CN106371201B - Based on the Fourier's overlapping associations imaging system and method for calculating ghost imaging - Google Patents

Abstract

The present invention proposes a Fourier overlap correlation imaging system and method based on computational ghost imaging. The system includes: a spatial filter; a spatial light modulator; an imaging module; a high-speed photosensitive array; The image of the position, and as the low-resolution image of the oblique plane wave illumination with the single-pixel detector as the light source; the calculation module is used to perform Fourier transform on the low-resolution image, and obtain the frequency spectrum corresponding to the high-resolution image of the target in The incident angle and the numerical aperture of the objective lens are shifted and low-pass filtered, and the relevant parts of the spectrum overlap of the low-resolution image are spliced to obtain the spectrum of the target high-resolution image, and the target high-resolution image is obtained by using the phase recovery algorithm. The invention can improve the image collection efficiency of the whole imaging system, realize the measurement of a wider spectrum than the usual array sensor, realize image compression and reconstruction, and increase the rate of a single imaging.

Description

Fourier Overlay Correlation Imaging System and Method Based on Computational Ghost Imaging

technical field

The invention relates to the technical field of optical engineering, in particular to a Fourier overlapping correlation imaging system and method based on computational ghost imaging.

Background technique

The throughput of conventional imaging systems, such as microscopes, is often limited by the spatial bandwidth product defined by their optical imaging. The space-bandwidth product refers to the number of degrees of freedom an optical system can extract from an optical signal (usually the number of resolvable pixels). Therefore, conventional imaging systems usually cannot directly obtain images with wide field of view and high spatial resolution. At present, in the field of life science and biomedicine, it has become an urgent need to clearly observe a single cell and observe as many cells as possible in the same field of view. The collection of high-resolution images has become a key technical bottleneck.

Common ideas for improving the spatial bandwidth product of imaging systems include mechanical scanning methods based on synthetic apertures and lensless methods. However, the mechanical scanning method based on synthetic aperture requires a precise mechanical structure to ensure the control accuracy of the system, so as to achieve the expected space-bandwidth product, and the optical alignment and motion tracking make the imaging process complex and slow; such as digital coaxial holography and contact The lensless imaging method of imaging microscopy also has certain limitations. For example, digital coaxial holography cannot image continuous samples well, and contact imaging microscopy requires the sample to be close enough to the sensor.

Contents of the invention

The present invention aims to solve at least one of the above-mentioned technical problems.

To this end, an object of the present invention is to propose a Fourier overlap-correlation imaging system based on computational ghost imaging, which can improve the image acquisition efficiency of the entire imaging system and achieve measurement of a wider spectrum than the usual array sensor , and achieve image compression and reconstruction to increase the rate of single imaging.

Another object of the present invention is to propose a Fourier overlapping correlation imaging method based on computational ghost imaging.

In order to achieve the above object, the embodiment of the first aspect of the present invention discloses a Fourier overlap-correlation imaging system based on computational ghost imaging, including: a spatial filter, which is used to generate a spatially uniform collimation a Gaussian beam; a spatial light modulator, which is used to spatially modulate the collimated Gaussian beam to obtain spatially encoded structured illumination; an imaging module, which is used to convert the spatially encoded structure The light is projected on the imaging surface and is in contact with the imaging sample; the high-speed photosensitive array is arranged on the transmission surface or the reflection surface of the imaging sample, and is used to receive the field strength of the light field after imaging the sample in different directions; the processing module, The processing module is used to calculate the image corresponding to each single-pixel detector of the high-speed photosensitive array according to the principle of computational ghost imaging, and use the single-pixel detector as a low-resolution image of oblique plane wave illumination as a light source; module, the calculation module is used to perform Fourier transform on low-resolution images illuminated by oblique plane waves in different directions, to obtain the shift and low-pass filtering of the frequency spectrum corresponding to the high-resolution image of the target at the incident angle and the numerical aperture of the objective lens, Stitching the overlapped and related parts of the frequency spectrum of the low-resolution image to obtain the frequency spectrum of the target high-resolution image, and using a phase recovery algorithm to obtain the target high-resolution image.

The Fourier overlap correlation imaging system based on computational ghost imaging according to the embodiment of the present invention has the following advantages:

1. Simultaneous acquisition of images illuminated by different inclination angles, avoiding the limitation that only one or a few light-emitting diodes can be lit for each acquisition in the FPM system, and improving the image acquisition efficiency of the entire imaging system;

2. The single-pixel detector has a wider spectrum, which can realize the measurement of a wider spectrum than the usual array sensor;

3. Using the idea of computational ghost imaging, specific encoding can be performed on structured light, such as sinusoidal encoding or Hadamard encoding, which can realize image compression and reconstruction and increase the rate of single imaging.

In addition, the Fourier overlap correlation imaging system based on computational ghost imaging according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

In some examples, the spatial filter includes: an objective lens, a pinhole, a collimator lens, an optical adjustment mount, and a translation stage, wherein the pinhole is located at the focal point of the objective lens and is used to filter out high-order Uniform stray light to generate Gaussian beams with uniform spatial distribution, and then pass through the collimating lens to obtain the collimated Gaussian beams, and the optical adjustment mount is used to fix the objective lens and collimating lens and adjust the angle of the device, so that The outgoing beam is straight, and the translation stage is used to fix the pinhole, and at the same time adjust the distance between the pinhole and the objective lens, so as to ensure a Gaussian beam with a uniform spatial distribution in a suitable three-dimensional coordinate.

In some examples, the spatial light modulator is used to modulate the amplitude or phase of the collimated Gaussian beam to obtain spatially encoded structured illumination.

In some examples, the imaging module is a lens or a lens group.

In some examples, the field strengths of the light fields after imaging the sample in different directions correspond to images taken at the front of the imaging sample when inclined plane waves in different directions are irradiated onto the imaging sample.

In order to achieve the above object, the embodiment of the second aspect of the present invention proposes a Fourier overlap-correlation imaging method based on computational ghost imaging, which includes the following steps: constructing a spatial filter, and generating uniform spatial distribution through the spatial filter A collimated Gaussian beam; spatially modulate the collimated Gaussian beam to obtain spatially encoded structured illumination; project the spatially encoded structured illumination on the imaging surface and contact the imaging sample; receive imaging samples in different directions The field strength of the rear light field; according to the principle of computational ghost imaging, the image corresponding to each single-pixel detector of the high-speed photosensitive array is calculated, and it is used as a low-resolution image of oblique plane wave illumination with the single-pixel detector as the light source; Carry out Fourier transform to the low-resolution image of oblique plane wave illumination in different directions, obtain the shift and low-pass filtering of the frequency spectrum corresponding to the high-resolution image of the target at the incident angle and the numerical aperture of the objective lens, and convert the low-resolution image to The overlapping and related parts of the spectrum are spliced to obtain the spectrum of the target high-resolution image, and the target high-resolution image is obtained by using the phase recovery algorithm.

The Fourier overlap correlation imaging method based on computational ghost imaging according to the embodiment of the present invention has the following advantages:

1. Simultaneous acquisition of images illuminated by different inclination angles, avoiding the limitation that only one or a few light-emitting diodes can be lit for each acquisition in the FPM system, and improving the image acquisition efficiency of the entire imaging system;

2. The single-pixel detector has a wider spectrum, which can realize the measurement of a wider spectrum than the usual array sensor;

3. Using the idea of computational ghost imaging, specific encoding can be performed on structured light, such as sinusoidal encoding or Hadamard encoding, which can realize image compression and reconstruction and increase the rate of single imaging.

In addition, the Fourier overlap correlation imaging method based on computational ghost imaging according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

In some examples, the spatial filter includes: an objective lens, a pinhole, a collimator lens, an optical adjustment mount, and a translation stage, wherein the pinhole is located at the focal point of the objective lens and is used to filter out high-order Uniform stray light to generate Gaussian beams with uniform spatial distribution, and then pass through the collimating lens to obtain the collimated Gaussian beams, and the optical adjustment mount is used to fix the objective lens and collimating lens and adjust the angle of the device, so that The outgoing beam is straight, and the translation stage is used to fix the pinhole, and at the same time adjust the distance between the pinhole and the objective lens, so as to ensure a Gaussian beam with a uniform spatial distribution in a suitable three-dimensional coordinate.

In some examples, the spatially modulating the collimated Gaussian beam further includes: performing amplitude or phase modulation on the collimated Gaussian beam to obtain the spatially encoded structured illumination.

In some examples, the spatially coded structured illumination is projected on the imaging surface through a lens or a lens group.

In some examples, the field strengths of the light fields after imaging the sample in different directions correspond to images taken at the front of the imaging sample when inclined plane waves in different directions are irradiated onto the imaging sample.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and comprehensible from the description of the embodiments in conjunction with the following drawings, wherein:

Fig. 1 is a structural block diagram of a Fourier overlapping correlation imaging system based on computational ghost imaging according to an embodiment of the present invention;

2 is an experimental schematic diagram of a Fourier overlap-correlation imaging system based on computational ghost imaging according to another embodiment of the present invention;

FIG. 3 is a schematic diagram of the principle of a spatial filter according to an embodiment of the present invention; and

Fig. 4 is a flow chart of a Fourier overlap correlation imaging method based on computational ghost imaging according to an embodiment of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", " The orientations or positional relationships indicated by "vertical", "horizontal", "top", "bottom", "inner" and "outer" are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and Simplified descriptions, rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and thus should not be construed as limiting the invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and should not be understood as indicating or implying relative importance.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

The Fourier overlap correlation imaging system and method based on computational ghost imaging according to embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a structural block diagram of a Fourier overlap correlation imaging system based on computational ghost imaging according to an embodiment of the present invention. Fig. 2 is an experimental schematic diagram of a Fourier overlap correlation imaging system based on computational ghost imaging according to another embodiment of the present invention. As shown in FIG. 1 , combined with FIG. 2 , the Fourier overlap correlation imaging system 100 based on computational ghost imaging includes: a spatial filter 110, a spatial light modulator 120, an imaging module 130, a high-speed photosensitive array 140, and a processing module, 150 and computing module 160.

Wherein, the spatial filter 110 is used to generate a clean collimated Gaussian beam with uniform spatial distribution.

In one embodiment of the present invention, as shown in FIG. 3 , the spatial filter 110 includes, for example: an objective lens, a pinhole, a collimating lens, an optical adjustment mount, and a translation stage, wherein the pinhole is located at the focal point of the objective lens for Filter out high-order inhomogeneous stray light to generate a Gaussian beam with uniform spatial distribution, and then pass through a collimator lens to obtain a collimated Gaussian beam. The optical adjustment frame is used to fix the objective lens and collimator lens and adjust the angle of the device so that the outgoing beam Straight, the translation stage is used to fix the pinhole and adjust the distance between the pinhole and the objective lens to ensure a uniformly distributed Gaussian beam in the appropriate three-dimensional coordinates.

The spatial light modulator 120 is used for spatially modulating the collimated Gaussian beam to obtain spatially coded structured illumination. Specifically, in an embodiment of the present invention, the spatial light modulator 120 is used to modulate the amplitude or phase of the collimated Gaussian beam to obtain spatially coded structured illumination. In other words, the spatial light modulator 120 is used to modulate the amplitude or phase of the collimated Gaussian beam, so as to obtain the required illumination mode.

The imaging module 130 is used for projecting the spatially coded structured illumination onto the imaging surface and contacting the imaging sample. In one embodiment of the present invention, the imaging module 130 is, for example, a lens or a lens group. In other words, the imaging module 130 is used to apply the incident illumination mode on the sample plane, which may be a lens or a lens group, or directly irradiate the sample, and the imaging system is vacant this time.

The high-speed photosensitive array 140 is arranged on the transmission surface or the reflection surface of the imaging sample, and is used to receive the field intensity of the light field after imaging the sample in different directions. In one embodiment of the present invention, the field strength of the light field after imaging the sample in different directions corresponds to the images taken at the front of the imaging sample when inclined plane waves in different directions are irradiated onto the imaging sample. In other words, the high-speed photosensitive array 140 is used to receive intensities at different angles after being transmitted or reflected by the sample. According to the principle of reversible single-pixel imaging optical path, it corresponds to images taken at the front end of the sample when oblique plane waves in different directions are irradiated on the sample. More specifically, model the correlation between the intensity of each photosensitive element and the illumination mode and use the constraint of natural scene sparsity to perform compressive sensing imaging, corresponding to the oblique plane wave generated at the angle of the photosensitive element irradiated on the sample, The image seen from the front of the sample.

The processing module 150 is used to calculate the image corresponding to each single-pixel detector of the high-speed photosensitive array according to the principle of computational ghost imaging, and use the single-pixel detector as a low-resolution image illuminated by an oblique plane wave as a light source. Specifically, the spatial light modulator 120 modulates multiple groups of different structured illuminations, and the high-speed photosensitive array 140 receives the corresponding light field intensity. Then, for each single-pixel detector of the array, the processing module 150 calculates according to the principle of computational ghost imaging The image of the corresponding position is taken as a low-resolution image of the oblique plane wave illumination using the point single-pixel detector as the light source. In other words, the processing module 150 is used to obtain the imaging result of each different angle through multiple correlations between different illumination modes and the intensity on each photosensitive element as a low-resolution image iteratively updated in Fourier The overlapping regions of the leaf spectra are used to computationally reconstruct a high-resolution image of the sample.

The calculation module 160 is used to perform Fourier transform on the low-resolution images illuminated by oblique plane waves in different directions to obtain the shift and low-pass filtering of the frequency spectrum corresponding to the high-resolution image of the target at the incident angle and the numerical aperture of the objective lens, and convert the low-resolution The frequency spectrum overlapping related parts of the high-resolution image are spliced to obtain the frequency spectrum of the target high-resolution image, and the target high-resolution image is obtained by using the phase recovery algorithm. In other words, the Fourier overlap correlation imaging process, iteratively updates the low-resolution images illuminated by oblique plane waves in different directions in the overlapping area of the Fourier spectrum, and obtains the spectrum of the high-resolution image after the frequency domain is broadened, and finally calculates A high-resolution image of the sample is reconstructed using a phase recovery algorithm.

In some examples, the system of the embodiment of the present invention is applicable to wide-scale imaging systems, from micron scale to meter scale, where imaging systems of different scales are realized by adjusting the imaging module between the spatial light modulator and the sample.

Further, the imaging system of the embodiment of the present invention is suitable for wide-spectrum imaging systems, from terahertz spectrum, infrared spectrum, visible spectrum, ultraviolet spectrum to X-ray spectrum, wherein imaging systems of different spectrums pass Substitutions are available for different high-speed sensor implementations.

That is to say, the system of the embodiment of the present invention includes a method for improving the imaging rate and imaging quality in the relevant imaging process by encoding and optimizing the illumination mode. More specifically, four-step phase-shifted sinusoidal mode illumination with different spatial frequencies is used to directly obtain the Liier spectra of low-resolution images at different spatial angles from different photosensitive elements, and then iteratively update the overlapped Fourier spectra. region, so as to obtain the frequency spectrum of the high-resolution image after frequency domain widening.

To sum up, the implementation principle of the Fourier overlapping correlation imaging system based on computational ghost imaging in the above embodiments of the present invention can be summarized as follows: the system of the present invention generates displacement in the frequency domain through Fourier transform according to the characteristics of tilted plane waves in different directions and Single-pixel imaging is proposed with the characteristic of reversible optical path, which is characterized in that a collimated beam system with uniform light intensity distribution is built, and the collimated beam is incident on a spatial light modulator to modulate the amplitude or phase of the incident light field to obtain the modulated The light beam passes through the imaging optical system or directly irradiates the imaging sample, and it is transmitted or reflected to the high-speed photosensitive array (single-pixel detector array) for simultaneous acquisition. The same sample is irradiated by light beams with known modulation modes multiple times and the light intensity corresponding to each photosensitive element (single-pixel detector) is collected, and the correlation between the modulation mode and the light intensity of the photosensitive element or compressed sensing method is used to obtain each photosensitive element. The imaging result of the angle corresponding to the component. According to the characteristic of single-pixel imaging with reversible optical path, the imaging result of each single pixel on the same sample corresponds to the result of shooting at the front of the incident sample by the oblique plane wave illumination in different directions generated by using this single pixel as a point source. Therefore, the frequency spectrum of the low-resolution image obtained for each single pixel is equivalent to the frequency spectrum of the target high-resolution image within a certain range under the corresponding incident angle. The spectra of all single-pixel images represent spectra at different angles, that is, at different translation positions in the frequency domain, and eventually overlap and correlate with each other to form a spectrum with a larger overall range. Use all the single-pixel imaging results collected synchronously to perform Fourier transform, and then determine the position in the high-resolution image spectrum of the target according to the incident angle corresponding to each photosensitive element, and splicing the overlapping and related spectra in the frequency domain to obtain the target Spectrum of the high-resolution image, and the target high-resolution sample image is obtained through inverse Fourier transform. Because it is equivalent to increasing the illumination at different angles and broadening the frequency spectrum, it can provide the characteristics of wide field of view and high spatial resolution. At the same time, the feature of synchronous acquisition of the photosensitive array avoids the limitations of the time-sharing lighting of the point source array in the traditional Fourier overlapping correlation imaging system that hinders the improvement of the imaging rate, realizes the characteristics of high time resolution, and can perform real-time imaging of dynamic scenes.

The Fourier overlap correlation imaging system based on computational ghost imaging according to the embodiment of the present invention has the following advantages:

1. Simultaneous acquisition of images illuminated by different inclination angles, avoiding the limitation that only one or a few light-emitting diodes can be lit for each acquisition in the FPM system, and improving the image acquisition efficiency of the entire imaging system;

2. The single-pixel detector has a wider spectrum, which can realize the measurement of a wider spectrum than the usual array sensor;

3. Using the idea of computational ghost imaging, specific encoding can be performed on structured light, such as sinusoidal encoding or Hadamard encoding, which can realize image compression and reconstruction and increase the rate of single imaging.

A further embodiment of the present invention also proposes a Fourier overlap correlation imaging method based on computational ghost imaging.

Fig. 4 is a flowchart of a Fourier overlap-correlation imaging method based on computational ghost imaging according to an embodiment of the present invention. As shown in Figure 4, the method includes the following steps:

Step S1: Construct a spatial filter, and generate a clean, uniformly distributed collimated Gaussian beam through the spatial filter.

In one embodiment of the present invention, the constructed spatial filter includes, for example: an objective lens, a pinhole, a collimator lens, an optical adjustment mount, and a translation stage, wherein the pinhole is located at the focal point of the objective lens to filter out high-order Inhomogeneous stray light produces a Gaussian beam with uniform spatial distribution, and then passes through a collimator lens to obtain a collimated Gaussian beam. The optical adjustment frame is used to fix the objective lens and collimator lens and adjust the angle of the device to make the outgoing beam straight. The translation stage It is used to fix the pinhole and adjust the distance between the pinhole and the objective lens at the same time to ensure a Gaussian beam with uniform distribution in space in a suitable three-dimensional coordinate.

Step S2: spatially modulate the collimated Gaussian beam to obtain spatially encoded structured illumination.

Specifically, in an embodiment of the present invention, performing spatial modulation on the collimated Gaussian beam further includes: performing amplitude or phase modulation on the collimated Gaussian beam to obtain spatially coded structured illumination. In other words, the amplitude or phase of the collimated Gaussian beam is modulated to obtain the desired illumination pattern.

Step S3: Projecting the spatially encoded structured illumination onto the imaging surface and making contact with the imaging sample.

In one embodiment of the invention, the spatially encoded structured illumination is projected onto the imaging surface, for example by a lens or a lens group. In other words, the incident illumination mode acts on the sample plane, which can be a lens or a lens group, or directly irradiates the sample, and the imaging system is vacant this time.

Step S4: receiving the field strength of the light field after imaging the sample in different directions. Specifically, the field strength of the light field after imaging the sample in different directions corresponds to the images taken at the front end of the imaging sample when inclined plane waves in different directions are irradiated onto the imaging sample. In other words, for example, the high-speed photosensitive array receives intensities at different angles after being transmitted or reflected by the sample. According to the principle of reversible single-pixel imaging optical path, it corresponds to the images taken at the front of the sample when oblique plane waves in different directions are irradiated on the sample. More specifically, model the correlation between the intensity of each photosensitive element and the illumination mode and use the constraint of natural scene sparsity to perform compressive sensing imaging, corresponding to the oblique plane wave generated at the angle of the photosensitive element irradiated on the sample, The image seen from the front of the sample.

Step S5: Calculate the image corresponding to each single-pixel detector of the high-speed photosensitive array according to the principle of computational ghost imaging, and use the single-pixel detector as a low-resolution image illuminated by an oblique plane wave as a light source. Specifically, the spatial light modulator modulates multiple sets of different structured illumination, and the high-speed photosensitive array receives the corresponding light field intensity. Then, for each single-pixel detector of the array, the image of the corresponding position is calculated according to the principle of computational ghost imaging. Low-resolution image as an oblique plane-wave illumination with the point single-pixel detector as the light source. In other words, the imaging result of each different angle is obtained by correlating the intensity of different illumination modes with each photosensitive element multiple times, as a low-resolution image with a changed illumination tilt angle, iteratively updating the overlapping area of the Fourier spectrum , to computationally reconstruct a high-resolution image of the sample.

Step S6: Perform Fourier transform on the low-resolution images illuminated by oblique plane waves in different directions to obtain the shift and low-pass filtering of the frequency spectrum corresponding to the target high-resolution image at the incident angle and the numerical aperture of the objective lens, and convert the low-resolution image to The overlapping and related parts of the spectrum are spliced to obtain the spectrum of the target high-resolution image, and the target high-resolution image is obtained by using the phase recovery algorithm. In other words, this step is the process of Fourier overlap correlation imaging, which iteratively updates the low-resolution images illuminated by oblique plane waves in different directions in the overlapping area of the Fourier spectrum to obtain the spectrum of the high-resolution image after the frequency domain is broadened, and finally A high-resolution image of the sample is computationally reconstructed using a phase recovery algorithm.

In some examples, the imaging method of the embodiment of the present invention is applicable to a wide-scale imaging system, from micrometer to meter, wherein imaging systems of different scales are realized by adjusting the imaging module between the spatial light modulator and the sample.

Further, the imaging method of the embodiment of the present invention is applicable to imaging systems of wide spectrum, from terahertz spectrum, infrared spectrum, visible spectrum, ultraviolet spectrum to X-ray spectrum, wherein imaging systems of different spectrums pass Substitutions are available for different high-speed sensor implementations.

That is to say, the method in the embodiment of the present invention is a method for encoding and optimizing the illumination mode to improve the imaging rate and imaging quality in the related imaging process. More specifically, four-step phase-shifted sinusoidal mode illumination with different spatial frequencies is used to directly obtain the Liier spectra of low-resolution images at different spatial angles from different photosensitive elements, and then iteratively update the overlapped Fourier spectra. region, so as to obtain the frequency spectrum of the high-resolution image after frequency domain widening.

In summary, the main principle of the Fourier overlap-correlation imaging method based on computational ghost imaging in the above-mentioned embodiments of the present invention can be summarized as follows: the method is based on the characteristics of displacement in the frequency domain of plane waves inclined in different directions through Fourier transform and the single The pixel imaging has the characteristic of reversible optical path, which is characterized in that a collimated beam system with uniform light intensity distribution is built, and the collimated beam is incident on the spatial light modulator to modulate the amplitude or phase of the incident light field to obtain the modulated beam After passing through the imaging optical system or directly irradiating the imaging sample, it is transmitted or reflected to the high-speed photosensitive array (single-pixel detector array) for simultaneous acquisition. The same sample is irradiated by light beams with known modulation modes multiple times and the light intensity corresponding to each photosensitive element (single-pixel detector) is collected, and the correlation between the modulation mode and the light intensity of the photosensitive element or compressed sensing method is used to obtain each photosensitive element. The imaging result of the angle corresponding to the component. According to the characteristic of single-pixel imaging with reversible optical path, the imaging result of each single pixel on the same sample corresponds to the result of shooting at the front of the incident sample by the oblique plane wave illumination in different directions generated by using this single pixel as a point source. Therefore, the frequency spectrum of the low-resolution image obtained for each single pixel is equivalent to the frequency spectrum of the target high-resolution image within a certain range under the corresponding incident angle. The spectra of all single-pixel images represent spectra at different angles, that is, at different translation positions in the frequency domain, and eventually overlap and correlate with each other to form a spectrum with a larger overall range. Use all the single-pixel imaging results collected synchronously to perform Fourier transform, and then determine the position in the high-resolution image spectrum of the target according to the incident angle corresponding to each photosensitive element, and splicing the overlapping and related spectra in the frequency domain to obtain the target Spectrum of the high-resolution image, and the target high-resolution sample image is obtained through inverse Fourier transform. Because it is equivalent to increasing the illumination at different angles and broadening the frequency spectrum, it can provide the characteristics of wide field of view and high spatial resolution. At the same time, the feature of synchronous acquisition of the photosensitive array avoids the limitations of the time-sharing lighting of the point source array in the traditional Fourier overlapping correlation imaging system that hinders the improvement of the imaging rate, realizes the characteristics of high time resolution, and can perform real-time imaging of dynamic scenes.

The Fourier overlap correlation imaging method based on computational ghost imaging according to the embodiment of the present invention has the following advantages:

1. Simultaneous acquisition of images illuminated by different inclination angles, avoiding the limitation that only one or a few light-emitting diodes can be lit for each acquisition in the FPM system, and improving the image acquisition efficiency of the entire imaging system;

2. The single-pixel detector has a wider spectrum, which can realize the measurement of a wider spectrum than the usual array sensor;

3. Using the idea of computational ghost imaging, specific encoding can be performed on structured light, such as sinusoidal encoding or Hadamard encoding, which can realize image compression and reconstruction and increase the rate of single imaging.

In the description of this specification, descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims (10)

1. A Fourier overlap correlation imaging system based on computational ghost imaging, characterized in that it comprises: a spatial filter for generating a collimated Gaussian beam with uniform spatial distribution; a spatial light modulator, configured to spatially modulate the collimated Gaussian beam to obtain spatially coded structured illumination; an imaging module, the imaging module is used to project the spatially coded structured illumination onto an imaging surface and contact the imaging sample; A high-speed photosensitive array, the high-speed photosensitive array is arranged on the transmission surface or the reflective surface of the imaging sample, and is used to receive the field strength of the light field after imaging the sample in different directions; A processing module, the processing module is used to calculate the image corresponding to each single-pixel detector of the high-speed photosensitive array according to the principle of computational ghost imaging, and use the single-pixel detector as a low-resolution image of the oblique plane wave illumination with the single-pixel detector as the light source image; A calculation module, the calculation module is used to perform Fourier transform on the low-resolution images of oblique plane wave illumination in different directions, and obtain the value corresponding to the frequency spectrum of the target high-resolution image at the angle of incidence corresponding to the oblique plane wave illumination and the objective lens Aperture shifting and low-pass filtering, splicing the overlapping and related parts of the spectrum of the low-resolution image to obtain the spectrum of the target high-resolution image, and using a phase recovery algorithm to obtain the target high-resolution image. 2. The Fourier overlap correlation imaging system based on computational ghost imaging according to claim 1, wherein the spatial filter comprises: an objective lens, a pinhole, a collimating lens, an optical adjustment mount, and a translation stage, wherein , The pinhole is located at the focal point of the objective lens and is used to filter out high-order inhomogeneous stray light to generate a Gaussian beam with uniform spatial distribution, and then pass through the collimating lens to obtain the collimated Gaussian beam. The optical adjustment frame is used to fix the objective lens and collimator lens and adjust the angle of the device so that the outgoing beam is straight. The translation stage is used to fix the pinhole and adjust the distance between the pinhole and the objective lens to ensure A spatially uniform Gaussian beam is obtained within a suitable three-dimensional coordinate. 3. The Fourier overlap correlation imaging system based on computational ghost imaging according to claim 1, wherein the spatial light modulator is used to modulate the amplitude or phase of the collimated Gaussian beam to obtain a spatial Encoded structured lighting. 4 . The Fourier overlap correlation imaging system based on computational ghost imaging according to claim 1 , wherein the imaging module is a lens or a lens group. 5. The Fourier overlap-correlation imaging system based on computational ghost imaging according to claim 1, wherein the field strength of the light field after imaging samples in different directions corresponds to the irradiation of inclined plane waves in different directions on the imaging samples, Image taken at the front of the imaged sample. 6. A Fourier overlap correlation imaging method based on computational ghost imaging, characterized in that, comprising the following steps: Constructing a spatial filter, and generating a collimated Gaussian beam with uniform spatial distribution through the spatial filter; spatially modulating the collimated Gaussian beam to obtain spatially encoded structured illumination; projecting the spatially encoded structured illumination onto an imaging surface, and contacting the imaging sample; The field strength of the light field after receiving imaging samples in different directions; Calculate the image corresponding to each single-pixel detector of the high-speed photosensitive array according to the principle of computational ghost imaging, and use the single-pixel detector as a low-resolution image of oblique plane wave illumination as the light source; Carry out Fourier transform to the low-resolution image of oblique plane wave illumination in different directions, obtain the frequency spectrum corresponding to the high-resolution image of the target at the angle of incidence corresponding to the oblique plane wave illumination and the numerical aperture of the objective lens and low-pass filter, the The overlapped and related parts of the frequency spectrum of the low-resolution image are spliced to obtain the frequency spectrum of the target high-resolution image, and a phase recovery algorithm is used to obtain the target high-resolution image. 7. The Fourier overlap correlation imaging method based on computational ghost imaging according to claim 6, wherein the spatial filter comprises: an objective lens, a pinhole, a collimating lens, an optical adjustment mount, and a translation stage, wherein , The pinhole is located at the focal point of the objective lens and is used to filter out high-order inhomogeneous stray light to generate a Gaussian beam with uniform spatial distribution, and then pass through the collimating lens to obtain the collimated Gaussian beam. The optical adjustment frame is used to fix the objective lens and collimator lens and adjust the angle of the device so that the outgoing beam is straight. The translation stage is used to fix the pinhole and adjust the distance between the pinhole and the objective lens to ensure A spatially uniform Gaussian beam is obtained within a suitable three-dimensional coordinate. 8. The Fourier overlap correlation imaging method based on computational ghost imaging according to claim 6, wherein said spatially modulating said collimated Gaussian light beam further comprises: Amplitude or phase modulation is performed on the collimated Gaussian beam to obtain the spatially coded structured illumination. 9 . The Fourier overlap correlation imaging method based on computational ghost imaging according to claim 6 , wherein the spatially encoded structured illumination is projected on the imaging surface through a lens or a lens group. 10. The Fourier overlap-correlation imaging method based on computational ghost imaging according to claim 6, wherein the field strength of the light field after imaging samples in different directions corresponds to the irradiation of inclined plane waves in different directions on the imaging samples, Image taken at the front of the imaged sample.