CN106290285A - A kind of non-intrusion type laser scanning imaging method based on stochastical sampling - Google Patents

Abstract

The invention discloses a kind of non-intrusion type laser scanning imaging method based on stochastical sampling, including S1: generate the random matrix Φ that element only comprises 0 and 1, wherein the size of random matrix Φ and fluorescence intensity matrix I's and corresponding scanning angle matrix Θ is equivalently-sized；S2: by the angle on the scanning angle matrix Θ that element that laser scanning random matrix Φ intermediate value is 1 is corresponding, collect the fluorescence intensity on fluorescence intensity matrix I corresponding to element that random matrix Φ intermediate value is 1, obtain incomplete fluorescence intensity matrix wherein ο symbol and represent that corresponding element is multiplied；S3: by solving the reconstruction model under low-rank constraint, to obtain complete fluorescence intensity matrix I=U；S4: recover the picture of object from the complete fluorescence intensity matrix reconstructed.The non-intrusion type laser scanning imaging method based on stochastical sampling with low-rank reconstruct that the present invention proposes, it is possible to substantially reduce scanning process required time, keep higher image quality simultaneously.

Description

A kind of non-intrusion type laser scanning imaging method based on stochastical sampling

Technical field

The present invention relates to be calculated as the technical fields such as picture, biomedical imaging, image reconstruction, particularly relate to a kind of based on The non-intrusion type laser scanning imaging method of machine sampling.

Background technology

In the field such as medical imaging, industrial detection, generally require small knots such as such as biological tissue cell, industry chips Structure carries out imaging using the foundation as analyzing and diagnosing and detection.But owing to these image forming mediums are often translucent scattering Layer, traditional formation method based on geometric optics is the most applicable, unless destroyed scattering layer or assisted into toward injection in scattering layer The material of picture, but observed object is easily damaged by these means.In recent years, a kind of based on laser speckle scanning non- Intrusive mood formation method is suggested, and it can obtain being hidden in scattering layer object behind on the premise of not destroying scattering layer Clearly as.In this approach, beam of laser is mapped to the fixed position of scattering layer, forms laser speckle also under scattering process It is radiated in the plane at fluorescent object place.The fluorescence that the speckle on fluorescent object that falls inspires is reflected back toward scattering layer and quilt Gather, that the fluorescent intensity collected adds up and as the laser total fluorescence volume under this incident angle.By laser according to sweeping The angle retouched in angle matrix scans one by one, and can obtain in corresponding fluorescence intensity matrix, i.e. fluorescence intensity matrix is every One element value is that laser is according to the total fluorescence volume under the angle incidence of corresponding element in scanning angle matrix.Finally can utilize phase Bit recovery algorithm recovers the picture of object from fluorescence intensity matrix.In this traditional method, in order to preferably be become As effect, the size of scan matrix needs sufficiently large, it is therefore desirable to the total number of angles of laser scanning is huge, and due to In reality, fluorescence signal is more weak, needs to strengthen the time of exposure of fluorescent collecting device, finally makes the collection of total imaging data Time is the veryest long.Owing to long laser irradiates, easily cause the infringement of tested article, it is therefore necessary to scanning will be reduced multiple Miscellaneous degree, reduces sweep time.

Fig. 1 show traditional non-intrusion type imaging device schematic diagram based on laser speckle scanning, dissipates including translucent Penetrate layer 1, fluorescent object 2, translucent scattering layer 3 and optical filter 4.When beam of laser vertically injects scattering layer, at fluorescent object Place plane (being designated as u-v plane) formed speckle pattern, be designated as S (u, v).When laser is with (θ=(θ into θ angle with normal_x,θ_y)) enter When penetrating, " memory effect " that speckle exists makes the speckle in now u-v plane simply translate, and pattern does not occurs Change, the most now S '=S (u-d₁θ_x,v-d₁θ_y).Thus at total fluorescence volume of fluorescent collecting end be:

I (θ)=∫ ∫ O (u, v) S (u-d₁θ_x,v-d₁θ_y) dudv=[O*S] (θ).

Incident laser is scanned one by one according to the angle on scanning angle matrix Θ, records under each incident angle Total fluorescence volume, ultimately form fluorescence intensity matrix I, then utilize Phase Retrieve Algorithm to recover from described fluorescence intensity matrix Image to described fluorescent object.

The disclosure of background above technology contents is only used for assisting design and the technical scheme understanding the present invention, and it is not necessarily Belong to the prior art of present patent application, do not have tangible proof show foregoing present patent application the applying date In the case of Gong Kai, above-mentioned background technology should not be taken to evaluate novelty and the creativeness of the application.

Summary of the invention

For solving above-mentioned technical problem, the present invention proposes a kind of non-intrusion type laser based on stochastical sampling with low-rank reconstruct Scan imaging method, it is possible to substantially reduce scanning process required time, keep higher image quality simultaneously.

For reaching above-mentioned purpose, the present invention by the following technical solutions:

The invention discloses a kind of non-intrusion type laser scanning imaging method based on stochastical sampling, comprise the following steps:

S1: generate the random matrix Φ that element only comprises 0 and 1, the wherein size of random matrix Φ and fluorescence intensity matrix I And the scanning angle matrix Θ's of correspondence is equivalently-sized；

S2: by the angle on the scanning angle matrix Θ that element that laser scanning random matrix Φ intermediate value is 1 is corresponding, receive Collection random matrix Φ intermediate value is the fluorescence intensity on the fluorescence intensity matrix I corresponding to element of 1, obtains incomplete fluorescence intensity MatrixWherein ο symbol represents that corresponding element is multiplied；

S3: by solving the reconstruction model under the constraint of following low-rank, to obtain complete fluorescence intensity matrix I=U；

$I=\arg \underset{U}{min}\{TV\left(U\right)+\mathrm{\η}\·\underset{P_k\∈\mathrm{\Δ}}{\mathrm{\Σ}}\left(w\right(P_k)\·|\left|P_k\right|{|}_{*})\}$

$s.t.U_{i,j}={\hat{I}}_{i,j},\∀(i,j)\∈\mathrm{\Ω}$

Wherein, TV is total variance function, P_kFor the matrix-block of p × p, w (P_k) it is matrix-block P_kCorresponding weighting function, | |·||_*For nuclear norm, η is regular parameter, and Δ is all matrix-block P of matrix U to be asked_kSet, Ω is the element acquired The set of index；

S4: recover the picture of object in the complete fluorescence intensity matrix reconstructed from step S3.

Preferably, in step S1, element 1 proportion in random matrix Φ is more than 20%.

Preferably, step S2 use galvanometer scanning system carry out laser scanning.

Preferably, the matrix-block P in step S3_kCorresponding weighting function w (P_k) carry out value according to following formula:

$w\left(P_k\right)=\left\{\begin{array}{cc}{{\mathrm{\ξ}}_k}^2,& {\mathrm{\ξ}}_k>\mathrm{\λ}\\ 0,& {\mathrm{\ξ}}_k\≤\mathrm{\λ}\end{array}\right.$

Wherein, ξ_kFor matrix-block P_kIn the number of element that acquires, λ is threshold value.

Preferably, wherein threshold value λ=0.2 p²。

Preferably, step S4 specifically includes: use the complete fluorescence that Phase Retrieve Algorithm reconstructs from step S3 Intensity matrix recovers the picture of object.

Compared with prior art, the beneficial effects of the present invention is: the non-intrusion type based on stochastical sampling of the present invention swashs Photoscanning formation method, the method utilizing stochastical sampling and low-rank reconstruct, obtain incomplete fluorescence intensity by stochastical sampling Matrix, then by rebuilding fluorescence intensity matrix with the restructing algorithm of low-rank constraint with total variance constraint, and eventually passes through phase Bit recovery obtains the picture of object；By the method for the present invention, it is greatly shortened the acquisition time of imaging data, can also keep simultaneously Higher image quality.

Accompanying drawing explanation

Fig. 1 is traditional non-intrusion type imaging device schematic diagram based on laser speckle scanning；

Fig. 2 is that the flow process of the non-intrusion type laser scanning imaging method based on stochastical sampling of the preferred embodiment of the present invention is shown It is intended to.

Fig. 3 is that the non-intrusion type laser scanning imaging method based on stochastical sampling by the preferred embodiment of the present invention is carried out The effect schematic diagram of imaging.

Detailed description of the invention

Below against accompanying drawing and combine preferred embodiment the invention will be further described.

As in figure 2 it is shown, the preferred embodiment of the present invention discloses a kind of non-intrusion type laser scanning imaging based on stochastical sampling Method, comprises the following steps:

S1: generate the random matrix Φ that element only comprises 0 and 1, the wherein size of random matrix Φ and fluorescence intensity matrix I And the scanning angle matrix Θ's of correspondence is equivalently-sized；

Wherein, in random matrix Φ, element 1 proportion is ρ, then the method spent time be only the ρ of traditional method × 100%；Depending on ratio shared by the probability distribution of random matrix Φ, element 1 can be according to actual imaging effect, more preferably In embodiment, ρ >=0.2.

S2: by the angle on the scanning angle matrix Θ that element that laser scanning random matrix Φ intermediate value is 1 is corresponding, receive Collection random matrix Φ intermediate value is the fluorescence intensity on the fluorescence intensity matrix I corresponding to element of 1, obtains incomplete fluorescence intensity MatrixWherein ο symbol represents that corresponding element is multiplied；

Wherein, under the guidance of the random matrix Φ of step S1 generation, complete fluorescence intensity matrix is used at random, The most only gather the element Φ that random matrix Φ intermediate value is 1_i,jCorresponding fluorescence intensity I_i,j；Laser scanning device uses speckle scanning The device of imaging, wherein can use traditional based on programme controlled galvanometer scanning system, and then control system only scans and refers to Fixed angle and skipping need not the angle gathered；Can also use and directly control LASER Light Source rotation.

S3: by solving the reconstruction model under the constraint of following low-rank, to obtain complete fluorescence intensity matrix I=U；

$I=\arg \underset{U}{min}\{TV\left(U\right)+\mathrm{\η}\·\underset{P_k\∈\mathrm{\Δ}}{\mathrm{\Σ}}\left(w\right(P_k)\·|\left|P_k\right|{|}_{*})\}$

$s.t.U_{i,j}={\hat{I}}_{i,j},\∀(i,j)\∈\mathrm{\Ω}$

Wherein, TV (Total Variation) is total variance function, P_kFor the matrix-block of p × p, w (P_k) it is matrix-block P_k Corresponding weighting function, | | | |_*For nuclear norm, η is regular parameter, and Δ is all matrix-block P of matrix U to be asked_kSet, Ω is the set of the index of the element acquired；Represent optimized-typeTaking U during minima, s.t. is the abbreviation of subject to, means constraints.

Wherein, the constraints of this reconstruction model belongs to fidelity item, it is intended that the fluorescence intensity matrix of reconstruct connects as far as possible The imperfect fluorescence intensity matrix closely gathered；In object function, the nuclear norm of the matrix-block of total variance function and band weighting With for regular terms, it is intended that each local matrix-block of the matrix reconstructed is smooth and local low-rank, and regular parameter η uses Regulate and control the proportion of two regular terms, make the structure of final reconstruct reach optimum.It addition, reconstruction model is because of different matrix-blocks In the proportion of element of known fluorescence intensity different and give the weight that different matrix-block is different, can basis when implementing Quality reconstruction optimum selecting weighting function.

When implementing, matrix-block P_kCorresponding weighting function w (P_k) carry out value according to following formula:

$w\left(P_k\right)=\left\{\begin{array}{cc}{{\mathrm{\ξ}}_k}^2,& {\mathrm{\ξ}}_k>\mathrm{\λ}\\ 0,& {\mathrm{\ξ}}_k\≤\mathrm{\λ}\end{array}\right.$

Wherein, ξ_kFor matrix-block P_kIn the number of element that acquires, λ is threshold value, can be set as 0.2 p², i.e. matrix / 5th of the total element number of block, depending on actual weighting function and the selection of threshold value should be according to actual quality reconstruction.

S4: recover the picture of object in the complete fluorescence intensity matrix reconstructed from step S3.

Specifically, the complete fluorescence intensity matrix that employing Phase Retrieve Algorithm reconstructs from step S3 recovers thing The picture of body, can use following steps further:

1) calculate fluorescence intensity matrix auto-correlation I I=(O*S) (O*S)=(O O) * (S S), due to speckle from It is related as peaking function, therefore has I I ≈ O O；Wherein, I is Integrated Intensity (total light intensity), and O is that Object (treats Imaging object), S is Speckle (laser speckle), and * is convolution symbol (Convolution), cross-correlation symbol (Correlation)。

(2) auto-correlation is done Fourier transformation can obtain

(3) utilize the Hybrid-Input-Output algorithm (Mixed design output algorithm) can be fromAnd O non- The priori conditions such as negativity recover O.

As it is shown on figure 3, be that the non-intrusion type laser scanning imaging method based on stochastical sampling by the present invention becomes The effect schematic diagram of picture, in Fig. 3, the leftmost side one is classified as the picture that traditional method all gathered obtains, and remaining is respectively classified as employing Picture obtained by the method for the present invention, the most dextrosinistral sample rate ρ is respectively 0.1,0.15,0.2,0.25, namely imaging Acquisition time needed for data is only 0.1 times traditional, 0.15 times, 0.2 times and 0.25 times, is i.e. greatly shortened adopting of imaging data The collection time；And it can be seen that keep higher image quality by the image of the method gained of the present invention, especially exist When ρ=0.2 and ρ=0.25, image quality is had little to no effect.I.e. when applying the present invention, during ρ >=0.2, it is greatly shortened Scanning process required time, does not the most affect image quality.

The non-intrusion type laser scanning imaging method based on stochastical sampling of the present invention, utilizes stochastical sampling to reconstruct with low-rank Method, obtain incomplete fluorescence intensity matrix by stochastical sampling, then by retraining with total variance with low-rank constraint Restructing algorithm rebuild fluorescence intensity matrix, and eventually pass through phase recovery and obtain the picture of object；By the method for the present invention, greatly The big acquisition time shortening imaging data, can also keep higher image quality simultaneously.

Above content is to combine concrete preferred implementation further description made for the present invention, it is impossible to assert Being embodied as of the present invention is confined to these explanations.For those skilled in the art, do not taking off On the premise of present inventive concept, it is also possible to make some equivalents and substitute or obvious modification, and performance or purposes are identical, all answer When being considered as belonging to protection scope of the present invention.

Claims (6)

1. a non-intrusion type laser scanning imaging method based on stochastical sampling, it is characterised in that comprise the following steps:

S1: generate the random matrix Φ that element only comprises 0 and 1, wherein the size of random matrix Φ and fluorescence intensity matrix I and Corresponding scanning angle matrix Θ's is equivalently-sized；

S2: by the angle on the scanning angle matrix Θ that element that laser scanning random matrix Φ intermediate value is 1 is corresponding, collect with Machine matrix Φ intermediate value is the fluorescence intensity on the fluorescence intensity matrix I corresponding to element of 1, obtains incomplete fluorescence intensity matrixWhereinSymbol represents that corresponding element is multiplied；

S3: by solving the reconstruction model under the constraint of following low-rank, to obtain complete fluorescence intensity matrix I=U；

$I=\arg \underset{U}{min}\{TV\left(U\right)+\mathrm{\η}\·\underset{P_k\∈\mathrm{\Δ}}{\mathrm{\Σ}}\left(w\right(P_k)\·|\left|P_k\right|{|}_{*})\}$

$\begin{array}{ccc}s.t.& U_{i,j}={\hat{I}}_{i,j},& \∀(i,j)\∈\mathrm{\Ω}\end{array}$

Wherein, TV is total variance function, P_kFor the matrix-block of p × p, w (P_k) it is matrix-block P_kCorresponding weighting function, | | | |_* For nuclear norm, η is regular parameter, and Δ is all matrix-block P of matrix U to be asked_kSet, Ω is the index of the element acquired Set；

S4: recover the picture of object in the complete fluorescence intensity matrix reconstructed from step S3.

Non-intrusion type laser scanning imaging method the most according to claim 1, it is characterised in that random matrix in step S1 Element 1 proportion in Φ is more than 20%.

Non-intrusion type laser scanning imaging method the most according to claim 1, it is characterised in that use galvanometer in step S2 Scanning system carries out laser scanning.

Non-intrusion type laser scanning imaging method the most according to claim 1, it is characterised in that the matrix-block in step S3 P_kCorresponding weighting function w (P_k) carry out value according to following formula:

$w\left(P_k\right)=\left\{\begin{array}{cc}{{\mathrm{\ξ}}_k}^2,& {\mathrm{\ξ}}_k>\mathrm{\λ}\\ 0,& {\mathrm{\ξ}}_k\≤\mathrm{\λ}\end{array}\right.$

Wherein, ξ_kFor matrix-block P_kIn the number of element that acquires, λ is threshold value.

Non-intrusion type laser scanning imaging method the most according to claim 4, it is characterised in that wherein threshold value λ=0.2 p²。

6. according to the non-intrusion type laser scanning imaging method described in any one of claim 1 to 5, it is characterised in that step S4 In specifically include: use in the complete fluorescence intensity matrix that reconstructs from step S3 of Phase Retrieve Algorithm and recover object Picture.