method for detecting the non-interference phase detecting device based on the embedded data may include the following steps:

in the encoding stage, the embedded data 105 is encoded into the raw phase data 107 together with the unknown phase data;

recording the original phase data 107 into the holographic material 12, and obtaining phase data to be detected after information reading;

and performing iterative calculation on the spectral intensity distribution 108 subjected to Fourier transform on the phase data to be detected to obtain detected phase data 109.

Referring to fig. 1 and fig. 2, in the method for detecting a non-interference phase based on embedded data according to embodiment 1, further, when the embedded data 105 and the unknown phase data are encoded into the original phase data 107 together, a preset ratio of the embedded data 105 and the unknown phase data are encoded into the original phase data 107 together.

Further, when the original phase data 107 is recorded into the hologram material, the original phase data 107 is recorded into the hologram material through an optical system.

Further, when the original phase data 107 is recorded in the holographic material 12 through the optical system, the original phase data 107 is uploaded through the phase modulation spatial light modulator 10, and then the original phase data 107 is recorded in the holographic material 12 through the optical system.

Further, when the detected phase data is obtained by performing iterative computation on the frequency spectrum intensity distribution subjected to fourier transform on the phase data to be detected, the detected phase data 109 is obtained by performing iterative computation on the frequency spectrum intensity distribution 108 subjected to fourier transform on the phase data to be detected after the phase data to be detected passes through the lens 102.

Further, after the phase data to be detected passes through the lens 102, the spectral intensity distribution of the phase data to be detected after fourier transform is subjected to iterative computation to obtain the detected phase data 109, and the spectral intensity distribution of the fourier transform is obtained by the photodetector 15.

Further, the proportion of the embedded data 105 to the raw phase data 107 is adjusted.

Further, when the proportion of the embedded data 105 in the original phase data 107 is adjusted, the adjustment is performed according to the requirements on parameters such as data conversion rate, coding rate and error rate. The higher the embedded data 105 occupancy, the higher the phase retrieval accuracy and the fewer iterations are required.

Further, the arrangement of the embedded data 105 may be a regular position arrangement or a random position arrangement.

Further, the phase encoding of the embedded data 105 is chosen to be a regular phase distribution or a random phase distribution. The random phase distribution can result in an increased spectral aliasing effect of the embedded data 105 with the unknown phase data 106.

Further, the phase encoding value of the embedded data 105 is selected to be the same or different from the phase encoding value of the unknown phase data.

Further, the spatial frequency of the embedded data 105 is selected to be the same or different than the spatial frequency of the unknown phase data.

Further, the light intensity of the embedded data 105 unit constituted by the embedded data 105 is selected to be the same as or different from the light intensity of the unknown phase data unit.

Further, the location of the embedded data 105 and the location of the unknown phase data are selected to be adjacent or non-adjacent.

Wherein the iterative calculation step can be:

the method comprises the steps of firstly, giving a random initial guess phase matrix to phase data to be detected, and then updating the initial guess phase matrix by using embedded data to obtain an updated phase matrix.

And secondly, calculating Fourier transform spectrum distribution of the updated phase matrix by utilizing Fourier transform, and obtaining a complex amplitude distribution (comprising an amplitude part and a phase part) on a Fourier plane, wherein the amplitude is replaced by the square root of the spectrum intensity distribution of the Fourier transform of the phase data to be measured, and the phase is kept unchanged to form an updated complex amplitude distribution. Calculating the intensity distribution of the updated complex amplitude distribution, comparing and judging the intensity distribution with the frequency spectrum intensity distribution 108 of the Fourier transform of the phase data to be detected, if the difference ratio of the two is smaller than a set threshold value, considering the updated phase matrix as the phase data to be detected, and ending the iteration; and if the difference ratio of the two is larger than or equal to the set threshold, continuing to perform the iterative calculation of the next step.

And thirdly, performing inverse Fourier transform calculation on the updated complex amplitude distribution to obtain a complex amplitude distribution on the object plane, wherein the amplitude is updated according to the original input amplitude distribution, the phase is updated by embedded data, namely, the updated phase matrix is generated again, and the second step is continued until the iteration is finished.

Specifically, as shown in fig. 2, at the encoding stage, the designed embedded data 105 with a certain proportion and the unknown phase data are encoded into the original phase data 107 together; the original phase data 107 is uploaded as the object plane 101 by the spatial light modulator 10, recorded in the hologram material 12 via an optical system, and after information is read, phase data to be detected is obtained. An optical system for recording materials and reading information is omitted in the model of fig. 2, the read information is phase data to be detected, the phase data to be detected and the original phase data 107 are in a 4f system, that is, the distance between an object plane 101 where the phase data to be detected is located and a fourier transform plane 103 where the original phase data 107 is located is four times the focal length of the lens 102, the phase data to be detected and the original phase data 107 are the same as the object plane 101, and the only difference is that the phase data to be detected has noise caused by material reading; after the phase data to be detected passes through the lens 102, the spectrum intensity distribution of Fourier transform is obtained by the photoelectric detector 15; the detected phase data 109 is obtained through iterative calculation. The intensity distribution of the fourier spectrum 108 after each iteration is different from the intensity of the fourier plane spectrum correspondingly photographed by the original phase data 107, the difference gradually decreases with the increase of the number of iterations, and when the difference is smaller than a preset value or a preset range, the condition of stopping the iteration can be considered to be satisfied, and the phase distribution after the iteration is considered to be the phase data after the detection. In the process, the intensity difference of the Fourier surface is a judgment standard and can be characterized by the intensity error rate of the Fourier surface.

Taking the fourth-order phase encoding 0, pi/2, pi, 3 pi/2 as an example, under different embedded data 105 proportions, a curve of the intensity error rate of the Fourier surface and the iteration times is shown in FIG. 3, and the curve can visually display the speed of the convergence speed of the phase detection. It can be seen that when the embedded data 105 is low in proportion, for example, when the embedded data 105 is 20%, about 200 iterations are required to converge to the end; when the embedded data 105 is increased in proportion, the convergence rate is significantly increased, which is an effect of the embedded data 105 increasing the phase detection convergence rate.

The higher the proportion of the embedded data 105 is, the more the convergence speed is accelerated, and the phase detection accuracy is improved, as shown in table one. Under the conditions of four-order and eight-order phase encoding, phase detection is carried out by using different embedded data 105 proportion conditions respectively; it can be seen that the higher the proportion of embedded data 105, the lower the number of iterations and the bit error rate. But at the same time, the higher the proportion of the embedded data 105 is, the lower the coding rate is, so the proportion of the embedded data 105 can be adjusted according to the specific requirements of parameters such as data conversion rate, coding rate and bit error rate.

Table a comparison of the fourth and eighth order phase encodings at different ratios of embedded data 105:

in addition to the occupation ratio being an important parameter, the position distribution and the code distribution of the embedded data 105 also have an influence on the phase detection. Fig. 4 shows the position distribution of the embedded data 105, where the black part is the embedded data 105, the white part is the unknown phase data 106, and the embedded data 105 may be distributed at regular positions or at random positions. The advantage of regular position distribution is that the code placement has a uniform rule and is therefore simple in coding. The advantage of random position distribution is that the problem of too strong frequency periodicity caused by regular position distribution with a certain probability can be avoided.

Fig. 5 shows the phase encoding distribution of the embedded data 105, with the hatched portion being the embedded data 105 with color and the white portion being the unknown phase data 106. Taking the case that the proportion of the embedded data 105 is 50% and the positions of the embedded data 105 are regularly distributed as an example, the phase encoding distribution of the embedded data 105 may be regularly or randomly distributed. Fig. 6 shows the spectral distribution in the fourier plane, and a regular phase distribution may result in a regular spectral distribution in the fourier plane, which has the advantage of producing a distinctive spectral distribution that can be used for positioning and spectral feature extraction, but has the disadvantage of insufficient spectral aliasing with the unknown phase data 106. The random phase distribution causes a random frequency spectrum distribution on the fourier plane, which is similar to the frequency spectrum distribution of the unknown phase data 106, i.e., random, so that the degree of frequency spectrum aliasing is high, which is beneficial to improving the iteration efficiency of phase detection. In summary, the position distribution and the phase encoding distribution of the embedded data 105 also need to be selected according to the specific application scenario.

The phase encoding value of the embedded data 105 may be selected to be the same as or different from the phase encoding value of the unknown phase data, as desired. For example, the phase code of the unknown phase data takes on the fourth order of 0, pi/2, pi, 3 pi/2, the phase code of the embedded data 105 may take on the fourth order of the same phase 0, pi/2, pi, 3 pi/2, or may take on any four orders of different phases such as 0, pi/3, pi/2, 3 pi/2, or may take on any order of different phases such as five orders of 0, pi/3, pi/2, pi, 3 pi/2.

The spatial frequency of the embedded data 105 may be selected to be the same or different than the spatial frequency of the unknown phase data, as desired. As shown in fig. 7, it can be seen that the area of the embedded data 105 is larger than the area of the unknown phase data 106, i.e. the spatial frequency of the embedded data 105 is lower than the spatial frequency of the unknown phase data 106.

The light intensity of the embedded data 105 unit may be selected to be the same as or different from the light intensity of the unknown phase data unit, as desired. Fig. 8 is an example of the light intensity of the embedded data 105 unit being different from the light intensity of the unknown phase data 106 unit, the embedded data 105 being a black portion, the unknown phase data 106 being a white portion, and fig. 9 is a graph obtained by plotting the light intensity at the observation line 104 in fig. 8. Here, the observation line 104 is a horizontal line in fig. 8.

The location of the embedded data 105 may be selected to be adjacent or non-adjacent to the location of the unknown phase data, as desired. Fig. 10 is an example of the position of the embedded data 105 not being adjacent to the position of the unknown phase data 106.

While the present invention has been described in detail with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, and various changes can be made without departing from the spirit and scope of the present invention.

Many other changes and modifications can be made without departing from the spirit and scope of the utility model. It is to be understood that the utility model is not to be limited to the specific embodiments, but only by the scope of the appended claims.

Claims (6)

1. The non-interference phase detection device based on embedded data comprises an object plane, an optical system, a lens, a Fourier transform plane and an iterative computation processor which are sequentially arranged; the method is characterized in that the object plane is used for uploading original phase data; the optical system is used for recording the original phase data on a holographic material and reading information to obtain phase data to be detected; the lens is used for generating the frequency spectrum intensity distribution of the Fourier transform of the phase data to be detected; the Fourier transform surface is used for receiving and obtaining the frequency spectrum intensity distribution of the phase data to be detected through Fourier transform; the iterative computation processor is used for performing iterative computation on the frequency spectrum intensity distribution subjected to Fourier transform on the phase data to be detected so as to obtain detected phase data;

the object plane is a phase modulation spatial light modulator; the embedded data and the unknown phase data are together coded into the original phase data; uploading the original phase data by using the spatial light modulator as the object plane;

the optical system comprises a first objective lens, a holographic material and a second objective lens which are sequentially arranged along the light propagation direction; the lens is a Fourier transform lens; the Fourier transform surface is a photoelectric detector; the front of the modulation spatial light modulator is sequentially provided with a laser, a pinhole filter, a collimating lens, a shutter, a holographic diaphragm group, a first relay lens, a second relay lens, a first non-polarization stereo beam splitter and a half wave plate along the light beam propagation direction, and the half wave plate is arranged in the transmission light propagation direction of the first non-polarization stereo beam splitter.

2. The non-interferometric phase detection device based on embedded data according to claim 1, characterized in that the holographic aperture set is a first coaxial holographic aperture set, the center of the first coaxial holographic aperture set is an information light portion, the periphery of the information light portion is a reference light portion, and the information light portion and the reference light portion constitute a coaxial structure.

3. The non-interference phase detection device based on embedded data according to claim 2, wherein a second coaxial holographic diaphragm set is disposed between the second objective lens and the fourier transform lens, a center of the second coaxial holographic diaphragm set is an information light portion, a periphery of the information light portion is a reference light portion, and the information light portion and the reference light portion constitute a coaxial structure.

4. The non-interferometric phase detection device based on embedded data of claim 3, characterized in that the shape of the second set of coaxial holographic diaphragms is the same as the first set of coaxial holographic diaphragms.

5. The non-interferometric phase detection device based on embedded data of claim 4, characterized in that the light intensity transmittance of the reference light portion of the second coaxial holographic stop set is smaller than the light intensity transmittance of the reference light portion of the first coaxial holographic stop set.

6. The non-interferometric phase detection device based on embedded data of claim 1, characterized in that the holographic diaphragm set is an off-axis holographic diaphragm set, on which the information light transmission part is arranged; a second non-polarized stereo beam splitter is arranged between the shutter and the off-axis holographic diaphragm group; the off-axis holographic diaphragm group is arranged on a transmission light path of the second non-polarization stereo beam splitter; the first plane reflector is arranged on a reflection light path of the second non-polarized three-dimensional beam splitter, the second plane reflector is arranged on a reflection light path of the first plane reflector, and the holographic material is arranged on a reflection light path of the second plane reflector.

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