Correlation imaging method and correlation imaging system for correcting non-uniform light field

Abstract

The invention is applicable to the technical field of correlated imaging, and provides a correlated imaging method and a correlated imaging system for correcting non-uniformity of a light field, and the method comprises the steps: transmitting detection light to irradiate a to-be-detected target; receiving target light generated after the detection light irradiates the to-be-detected target, and detecting a light intensity value of the received target light; modulating the probe light or the target light through a modulator; reconstructing an image of a to-be-measured target according to the modulation information of the modulator and the light intensity value of the target light; correcting the image of the to-be-measured target according to the related feature information; according to the pre-calibration information of the probe light or the emission speckle before the target to be detected is detected, the deviation of reconstructing the image of the target to be detected caused by the non-uniform emission light field is corrected, the result accuracy of reconstructing the image of the target to be detected is improved, the complexity of the imaging algorithm is not improved, and the method has a wide application scene.

Description

Technical Field

[0001] The invention belongs to the technical field of correlation imaging and provides a correlation imaging method and a correlation imaging system for correcting light field inhomogeneity. Background Art

[0002] "Correlation imaging" is an imaging method based on the second-order coherence of the light field and using a single-pixel detector, also known as "ghost imaging" or "single-pixel imaging". Since objects can be imaged using only detectors without spatial resolution, correlation imaging has a wide range of application wavelengths and a certain degree of anti-scattering ability, and has a wide range of application scenarios.

[0003] In practical applications, existing correlation imaging devices often use lasers as light sources. However, the uneven distribution of the laser cross section will affect the accuracy of imaging. Therefore, there is an urgent need to design a new laser radar based on correlation imaging. Summary of the invention

[0004] The purpose of an embodiment of the present invention is to provide a correlation imaging method for correcting light field unevenness, aiming to solve the problem in the prior art that the laser radar based on correlation imaging requires the detector therein to have a higher dynamic range, thereby increasing the cost of the laser radar.

[0005] The embodiment of the present invention is implemented as follows: a correlation imaging method for correcting light field inhomogeneity, the method comprising the following steps:

[0006] Emitting detection light to illuminate the target to be measured;

[0007] receiving target light generated after the detection light irradiates the target to be measured, and detecting the light intensity value of the received target light;

[0008] Modulating the detection light or the target light by a modulation element;

[0009] Reconstructing an image of the target to be measured according to the modulation information of the modulator and the light intensity value of the target light;

[0010] Correcting the image of the target to be measured according to relevant characteristic information;

[0011] The relevant characteristic information includes: pre-calibrated intensity distribution information of the detection light, or pre-calibrated spatial and intensity distribution information of emission speckles generated by the modulation of the detection light.

[0012] The purpose of the embodiment of the present invention is also to provide a correlation imaging system, the correlation imaging system comprising: a transmitting device, a receiving device and a light field correction module;

[0013] The transmitting device is used to transmit the detection light to the target to be detected;

[0014] The receiving device is used to receive the target light generated after the detection light irradiates the target to be detected, and detect the received target light;

[0015] The light field correction module includes an information acquisition unit, an information processing unit and a correction unit. The information acquisition unit is in communication connection with the transmitting device and is used to acquire the intensity distribution information of the detection light emitted by the transmitting device.

[0016] The information processing unit is in communication with the receiving device and is used to reconstruct an image of the target to be measured according to the light intensity value of the target light detected by the receiving device.

[0017] The correction unit is used to correct the image of the target to be measured according to the intensity distribution information of the detection light.

[0018] An associated imaging method for correcting light field unevenness provided in an embodiment of the present invention can correct the deviation of the image of the target to be measured caused by the uneven light field of the emitted light according to the pre-calibration information of the detection light or the emission speckle before detecting the target to be measured, thereby improving the accuracy of the result of reconstructing the image of the target to be measured without increasing the complexity of the imaging algorithm, and has a wide range of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A flow chart of a correlation imaging method for correcting light field inhomogeneity provided by an embodiment of the present invention;

[0020] Figure 2 A flow chart of another method for correlating imaging to correct light field inhomogeneity provided by an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of an optical path structure of a correlation imaging system provided by an embodiment of the present invention;

[0022] Figure 4 A schematic diagram of the optical path structure of another correlation imaging system provided by an embodiment of the present invention;

[0023] Figure 5a A schematic diagram of the light reflection principle when all micromirrors of a DMD are flipped to an on state in one embodiment;

[0024] Figure 5b A schematic diagram of the light reflection principle when some micromirrors of a DMD are flipped to an on state in another embodiment;

[0025] Figure 6 A structural block diagram of a correlation imaging system provided by an embodiment of the present invention;

[0026] Figure 7 Schematic diagram of the connection principle of the light field correction module in an embodiment of the present invention;

[0027] Figure 8 Schematic diagram of the structure of the light field correction module in an embodiment of the present invention.

[0028] In the accompanying drawings: 100-transmitting device; 101-light source; 102-transmitting element; 103-modulating element; 200-receiving device; 201-receiving element; 202-detector; 203-light collector; 300-light field correction module; 301-information acquisition unit; 3011-first acquisition unit; 3012-second acquisition unit; 302-information processing unit; 303-correction unit. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] It can be understood that the terms "first", "second", etc. used in the present application can be used in this article to describe various elements, but unless otherwise specified, these elements are not limited by these terms. These terms are only used to distinguish the first element from another element.

[0031] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0032] like Figure 1 FIG. 1 is a flow chart of a method for correlating imaging for correcting light field inhomogeneity provided by an embodiment of the present invention, wherein the method comprises the following steps:

[0033] S102: emitting detection light to illuminate the target to be detected;

[0034] S104: receiving target light generated after the detection light irradiates the target to be measured, and detecting a light intensity value of the received target light;

[0035] S106: modulating the detection light or the target light through a modulator;

[0036] S108: reconstructing an image of the target to be measured according to the modulation information of the modulator and the light intensity value of the target light;

[0037] S110: Correcting the image of the target to be measured according to relevant characteristic information;

[0038] The relevant characteristic information includes: pre-calibrated intensity distribution information of the detection light, or pre-calibrated spatial and intensity distribution information of emission speckles generated by the modulation of the detection light.

[0039] In the embodiments of the present invention, the deviation of the image of the target to be measured caused by the uneven light field of the emitted light can be corrected according to the pre-calibration information of the detection light or the emission speckle before detecting the target to be measured, thereby improving the accuracy of the result of reconstructing the image of the target to be measured without increasing the complexity of the imaging algorithm, and has a wide range of application scenarios.

[0040] In an example of the present embodiment, a correlation imaging system using the method includes a transmitting device and a receiving device, wherein the transmitting device transmits detection light to illuminate the target to be measured, and the receiving device receives the target light generated after the detection light illuminates the target to be measured, and detects the light intensity value of the received target light; at the same time, the detection light or the target light can be modulated by a modulator; thereafter, the image of the target to be measured is reconstructed according to the modulation information of the modulator and the light intensity value of the target light, and the image of the target to be measured is corrected according to the pre-calibrated intensity distribution information of the detection light, or according to the pre-calibrated spatial and intensity distribution information of the emission speckle generated by the modulation of the detection light; wherein the modulation information is the control signal received by the correlation imaging system, including information for modulating the spatial and intensity distribution of the detection light.

[0041] In an example of this embodiment, modulating the detection light or the target light by a modulator includes: modulating the detection light by a modulator, such as Figure 3 As shown; the target light is modulated by a modulator, such as Figure 4 shown.

[0042] In one example of the present embodiment, before detecting the target to be measured, the intensity distribution of the detection light emitted (or emitted) by the emitting device is pre-calibrated to determine the intensity distribution information of the detection light, and the image of the target to be measured is corrected in the reconstruction operation; for example: if the intensity distribution of the detection light is strong in the middle and weak in the periphery, then in the reconstruction operation, the middle part of the image of the target to be measured is weakened and the surrounding part is strengthened to achieve the purpose of correcting the uniformity of the light field, and the image of the target to be measured is reconstructed in combination with the light intensity value of the target light to obtain a high-precision image of the target to be measured.

[0043] In an example of this embodiment, before detecting the target to be measured, the emission speckle modulated by the modulation element is pre-calibrated, and the spatial and intensity distributions of the emission speckle are recorded; during reconstruction, a reconstruction operation is performed using the calibrated emission speckle and the obtained light intensity value of the target light; the correction and reconstruction of the image of the target to be measured are achieved, and the correction and reconstruction steps can be integrated.

[0044] In an example of this embodiment, the reconstructed image of the target to be measured is reconstructed by calculation through an association algorithm, and the association algorithm satisfies:

[0045]

[0046] Among them, Image(x) represents the image of the target to be measured, δS i =S i - <s>represents the light intensity fluctuation of the target light, S i represents the light intensity value of the target light detected after the i-th modulation, <s>is the average light intensity of the target light detected after N modulations; I i (x) represents the emission speckle, i is the i-th modulation, and x represents the spatial coordinate.

[0047] In this example, the emission speckle can be Hadamard speckle, Fourier speckle or random speckle, etc. When the emission speckle is modulated into Hadamard speckle, Fourier speckle or random speckle, correspondingly, a related algorithm can be used for reconstruction, such as: Hadamard transform algorithm, Fourier transform algorithm, etc. Therefore, this example is not limited to the association algorithm to reconstruct the image of the target to be measured; those skilled in the art can flexibly select the reconstruction algorithm to be used according to actual needs. The purpose of reducing the cost of detecting the target to be measured is achieved;

[0048] In the actual imaging process of correlation imaging, it is impossible to accurately know the emission speckle pattern I irradiated on the target to be measured. i (x), so it is often through the modulation signal I' of the modulator i (x) Calculation I i (x). Therefore, if the intensity distribution of the detection light emitted by the light source is uneven, then i (x) Calculation I i (x) process, thus affecting the accuracy of the reconstructed image, and this problem needs to be solved.

[0049] In some examples, after reconstructing the image of the target to be measured, the image of the target to be measured can be corrected according to relevant characteristic information; wherein the relevant characteristic information includes: pre-calibrated intensity distribution information of the detection light, or pre-calibrated spatial and intensity distribution information of emission speckles generated by the modulation of the detection light;

[0050] Specifically, first, before detecting the target to be measured, the emission speckle pattern can be pre-calibrated to accurately obtain the emission speckle pattern I irradiated on the target to be measured. i (x) distribution; in actual detection, the modulation element sends a modulation signal I′ i (x), in the process of reconstructing the image of the target to be measured, the pre-calibrated emission speckle I is used i (x) greatly reduces the error and improves the accuracy of reconstruction; secondly, the intensity distribution of the detection light emitted by the light source is pre-calibrated, and the intensity distribution of the detection light can be used to correct the image of the target to be measured during the process of reconstructing the image of the target to be measured, thereby improving the accuracy of imaging.

[0051] In addition, the correlation imaging method in this embodiment can be applied to both the imaging system of the pre-modulation mode and the imaging system of the post-modulation mode. Similarly, if the intensity of the detection light emitted by the light source of the transmitting device is uneven, the intensity distribution of the target image to be measured by the receiving device will be uneven. At this time, no matter how the modulator is modulated, the distribution of the final reconstructed image will be uneven, affecting the accuracy of the reconstruction; similarly, the intensity distribution of the light source can be pre-calibrated, and the image of the target to be measured can be corrected during the reconstruction process. In this way, the output light of the light source has a variety of options, which can be applied not only to laser radar, but also to fields such as correlation imaging cameras, and has a wide range of application scenarios.

[0052] In another embodiment, the method further includes: when the detection light is modulated by the modulator, according to the intensity distribution information of the detection light, controlling the modulator to correct the detection light so that the output light field of the modulator emits a uniform speckle.

[0053] In this embodiment, the modulator is controlled so that the modulator emits a uniform speckle in the outgoing light field, thereby achieving the effect of correcting the uneven light field. For example, when the modulator adopts a digital micromirror array (DMD), because the DMD is composed of a series of periodically arranged micrometer-sized aluminum mirrors, each micromirror can independently rotate ±12° along its diagonal, where a rotation of +12° is called an "on state" and a rotation of -12° is called an "off state". When a control signal is input to the DMD, the corresponding micromirror in the DMD rotates to the on state, and the other micromirrors rotate to the off state, thereby deflecting the incident light and completing the modulation of the incident light. When the modulated detection light is a laser, because the cross-section of the laser follows a Gaussian distribution, that is, the intensity distribution of the laser is strong in the middle and weak on both sides; therefore, when the emission speckle to be designed is a light spot with uniform intensity, if all the micromirrors in the DMD are rotated to the on state, the outgoing light spot is also strong in the middle and weak on both sides, such as Figure 5a As shown; therefore, the micromirrors of the DMD are modified according to the intensity distribution of the laser cross section, so that there are fewer on-state micromirrors in the middle position and more on-state micromirrors at the edge position, which can reduce the intensity of the emitted light in the middle position and make the emission speckle uniform, as shown in Figure 5b Similarly, when the modulation element is a micromirror array with a modulation function, the emission speckle can also be corrected through the above modulation steps, and the incident light is modulated by optimizing the position of the micromirror in the on state on the DMD to generate a uniform emission speckle to illuminate the target to be measured, thereby achieving detection of the target to be measured.

[0054] In one example, if Figure 2 As shown, the method specifically comprises the following steps:

[0055] S202: emitting detection light to illuminate the target to be detected;

[0056] S204: modulating the detection light by a modulation element;

[0057] S206: controlling the modulation element to correct the detection light according to the intensity distribution information of the detection light;

[0058] S208: receiving target light generated after the detection light irradiates the target to be measured, and detecting a light intensity value of the received target light;

[0059] S210: Reconstructing an image of the target to be measured according to the modulation information of the modulator and the light intensity value of the target light.

[0060] In this example, the correction of the detection light is completed in the modulation stage, rather than in the reconstruction stage of the image of the target to be measured. The principle is as follows Figure 5a , Figure 5b As shown: the intensity distribution information of the emitted detection light is measured in advance, or can be directly obtained or inferred based on the parameters of the light source itself. If the pre-measured intensity distribution information of the detection light is strong in the middle and weak on both sides, the number of open micromirrors in the middle position of the modulator can be reduced, and the number of open micromirrors at the edge position can be increased, thereby reducing the intensity of the emitted light in the middle position and making the emitted light spot uniform, thereby improving the accuracy of reconstructing the image of the target to be measured.

[0061] Preferably, the modulation and correction of the detection light are both performed by using a digital micromirror array as a modulation element.

[0062] As mentioned above, since the digital micromirror array is composed of a series of micron-sized aluminum mirrors arranged periodically, the original control program of the digital micromirror array can be used to output control signals during modulation and correction without the need for complex improvements. It can be seen that part of a series of micron-sized aluminum mirrors is deflected, while other parts are not deflected, thereby achieving correction when the detection light is laser, making the light field emitted by the laser uniform and then irradiating the target to be measured.

[0063] As shown in Figure 5- Figure 7 As shown, in another embodiment, a correlation imaging system is used in the correlation imaging method for correcting light field non-uniformity as described above, and the correlation imaging system includes: a transmitting device 100, a receiving device 200 and a light field correction module 300;

[0064] The transmitting device 100 is used to transmit detection light to the target to be detected;

[0065] The receiving device 200 is used to receive the target light generated after the detection light irradiates the target to be detected, and detect the received target light;

[0066] The light field correction module 300 includes an information acquisition unit 301, an information processing unit 302 and a correction unit 303. The information acquisition unit 301 is connected to the transmitting device 100 for communication and is used to obtain the intensity distribution information of the detection light emitted by the transmitting device 100.

[0067] The information processing unit 302 is in communication with the receiving device 200 and is used to reconstruct an image of the target to be measured according to the light intensity value of the target light detected by the receiving device 200.

[0068] The correction unit 303 is used to correct the image of the target to be measured according to the intensity distribution information of the detection light.

[0069] In this embodiment, by setting up a light field correction module 300, it is possible to correct the deviation of the image of the target to be measured caused by the uneven light field of the emitted light according to the pre-calibration information of the detection light or the emission speckle before detecting the target to be measured, thereby improving the accuracy of the result of reconstructing the image of the target to be measured without increasing the complexity of the imaging algorithm, and has a wide range of application scenarios.

[0070] In an example of this embodiment, one case is to use the pre-calibration information of the detection light before the target to be measured, and the pre-calibration information includes the intensity distribution of the calibrated detection light. Another case is to use the pre-calibration information of the emission speckle before the target to be measured, and the emission speckle can be generated by modulating the detection light by a modulator; the modulator can be a spatial light modulator (SLM) or a digital micromirror array (DMD), or a reflector, and the reflector is rotatably installed on the optical path of the detection light through a linear drive; and the linear drive is electrically connected to the drive control board, and the drive control board converts the digital angle information into a voltage signal through D / A, and then outputs it to the linear drive through operational amplification, and then drives the reflector to deflect through the linear drive to achieve modulation; at the same time, the reflector is built-in with a feedback device, such as an angle sensor, and the angle sensor will feedback the corresponding analog angle information directly to the drive control board, and complete the A / D conversion of the angle information in the drive control board, and then combine it with the pre-calibration information of the reflector to obtain the pre-calibration information of the emission speckle.

[0071] In one embodiment, the transmitting device 100 includes a light source 101 and a transmitting element 102, wherein the light source 101 is used to transmit detection light to illuminate the target to be measured, and the transmitting element 102 is arranged on the optical path of the detection light; the receiving device 200 includes at least a receiving element 201 and a detector 202, wherein the receiving element 201 is used to receive the target light, and the detector 202 is arranged on the optical path of the outgoing light of the receiving element 201, and the detector 202 is used to detect the light intensity value of the target light emitted by the receiving element 201;

[0072] Specifically, the light source 101 can be a laser, LED, etc., the transmitting element 102 can be a single lens or a lens group, the receiving element 201 can be a single lens, a lens group or a Fresnel lens, etc., the detector 202 can be a single-pixel detector, and the single-pixel detector is connected to an information processor matched therewith, such as: FPGA (field programmable gate array) or PLC (programmable array logic) controller, etc., preferably FPGA; the FPGA is communicatively connected to a host computer, and the host computer can be installed with the light field correction module 300, and the light field correction module 300 can obtain signals of the light source 101, the single-pixel detector, etc. through the FPGA; the host computer is generally composed of a microcomputer, a portable computer, etc. It can be seen that the information acquisition unit 301 included in the light field correction module 300 can be an FPGA, the information processing unit 302 and the correction unit 303 jointly use a host computer, and the correction unit 303 can also be a linear drive that controls the deflection of the modulator 103 or the micromirror array drive in the above-mentioned DMD. The FPGA is connected to the light source of the emitting device 100 for communication, and the single-pixel detector is connected to the modulator 103; it is used to obtain the intensity distribution information of the detection light emitted by the light source 101 in the emitting device 100, and to obtain the spatial and intensity distribution information of the modulated emission speckle of the modulator 103.

[0073] In one example, the laser can emit a fixed frequency pulse laser, and the emitted laser passes through the modulator 103 and the transmitter 102 and irradiates the target to be measured, and then the diffusely scattered echo signal (i.e., the target light) generated by the target to be measured passes through the receiving element 201 again and is then detected by the single-pixel detector. At the same time, the light field correction module 300 in the host computer completes the acquisition of the target light intensity value based on the synchronization signal emitted by the acquisition laser as a reference, and realizes the reconstruction of the image of the target to be measured. In addition, before the system works, the information acquisition unit 301 completes the acquisition of the intensity distribution information of the detection light. After the information processing unit 302 reconstructs the image of the target to be measured according to the light intensity value of the target light detected by the receiving device 200, the correction unit 303 corrects the image of the target to be measured according to the intensity distribution information of the detection light.

[0074] In another example, the receiving device 200 also includes a light collector 203; the receiving element 201 is used to receive the target light generated after the detection light irradiates the target to be measured; the light collector 203 is arranged on the optical path of the target light emitted by the receiving element 201, and is used to collect the target light; the detector 202 is used to receive and detect the target light emitted by the light collector 203.

[0075] like Figure 3-Figure 7 As shown, in a preferred embodiment, it also includes a modulator 103, which is arranged on the optical path of the detection light, and the modulator 103 can modulate the detection light and generate an emission speckle to irradiate the target to be measured;

[0076] Alternatively, the modulator 103 is disposed on the optical path of the target light, and the modulator 103 is capable of receiving the target light and modulating the image of the target to be measured formed in the modulator 103 to generate a receiving speckle to irradiate the receiving device 200;

[0077] The information acquisition unit 301 is further used to acquire the spatial and intensity distribution information of the emission speckle;

[0078] The information processing unit 302 can reconstruct the image of the target to be measured according to the spatial and intensity distribution information of the emission speckle and the light intensity value of the target light.

[0079] In the first example of the present invention, a modulator 103 is arranged on the optical path of the detection light, and the modulator 103 is used to modulate the detection light.

[0080] In this example, the modulation is performed before the detection light irradiates the target to be detected, which is the pre-modulation mode. Figure 3 As shown, the solid line represents the emitted detection light, and the dotted line represents the received target light: the laser emitted by the transmitting device 100 irradiates the modulator 103, the modulator 103 performs known and controllable modulation on the incident laser, and emits it to irradiate the target to be measured; the receiving device 200 collects and detects the target light reflected by the target to be measured; and can perform correlation imaging calculation on the modulation information of the detection light and the intensity data of the detected target light according to the modulator 103, and reconstruct the image of the target to be measured.

[0081] like Figure 4 As shown, in the second example of the present invention, a modulator 103 is arranged on the optical path of the target light, and the modulator 103 is used to modulate the target light.

[0082] In the above example, the receiving device 200 first collects the target light reflected by the target to be measured, and images it onto the modulator 103, and the modulator 103 performs known and controllable modulation on the image of the target to be measured; the receiving device 200 then converges and detects the target light emitted by the modulator 103; and can perform associated imaging calculations based on the modulation of the target light by the modulator 103 and the intensity data of the detected target light, to reconstruct the image of the target to be measured.

[0083] In this embodiment, when performing pre-modulation or post-modulation, the modulation of the detection light and the target light can be achieved by moving the modulation element 103, and then different modulation speckles (or emission speckles) are modulated to form a series of modulation speckles, which are respectively irradiated to different sub-fields of the field of view to be measured (such as sub-field 1, sub-field 2, and sub-field 3 in the figure) to achieve the illumination of the target to be measured; at the same time, the modulation speckles can be corrected according to relevant characteristic information, and this embodiment does not make any specific restrictions.

[0084] In another example of the present embodiment, the modulation element 103 is one of frosted glass, a spatial light modulator and a digital micromirror array; in actual application, the modulation element 103 can cooperate with the light field correction module 300 to realize reconstruction and correction of the image of the target to be measured, and the accuracy of the reconstructed image is relatively high; taking the digital micromirror array as an example: when the modulated detection light is a laser, the cross section of the laser follows a Gaussian distribution, that is, the intensity distribution of the laser is strong in the middle and weak on both sides; therefore, the micromirrors of the DMD can be modified according to the intensity distribution of the laser cross section, so that there are fewer open micromirrors in the middle position and more open micromirrors in the edge position, so that the intensity of the emitted light in the middle position can be reduced, so that the emission speckle becomes uniform; such as Figure 5a , Figure 5b shown.

[0085] like Figure 8 As shown, in an example of this embodiment, the information acquisition unit 301 includes a first acquisition unit 3011 and / or a second acquisition unit 3012, the first acquisition unit 3011 is communicatively connected to the transmitting device 100, and the second acquisition unit 3012 is communicatively connected to the modulating element 103.

[0086] Specifically, when the light source 101 in the transmitting device 100 adopts a laser and the modulator 103 adopts a DMD, the first acquisition unit 3011 can adopt a laser signal line, and the second acquisition unit 3012 can adopt an FPGA signal line or a PLC signal line to realize the transmission of relevant data, which will not be described in detail here.

[0087] In an example of this embodiment, the correction unit 303 is further used to output optimization information according to the intensity distribution information of the detection light, and the optimization information controls the modulator 103 to correct the detection light so that the modulator 103 emits a uniform speckle in the outgoing light field.

[0088] Specifically, taking the case where the modulator 103 adopts DMD as an example, the correction unit 303 can be an external drive, or a micromirror driving chip of the DMD, or other components or driving programs capable of controlling the deflection of the DMD; the pulsed laser is used as the detection light to irradiate the DMD, and the intensity distribution of the detection light is strong in the middle and weak in the periphery. When performing correction, the "on state" of some micromirrors in the middle part of the DMD can be changed so that the light intensity of the output light emitted by the micromirrors in the middle part and the output light emitted by the micromirrors in the periphery are uniform, thereby achieving the purpose of correction; Figure 5a , Figure 5b shown.

[0089] In one example of the present invention, the modulator 103 may be frosted glass, a spatial light modulator, or the like; when the modulator 103 is frosted glass, the modulation of the detection light or the image of the target to be detected may be known; for example, for frosted glass, modulation may be achieved by using a method of pre-calibrating a frosted glass modulation pattern; the modulation of light by SLM is controllable, and by inputting different control signals, i.e., modulation information, the SLM modulates the light differently.

[0090] Therefore, the coordination of the modulator 103 and the light field correction module 300 in this embodiment can realize the modulation and correction of the detection light and the target light. The detection accuracy of the target to be detected is improved, and the operation complexity is not high, which is conducive to implementation; it can be applied to both the imaging system of the first modulation mode and the imaging system of the post-modulation mode, and can be applied not only to laser radar, but also to the fields of correlation imaging cameras, and has a wide range of application scenarios.

[0091] In the above-mentioned embodiment of the present invention, a correlation imaging method for correcting light field unevenness is provided, and based on the correlation imaging method for correcting light field unevenness, a correlation imaging system is provided, which can correct the deviation of the image of the target to be measured caused by the uneven light field of the emitted light according to the pre-calibration information of the detection light or the emission speckle before detecting the target to be measured, thereby improving the accuracy of the result of reconstructing the image of the target to be measured without increasing the complexity of the imaging algorithm, and has a wide range of application scenarios; and the correlation imaging method for correcting light field unevenness can be applied to both pre-modulation systems and post-modulation systems, and can be applied not only to laser radars but also to fields such as single-pixel cameras, and has a wide range of application scenarios; and the design cost of the equipment is low, and the cost can be effectively reduced while ensuring the image quality.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.< / s> < / s>

Claims

1. A correlation imaging method for correcting light field inhomogeneity, characterized in that: The method comprises the following steps: Emitting detection light to illuminate the target to be measured; receiving target light generated after the detection light irradiates the target to be measured, and detecting the light intensity value of the received target light; Modulating the detection light or the target light by a modulation element; Reconstructing an image of the target to be measured according to the modulation information of the modulator and the light intensity value of the target light; Correcting the image of the target to be measured according to relevant characteristic information; The relevant characteristic information includes: pre-calibrated intensity distribution information of the detection light, or pre-calibrated spatial and intensity distribution information of emission speckles generated by the modulation of the detection light.

2. The method for correlative imaging for correcting light field inhomogeneity according to claim 1, characterized in that: The reconstructed image of the target to be measured is reconstructed by calculation through an association algorithm, and the association algorithm satisfies: Among them, Image(x) represents the image of the target to be measured, δS i =S i - <s>represents the light intensity fluctuation of the target light, S i represents the light intensity value of the target light detected after the i-th modulation, <s>is the average light intensity of the target light detected after N modulations; I i (x) represents the emission speckle, i is the i-th modulation, and x represents the spatial coordinate.< / s> < / s> <s> <s> 3. The method for correlative imaging for correcting light field inhomogeneity according to claim 1, characterized in that: The method further comprises: When the detection light is modulated by the modulator, the modulator is controlled to correct the detection light according to the intensity distribution information of the detection light, so that the outgoing light field of the modulator emits a uniform speckle.

4. The method for correlative imaging for correcting light field inhomogeneity according to claim 3, characterized in that: The modulation and correction of the detection light are both performed by using a digital micromirror array as a modulation element.

5. A correlation imaging system, characterized in that: A correlation imaging method for correcting light field inhomogeneity as claimed in any one of claims 1 to 4, wherein the correlation imaging system comprises: a transmitting device, a receiving device and a light field correction module; The transmitting device is used to transmit the detection light to the target to be detected; The receiving device is used to receive the target light generated after the detection light irradiates the target to be detected, and detect the received target light; The light field correction module includes an information acquisition unit, an information processing unit and a correction unit. The information acquisition unit is in communication connection with the transmitting device and is used to acquire the intensity distribution information of the detection light emitted by the transmitting device. The information processing unit is in communication with the receiving device and is used to reconstruct an image of the target to be measured according to the light intensity value of the target light detected by the receiving device. The correction unit is used to correct the image of the target to be measured according to the intensity distribution information of the detection light.

6. The correlation imaging system according to claim 5, characterized in that: It also includes a modulator, which is arranged on the optical path of the detection light, and can modulate the detection light and generate an emission speckle to irradiate the target to be measured; Alternatively, the modulator is arranged on the optical path of the target light, and the modulator is capable of receiving the target light and modulating the image of the target to be measured formed in the modulator to generate a receiving speckle to irradiate the receiving device; The information acquisition unit is further used to acquire the spatial and intensity distribution information of the emission speckle; The information processing unit can reconstruct an image of the target to be measured according to the spatial and intensity distribution information of the emission speckle and the light intensity value of the target light.

7. The correlation imaging system according to claim 6, characterized in that: The information acquisition unit includes a first acquisition unit and / or a second acquisition unit, the first acquisition unit is communicatively connected to the transmitting device, and the second acquisition unit is communicatively connected to the modulating element.

8. The correlation imaging system according to claim 7, characterized in that: The correction unit is further used to output optimization information according to the intensity distribution information of the detection light, and the optimization information controls the modulator to correct the detection light so that the modulator emits a uniform speckle in the output light field.

9. The correlation imaging system according to claim 6, 7 or 8, characterized in that: The modulation element is one of ground glass, a spatial light modulator and a digital micromirror array.

10. The correlation imaging system according to claim 5, characterized in that: The emitting device comprises a light source and an emitting element. The light source is used to emit detection light to illuminate the target to be measured, and the emitting element is arranged on the optical path of the detection light; The receiving device at least includes a receiving element and a detector. The receiving element is used to receive the target light. The detector is arranged on the optical path of the outgoing light of the receiving element. The detector is used to detect the light intensity value of the target light emitted by the receiving element. < / s> < / s>

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