CN111551955B - A bionic block ghost imaging method and system - Google Patents

Abstract

The invention discloses a bionic block ghost imaging method and system, which belong to the technical field of photoelectric imaging. The system of the invention includes a light source, a collimating optical system, a beam splitter, a spatial light modulator, a receiving optical system, and an area array detector. The implementation method of the invention is as follows: initializing parameters for generating bionic speckles and parameters for ghost imaging sampling; obtaining higher imaging quality through bionic speckle sampling; The speckle can reduce the sampling times of ghost imaging; use the block bionic speckle to sample the target, and obtain the measurement value of each block; carry out image reconstruction according to the block bionic speckle and the measured value; Image stitching to obtain the entire reconstructed image, that is, to achieve bionic segmentation ghost imaging that takes into account both imaging efficiency and imaging quality. The invention combines the bionic speckle with the segmented ghost imaging, and effectively improves the ghost imaging efficiency under the condition of the same imaging quality as compared with the traditional ghost imaging system.

Description

A bionic block ghost imaging method and system

technical field

The invention relates to a bionic block ghost imaging method and system, and belongs to the technical field of photoelectric imaging.

Background technique

Compared with the traditional optical imaging system, the biggest difference of ghost imaging is that the image reconstruction is performed by correlating the light field intensity distribution information of the light source and the total light intensity information after modulation by the target. At present, ghost imaging technology has the advantages of simple structure, strong anti-interference ability, and imaging resolution beyond the diffraction limit. It has been widely used in 2D and 3D imaging, remote sensing, microscopic imaging and other fields. The imaging efficiency of ghost imaging to achieve high-quality imaging is not high. Although reducing the number of sampling can improve the imaging efficiency, the imaging quality will also decrease. Therefore, taking into account the imaging efficiency and imaging quality is still a difficult problem.

Traditional ghost imaging systems use single-point detectors or barrel detectors, each projected speckle corresponds to only one measurement value, and the bandwidth of data transmission is not fully occupied, which greatly limits the real-time performance of the imaging system. By adopting the block and parallel transmission scheme, more data information can be obtained in the same time, thereby improving the imaging efficiency of the imaging system. In addition, with the development of bionic technology, the application of bionic projection speckle based on high resolution at the center and low resolution at the edge to ghost imaging can improve the imaging quality. In view of this, taking advantage of the two characteristics, a bionic block ghost imaging method is proposed and an imaging system is designed, which provides a new technical approach for real-time ghost imaging with high imaging quality and high resolution.

SUMMARY OF THE INVENTION

In order to solve the problem that it is difficult to balance imaging efficiency and imaging quality in the existing ghost imaging methods, the purpose of the present invention is to provide a bionic block ghost imaging method and system, which can take both imaging efficiency and imaging quality into consideration.

The purpose of the present invention is achieved through the following technical solutions.

The invention discloses a bionic block ghost imaging method and system. The parameters for generating bionic speckle and the parameters for ghost imaging sampling are initialized; a group of bionic speckles are generated according to the set bionic speckle parameters, Sampling to obtain higher imaging quality; by dividing the bionic speckle into blocks, the use of lower resolution bionic speckle can reduce the number of sampling times for ghost imaging; using the block bionic speckle to sample the target to obtain the measurement of each block According to the segmented bionic speckle and measured values, image reconstruction is performed; the reconstructed segmented images are stitched to obtain the entire reconstructed image, that is, the bionic segmented ghost imaging that takes into account both imaging efficiency and imaging quality is realized. The invention combines the bionic speckle with the segmented ghost imaging, and compared with the traditional ghost imaging system, the imaging efficiency of the ghost imaging system is effectively improved under the condition of the same imaging quality.

A bionic block ghost imaging method disclosed in the present invention includes the following steps:

Step 1: Initialize parameters for generating bionic speckles and parameters for ghost imaging sampling.

Step 1.1: Initialize the parameters for generating bionic speckle.

Set the image resolution X×X, the number of blocks N, the maximum value Q of the bionic speckle discrete angle, the maximum value K of the number of bionic speckle discrete rings, and the radius r ₀ of the bionic speckle inner ring. The number of blocks N is a square number.

Step 1.2: Initialize ghost imaging sampling parameters.

Set the sampling ratio to a, the sampling times to be A=X×X×a/N, and A is rounded to the nearest integer.

Step 2: Generate a set of bionic speckles according to the bionic speckle parameters set in step 1, and obtain higher imaging quality through bionic speckle sampling.

According to the bionic speckle parameters set in step 1, A sheets of bionic speckle P are generated, and the calculation formula of the bionic speckle is shown in formula (1).

Where: rk represents the radius of the _kth ring of the speckle, (1+sin(π/Q))/(1-sin(π/Q)) represents the increase factor ε, and θq is the degree of the _q sector. Bionic speckle P is an image with a resolution of X×X.

Step 3: By dividing the bionic speckle into blocks, using a lower resolution speckle can reduce the sampling times of ghost imaging.

的矩阵。此处采用先行后列或者先列后行的方式对其进行拆分并编号，其中p₁为1号散斑，p_N为N号散斑。Divide the bionic speckle P into N equal parts to obtain p ₁ , p ₂ , ..., p _N , each p _i is

matrix. Here, it is divided and numbered in the manner of row-first-column or row-first-row, wherein p ₁ is the No. 1 speckle, and p _N is the No. N speckle.

After splitting the A bionic speckles, p _i ={p _i1 ,p _i2 ,...,p _iA }(i=1,2,...,N).

Step 4: Use the block bionic speckle of step 3 to sample the target, and obtain the measurement value of each block.

The bionic speckle is projected onto the target O to be imaged for sampling, and the target O and the bionic speckle are differentiated into o ₁ , o ₂ , ... o _N in the same way.

The light source is projected on the target O to be imaged, and the detector _obtains the measurement values _{y 1} , _{y 2} , . y _i1 , y _i2 ,...,y _iA }(i=1,2,...,N).

y _i =∫∫pi (x,y)×o _{i (} x,y)dxdy,(i=1,2...,N) (3)

Step 5: Perform image reconstruction according to the block bionic speckle of Step 3 and the measured value of Step 4.

图像。p _i and y _i are the measured values of the speckle numbered i and its corresponding number, and the reconstruction algorithm is used to calculate the reconstructed image o _i ', the calculation formula is shown in formula (4), o _i ' is the resolution rate

image.

Step 6: Splicing the reconstructed segmented images in step 5 to obtain the entire reconstructed image, that is, to achieve bionic segmented ghost imaging that takes both imaging efficiency and imaging quality into consideration.

According to the method of splitting the speckle selected in step 3, image splicing is performed on o _i ' to obtain the entire reconstructed image O', where O' is an image with a resolution of X×X. The manner of splitting the speckles is row-before-column or row-first-row.

The invention also discloses a bionic segmented ghost imaging system for realizing the bionic segmented ghost imaging method. The system includes a light source, a collimating optical system, a beam splitter, a spatial light modulator, a receiving optical system, and an area array. detector.

The light source, the collimating optical system, the beam splitter, and the spatial light modulator are located on the same optical path in sequence; the light source, the collimating optical system and the beam splitter are used to generate the area array light irradiating the spatial light modulator; the light source, the collimating optical system , beam splitter and spatial light modulator are used to generate speckles carrying known light field distribution information and project them onto the target to be imaged; the receiving optical system and the area array detector complete the collection of the total light intensity of the reflected light from the target. The correlation operator performs reconstruction operations on the bionic speckle information and the information collected by the area array detector and image mosaic operations.

The invention also discloses a working method of a bionic segmented ghost imaging system. The light source emits a beam of light, which is divided by a collimating optical system and a beam splitter and then irradiated to the surface of the spatial light modulator. The spatial light modulator calculates according to step 2. The generated bionic speckle reflects the beam to the target, the target reflected beam passes through the receiving optical system to the area array detector according to step 4, and the total light intensity of the reflected light from the target is received by the area array detector. After repeating the measurement for many times, the cross-correlation operation is performed on the bionic speckle information and the light intensity information collected by the area array detector according to step 5, and the reconstructed image of the target block is obtained. Block images are stitched to obtain the entire reconstructed image, that is, to achieve bionic block ghost imaging that takes into account both imaging efficiency and imaging quality.

Beneficial effects:

1. Compared with the traditional ghost imaging system, a bionic segmented ghost imaging method and system disclosed in the present invention adopts the bionic vision mechanism combined with the segmented ghost imaging method, which greatly improves the imaging efficiency under the condition of the same imaging quality, and can achieve High-quality real-time imaging.

2. The method and system for bionic segmented ghost imaging disclosed in the present invention adopts the method of segmented ghost imaging, that is, in step 3, the number of sampling times of ghost imaging and the calculation amount of reconstruction algorithm are reduced by segmenting the bionic speckle, and the calculation amount of the reconstruction algorithm is increased. Imaging efficiency of ghost imaging.

Description of drawings

Figure 1 Schematic diagram of the bionic block ghost imaging system;

Figure 2 Bionic speckle pattern (resolution 64*64);

Fig. 3 is a flow chart of the method of bionic segmentation ghost imaging;

Fig. 4 Comparison of reconstructed images of bionic segmented ghost imaging and traditional ghost imaging under the same sampling times (using a total variational reconstruction algorithm);

Fig. 5 Comparison of reconstruction efficiency between bionic segmented ghost imaging and traditional ghost imaging at the same PSNR (imaging time of traditional ghost imaging/imaging time of bionic segmented ghost imaging).

Among them: 1-host computer, 2-light source, 3-collimating optical system, 4-diffractive optical element, 5-spatial light modulator, 6-target, 7-receiving optical system, 8-area array detector, 9- capture card.

Detailed ways

The specific embodiments of the present invention will be described below with reference to the accompanying drawings.

For a bionic block ghost imaging method disclosed in this embodiment, the applied system structure is shown in FIG. 1 , and the specific implementation steps are as follows:

Step 1: Initialize parameters for generating bionic speckles and parameters for ghost imaging sampling. Initialize the parameters for generating bionic speckle, set the image resolution to 64×64, the number of blocks to 16, the maximum value of the bionic speckle discrete angle to 24, the maximum value of the number of bionic speckle discrete rings to 4, and the radius of the bionic speckle inner ring to 19.7; initialization Ghost imaging sampling parameters, the sampling ratio is 0.1, and the sampling times is 26 times.

Step 2: Generate a set of bionic speckles according to the bionic speckle parameters set in step 1, and obtain higher imaging quality through bionic speckle sampling.

According to the bionic speckle parameters set in step 1, 26 bionic speckle patterns P are generated and loaded into the DMD (digital micromirror device). The bionic speckle calculation formula is shown in formula (6).

Where: rk represents the radius of the _kth ring of the speckle, (1+sin(π/Q))/(1-sin(π/Q)) represents the increase factor ε, and θq is the degree of the _q sector. The bionic speckle P is an image with a resolution of 64 × 64, as shown in Figure 2.

Step 3: By dividing the bionic speckle into blocks, using a lower resolution speckle can reduce the sampling times of ghost imaging.

Divide the bionic speckle P into 16 equal parts to obtain p ₁ , p ₂ , ..., p ₁₆ , and each p _i is a 16×16 matrix.

After splitting 26 bionic speckles, p _i ={p _i1 ,p _i2 ,...,p _i26 }(i=1,2,...,16).

Step 4: Use the block bionic speckle of step 3 to sample the target 6 to obtain the measurement value of each block.

The light source 2 is collimated and split through a collimating lens and a DOE (diffractive optical element 4), the split light is projected onto the DMD micromirror surface for modulation, and the modulated light is irradiated to the target 60 to be imaged for sampling.

_The array light is irradiated on the target _6O to be imaged, and the CCD detector obtains the detection values y ₁ , _{y 2} , . ={y _i1 ,y _i2 ,...,y _i26 }(i=1,2,...,16).

y _i =∫∫pi (x,y)×o _{i (} x,y)dxdy,(i=1,2...,16) (8)

Step 5: Perform image reconstruction according to the block bionic speckle of Step 3 and the measured value of Step 4.

p _i and y _i are the speckle numbered _i and the measured value of its corresponding number, and the reconstructed image oi ' is obtained by calculating it by using the TV (total variation) reconstruction algorithm, and _oi ' is the resolution of 16× 16 images.

Step 6: Splicing the reconstructed segmented images in step 5 to obtain the entire reconstructed image, that is, to achieve bionic segmented ghost imaging that takes both imaging efficiency and imaging quality into consideration.

According to the method of splitting the speckle selected in step 3, image stitching is performed on o _i ' to obtain the entire reconstructed image O', where O' is an image with a resolution of 64×64. The manner of splitting the speckles is row-before-column or row-first-row. The obtained reconstructed image O' is shown in Fig. 4 .

A bionic segmented ghost imaging system disclosed in this embodiment is used to implement the bionic segmented ghost imaging method. The system includes a laser light source 2 , a collimating optical system 3 , DOE, DMD, a receiving optical system 7 , and a CCD detector.

Laser light source 2, collimating optical system 3, DOE, and DMD are located on the same optical path in sequence; laser light source 2, collimating optical system 3 and DOE are used to generate surface array light irradiated to the DMD; laser light source 2, collimating optics The system 3, DOE and DMD are used to generate speckles carrying known light field distribution information and project them onto the target 6 to be imaged; the receiving optical system 7 and the CCD detector complete the collection of the total light intensity of the reflected light from the target 6 . The computer performs reconstruction operations and block image splicing operations on the bionic speckle information and the information collected by the area array detector 8 .

The working method of a bionic segmented ghost imaging system disclosed in this embodiment is as follows: a light source 2 emits a beam of light, which is split by a collimating optical system 3 and a beam splitter and then irradiated to the surface of the spatial light modulator 5, and the spatial light modulator 5. The bionic speckle calculated and generated according to step 2 reflects the beam to the target 6, and the reflected beam from the target 6 passes through the receiving optical system 7 to the area array detector 8 according to step 4, and the total light intensity of the reflected light from the target 6 is received by the area array detector 8. . After repeating the measurement for many times, the cross-correlation operation is performed on the bionic speckle information and the light intensity information collected by the area array detector 8 according to step 5 to obtain the reconstructed image of the target 6 blocks, and the reconstructed image in step 5 is reconstructed according to step 6 After splicing the segmented images, the entire reconstructed image is obtained, that is, the bionic segmented ghost imaging that takes into account both the imaging efficiency and the imaging quality is realized.

The above-mentioned specific descriptions further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above-mentioned descriptions are only specific embodiments of the present invention, and are not intended to limit the protection of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (2)

1. a bionic block ghost imaging method, is characterized in that: comprise the steps, Step 1: Initialize parameters for generating bionic speckle and parameters for ghost imaging sampling; Step 2, generating a set of bionic speckles according to the bionic speckle parameters set in step 1, and obtaining higher imaging quality through bionic speckle sampling; Step 3: By dividing the bionic speckle into blocks, using a lower resolution speckle can reduce the sampling times of ghost imaging; Step 4. Use the block bionic speckle of step 3 to sample the target, and obtain the measurement value of each block; Step 5: Perform image reconstruction according to the block bionic speckle of Step 3 and the measurement value of Step 4; Step 6, stitching the reconstructed segmented images in step 5 to obtain the entire reconstructed image, that is, to achieve bionic segmented ghost imaging that takes into account both imaging efficiency and imaging quality; The implementation method of step 1 is: Step 1.1: Initialize the parameters for generating bionic speckle; Set the image resolution X×X, the number of blocks N, the maximum value Q of the bionic speckle discrete angle, the maximum value K of the number of bionic speckle discrete rings, and the radius r ₀ of the bionic speckle inner ring; the number of blocks N is the square of; Step 1.2: Initialize ghost imaging sampling parameters; Set the sampling ratio to a, the sampling times to be A=X×X×a/N, and A is rounded to the nearest integer; The implementation method of step 2 is: According to the bionic speckle parameters set in step 1, A sheets of bionic speckle P are generated, and the calculation formula of bionic speckle is shown in the formula;

Where: r _k represents the radius of the kth ring of the speckle, (1+sin(π/Q))/(1-sin(π/Q)) represents the increase coefficient ε, θ _q is the degree of the q sector; bionic Speckle P is an image of resolution X×X; The implementation method of step 3 is: Divide the bionic speckle P into N equal parts to obtain p ₁ , p ₂ , ..., p _N , each p _i is

The matrix of ; here is split and numbered in the manner of row first, column first or row first, where p ₁ is the speckle No. 1, and p _N is the speckle No. N;

After splitting A bionic speckles, p _i ={p _i1 ,p _i2 ,...,p _iA }(i=1,2,...,N); The implementation method of step 4 is: Project the bionic speckle to the target O to be imaged for sampling, and the target O and the bionic speckle are divided into o ₁ , o ₂ , ... o _N in the same way; The light source is projected on the target O to be _imaged , and the detector _obtains the measured values _{y 1} , _{y 2} , . y _i2 ,...,y _iA }(i=1,2,...,N); y _i =∫∫pi (x,y)×o _{i (} x,y)dxdy,(i=1,2...,N) (3) The implementation method of step 5 is: p _i and y _i are the measured values of the speckle numbered i and its corresponding number, and the reconstruction algorithm is used to calculate it to obtain the reconstructed image o _i ', the calculation formula is shown in the formula, o _i ' is the resolution of

image;

The implementation method of step 6 is: According to the method of splitting the speckles in step 3, o _i ' is stitched to obtain the entire reconstructed image O', and O' is an image with a resolution of X × X; the method of splitting the speckles is to first row and then column or row before row;

. 2. A bionic segmented ghost imaging system for realizing a bionic segmented ghost imaging method as claimed in claim 1, characterized in that: comprising a light source (2), a collimating optical system (3), a beam splitter , a spatial light modulator (5), a receiving optical system (7), an area array detector (8); The light source (2), the collimating optical system (3), the beam splitter, and the spatial light modulator (5) are located on the same optical path in sequence; the light source (2), the collimating optical system (3) and the beam splitter are used for The area array light of the spatial light modulator (5); the light source (2), the collimating optical system (3), the beam splitter and the spatial light modulator (5) are used to generate the speckle carrying the known light field distribution information and project onto the light source. on the target to be imaged (6); the receiving optical system (7) and the area array detector (8) complete the collection of the total light intensity of the reflected light of the target (6); the correlation operator combines the bionic speckle information with the area array detector ( 8) Reconstruction operation and block image splicing operation are performed on the collected information; The light source (2) emits a beam of light, which is split by the collimating optical system (3) and the beam splitter and then irradiated to the surface of the spatial light modulator (5), and the spatial light modulator (5) calculates and generates the bionic speckle according to step 2 The reflected beam is reflected to the target (6), and the reflected beam of the target (6) passes through the receiving optical system (7) to the area array detector (8) according to step 4, and the total light intensity of the reflected light from the target (6) is detected by the area array detector (8). ) to receive; after repeating the measurement for many times, according to step 5, the cross-correlation operation is performed on the bionic speckle information and the light intensity information collected by the area array detector (8) to obtain the reconstructed image of the target (6) blocks, according to In step 6, the segmented images reconstructed in step 5 are stitched together to obtain the entire reconstructed image, that is, to achieve bionic segmented ghost imaging that takes both imaging efficiency and imaging quality into consideration.

Images