CN104484894A - Multi-wavelength lamination imaging technology facing to three-dimensional information recovery - Google Patents

Abstract

The invention discloses a multi-wavelength lamination imaging technology facing to three-dimensional information recovery. Samples to be tested are irradiated by various wavelengths and are translated successively in a lamination scanning way in a measurement plane, and corresponding series intensity images are recorded by an image sensor, the recorded series intensity images are processed, and a three-dimensional image of each sample to be tested can be obtained in a computer by an iterative reconstruction algorithm based on multi-wavelength lamination scanning. According to the selection of diffraction distance in a multi-wavelength lamination algorithm, the information of the surface layer, the bottom layer and each inner layer of each sample to be tested can be respectively recovered, i.e. the three-dimensional complex amplitude information of the sample to be tested can be recovered, and the problem that layers in the traditional lamination imaging are mutually overlapped and are difficult to distinguish can be effectively solved. According to the multi-wavelength lamination imaging technology, various wavelengths are adopted, so that the quality of the recovered image can be greatly improved, and meanwhile, the anti-noise capability of the system is better. The multi-wavelength lamination imaging technology has the advantages of high imaging efficiency and good transportability and is suitable for the three-dimensional imaging of the surface layer of a reflection-type object, the imaging of the surface layer and the bottom layer of a transmission-type thin object and the three-dimensional imaging of each layer of a transmission-type thick object.

Description

Towards the multi-wavelength lamination imaging technique of three dimensional signal space

Technical field

The present invention relates to 3 Dimension Image Technique, be specifically related to a kind of thicker testing sample be recovered the three-dimensional complex amplitude image information of its top layer and inside with multi-wavelength illumination by the mode of lamination scanning.

Background technology

Lamination imaging technique is a kind of lensless scanning coherent diffraction imaging technology, by controlling illuminating bundle or object, the diverse location in illuminated objects, and then recovers subject image with a series of diffraction patterns obtained.See (Ultramicroscopy 10 (3): 187 ~ 198,1987).Lamination iterative algorithm belongs to a kind of Phase Retrieve Algorithm in essence, but its Phase Retrieve Algorithm again from traditional is different, retrain when carrying out phase recovery to the Diffraction fringe distribution of each position, eliminate the ambiguity understood, therefore relative to traditional Phase Retrieve Algorithm, speed of convergence is enhanced, and can recover sample image information faster.When replacing Single wavelength to irradiate with multi-wavelength, its image quality can be greatly improved.Along with going deep into of research, lamination imaging technique shows the huge advantage in significantly picture imaging and high-resolution imaging.

But traditional lamination imaging carries out iteration by the diffraction pattern of scan aperture and sample, clearly can only rebuild amplitude and the phase information of thinner sample, have good application in recovery two dimensional image field.But along with sample thickness increases, the strength information that CCD receives derives from that sample is each stackedly to be added, and what recover is each stacked image be added together, and is difficult to the information telling each layer; So when sample is thick object, the image that conventional two-dimensional lamination imaging technique recovers is unsatisfactory, and can not obtain sample successively detailed information clearly, this also becomes one of its major defect.See (Acta Crystallogr:A 25,495,1969).And it is also immature at present to carry out three-dimensional complex amplitude imaging technique to thick object, in order to recover the complex amplitude information of object, in lamination algorithm, often need a large amount of scan aperture illuminations and iterations.See (Opt.Soc.29 (8), 1606-1614,2014).

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, solving the problem of interference mutually between layers in traditional thick object lamination imaging process, and three-dimensional imaging can be carried out to thick object.Meanwhile, adopt multi-wavelength lighting engineering, the picture quality recovered is had and significantly improves.

The present invention realizes by following technical measures:

First to throw light on testing sample with red laser, and testing sample is carried out translation by the mode of lamination scanning in object plane, record the intensity image corresponding to each scanning position successively with imageing sensor.Subsequently respectively with green laser and blue laser illumination sample to be tested repeat above-mentioned steps; The last lamination iterative algorithm the process on computers intensity image of record being carried out to throw light on based on multi-wavelength, reappears the complex amplitude image of each layer of testing sample.

The scanning of described lamination is so a kind of scan mode, the testing sample distance that translation is certain successively in object plane, need to ensure between adjacent flat pan position on testing sample by the region memory of beam lighting certain overlapping during translation.

The present invention's imaging algorithm used is the iterative reconstruction algorithm based on the scanning of multi-wavelength lamination, and its specific implementation process is:

(1) guess the COMPLEX AMPLITUDE of first face object and probe, and start following iterative process.First surface is n ₁, second is n ₂, the 3rd is n ₃n face is n _n.

(2) complex amplitude that ground floor wavelength is λ outgoing wave is calculated

${\mathrm{\ψ}}_{e,1,{\mathrm{\λ}}_i}=P(r-R_c)\·O_1\left(r\right)---\left(1\right)$

(3) propagation wave is front to second face, then the incident wavefront in second face is: here P Δ z _ndistance, delta z _n=z _n+1-z _nfor angular spectrum propagation factor.

(4) COMPLEX AMPLITUDE of second face outgoing is calculated and wavefront is gone out the 3rd face, corresponding incident complex amplitude is

(5) diffraction process of multiple is calculated, until obtain the outgoing complex amplitude of each

(6) front propagation is to CCD face, here F represents Fourier transform or distance is the Fresnel transform of d.

(7) will mould be updated to namely have;

${\mathrm{\ψ}}_{c,{\mathrm{\λ}}_i}^{\′}=\sqrt{I_{c,\mathrm{\λ}}\left(u\right)}\frac{{\mathrm{\ψ}}_{c,{\mathrm{\λ}}_i}}{\left|{\mathrm{\ψ}}_{c,{\mathrm{\λ}}_i}\right|}---\left(2\right)$

(8) be diffracted into the N number of by inverse for the wavefront after CCD upgrades, obtain one and upgrade

${\mathrm{\ψ}}_{e,N,{\mathrm{\λ}}_i}=F\left[{\mathrm{\ψ}}_{c,{\mathrm{\λ}}_i}^{\′}u\right]---\left(3\right)$

(9) make and upgrade the incident wavefront of N number of and the wavefront of the N number of:

${\mathrm{\ψ}}_{i,N,{\mathrm{\λ}}_i}^{\′}\left(r\right)=u[{\mathrm{\ψ}}_{i,N,{\mathrm{\λ}}_i}\left(r\right),O_N\left(r\right),\mathrm{\Δ\ψ}\left(r\right)]---\left(4\right)$

$O_N^{\′}\left(r\right)=u[O_N\left(r\right),{\mathrm{\ψ}}_{i,N,{\mathrm{\λ}}_i}\left(r\right),\mathrm{\Δ\ψ}\left(r\right)]---\left(5\right)$

Here function U can be written as:

$u[f\left(r\right),g\left(r\right),\mathrm{\Δ\ψ}\left(r\right)]=f\left(r\right)+\mathrm{\α}\frac{g^{*}\left(r\right)}{{\left|g\left(r\right)\right|}_{\max }}\mathrm{\Δ\ψ}\left(r\right)---\left(6\right)$

(10) the inverse incident wave being diffracted into renewal to N-1 face:

${\mathrm{\ψ}}_{e,N-1,{\mathrm{\λ}}_i}^{\′}\left(r\right)=P_{-\mathrm{\Δ}{z}_{(N-1)}}\left[{\mathrm{\ψ}}_{i,N,{\mathrm{\λ}}_i}^{\′}\left(r\right)\right]---\left(7\right)$

(11) make and upgrade the incident wavefront in N-1 face and the COMPLEX AMPLITUDE in N-1 face:

${\mathrm{\ψ}}_{i,N-1,{\mathrm{\λ}}_i}^{\′}\left(r\right)=u[{\mathrm{\ψ}}_{i,N-1,{\mathrm{\λ}}_i}\left(r\right),O_{N-1}\left(r\right),\mathrm{\Δ\ψ}\left(r\right)]---\left(8\right)$

$O_{N-1}^{\′}\left(r\right)=u[O_{N-1}\left(r\right),{\mathrm{\ψ}}_{i,N-1,{\mathrm{\λ}}_i}\left(r\right),\mathrm{\Δ\ψ}\left(r\right)]---\left(9\right)$

(12) repeat step 10-11, calculate N-2 face (λ respectively ₁, λ ₂, λ ₃), N-3 face (λ ₁, λ ₂, λ ₃), known to first face.

(13) make and upgrade the COMPLEX AMPLITUDE in illumination aperture and first face,

P′(r-R _c)＝u[P(r-R _c)，O ₁(r)，ΔΨ(r)] (10)

O′ ₁(r)＝u[O ₁(r)，P(r-R _c)，ΔΨ(r)] (11)

Repeat 1-14 until all probe carry out traveling through once, then complete an iteration.Reach iteration threshold or maximum iteration time.

The present invention compared with prior art has following advantage:

(1) utilize formation method of the present invention successively can recover the complex amplitude information of each focal plane of thick sample, and finally synthesize the three-dimensional image information of thick object.

(2) because the present invention is thrown light on the laser instrument of multi-wavelength respectively, the three-dimensional image information recovered significantly is improved.

(3) the present invention is thrown light on the laser instrument of multi-wavelength respectively, can recover the image can not recovered out when adopting Single wavelength illumination.

3-D stacks formation method based on multi-wavelength illumination disclosed in this invention, is applicable to each level three-dimensional imaging of reflection-type object and the thick object of transmission-type.

Accompanying drawing explanation

Fig. 1 a is that formation method of the present invention is imaged as the light channel structure figure of embodiment at the 3-D stacks thrown light on transmission-type multi-wavelength.

Fig. 1 b is that formation method of the present invention is imaged as the light channel structure figure of embodiment at the 3-D stacks thrown light on reflective multi-wavelength.

Fig. 2 a is the amplitude image picture of the ground floor testing sample that in embodiment, Numerical Experiment is used;

Fig. 2 b is the position phase images of the ground floor testing sample that in embodiment, Numerical Experiment is used;

Fig. 2 c is the amplitude image picture of the second layer testing sample that in embodiment, Numerical Experiment is used;

Fig. 2 d is the position phase images of the second layer testing sample that in embodiment, Numerical Experiment is used;

Fig. 2 e is the amplitude image picture of the third layer testing sample that in embodiment, Numerical Experiment is used;

Fig. 2 f is the position phase images of the third layer testing sample that in embodiment, Numerical Experiment is used;

Fig. 3 a is the lamination scanning schematic diagram of Numerical Experiment in embodiment;

Fig. 3 b is the schematic diagram of Numerical Experiment scanning position central point position in embodiment;

Fig. 4 a is the amplitude image picture adopting the ground floor testing sample rebuild under single wavelength laser lighting condition in embodiment in Numerical Experiment;

Fig. 4 b is the position phase images adopting the ground floor testing sample rebuild under single wavelength laser lighting condition in embodiment in Numerical Experiment;

Fig. 4 c is the amplitude image picture adopting the second layer testing sample rebuild under single wavelength laser lighting condition in embodiment in Numerical Experiment;

Fig. 4 d is the position phase images adopting the second layer testing sample rebuild under single wavelength laser lighting condition in embodiment in Numerical Experiment;

Fig. 4 e is the amplitude image picture adopting the third layer testing sample rebuild under single wavelength laser lighting condition in embodiment in Numerical Experiment;

Fig. 4 f is the position phase images adopting the third layer testing sample rebuild under single wavelength laser lighting condition in embodiment in Numerical Experiment;

Fig. 5 a is the amplitude image picture adopting the ground floor testing sample rebuild in three kinds of different wave length laser illumination situations in embodiment in Numerical Experiment;

Fig. 5 b is the position phase images adopting the ground floor testing sample rebuild in three kinds of different wave length laser illumination situations in embodiment in Numerical Experiment;

Fig. 5 c is the amplitude image picture adopting the second layer testing sample rebuild in three kinds of different wave length laser illumination situations in embodiment in Numerical Experiment;

Fig. 5 d is the position phase images adopting the second layer testing sample rebuild in three kinds of different wave length laser illumination situations in embodiment in Numerical Experiment;

Fig. 5 e is the amplitude image picture adopting the third layer testing sample rebuild in three kinds of different wave length laser illumination situations in embodiment in Numerical Experiment;

Fig. 5 f is the position phase images adopting the third layer testing sample rebuild in three kinds of different wave length laser illumination situations in embodiment in Numerical Experiment;

When Fig. 6 a is the random noise introducing 10% in embodiment in Numerical Experiment, the amplitude image picture of the ground floor testing sample rebuild under adopting single wavelength laser lighting condition;

When Fig. 6 b is the random noise introducing 10% in embodiment in Numerical Experiment, the position phase images of the ground floor testing sample rebuild under adopting single wavelength laser lighting condition;

When Fig. 6 c is the random noise introducing 10% in embodiment in Numerical Experiment, the amplitude image picture of the second layer testing sample rebuild under adopting single wavelength laser lighting condition;

When Fig. 6 d is the random noise introducing 10% in embodiment in Numerical Experiment, the position phase images of the second layer testing sample rebuild under adopting single wavelength laser lighting condition;

When Fig. 6 e is the random noise introducing 10% in embodiment in Numerical Experiment, the amplitude image picture of the third layer testing sample rebuild under adopting single wavelength laser lighting condition;

When Fig. 6 f is the random noise introducing 10% in embodiment in Numerical Experiment, the position phase images of the third layer testing sample rebuild under adopting single wavelength laser lighting condition;

When Fig. 7 a is the random noise introducing 10% in embodiment in Numerical Experiment, the amplitude image picture of the ground floor testing sample rebuild under adopting three kinds of different wave length laser illumination situations;

When Fig. 7 b is the random noise introducing 10% in embodiment in Numerical Experiment, the position phase images of the ground floor testing sample rebuild under adopting three kinds of different wave length laser illumination situations;

When Fig. 7 c is the random noise introducing 10% in embodiment in Numerical Experiment, the amplitude image picture of the second layer testing sample rebuild under adopting three kinds of different wave length laser illumination situations;

When Fig. 7 d is the random noise introducing 10% in embodiment in Numerical Experiment, the position phase images of the second layer testing sample rebuild under adopting three kinds of different wave length laser illumination situations;

When Fig. 7 e is the random noise introducing 10% in embodiment in Numerical Experiment, the amplitude image picture of the third layer testing sample rebuild under adopting three kinds of different wave length laser illumination situations;

When Fig. 7 f is the random noise introducing 10% in embodiment in Numerical Experiment, the position phase images of the third layer testing sample rebuild under adopting three kinds of different wave length laser illumination situations;

Wherein, 1. red laser, 2. green laser, 3. blue laser, 4. beam splitter, 5. collimating and beam expanding system, 6. two-dimension translational platform and testing sample (a. ground floor testing sample, b. second layer testing sample, c. third layer testing sample), 7. CCD image sensor, 8. computing machine, 9. catoptron.

Embodiment

Below in conjunction with accompanying drawing and embodiment, the present invention will be further described.

Fig. 1 a and Fig. 1 b is formation method of the present invention at the light channel structure figure of two kinds of exemplary embodiment of transmission-type and the imaging of reflective multi-wavelength lamination respectively.This structure comprises red laser 1, green laser 2, blue laser 3, beam splitter 4, collimating and beam expanding system 5, two-dimension translational platform and testing sample 6, CCD image sensor 7, computing machine 8, catoptron 9.Translate stage 6 is d to the distance of imageing sensor 7.Translate stage 6 and imageing sensor 7 have controlled phase-shift phase interpolation by computing machine 8 respectively, lamination scans and image record.First open red laser 1, closedown green laser 2, blue laser 3 are tested, and record the intensity image under one group of red light irradiation; Open green laser 2 subsequently, closedown red laser 1, blue laser 3 are tested, and record the intensity image under one group of green glow irradiation; Then open blue laser 3, closedown red laser 1, green laser 2 are tested, and record the intensity image under one group of blue light illumination; The last three-dimensional complex amplitude information extracting testing sample from the intensity image of recorded three kinds of wavelength is completed by the computer program designed according to the inventive method.

Fig. 2 a Fig. 2 d is the initial setup data used during the Computer Numerical Simulation of carrying out for above-described embodiment is tested.Fig. 2 a and Fig. 2 b is amplitude and the phase information of ground floor testing sample used in experiment, and they are 256 × 256 pixels, amplitude by naturalization to [0,1], position by naturalization to [0,2 π].Fig. 2 c and Fig. 2 d is amplitude and the phase information of second layer testing sample used in experiment, and they are 256 × 256 pixels, amplitude by naturalization to [0,1], position by naturalization to [0,2 π].Fig. 2 e and Fig. 2 f is amplitude and the phase information of third layer testing sample used in experiment, and they are 256 × 256 pixels, amplitude by naturalization to [0,1], position by naturalization to [0,2 π].

Fig. 3 a is lamination scanning schematic diagram, and the circular port of illuminator probe to be radius be 70 pixels, the overlapping ratio in adjacent illumination region is 0.64.Fig. 3 b is the lamination scanning position figure used in experiment, and have 4 × 4 scanning positions in figure, the central point of each scanning position uses "+" to mark, and uses symbol P _mn(m, n are respectively the row and column ordinal number of scan matrix) carries out marking to show difference.In experiment, three kinds of laser wavelength lambda are respectively 632.8nm, 532nm and 473nm, and the spacing d of imageing sensor and translate stage is 30mm, and the pixel size of imageing sensor is 6.45 μm.

Fig. 4 a and Fig. 4 b is respectively and is adopting amplitude and the position phase images of the ground floor testing sample recovered with designed computer program under single wavelength laser lighting condition; Fig. 4 c and Fig. 4 d is respectively amplitude and the position phase images of the second layer testing sample recovered; Fig. 4 e and Fig. 4 f is respectively amplitude and the position phase images of the third layer testing sample recovered.Wherein iterations k=200.

As can be seen from Fig. 4 a ~ 4f we, under single wavelength laser lighting condition, the thick object dimensional information effect recovered in example is not very desirable, is difficult to tell original image.

Fig. 5 a and Fig. 5 b is respectively amplitude and the position phase images of the testing sample using the inventive method to recover with designed computer program in three kinds of different wave length laser illumination situations; Fig. 5 c and Fig. 5 d is respectively amplitude and the position phase images of the second layer testing sample recovered; Fig. 5 e and Fig. 5 f is respectively amplitude and the position phase images of the third layer testing sample recovered.Wherein iterations k=200.

As can be seen from the contrast of Fig. 4 and Fig. 5 we, in the present invention propose adopt multi-wavelength irradiate lamination imaging technique, not only can recover the 3-D view of the original more accurately, when even being substantially difficult to tell original image information in Single wavelength irradiation example, still can recover the three-dimensional image information of each level of the original very accurately.

Fig. 6 a and Fig. 6 b is respectively when the random noise of introducing 10%, adopts ground floor amplitude and the position phase images of the testing sample recovered with designed computer program under single wavelength laser lighting condition; Fig. 6 c and Fig. 6 d is respectively when the random noise of introducing 10%, adopts second layer amplitude and the position phase images of the testing sample recovered with designed computer program under single wavelength laser lighting condition; Fig. 6 e and Fig. 6 f is respectively when the random noise of introducing 10%, adopts third layer amplitude and the position phase images of the testing sample recovered with designed computer program under single wavelength laser lighting condition;

When Fig. 7 a and Fig. 7 b is respectively the random noise of introducing 10%, adopt ground floor amplitude and the position phase images of the testing sample recovered with designed computer program under three-wavelength laser lighting condition proposed by the invention; When Fig. 7 c and Fig. 7 d is respectively the random noise of introducing 10%, adopt second layer amplitude and the position phase images of the testing sample recovered with designed computer program under three-wavelength laser lighting condition proposed by the invention; When Fig. 7 e and 7f is respectively the random noise of introducing 10%, adopt third layer amplitude and the position phase images of the testing sample recovered with designed computer program under three-wavelength laser lighting condition proposed by the invention;

As can be seen from the result of Fig. 6, when introducing 10% random noise, the impact that the result adopting the illumination of Single wavelength to carry out rebuilding is subject to is very large, rebuilds image and is difficult to further differentiate.And the result of Fig. 7, when introducing the random noise of 10%, adopt the result images rebuild when three wavelength illumination still very clear.The experimental result of comparison diagram 6 and Fig. 7 can be found out, has stronger noise resisting ability compared with the result images reconstructed throws light on traditional Single wavelength when employing three kinds of wavelength illumination proposed by the invention.

Said method and embodiment are all recorded the intensity image of testing sample different parts by the mode of multi-wavelength irradiation lamination scanning, and carry out lamination iterative approximation to recover for the purpose of the three-dimensional complex amplitude information of sample to be tested to intensity image.Enforcement of the present invention is not limited to above-mentioned specific embodiments.As long as carry out three-D imaging method, device and system by the lamination scanning under multi-wavelength illumination and lamination iterative approximation to object, all belong to protection scope of the present invention.

Claims (7)

1., towards a multi-wavelength monolithic three-dimensional imaging technique for thick object, its imaging process comprises the following steps:

The first step, adopts red laser illumination, testing sample is carried out translation in the mode of lamination scanning in object plane, and records the intensity image corresponding to each scanning position successively with imageing sensor;

Second step, adopts green laser illumination, testing sample is carried out translation in the mode of lamination scanning in object plane, and records the intensity image corresponding to each scanning position successively with imageing sensor;

3rd step, adopts blue laser illumination, testing sample is carried out translation in the mode of lamination scanning in object plane, and records the intensity image corresponding to each scanning position successively with imageing sensor;

4th step, uses the iterative algorithm based on the lamination scanning of multi-wavelength illumination to rebuild the three-dimensional complex amplitude image of testing sample.

2. as in claim 1 use based on multi-wavelength lamination scanning iterative reconstruction algorithm, it is characterized in that, the complex amplitude information of each layer of testing sample can be gone out by choosing different diffraction range recovery, and then recover the three-dimensional complex amplitude image information of testing sample.

3. as in claim 1 use based on multi-wavelength irradiate lamination scanning method, it is characterized in that, the laser instrument same testing sample being chosen to multiple different wave length throws light on, and increases substantially to make the three-dimensional complex amplitude picture quality of sample recovered.

4. as in claim 1 use based on multi-wavelength irradiate lamination scanning method, it is characterized in that, the laser instrument same testing sample being chosen to multiple different wave length throws light on, and system can be made to have stronger noise resisting ability.

5. as claim 1, lamination scanning described in 2,3 and 4, is characterized in that, the testing sample distance that translation is certain successively in object plane two-dimensional coordinate completes scanning, and to ensure between adjacent flat pan position on testing sample by the region memory of beam lighting certain overlapping.

6., as claim 1, the lamination scanning described in 2,3 and 4, is characterized in that, can be optimized design according to the relative size of actual illumination light beam and testing sample.

7., as described in claim 1 towards the multi-wavelength lamination imaging technique of thick object dimensional imaging, be applicable to the top layer three-dimensional imaging of reflection-type object, each level three-dimensional imaging of the top layer of transmission-type thin objects and bottom imaging and the thick object of transmission-type.