CN201421432Y - A coherent diffraction imaging processing device - Google Patents

Abstract

The utility model discloses a coherent diffraction imaging processing device. It includes a light source, a sample stage for placing samples, and an image recording and processing device. It is characterized in that it also includes a beam expander and wave front shaper, a multi-pinhole plate and a stepping rotation bracket; the multi-pinhole plate is installed on the stepping rotation bracket Above, the center of the reference pinhole on the multi-pinhole plate coincides with the rotation center of the stepping rotating bracket; the light source, beam expander and wave surface shaper, sample, multi-pinhole plate and image recording and processing device are arranged in sequence along the direction of beam advancement The image recording and processing device includes an image sensor, which is placed behind the stepping and rotating bracket and connected with the computer; meanwhile, the computer is also connected with the stepping and rotating bracket. It is simple in structure, easy to adjust, and low in cost. It is suitable for a variety of different light sources, and can realize the imaging of multiple objects or three-dimensional objects without imaging lenses. It is especially suitable for occasions such as X-rays where it is difficult to prepare high-quality imaging lenses. .

Description

A coherent diffraction imaging processing device

technical field

The utility model relates to a coherent diffraction imaging technology, in particular to a coherent diffraction imaging processing device which uses a multi-pinhole plate to realize the recording and reproduction of general complex amplitude objects.

Background technique

Coherent diffraction imaging is a technology that utilizes the far field of object waves or the intensity distribution of Fraunhofer diffraction to realize imaging of complex or three-dimensional objects. Because it can avoid the limitations of imaging lens aperture and aberration on resolution, this technology is especially suitable for fields such as X-rays and electron beams that lack or are difficult to manufacture high-quality imaging lenses. The key problem of coherent diffraction imaging technology is how to accurately and quickly recover the amplitude and phase information of the measured object wave from one or more diffraction intensity patterns. At present, one of the main ways to solve this problem is to use iterative algorithm. Traditional iterative methods generally require a long iteration time, and there are uncertainties in the iterative results; there are also some harsh restrictions on the measured object, such as the object must be specially fixed, and the measured object is required to be a pure amplitude object or a pure phase object ,etc.

In order to improve the accuracy and imaging speed of phase recovery, some improved diffraction imaging techniques have been developed in recent years, such as super-sampling diffraction imaging technology, partition scanning diffraction imaging technology, etc. (see Phys.Rev.Lett.93, 023903 (2004 ); Phys. Rev. Lett. 98, 034801 (2007); Phys. Rev. Lett. 100, 155503 (2008); Science 321, 379 (2008)). But none of the above techniques can fundamentally avoid the uncertainty of iterative algorithms and iterative results. The phase recovery process still needs to involve a large number of iterative processes; this means that it is still relatively difficult to achieve dynamic or real-time imaging with these methods.

Utility model content

The purpose of the utility model is to overcome the existing problems and deficiencies in the prior art, and provide a coherent diffraction imaging processing device, which allows the object wave emitted by the imaged object to pass through a rotatable multi-pinhole plate first, and then The image sensor is used to record the Fraunhofer diffraction intensity distribution of the object wave passing through the multi-pinhole plate, and finally the amplitude and phase distribution information of the measured object wave is extracted by means of computer image processing technology.

In order to achieve the above object, the utility model adopts the following technical solutions:

A coherent diffraction imaging processing device, which includes a light source, a sample stage for placing samples, and an image recording and processing device, and is characterized in that it also includes a beam expander and wavefront shaper, a multi-pinhole plate and a stepping rotary support; a multi-pin The orifice plate is installed on the stepping rotating bracket, and the center of the reference pinhole on the multi-pinhole plate coincides with the rotation center of the stepping rotating bracket; the light source, beam expander and wave surface shaper, sample, multi-pin are arranged in sequence along the direction of beam advance The orifice plate and the image recording and processing device; the image recording and processing device includes an image sensor, the image sensor is placed behind the stepping and rotating bracket, and is connected with a computer; meanwhile, the computer is also connected with the stepping and rotating bracket.

The distance Z1 between the sample and the multi-pinhole plate ensures that the phase change of the object wave irradiated on the multi-pinhole plate on the clear aperture of each pinhole is not greater than π/4 radians; the image sensor and the multi-pinhole plate The distance Z2 between them satisfies the Fraunhofer diffraction condition, that is, the light field distribution on the image sensor recording plane is proportional to the Fourier transform of the object wave passing through the multi-pinhole plate.

A coherent diffraction imaging processing device, which includes a light source, a sample stage for placing samples, and an image recording and processing device, and is characterized in that it also includes a beam expander and wavefront shaper, a multi-pinhole plate, a stepping and rotating bracket, and a Fourier Leaf transformation lens, the multi-pinhole plate is installed on the stepping rotation bracket, the center of the reference pinhole on the multi-pinhole plate coincides with the rotation center of the stepping rotation bracket; the light source, beam expansion and wave surface shaping are arranged in sequence along the direction of the beam advance device, sample, multi-pinhole plate, Fourier transform lens, and image recording and processing device; the image recording and processing device includes an image sensor, which is placed behind the stepping and rotating bracket and connected to the computer; at the same time, the computer is also connected to the stepper into the swivel bracket connection.

The distance Z1 between the sample and the multi-pinhole plate ensures that the phase change of the object wave irradiated on the multi-pinhole plate on the clear aperture of each pinhole is not greater than π/4 radians; the image sensor is located in the Fourier transform The light field distribution on the back focal plane of the lens, that is, the recording plane of the image sensor, is proportional to the Fourier transform of the object wave passing through the multi-pinhole plate.

The multi-pinhole plate is composed of a reference pinhole and several measuring pinholes arranged on an opaque thin plate; the distribution of each pinhole on the multi-pinhole plate meets the following requirements: two identical multi-pinhole plates are placed overlappingly, When one of the pinholes is translated so that the reference pinhole overlaps with any measurement pinhole of the other piece, the other pinholes will not overlap; the size of the pinhole satisfies that the phase change of the object wave within the range of a pinhole is not more than 1/4 one wavelength.

The pinholes on the multi-pinhole plate are evenly distributed on a semicircular ring, the center of the pinholes are equally spaced, not less than 1.5 times the diameter of the pinhole, and the pinholes at one end of the semicircular ring in the center of the pinhole plate are used as a reference pinhole, other pinholes are measuring pinholes.

The pinholes on the multi-pinhole plate are distributed on three straight lines at 120 degrees to each other, wherein the pinhole located at the intersection of the three straight lines in the center of the pinhole plate is a reference pinhole, and the other pinholes are all measuring pinholes; the reference needle The distance D0 between the center of the hole and the center of the adjacent measuring pinhole is not less than 1.5 times the diameter of the pinhole, and the intervals between the centers of other measuring pinholes are equal, which are twice as long as D0.

This method does not require an iterative process at all. The phase recovery process is only performed in one diffraction intensity image, and does not involve the interactive processing of multiple images, so the phase recovery process can be performed simultaneously with the scanning and recording process of the diffraction pattern. This can not only greatly reduce the requirements on the scanning recording process and positioning accuracy, but also greatly increase the diffraction imaging speed, thus providing the possibility for real-time coherent diffraction imaging.

In order to realize the utility model, a specially designed diffraction imaging processing device must be used. The diffraction imaging processing device of the utility model comprises a light source, a beam expander and a wave surface shaper, a sample stage, an object to be imaged, a multi-pinhole plate, a stepping rotating frame, an image sensor and a computer. A light source, a beam expander and a wavefront shaper, an imaged object, a multi-pinhole plate and an image sensor are arranged coaxially (optical axis) in sequence along the light beam advancing direction. The object to be imaged is placed on the sample stage. The multi-pinhole plate is fixed on a step-rotation frame that can rotate in precise steps. The image sensor and the stepping rotating frame are connected with the computer, and the quantitative rotation of the rotating frame and the synchronous recording of the image sensor are controlled by the computer. The distance between adjacent parts is adjustable.

The method of the present utility model is:

(1) A monochromatic light is emitted from the light source, and the object to be imaged is illuminated after beam expansion and wavefront shaping. The light wave (that is, the object wave) passing through the object travels a distance Z1 and then irradiates a specially designed multi-pinhole plate. This multi-pinhole board has a reference pinhole and multiple measurement pinholes.

(2) The object wave passing through the multi-pinhole plate continues to travel distance Z2 to reach the recording plane, and forms its Fraunhofer diffraction light field on the recording plane. A two-dimensional image sensor (such as a CCD) is used to record the intensity distribution pattern of the Fraunhofer diffraction light field at the recording plane.

(3) Perform an inverse Fourier transform on the Fraunhofer diffraction intensity pattern in the computer to obtain a correlation function pattern (generally a complex variable function) of the complex amplitude of the object wave passing through the multi-pinhole plate. By extracting the function value of the point corresponding to the center position of each measuring pinhole on the multi-pinhole plate in the correlation function pattern, the relative amplitude and phase value of the measured object wave at each measuring pinhole can be obtained.

(4) Rotate the multi-pinhole plate with the center of the reference pinhole as the axis, so that the measuring pinhole scans on the plane where the multi-pinhole plate is located. Record the Fraunhofer diffraction intensity patterns of the object wave passing through the multi-pinhole plate at different rotation angles, and repeat step (3) for each recorded diffraction intensity pattern, to obtain the object wave on the plane where the multi-pinhole plate is located A 2D sampled array of the complex amplitude distribution of . Using this sampling array, the imaged object can be reproduced in a computer.

In the above method, the light source in step (1) can be a visible light source, or other coherent wave sources, such as ultraviolet light, X-rays, electron beams, etc. The beam expansion and wave surface shaping processing unit mainly includes a beam expander, a limiting diaphragm, a collimator or a converging device, which are arranged coaxially in sequence along the beam propagation direction, and the purpose is to perform wave front shaping on the light wave emitted from the light source to generate a subsequent optical path Coherent plane or spherical waves required. The multi-pinhole plate used in step (1) is formed by preparing several tiny pinholes on an opaque thin plate. The pinholes on the multi-pinhole board include a reference pinhole and several measurement pinholes. Their arrangement on the multi-pinhole board meets the following requirements: If two identical multi-pinhole boards are placed on top of each other, when one of them is translated so that the reference pinhole overlaps with any measurement pinhole of the other, the other None of the pinholes overlap. The shape of the pinholes on the multi-pinhole board can be a round hole or a light-through hole of other shapes. The size of the pinhole depends on the spatial variation of the complex amplitude distribution of the object wave propagating to the multi-pinhole plate, and it is generally required that the phase change of the object wave within a pinhole range is not greater than π/4 radians. When the size of the pinholes is constant, the above conditions can be met by properly selecting the distance Z1 between the multi-pinhole plate and the object to be imaged.

其中A_m为第m个针孔处的物波的振幅，为第m个针孔处的物波的相位，

为针孔板所在平面上的坐标变量(以参考针孔的中心为坐标原点)，

为第m个针孔中心的坐标，j为虚数，

为第m个针孔的孔径函数；在记录平面上得到的衍射光场的强度分布可表示为：The distance Z2 between the recording plane and the multi-pinhole plate in step (2) satisfies the Fraunhofer diffraction condition, that is, the diffracted light field on the recording plane is proportional to the object passing through the multi-pinhole plate on the plane of the multi-pinhole plate Fourier transform of a wave. Let the complex amplitude of the object wave passing through the mth pinhole on the multi-pinhole plate be

where A _m is the amplitude of the object wave at the mth pinhole, is the phase of the object wave at the mth pinhole,

is the coordinate variable on the plane where the pinhole plate is located (with the center of the reference pinhole as the coordinate origin),

is the coordinate of the center of the mth pinhole, j is an imaginary number,

is the aperture function of the mth pinhole; the intensity distribution of the diffracted light field obtained on the recording plane can be expressed as:

为傅立叶变换算符，N为针孔板上测量针孔的数目，m＝0对应参考针孔，

为记录平面上的坐标变量。Among them, I ₀ is the integral constant,

is the Fourier transform operator, N is the number of measuring pinholes on the pinhole plate, m=0 corresponds to the reference pinhole,

is the coordinate variable on the recording plane.

为The inverse Fourier transform of the diffraction intensity pattern in step (3) can be realized by reading the diffraction intensity pattern into the calculation with a computer program, or by a dedicated DSP chip. Since the intensity distribution of the Fraunhofer diffraction of the object wave described by formula (2) is proportional to the modulus of the Fourier transform function of the object wave, the result of its inverse Fourier transform is just the correlation function of the object wave. In general, it is a very difficult task to recover the complex amplitude function of the object wave from this correlation function, and an iterative algorithm is required. In this method, since the recorded diffraction intensity distribution is the Fraunhofer diffraction intensity of the object wave passing through the aforementioned multi-pinhole plate, the value of the correlation function at the point corresponding to the center position of any measuring pinhole is just proportional to The product of the complex amplitude of the object wave passing through the pinhole and the complex conjugate amplitude of the object wave passing through the reference pinhole (with the center of the reference pinhole as the coordinate center). Therefore, the method does not require any iterative algorithm. The complex amplitude of the object wave transmitted through the multi-pinhole plate can be directly extracted from the inverse Fourier transform pattern of the diffraction intensity pattern. The specific calculation process is as follows: Inverse Fourier transform is performed on formula (1), and the obtained correlation function

for

为第n个针孔处的物波的相位，Among them, A _n is the amplitude of the object wave at the nth pinhole,

is the phase of the object wave at the nth pinhole,

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; mn</span>}}<span\; class="notranslate">\; (</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; \&Integral;</span><span\; class="notranslate">\; \&Integral;</span>\mathrm{<span\; class="notranslate">\; circle</span>}<span\; class="notranslate">\; (</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}<span\; class="notranslate">\; -</span>{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; cir</span>}{\mathrm{<span\; class="notranslate">\; c</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; (</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}<span\; class="notranslate">\; -</span>{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; d</span>}\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}<span\; class="notranslate">\; ;</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

in, is the integral variable, and * is the conjugate symbol. According to the geometric meaning of the correlation operation shown in (3), and considering the distribution characteristics of the pinholes on the aforementioned pinhole plate, it can be known that (2) in the coordinate vector $\stackrel{\&Right\; Arrow;}{r}={\stackrel{\&Right\; Arrow;}{r}}_m$ The value at is proportional to the product of the complex amplitude of the object wave at the mth pinhole and the complex conjugate value of the object wave at the reference pinhole, that is

where P ₀ is a constant proportional to the area of the pinhole. Equation (4) shows that the value at the position corresponding to the center point of each measuring pinhole in the inverse Fourier transform pattern given by Equation (2) is just the relative value of the object wave passing through the pinhole we want to obtain. Complex amplitude value.

The rotatable multi-pinhole plate in step (4) takes a straight line passing through the center of the reference pinhole vertically as the axis of rotation. In this way, during the rotation process of the multi-pinhole plate, the position of the reference pinhole remains unchanged, thereby ensuring that the reference point of the object wave complex amplitude distribution measured at different rotation angles remains consistent.

The principle of the utility model is: the object wave emitted by the imaged object first passes through a rotatable multi-pinhole plate for sampling, and then an image sensor records the intensity of the Fraunhofer diffraction of the object wave passing through the multi-pinhole plate Then do inverse Fourier transform on the diffraction intensity distribution to obtain the autocorrelation function of the recorded object wave, and from the autocorrelation function, the points corresponding to the center position coordinates of each measuring pinhole can directly extract the measured object wave Amplitude and phase information to achieve diffraction imaging of complex amplitude objects.

The utility model has the following advantages and beneficial effects:

(1) No imaging lens is required. The amplitude and phase information of the object wave is recovered from the Fraunhofer diffraction intensity pattern of the object wave by a simple algorithm.

(2) The process of extracting the amplitude and phase information of the object wave from the Fraunhofer diffraction intensity pattern of the object wave does not require any iterative process, and the amplitude and phase information are obtained from the inverse Fu of the Fraunhofer diffraction intensity It is directly extracted from the leaf transform pattern.

(3) The extraction process of amplitude and phase information can be carried out synchronously with the recording process of the diffraction pattern, with high efficiency and fast speed, which provides a feasible way for the realization of dynamic coherent diffraction imaging.

(4) The extraction of amplitude and phase information does not involve interactive processing between multiple patterns, which can greatly reduce the requirements for the stability and scanning accuracy of the recording system.

(5) The multi-pinhole plate used in the present invention is easy to prepare, and is especially suitable for the wave bands that are difficult to be imaged by traditional imaging techniques such as X-rays.

Description of drawings

Fig. 1 is the process block diagram of coherent diffraction imaging method of the present utility model;

Fig. 2 is the pinhole distribution schematic diagram of the first design example of the multi-pinhole plate in the coherent diffraction imaging method of the present invention;

Fig. 3 is a schematic diagram of pinhole distribution of the second design example of the multi-pinhole plate of the present invention;

Fig. 4 is a schematic structural view of the first embodiment of the coherent diffraction imaging processing device of the present invention;

5 is a schematic structural view of a second embodiment of the coherent diffraction imaging processing device of the present invention;

Figure 6a is an example of an experimental result of coherent diffraction imaging using the coherent diffraction imaging method and device of the present invention;

Figure 6b is an example of an experimental result of coherent diffraction imaging using the coherent diffraction imaging method and device of the present invention;

Figure 6c is an example of an experimental result of coherent diffraction imaging using the coherent diffraction imaging method and device of the present invention;

Fig. 6d is an example of an experimental result of coherent diffraction imaging using the coherent diffraction imaging method and device of the present invention.

Among them, light source 1, beam expander and wave surface shaper 2, sample stage 3, sample 4, stepping and rotating bracket 5, multi-pinhole plate 6, image sensor 7, computer 8, and Fourier transform lens 9.

Detailed ways

In order to better understand the utility model, the utility model will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, the utility model method comprises the following steps: (1) a beam of monochromatic light emitted by the light source is processed by a beam expanding and wavefront shaping processing unit to form a beam of coherent plane waves (or converging spherical light); Coherent plane wave (or spherical wave) illuminates the imaged object placed on the sample stage; (2) The object wave that passes through the object propagates a certain distance Z1 and then irradiates a multi-pinhole fixed on a rotating support with a special pinhole distribution The pinholes on the multi-pinhole board consist of a reference pinhole and several measuring pinholes; (3) the object wave passing through the multi-pinhole board continues to propagate, and in the far field (or through a Fourier transform after changing the lens) to form the Fraunhofer diffraction light field; (4) use a two-dimensional image sensor (such as CCD) to record the Fraunhofer diffraction intensity pattern of the object wave passing through the multi-pinhole plate; (5) use the image The processing technology performs inverse Fourier transform on the Fraunhofer diffraction intensity pattern to obtain the correlation function pattern of the complex amplitude of the object wave passing through the multi-pinhole plate; Extract the function value of the point corresponding to the central position of , and then get the relative amplitude and phase value of the complex amplitude of the object wave passing through the multi-pinhole plate at each measuring pinhole; (6) take the center of the reference pinhole as the axis Rotate the multi-pinhole plate to make the measurement pinholes scan on the plane where the multi-pinhole plate is located. Record the Fraunhofer diffraction intensity patterns of the object wave passing through the multi-pinhole plate at different rotation angles, and repeat step (5) for each recorded diffraction intensity pattern, to obtain the object wave on the plane where the multi-pinhole plate is located. A 2D sampled array of the complex amplitude distribution of . Using this sampling array, the imaged object can be reproduced in a computer.

Fig. 2 is a typical implementation of the multi-pinhole plate of the present invention. The pinholes on the pinhole plate are evenly distributed on a semicircular ring, and the distance between the centers of the pinholes is not less than 1.5 times the diameter of the pinholes. The pinhole located at one end of the semicircular ring in the center of the pinhole plate is a reference pinhole, and the other pinholes are measuring pinholes. Place the multi-pinhole plate on the rotation stand so that the center of the reference pinhole coincides with the axis of rotation.

Fig. 3 is the second embodiment of the multi-pinhole plate described in the method of the present invention. The pinholes on the multi-pinhole plate are distributed on three straight lines at 120 degrees to each other. The pinhole located at the intersection of the three straight lines in the center of the pinhole plate is the reference pinhole, and the other pinholes are measurement pinholes. The distance D0 between the center of the reference pinhole and the center of the adjacent measuring pinhole is not less than 1.5 times the diameter of the pinhole. The intervals between the centers of other measuring pinholes are equal, which are twice of D0. Place the multi-pinhole plate on the rotation stand so that the center of the reference pinhole coincides with the axis of rotation.

Fig. 4 is a typical implementation of the coherent diffraction imaging processing device of the present invention. The device includes a light source 1 , a beam expander and wave front shaper 2 , a sample stage 3 , a sample 4 , a stepping and rotating support 5 , a multi-pinhole plate 6 , an image sensor 7 , and a computer 8 . A light source 1 , a beam expander and wavefront shaper 2 , a sample stage 3 , a sample 4 , a stepping and rotating support 5 , a multi-pinhole plate 6 , and an image sensor 7 are arranged coaxially (optical axis) in sequence along the beam advancing direction. The mutual positions of the light source 1, the beam expander and the wave surface shaper 2 ensure that the monochromatic light emitted by the light source 1 passes through the beam expander and the wave surface shaper 3 to form a beam of plane waves or spherical waves. The relative distance Z1 between the sample (object to be imaged) 4 and the multi-pinhole plate 6 ensures that the phase change of the object wave irradiated on the multi-pinhole plate on the clear aperture of each pinhole is not greater than π/4 radians. And the distance Z2 between the multi-pinhole plate 6 and the photosensitive plane of the image sensor 7 guarantees to meet the Fraunhofer diffraction condition, so that the diffracted light field of the object wave passing through the multi-pinhole plate 6 on the photosensitive plane of the image sensor is proportional to Fourier transform of the object wave. The stepping rotary support 5 is controlled by a stepping driver controlled by a computer 8 . The stepping and rotating bracket 7 and the image sensor 8 are controlled by the same computer 8 to realize the synchronous recording of the rotation of the multi-pinhole plate and the diffraction intensity image. The complex amplitude information of the object wave is extracted from the recorded diffraction intensity pattern and the imaging is completed by a computer program designed according to the method of the utility model.

Fig. 5 is the second kind of embodiment of the device of the present utility model, has one more Fourier transform lens 9 than Fig. 4, promptly places Fourier transform lens 9 between multi-pinhole plate 6 and image sensor 7, image The sensor recording plane is located on the back focal plane of the Fourier transform lens 9 . This makes the device compact and the size of the Fraunhofer diffraction intensity pattern propagating onto the recording plane of the sensor can be easily enlarged or reduced by changing the focal length of the lens 9 .

Figures 6a-6d are examples of experimental results of coherent diffraction imaging using the coherent diffraction imaging method and device of the present invention. In the experiment, the light source is He-Ne laser, and the wavelength of the output light wave is 0.6328 microns; the object to be imaged is a miniature picture of the character "DM"; the multi-pinhole plate adopts the pinhole arrangement shown in Figure 2. The pinhole diameter is 28 microns, and the pinhole spacing is 56 microns. The experimental device adopts the second embodiment shown in Figure 3, in which the focal length of the Fourier transform lens is 240mm, the image sensor is a CCD digital camera, the number of pixels is 1300×1030, and the pixel size is 6.7 microns. Figure 6a is one of the Fraunhofer diffraction intensity patterns of the measured object waves recorded by the CCD. Fig. 6b and Fig. 6c are the two-dimensional sampling arrays of the amplitude and phase distribution of the object wave recovered from the recorded Fraunhofer diffraction intensity pattern by using the method of the present utility model respectively. Fig. 6d is a reconstructed image of the measured object obtained by digital diffraction in a computer using the measurement data shown in Fig. 6b and Fig. 6c.

The above methods and embodiments achieve the purpose of reproducing the amplitude and phase distribution of the object wave by recording the Fraunhofer diffraction intensity pattern after the object wave passes through a multi-pinhole plate and by image processing the pattern. The implementation of the present utility model is not limited to the specific embodiments described above. As long as the method, device and system for reproducing the amplitude and phase distribution of the object wave by recording the Fraunhofer diffraction intensity pattern after the object wave passes through the multi-pinhole plate described in the above method, all belong to this utility model. A new type of protection.

Claims (7)

1. A coherent diffraction imaging processing device comprises a light source, a sample stage for placing a sample, an image recording and processing device, and is characterized by also comprising a beam expanding and wave surface shaper, a multi-pinhole plate and a stepping rotating bracket; the multi-pinhole plate is arranged on the stepping rotating bracket, and the center of a reference pinhole on the multi-pinhole plate is superposed with the rotating center of the stepping rotating bracket; the light source, the beam expanding and wave surface shaper, the sample, the multi-pinhole plate and the image recording and processing device are sequentially arranged along the advancing direction of the light beam; the image recording and processing device comprises an image sensor which is arranged behind the stepping rotating bracket and is connected with the computer; meanwhile, the computer is also connected with the stepping rotating bracket.

2. The coherent diffraction imaging processing apparatus according to claim 1, wherein a distance Z1 between the sample and the multi-well plate ensures that a phase change of an object wave irradiated onto the multi-well plate at each pinhole clear aperture is not more than pi/4 radians; the distance Z2 between the image sensor and the multiwell plate satisfies the fraunhofer diffraction condition, i.e. the light field distribution on the recording plane of the image sensor is proportional to the fourier transform of the object wave transmitted through the multiwell plate.

3. A coherent diffraction imaging processing device comprises a light source, a sample stage for placing a sample, an image recording and processing device, and is characterized by also comprising a beam expanding and wave surface shaper, a multi-pinhole plate, a stepping rotating bracket and a Fourier transform lens, wherein the multi-pinhole plate is arranged on the stepping rotating bracket, and the center of a reference pinhole on the multi-pinhole plate is superposed with the rotating center of the stepping rotating bracket; the light source, the beam expanding and wave surface shaper, the sample, the multi-pinhole plate, the Fourier transform lens and the image recording and processing device are sequentially arranged along the advancing direction of the light beam; the image recording and processing device comprises an image sensor which is arranged behind the stepping rotating bracket and is connected with the computer; meanwhile, the computer is also connected with the stepping rotating bracket.

4. The coherent diffraction imaging processing apparatus according to claim 3, wherein the distance Z1 between the sample and the multi-well plate ensures that the phase change of the object wave irradiated onto the multi-well plate at each pinhole clear aperture is not more than pi/4 radians; the image sensor is located in the back focal plane of the fourier transform lens, i.e. the light field distribution in the image sensor recording plane is proportional to the fourier transform of the object wave transmitted through the multipinhole plate.

5. The coherent diffraction image processing apparatus according to claim 1, 2, 3 or 4, wherein the multi-well plate is an opaque thin plate provided with a reference well and a plurality of measurement wells; the distribution of each needle hole on the multi-needle hole plate meets the following requirements: two identical multi-pinhole plates are overlapped, when one of the plates is translated to enable the reference pinhole to be overlapped with any measuring pinhole of the other plate, the other pinholes cannot be overlapped; the size of the pinhole is such that the phase change of the object wave in the range of one pinhole is not more than a quarter wavelength.

6. The coherent diffraction imaging processing apparatus according to claim 5, wherein the pinholes of the multi-pinhole plate are uniformly distributed on a semicircular ring, the centers of the pinholes are equally spaced and are not less than 1.5 times of the diameter of the pinholes, the pinhole at one end of the semicircular ring at the center of the pinhole plate is a reference pinhole, and the other pinholes are measurement pinholes.

7. The coherent diffraction imaging processing apparatus according to claim 5, wherein the pinholes of the multi-pinhole plate are distributed on three straight lines which are 120 degrees with each other, wherein the pinhole at the intersection of the three straight lines at the center of the pinhole plate is a reference pinhole, and the other pinholes are measurement pinholes; the distance D0 between the center of the reference pinhole and the center of the adjacent measurement pinhole is not less than 1.5 times of the diameter of the pinhole, and the centers of the other measurement pinholes are equally spaced and are twice of D0.

Images