Single-pixel color imaging system based on multi-wavelength radio frequency marking

Abstract

The invention relates to the technical field of optical imaging, and discloses a single-pixel color imaging system based on multi-wavelength radio frequency marking. The system comprises a light source module used for generating three laser beams with three optical primary colors; the radio frequency driving module is used for generating a radio frequency complex frequency signal; the light path adjusting module is used for performing heterodyne interference processing on the three laser beams according to the radio frequency complex frequency signal, respectively forming a light spot array and a reference light source and then combining the beams, and generating a combined beam to be incident on a measured target; each laser beam corresponds to one group of sub light spot arrays; sub light spot arrays with aligned spatial positions exist among the three groups of sub light spot arrays; the detected target detection module is used for collecting light data generated after a detected target reflects the combined light beam; and the image inversion module is used for performing image inversion processing on the optical data to generate a true color image of the measured target. According to the system, the light spot array of multi-wavelength laser incidence can be registered in the spatial position.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical imaging technology, and in particular to a single-pixel color imaging system based on multi-wavelength radio frequency marking. BACKGROUND

[0002] In the field of optical imaging, traditional color imaging technology has long relied on expensive area array detectors (such as charge-coupled devices CCD / complementary metal-oxide-semiconductor CMOS). Such devices need to mechanically switch filters when performing multispectral imaging. The mechanical movement has inertia, and frequent switching will cause the imaging frame rate to decrease, limiting the imaging speed, and the signal-to-noise ratio in a weak light environment will decrease significantly, resulting in a decrease in image quality.

[0003] In related technologies, single-pixel imaging technology (SPI) is used to achieve image acquisition through encoding sampling and calculation reconstruction, solving the cost problem of area array detectors. However, the scheme in related technologies has two technical bottlenecks: first, a single-wavelength system cannot obtain color information; second, a multi-wavelength system using time sequence switching will cause a decrease in time resolution and spectral crosstalk. In particular, in the application of acousto-optic modulation technology, due to the dispersion characteristics of the acousto-optic modulator (AOD, Acousto-Optic Deflector), the angle between the two light beams Different wavelengths of laser need different radio frequency drives to obtain the same spatial modulation effect, making it difficult to achieve multi-wavelength synchronous modulation. SUMMARY

[0004] Therefore, the present application provides a single-pixel color imaging system based on multi-wavelength radio frequency marking to solve the problem that the color imaging scheme in related technologies cannot achieve multi-wavelength spatial registration. The technical solution is as follows: A single-pixel color imaging system based on multi-wavelength radio frequency marking is provided, which includes: A light source module for generating three laser beams respectively for optical primary colors; A radio frequency drive module for generating a radio frequency complex frequency signal; the radio frequency complex frequency signal includes three single frequency signal sequences with different frequency ranges, different frequency intervals, and the same number of signals; An optical path adjustment module for heterodyne interference processing of the three laser beams according to the radio frequency complex frequency signal, forming a spot array and a reference light source after combining, and generating a combined beam to be incident on a measured target; each of the laser beams in the spot array corresponds to a group of sub-spot arrays; each group of sub-spot arrays includes a split spot array corresponding to each single frequency signal sequence; there are spatially aligned split spot arrays between the three groups of sub-spot arrays; each spot corresponds to a different optical frequency; A target detection module is configured to collect light data generated after the measured target reflects the combined light beam; An image inversion module is configured to receive the light data and perform image inversion processing on the light data to generate a true-color image of the measured target.

[0005] In an alternative embodiment, the light source module includes a first laser, a second laser, and a third laser; the first laser is configured to generate a first laser beam with a center wavelength of 488 nm; the second laser is configured to generate a second laser beam with a center wavelength of 561 nm; and the third laser is configured to generate a third laser beam with a center wavelength of 640 nm.

[0006] In an alternative embodiment, the first laser beam, the second laser beam, and the third laser beam are parallel and adjacent laser beams with the same spacing distance between adjacent laser beams. The light source module further includes a first mirror, a first dichroic mirror, and a second dichroic mirror; the first mirror is configured to reflect the first laser beam to the optical path adjustment module; the first dichroic mirror is configured to reflect the second laser beam to the optical path adjustment module; and the second dichroic mirror is configured to reflect the third laser beam to the optical path adjustment module.

[0007] In an alternative embodiment, the radio frequency multi-frequency signal includes a first single-frequency signal sequence, a second single-frequency signal sequence, and a third single-frequency signal sequence. The first single-frequency signal sequence includes single-frequency signals with a first frequency range, a first interval, and a target number. The second single-frequency signal sequence includes single-frequency signals with a second frequency range, a second interval, and a target number. The third single-frequency signal sequence includes single-frequency signals with a third frequency range, a third interval, and a target number; wherein the greater the frequency interval, the greater the corresponding spot spacing distance in the spot array.

[0008] In an alternative embodiment, the optical path adjustment module includes a beam splitter, a modulation arm, and a reference arm. The beam splitter is configured to split the incident three laser beams into three laser beamlets incident on the modulation arm and three laser beamlets incident on the reference arm. The modulation arm is configured to modulate the three laser beamlets incident on the modulation arm into the spot array according to the radio frequency multi-frequency signal; wherein each incident laser beamlet on the modulation arm corresponds to a group of sub-spot arrays. The reference arm is used for beam combining of three laser beams incident on the reference arm and forming the reference light source; and the reference light source covers the spot array.

[0009] In an optional embodiment, the modulation arm comprises an acousto-optic modulator, which is used for modulating three laser beams incident on the modulation arm into three groups of one-dimensional sub-spot arrays respectively according to the radio frequency complex frequency signal; and there is a one-dimensional sub-spot array aligned in space position between the three groups of one-dimensional sub-spot arrays.

[0010] In an optional embodiment, the modulation arm comprises an acousto-optic modulator group; the acousto-optic modulator group comprises two acousto-optic modulators arranged orthogonally; and the acousto-optic modulator group is used for modulating three laser beams incident on the modulation arm into three groups of two-dimensional sub-spot arrays respectively according to the radio frequency complex frequency signal; and there is a two-dimensional sub-spot array aligned in space position between the three groups of two-dimensional sub-spot arrays.

[0011] In an optional embodiment, the reference arm comprises a second mirror, a third mirror, a fourth mirror, a third dichroic mirror and a fourth dichroic mirror. The three laser beams incident on the reference arm are reflected by the second mirror and the third mirror in sequence, and then are reflected by the fourth mirror, the third dichroic mirror and the fourth dichroic mirror in sequence to form a coaxial beam combining beam.

[0012] In an optional embodiment, the measured target detection module comprises a first single-pixel detector and a second single-pixel detector; the first single-pixel detector is used for collecting light data of a forward scattering channel generated after the measured target reflects the beam combining beam; and the second single-pixel detector is used for collecting light data of a side scattering channel generated after the measured target reflects the beam combining beam.

[0013] In an optional embodiment, the image inversion module is used for performing image inversion processing on the light data according to a color correction matrix, and the formula is as follows:

[0014] wherein, is a true color image of the measured target, is a color correction matrix, is a light energy size corresponding to the three laser beams in the light data respectively.

[0015] The technical scheme provided by the present application can have the following beneficial effects: The application provides a single-pixel color imaging system based on multi-wavelength radio frequency marking, three laser beams respectively for optical three primary colors are generated by a light source module to provide a basis for subsequent color imaging; a radio frequency driving module generates a radio frequency complex signal including three single frequency signal sequences with different frequency ranges, different frequency intervals and the same number of signals in a segmented multi-frequency interval radio frequency signal driving mode, and then a light path adjustment module performs heterodyne interference processing on the three laser beams according to the radio frequency complex signal to form a spot array and a reference light source after beam combination, the light frequency corresponding to each spot in the spot array is different, each laser beam corresponds to a group of sub-spot arrays, and each group of sub-spot arrays includes a light spot array corresponding to each single frequency signal sequence; by setting different radio frequency intervals and frequency ranges corresponding to the three laser beams, the same spot is obtained in the light spot array corresponding to the three laser beams, the product of the incident light wavelength and the frequency interval is the same, and there are spatially aligned light spot arrays between the three groups of sub-spot arrays, so that the spatial position registration problem of the multi-wavelength laser incident spot array is solved, each spot is subjected to different frequency modulation, the position and color of the spot can be distinguished through the spot frequency, the multi-band light data decoupling problem is solved, and color imaging is realized without using a surface array detector.

[0016] Moreover, the system realizes simultaneous acquisition of different waveband imaging images by multi-wavelength lasers, and the image inversion module is based on an image color reconstruction model of three-wavelength lasers, so that the time resolution is improved by three times and the imaging efficiency is improved compared with a multi-wavelength system using sequential switching. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0018] Figure 1 It is a structural schematic diagram of a single-pixel color imaging system based on multi-wavelength radio frequency marking according to an embodiment of the application; Figure 2 It is a structural schematic diagram of a one-dimensional single-pixel color imaging system based on multi-wavelength radio frequency marking according to an embodiment of the application; Figure 3 It is a schematic diagram of a radio frequency complex signal according to an embodiment of the application; Figure 4 It is a sub-spot array spatial registration schematic diagram according to an embodiment of the application; Figure 5is a schematic diagram of the spatial position correspondence relationship between the one-dimensional light spot array according to the embodiment of the present application and the measured sample; Figure 6 is a structural schematic diagram of a two-dimensional single-pixel color imaging system based on multi-wavelength radio frequency markers according to the embodiment of the present application; Figure 7 is a schematic diagram of the spatial position correspondence relationship between the two-dimensional light spot array according to the embodiment of the present application and the measured sample.

[0019] Legend of reference signs: 1-first laser; 2-second laser; 3-third laser; 4-first mirror; 5-first dichroic mirror; 6-second dichroic mirror; 7-first glass; 8-polarizing beam splitter; 9-second glass; 101-acousto-optic modulator; 102-acousto-optic modulator group; 11-second mirror; 12-third mirror; 13-fourth mirror; 14-third dichroic mirror; 15-fourth dichroic mirror; 16-beam shaper; 17-beam combiner; 18-X direction galvanometer; 19-first lens; 20-second lens; 21-Y direction galvanometer; 22-first microscope objective; 23-measured target; 24-second microscope objective; 25-third microscope objective; 26-third lens; 27-fourth lens; 28-imaging camera; 29-beam splitter; 30-first unit detector; 31-second unit detector; 32-data processing software and hardware platform; 33-second acousto-optic modulator. DETAILED DESCRIPTION

[0020] The technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0023] In addition, the technical features involved in the different embodiments of the application described below can be combined with each other as long as there is no conflict between them. In the field of optical imaging, traditional color imaging technology has long relied on expensive area array detectors (such as charge coupled device CCD / complementary metal oxide semiconductor CMOS). Such devices need to mechanically switch filters when multispectral imaging, and the inertia of mechanical movement will cause the imaging frame rate to drop when frequently switching, which limits the imaging speed, and the signal-to-noise ratio is significantly reduced in a weak light environment, resulting in a decrease in image quality.

[0024] In the related art, single-pixel imaging technology (SPI) is used to realize image acquisition through encoding sampling and calculation reconstruction, which solves the cost problem of area array detectors. However, the scheme in the related art has two technical bottlenecks: first, a single-wavelength system cannot obtain color information; second, a multi-wavelength system using time sequence switching will cause a decrease in time resolution and spectral crosstalk. In particular, in the application of acousto-optic modulation technology, due to the dispersion characteristics of the acousto-optic modulator (AOD, Acousto-Optic Deflector), the included angle between the two light beams Different wavelengths of laser need different radio frequency driving to obtain the same spatial modulation effect, which makes it difficult to achieve multi-wavelength synchronous modulation. Wherein, λ is the wavelength of incident light, is the frequency interval of radio frequency, is the speed of sound.

[0025] Figure 1 is a structural schematic diagram of a single-pixel color imaging system based on multi-wavelength radio frequency marking according to an embodiment of the present application. As Figure 1 shown, in the single-pixel color imaging system based on multi-wavelength radio frequency marking, it includes a light source module, a radio frequency driving module, a light path adjusting module, a measured target detection module, and an image inversion module.

[0026] The light source module is used to generate three laser beams respectively as optical three primary colors, which are blue, green and red, that is, the three laser beams are blue light, green light and red light, and the wavelengths corresponding to the three laser beams are different.

[0027] The radio frequency driving module is configured to generate a radio frequency complex frequency signal, the radio frequency complex frequency signal including three single frequency signal sequences with different frequency ranges, different frequency intervals, and the same number of signals, that is, the three single frequency signal sequences correspond to different frequency ranges, the three single frequency signal sequences correspond to different frequency intervals, and the number of single frequency signals included in the three single frequency signal sequences is the same. For example, the frequency ranges corresponding to the three single frequency signal sequences are sequentially increased, and there is no overlap.

[0028] The optical path adjustment module is configured to perform heterodyne interference processing on the three laser beams according to the radio frequency complex frequency signal, to form a spot array and a reference light source after beam combination, and to generate a combined beam to be incident on a measured target. Heterodyne interferometry is a technology for improving the precision and dynamic range of interferometric measurement by introducing a frequency difference (carrier frequency). Each of the laser beams in the spot array corresponds to a group of sub-spot arrays, that is, the spot array includes three groups of sub-spot arrays, and the three groups of sub-spot arrays correspond one-to-one to the three laser beams. Each group of sub-spot arrays includes a sub-spot array corresponding to each single frequency signal sequence, that is, each group of sub-spot arrays includes three groups of sub-spot arrays, and the three groups of sub-spot arrays correspond one-to-one to the three single frequency signal sequences. Since the angle between the beams corresponding to two adjacent spots in the spot array is , λ is the wavelength of the incident light, is the frequency interval of the radio frequency, is the speed of sound, and the wavelengths of the incident light corresponding to the three laser beams are different, and the speed of sound is a fixed value. Therefore, by setting the frequency intervals and frequency ranges of the radio frequencies corresponding to the three laser beams to be different, there are spots in the sub-spot arrays corresponding to the three laser beams that have the same product of the corresponding wavelength of the incident light and the frequency interval, so that there are spatially aligned sub-spot arrays between the three groups of sub-spot arrays corresponding to the three laser beams. In the spot array, the optical frequencies corresponding to each spot are different.

[0029] The measured target detection module is configured to collect light data generated after the measured target reflects the combined beam and transmit the light data to the image inversion module.

[0030] The image inversion module is configured to receive the light data collected by the measured target detection module and perform image inversion processing on the light data to generate a true color image of the measured target. Image inversion is a technique for reconstructing the original scene from observation data (such as blurred images, projection data, or indirect measurements) through mathematical models and algorithms. In the image inversion module, an image reconstruction algorithm can be set to perform image inversion processing on the light data.

[0031] Figure 1The working principle of the single-pixel color imaging system based on the multi-wavelength radio frequency marker is as follows: The light source module generates three laser beams respectively as optical three primary colors (RGB, red, green and blue), which are incident into the optical path adjustment module. The radio frequency driving module generates a radio frequency complex frequency signal acting on the optical path adjustment module, so that the optical path adjustment module performs heterodyne interference processing on the three laser beams according to the radio frequency complex frequency signal, respectively forms a spot array and a reference light source after beam combination, and generates a combined beam incident on the measured target. Through heterodyne interference processing, spatial radio frequency markers can be realized. After heterodyne interference processing, each spot has a unique frequency shift and deflection angle, and the beat frequency envelope corresponding to each spot has a different frequency. The envelope frequency and the wavelength of the spot and the position of the spot in the sub-spot array uniquely correspond, thereby realizing a unique correspondence between the frequency domain of the beat frequency envelope and the spatial position of the measured target.

[0032] The spot arrays in the combined beam and the reference light source are spatially overlapped, that is, three groups of sub-spot arrays corresponding to the three laser beams are spatially overlapped, and then incident on the measured target. Each spatial position of the measured target has three wavelength spots, which are respectively red (R, Red), green (G, Green), and blue (B, Blue) color components, acting on the measured target. The color of the measured target itself will produce different absorption and reflection effects on the incident three wavelength spots. By collecting the reflected light data of the measured target, the remaining energy of the three wavelength spots can be obtained, representing the absorption and reflection effects of the measured target at the corresponding spatial position on the three wavelength spots, and then the proportion of the three color components relative to the final color is obtained. According to the spot energy size of the spatial position, image inversion is performed to realize color reconstruction and obtain the final color, which is the color of the measured target at the spatial position. Only the spots in the three groups of sub-spot arrays with the same distance interval can completely overlap at the corresponding spatial position, that is, the spatial positions are aligned, and they are effective signals. The remaining spots, although overlapping, are invalid signals. By setting different RF frequency intervals and frequency ranges corresponding to the three laser beams, there are spots in the corresponding split spot arrays of the three laser beams with the same product of the incident light wavelength and the frequency interval, that is, the spots with the same distance interval, so that the spatial position alignment of the three groups of sub-spot arrays corresponding to the three laser beams can be realized by adjusting the split spot arrays, so that the spots corresponding to the three laser beams are overlapped in the spatial position, so as to realize multi-spot segmentation alignment by using a segmented multi-frequency interval RF signal (RF complex frequency signal). By collecting the energy of the spots in the three overlapped split spot arrays after penetrating and scattering the measured target, the effect of each spot on the corresponding spatial position of the measured sample can be obtained. Since the beat frequency corresponding to the spots of different wavelengths incident on the same spatial position of the measured target is different, the color and spatial position of each spot can be distinguished when frequency inversion is performed on each spot. The color of the three wavelength spots corresponding to the effective spatial position is reconstructed, and then the color of each spatial position of the measured target is obtained, realizing color imaging of the measured target.

[0033] In an alternative embodiment, the light source module includes a first laser, a second laser, and a third laser. The first laser is configured to generate a first laser beam with a center wavelength of 488 nm (corresponding to blue), the second laser is configured to generate a second laser beam with a center wavelength of 561 nm (corresponding to green), and the third laser is configured to generate a third laser beam with a center wavelength of 640 nm (corresponding to red).

[0034] In an alternative embodiment, the first laser, the second laser and the third laser are arranged in parallel and the interval distance between two adjacent lasers is the same, and the first laser beam, the second laser beam and the third laser beam are parallel and the interval distance between two adjacent laser beams is the same. The light source module further comprises a first mirror, a first dichroic mirror and a second dichroic mirror, the first mirror is used to reflect the first laser beam to the optical path adjustment module, the first dichroic mirror is used to reflect the second laser beam to the optical path adjustment module, and the second dichroic mirror is used to reflect the third laser beam to the optical path adjustment module, so that the three laser beams incident into the optical path adjustment module form a target included angle between two adjacent laser beams.

[0035] Optionally, an optical isolator is configured for each laser to prevent back-reflection light damage.

[0036] In an alternative embodiment, the radio frequency complex signal comprises a first single frequency signal sequence, a second single frequency signal sequence and a third single frequency signal sequence; the first single frequency signal sequence comprises a target number of single frequency signals with a first frequency range, a first interval and a first frequency range; the second single frequency signal sequence comprises a target number of single frequency signals with a second frequency range, a second interval and a second frequency range; the third single frequency signal sequence comprises a target number of single frequency signals with a third frequency range, a third interval and a third frequency range; wherein the greater the frequency interval, the greater the corresponding spot interval distance in the spot array.

[0037] For example, the radio frequency complex signal comprises 3N single frequency signal components. The first single frequency signal sequence comprises N single frequency signals, and the corresponding optical frequency shift of the first single frequency signal sequence is , , , , ; the second single frequency signal sequence comprises N single frequency signals, and the corresponding optical frequency shift of the second single frequency signal sequence is , , , , ; the third single frequency signal sequence comprises N single frequency signals, and the corresponding optical frequency shift of the third single frequency signal sequence is , , , , .

[0038] wherein, , , , , , .

[0039] By setting , the spot array generated by the same wavelength laser beam is composed of three groups of sub-spot arrays with different distance intervals. The greater the frequency interval, the farther the distance between the adjacent spots of the corresponding spot array, thereby ensuring that the three sub-spot arrays corresponding to the three laser beams with different wavelengths (for example, the wavelengths are , and ) contain three sub-spot arrays that are spatially aligned with each other, for example , , , are simultaneously irradiated on the same spatial position of the measured target, 、 、 are simultaneously irradiated on the same spatial position of the measured target, and so on, 、 、 are simultaneously irradiated on the same spatial position of the measured target.

[0040] In an optional embodiment, the optical path adjustment module includes a beam splitter, a modulation arm, and a reference arm. The beam splitter is used to split the incident three laser beams into three laser beams incident on the modulation arm and three laser beams incident on the reference arm, for example, the three laser beams incident on the modulation arm are the first laser beam (corresponding to the first laser beam), the second laser beam (corresponding to the second laser beam), and the third laser beam (corresponding to the third laser beam), and the three laser beams incident on the reference arm are the fourth laser beam (corresponding to the first laser beam), the fifth laser beam (corresponding to the second laser beam), and the sixth laser beam (corresponding to the third laser beam). The modulation arm is used to modulate the three laser beams incident on the modulation arm into the spot array according to the radio frequency complex signal; wherein each incident laser beam on the modulation arm corresponds to a group of sub-spot arrays; the reference arm is used to combine the three laser beams incident on the reference arm and form the reference light source; and the reference light source covers the spot array.

[0041] Optionally, the beam splitter is a polarization beam splitter, which is used to adjust the polarization state of the incident three laser beams.

[0042] Optionally, the system further comprises a first glass sheet, the three laser beams generated by the light source module pass through the first glass sheet before being incident on the beam splitter, and the first glass sheet is used to adjust the optical power of the three laser beams. Exemplarily, the first glass sheet is a 1 / 2 glass sheet.

[0043] Optionally, the system further comprises a second glass sheet, which is arranged between the polarizing beam splitter and the acousto-optic modulator, and is used to adjust the polarization state of the three laser beamlets incident on the acousto-optic modulator to meet the requirements of the acousto-optic modulator on the polarization state of the incident light before the three laser beamlets are incident on the acousto-optic modulator. Exemplarily, the second glass sheet is a 1 / 2 glass sheet.

[0044] In an optional embodiment, the modulation arm comprises an acousto-optic modulator, which is used to modulate the three laser beamlets incident on the modulation arm into three groups of one-dimensional sub-spot arrays according to the radio frequency complex frequency signal, the laser beamlets and the sub-spot arrays are one-to-one corresponding, and there is a spatially aligned one-dimensional split-spot array between the three groups of one-dimensional sub-spot arrays. Exemplarily, the acousto-optic modulator in the modulation arm is an AOD (Acousto-Optic Deflector). In the case where the modulation arm modulates the incident three laser beamlets into three groups of one-dimensional sub-spot arrays, the reference arm is used to correspondingly integrate the incident three laser beamlets into a one-dimensional linear light source.

[0045] In an optional embodiment, the modulation arm comprises an acousto-optic modulator group; the acousto-optic modulator group comprises two acousto-optic modulators arranged orthogonally; the acousto-optic modulator group is used to modulate the three laser beamlets incident on the modulation arm into three groups of two-dimensional sub-spot arrays according to the radio frequency complex frequency signal; and there is a spatially aligned two-dimensional split-spot array between the three groups of two-dimensional sub-spot arrays. In the case where the modulation arm modulates the incident three laser beamlets into three groups of two-dimensional sub-spot arrays, the reference arm is used to correspondingly integrate the incident three laser beamlets into a two-dimensional area light source.

[0046] In an alternative embodiment, the reference arm comprises a second mirror, a third mirror, a fourth mirror, a third dichroic mirror and a fourth dichroic mirror. The three laser beams of the incident reference arm are reflected by the second mirror and the third mirror in sequence, and then reflected by the fourth mirror, the third dichroic mirror and the fourth dichroic mirror in sequence to form a combined beam. Specifically, the fourth laser beam is reflected by the second mirror and the third mirror in sequence, and then reflected by the fourth dichroic mirror to obtain a reflected fourth laser beam; the fifth laser beam is reflected by the second mirror and the third mirror in sequence, and then reflected by the third dichroic mirror to obtain a reflected fifth laser beam; the sixth laser beam is reflected by the second mirror and the third mirror in sequence, and then reflected by the second mirror to obtain a reflected sixth laser beam; the reflected fourth laser beam, the reflected fifth laser beam and the reflected sixth laser beam are coaxial and spatially coincident to form a combined beam. The reference arm further comprises a beam shaper for shaping the combined beam into a reference light source, and an acousto-optic modulator for adjusting the frequency of the reference light source to a preset frequency, which can be set according to requirements. For example, the acousto-optic modulator in the reference arm is an AOFS (Acousto-Optic Frequency Shifter).

[0047] In an alternative embodiment, the measured target detection module comprises a first single-pixel detector and a second single-pixel detector; the first single-pixel detector is used to collect light data of a forward scattering channel generated after the measured target reflects the combined beam; the second single-pixel detector is used to collect light data of a side scattering channel generated after the measured target reflects the combined beam. The single-pixel detector (including the first single-pixel detector and the second single-pixel detector) simplifies the multi-wavelength light power receiving structure, and does not require the filter or light splitting component relied on by the area array detector in related technologies when performing multi-spectral imaging. The single-pixel detector can directly collect light data of the corresponding channel to the target surface and output as a time-domain electrical signal, which is sent to the data processing unit of the image inversion module, thereby reducing the system cost and improving the system adaptability. Since the wavelength and spatial position of the light data after the action of the measured target have been marked by frequency, the data processing unit can use frequency decoupling to calculate the wavelength and spatial position of the light to obtain image information from the time-domain electrical signal, and reconstruct a three-channel monochrome image through the Fourier single-pixel algorithm to generate a true color image of the measured target. For example, the data processing unit is a data processing software and hardware platform.

[0048] Optionally, the measured target detection module further comprises a beam-reducing lens group, a two-dimensional scanning galvanometer, a first microscopic objective, a second microscopic objective and a third microscopic objective. The beam-reducing lens group comprises a first lens and a second lens, the two-dimensional scanning galvanometer comprises an X-direction galvanometer and a Y-direction galvanometer, and the combined light beam is reflected by the X-direction galvanometer, then passes through the first lens for beam reduction, passes through the second lens for beam expansion, is reflected by the Y-direction galvanometer and then exits the measured target through the first microscopic objective. The X-direction galvanometer and the Y-direction galvanometer cooperate to realize X and Y two-dimensional scanning imaging, fully exert the high frame rate advantage of single-pixel imaging and realize fast scanning. By combining the cost advantage of single-pixel imaging with the information acquisition capability of multi-spectral imaging, the accuracy of color imaging can be ensured on the premise of saving cost.

[0049] Optionally, when the measured target is a static target, a moving device can be arranged in the system, and the moving device is used to drive the measured target to move and realize full-scan according to a preset path. Exemplarily, the moving device is a full-scan displacement table. When the measured target is a flow cytometer, the system can further integrate a flow cytometer, and the flow cytometer is used to drive the flow direction of the measured target to serve as a scanning axis and realize full-scan of the measured target.

[0050] Optionally, the system further comprises a second microscopic objective, a third lens, a third microscopic objective and a fourth lens, the second microscopic objective, the third lens and the first unit detector are coaxial, and the third microscopic objective, the fourth lens and the second unit detector are coaxial. The second microscopic objective is used to collect side scattering light of a light beam incident to the measured target and scattered by the measured target, and the third microscopic objective is used to collect forward scattering light of the light beam incident to the measured target and scattered by the measured target. Since the light beams emitted by the second microscopic objective and the third microscopic objective are parallel light, the third lens and the fourth lens are respectively arranged to realize light beam convergence, so that the light beams are respectively incident to the first unit detector and the second unit detector.

[0051] Optionally, the system further comprises a beam splitter and an imaging camera, the beam splitter is arranged between the fourth lens and the second unit detector, for splitting the light beam passing through the fourth lens into two paths, one path enters the second unit detector, and the other path enters the imaging camera, the imaging camera is used to observe the relative position relationship between the measured target and the light spot array. The light beams split into two paths both contain light signals after the action of the measured target, and the light energy distributions are the same. The light signals reflect the energy distribution of the incident light (including the reference light beam and the light spot array) after passing through the measured target, and further reflect the image shape of the measured target, for example, the light energy incident on the light shielding part of the measured target will be shielded, and the light energy incident on the part with weak light shielding ability of the measured target will penetrate after partial attenuation. The light energy distribution incident on the imaging camera and the unit detector is the same, and the unit detector only receives light energy and does not have imaging capability, so the image reflecting the appearance characteristics (such as the pattern contained in the measured target and the shape of the measured target) of the measured target can be directly observed through the imaging camera. The imaging camera is not necessarily a unit, and the role is to observe the spatial position correspondence between the incident light spot and the measured target.

[0052] Based on the standard primary color matching theory of CIE-RGB (a set of color measurement principles, data and calculation methods), the color of light of each wavelength can be represented by the color matching function of the three primary colors of red, green and blue, and a true color image is synthesized through a color correction matrix. In an optional embodiment, the image inversion module is configured to perform image inversion processing on the light data according to the color correction matrix, and the formula is as follows:

[0053] wherein, is a true color image of the measured target, is an image of the B channel (corresponding to blue), is an image of the G channel (corresponding to green), is an image of the R channel (corresponding to red), is a color correction matrix, , , corresponding to the B channel, , , corresponding to the G channel, , , corresponding to the R channel, is the light energy size corresponding to the three laser beams in the light data, specifically, the light energy size corresponding to the three wavelengths of light spots (corresponding to the three laser beams respectively) at the corresponding spatial position of the measured target collected by the unit detector (the first unit detector or the second unit detector), corresponding to the B channel, corresponding to the G channel, corresponding to the R channel.

[0054] exemplary, , , then:

[0055] then the color of the measured target = (0.065 x + 0.208 x + 0.285 x ) x red + (0.768 x + 0.791 x + 0.083 x ) x green + (1.189 x + 0.001 x + 0.000 x ) x blue.

[0056] The single-pixel color imaging system based on multi-wavelength radio frequency marking provided by the embodiment, through a light source module, three laser beams respectively corresponding to optical three primary colors are generated, providing a basis for subsequent color imaging; through a radio frequency driving module, a radio frequency complex frequency signal including three single frequency signal sequences with different frequency ranges, different frequency intervals and the same number of signals is generated in a segmented multi-frequency interval radio frequency signal driving mode, and then a light path adjustment module performs heterodyne interference processing on the three laser beams according to the radio frequency complex frequency signal, and a spot array and a reference light source are combined, each spot in the spot array corresponds to different light frequencies, each laser beam corresponds to a group of sub-spot arrays, and each group of sub-spot arrays includes a light spot array corresponding to each single frequency signal sequence. By setting different radio frequency frequency intervals and frequency ranges corresponding to the three laser beams, there are light spots with the same product of corresponding incident light wavelengths and frequency intervals in the light spot arrays corresponding to the three laser beams, so that there are spatially aligned light spot arrays between the three groups of sub-spot arrays, thereby solving the spatial position registration problem of the light spot array of the multi-wavelength laser. Each spot is modulated by different frequencies, and the position and color of the spot can be distinguished by the spot frequency, and the multi-band light data decoupling problem is solved, and color imaging is realized without using a surface array detector.

[0057] Moreover, the system realizes simultaneous acquisition of different waveband imaging images by multi-wavelength lasers, and the image inversion module is based on an image color reconstruction model of three-wavelength lasers, which improves the time resolution by three times and improves the imaging efficiency compared with a multi-wavelength system using sequential switching.

[0058] Figure 2is a structural schematic diagram of a one-dimensional multi-wavelength radio frequency tag based single-pixel color imaging system according to an embodiment of the present application. The one-dimensional multi-wavelength radio frequency tag based single-pixel color imaging system comprises a light source module, a radio frequency driving module, a light path adjustment module, a measured target detection module and an image inversion module.

[0059] The light source module comprises a first laser 1, a second laser 2, a third laser 3, a first mirror 4, a first dichroic mirror 5 and a second dichroic mirror 6.

[0060] The light path adjustment module comprises a first glass sheet 7, a polarizing beam splitter 8, a reference arm, a modulation arm and a beam combiner 17. The modulation arm comprises a second glass sheet 9 and an acousto-optic modulator 101. The modulation arm comprises a second mirror 11, a third mirror 12, a fourth mirror 13, a third dichroic mirror 14, a fourth dichroic mirror 15 and a beam shaper 16. The radio frequency driving module is not shown in Figure 2 , and is used to provide a radio frequency complex signal to the acousto-optic modulator 101.

[0061] The measured target detection module comprises an X-direction galvanometer 18, a first lens 19, a second lens 20, a Y-direction galvanometer 21, a first microscope objective 22, a second microscope objective 24, a third microscope objective 25, a third lens 26, a fourth lens 27, an imaging camera 28, a beam splitter 29, a first unit detector 30 and a second unit detector 31. A measured target 23 is arranged between the three microscope objectives.

[0062] The image inversion module comprises a data processing software and hardware platform 23.

[0063] Detailed descriptions of the above components are described in Figure 1 Embodiments, which will not be described here.

[0064] Exemplarily, Figure 3 is a schematic diagram of a radio frequency complex signal according to an embodiment of the present application, as shown in Figure 3 , the radio frequency complex signal is a segmented multi-frequency interval radio frequency driving signal, comprising three radio frequency signals, Figure 3The middle yellow curve is a time-domain radio frequency signal, and the red curve is a frequency-domain signal after FFT (Fast Fourier Transform) processing of the yellow time-domain radio frequency signal. According to the right side of the red curve, it can be clearly seen that the radio frequency complex frequency signal is divided into three sections, each section is composed of 10 frequency components, and the frequency interval between the 10 frequency points in each section is the same, and the frequency interval between the frequency points of different sections is different. Among them, one unit cell in the vertical direction (divided by a dashed line in the figure) represents 2.00 mV, one unit cell in the horizontal direction represents 40.0 μs (microseconds), the sampling rate is 25.0 MS / s (megacycles / second), the rising edge is stored, the storage depth is 10k (ten thousand) points collected once, and the trigger level is-240 μV (microvolts). Figure 4 is a schematic diagram of spatial registration of a sub-spot array according to an embodiment of the present application, as shown in Figure 4 , the first row is a sub-spot array corresponding to a laser beam with a center wavelength of 640 nm, the second row is a sub-spot array corresponding to a laser beam with a center wavelength of 561 nm, and the third row is a sub-spot array corresponding to a laser beam with a center wavelength of 488 nm. It should be noted that the three sub-spot arrays are actually overlapped in spatial position, Figure 4 , which is divided into three rows for display. From Figure 4 , it can be seen that the distance intervals between the spots in the sub-spot array with a frequency interval , the sub-spot array with a frequency interval , and the sub-spot array with a frequency interval in the first row, the second row and the third row are the same, and the three sub-spot arrays can be completely overlapped in spatial position by adjustment, that is, aligned in spatial position. The radio frequency complex frequency signal in Figure 3 is input into the acousto-optic modulator 101, and the acousto-optic modulator 101 diffracts the incident light beam into a one-dimensional spot array as shown in Figure 4 according to the radio frequency complex frequency signal. The number of spots in the spot array is determined by the number of frequency components of the radio frequency complex frequency signal loaded in the acousto-optic modulator 101, and the spacing (diffraction angle) between adjacent spots in the spot array is determined by the frequency interval.

[0065] Exemplarily, Figure 5is a schematic diagram of the spatial position correspondence relationship between the one-dimensional light spot array according to the embodiment of the present application and the measured sample, which is acquired by the imaging camera 28, and is used for observing the spatial correspondence relationship between the one-dimensional light spot array and the measured target in real time, so as to evaluate the difference between the one row of images of the measured target obtained by inversion and the actual images, and realize the image quality evaluation. In the system working process, the position of the one-dimensional light spot array can be moved by using the scanning mirror, the inversion imaging of different spatial positions of the measured target is realized, the imaging of one row of images of the measured target is realized by each scanning of the one-dimensional light spot array, and the whole imaging of the measured target is realized by splicing each row of images through the image inversion algorithm.

[0066] Figure 6 is a structural schematic diagram of the two-dimensional single-pixel color imaging system based on the multi-wavelength radio frequency marker according to the embodiment of the present application. Figure 2 The difference between the system shown in the embodiment and the system shown in the embodiment of the present application is that, Figure 6 The system shown in the embodiment adopts the acousto-optic modulator group 102 in the modulation arm and the second acousto-optic modulator 33 in the reference arm.

[0067] Optionally, the second acousto-optic modulator 33 is used for applying fixed frequency shift to the incident light spot, and an AOD or an AOFS can be adopted.

[0068] The detailed description of each component is described in the embodiment of the present application, which will not be repeated here. Figure 1

[0069] Exemplarily, Figure 7 is a schematic diagram of the spatial position correspondence relationship between the two-dimensional light spot array according to the embodiment of the present application and the measured sample. Figure 7 The difference between the system shown in the embodiment and the system shown in the embodiment of the present application is that, Figure 4 the acousto-optic modulator group 102 is adopted to generate the two-dimensional surface array light spot array, and the image of one face of the measured target can be acquired at one time.

[0070] Obviously, the above embodiments are only examples for clearly illustrating, but not limitation on the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the embodiments need not and cannot be exhausted. The obvious changes or variations derived therefrom are still within the protection scope of the present application.​

Claims

1. A single-pixel color imaging system based on multi-wavelength radio frequency tag, characterized in that: The system comprises: A light source module, used for generating three laser beams of three primary optical colors; A radio frequency driving module is configured to generate a radio frequency multi-frequency signal; the radio frequency multi-frequency signal includes three single frequency signal sequences with different frequency ranges, different frequency intervals and the same number of signals; An optical path adjustment module is configured to perform heterodyne interference processing on the three laser beams according to the RF complex frequency signal, respectively forming a light spot array and a reference light source, and then combining the light spot array and the combined light beam to be incident on the target to be measured; each laser beam in the light spot array corresponds to a group of sub-light spot arrays; each group of sub-light spot arrays includes a sub-light spot array corresponding to each single-frequency signal sequence; there is a sub-light spot array spatially aligned between the three groups of sub-light spot arrays; and each light spot corresponds to a different optical frequency; A target detection module, configured to collect light data generated by the target after the target reflects the combined light beam; The image inversion module is used to receive the light data and perform image inversion processing on the light data to generate a true color image of the measured target.

2. The system according to claim 1, wherein: The light source module includes a first laser, a second laser and a third laser; the first laser is used to generate a first laser beam with a central wavelength of 488nm; the second laser is used to generate a second laser beam with a central wavelength of 561nm; and the third laser is used to generate a third laser beam with a central wavelength of 640nm.

3. The system according to claim 2, characterized in that The first laser beam, the second laser beam and the third laser beam are parallel and the distances between adjacent laser beams are the same; The light source module also includes a first reflector, a first dichroic mirror and a second dichroic mirror; the first reflector is used to reflect the first laser beam to the optical path adjustment module; the first dichroic mirror is used to reflect the second laser beam to the optical path adjustment module; the second dichroic mirror is used to reflect the third laser beam to the optical path adjustment module.

4. The system according to any one of claims 1 to 3, characterized in that: The radio frequency multi-frequency signal includes a first single frequency signal sequence, a second single frequency signal sequence and a third single frequency signal sequence; The first single-frequency signal sequence includes single-frequency signals with a frequency range of the first frequency range, a frequency interval of the first interval, and a target number of single-frequency signals; The second single-frequency signal sequence includes single-frequency signals with a frequency range of the second frequency range, a frequency interval of the second interval, and a target number of the single-frequency signals; The third single-frequency signal sequence includes single-frequency signals with a frequency range of a third frequency range, a frequency interval of a third interval, and a target number; wherein, the larger the frequency interval, the larger the corresponding spot spacing distance in the spot array.

5. The system according to any one of claims 1 to 3, characterized in that: The optical path adjustment module includes a beam splitter, a modulation arm and a reference arm; The beam splitter is used to split the three incident laser beams into three laser beams incident on the modulation arm and three laser beams incident on the reference arm; The modulation arm is used to modulate the three laser beams incident on the modulation arm into the light spot array according to the radio frequency complex frequency signal; wherein each laser beam incident on the modulation arm corresponds to a group of sub-light spot arrays; The reference arm is used to split and combine the three laser beams incident on the reference arm and shape them into the reference light source; the reference light source covers the light spot array.

6. The system according to claim 5, characterized in that The modulation arm includes an acousto-optic modulator, which is used to modulate the three laser beams incident on the modulation arm into three groups of one-dimensional sub-spot arrays according to the radio frequency complex frequency signal; there is a one-dimensional sub-spot array with spatial position alignment between the three groups of one-dimensional sub-spot arrays.

7. The system according to claim 5, characterized in that The modulation arm includes an acousto-optic modulator group; the acousto-optic modulator group includes two orthogonally arranged acousto-optic modulators; the acousto-optic modulator group is used to modulate the three laser beams incident on the modulation arm into three groups of two-dimensional sub-spot arrays according to the radio frequency complex frequency signal; and there is a two-dimensional sub-spot array with spatially aligned positions between the three groups of two-dimensional sub-spot arrays.

8. The system according to claim 5, wherein: The reference arm includes a second reflector, a third reflector, a fourth reflector, a third dichroic mirror, and a fourth dichroic mirror; The three laser beams incident on the reference arm are reflected by the second reflector and the third reflector in sequence, and then respectively reflected by the fourth reflector, the third dichroic mirror and the fourth dichroic mirror to form a combined beam.

9. The system according to any one of claims 1 to 3, characterized in that: The target detection module includes a first single-pixel detector and a second single-pixel detector; the first single-pixel detector is used to collect light data of a forward scattering channel generated after the target reflects the combined light beam; the second single-pixel detector is used to collect light data of a side scattering channel generated after the target reflects the combined light beam.

10. The system according to any one of claims 1 to 3, characterized in that: The image inversion module is used to perform image inversion processing on the light data according to the color correction matrix. The formula is as follows: in, is the true color image of the target being measured, is the color correction matrix, are the light energy corresponding to the three laser beams in the light data.

Images