Method for correcting light field inhomogeneity and correlated imaging system

Abstract

The application is suitable for the field of correlation imaging technology, and provides a correlation imaging method for correcting non-uniform light field and a correlation imaging system.The method comprises the following steps: emitting probe light to irradiate a to-be-detected target; receiving target light generated after the probe light irradiates the to-be-detected target, and detecting the light intensity value of the received target light; modulating the probe light or the target light through a modulation member; reconstructing an image of the to-be-detected target according to modulation information of the modulation member and the light intensity value of the target light; and correcting the image of the to-be-detected target according to relevant characteristic information.The application corrects the deviation of the reconstructed image of the to-be-detected target caused by non-uniform light field of the emitted light according to pre-calibration information of the probe light or emitted speckle before detecting the to-be-detected target, improves the result accuracy of the reconstructed image of the to-be-detected target, and does not improve the complexity of the imaging algorithm, so that the application has a wide range of application scenarios.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of correlation imaging, and provides a correlation imaging method for correcting non-uniform light field and a correlation imaging system. BACKGROUND

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

[0003] In actual application, the existing correlation imaging device often uses laser as a light source, and the non-uniform cross-sectional distribution of the laser will affect the accuracy of imaging, therefore, it is urgent to design a new laser radar based on correlation imaging. SUMMARY

[0004] The purpose of the embodiment of the application is to provide a correlation imaging method for correcting non-uniform light field, aiming at solving the problem that the existing laser radar based on correlation imaging requires the detector to have a high dynamic range, thereby increasing the cost of the laser radar.

[0005] The embodiment of the application is implemented as follows: a correlation imaging method for correcting non-uniform light field, the method comprising the following steps:

[0006] Emitting detection light to irradiate a 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 member;

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

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

[0011] The relevant feature information comprises: pre-calibrated intensity distribution information of the detection light, or pre-calibrated spatial and intensity distribution information of emission speckles generated after the detection light is modulated.

[0012] The purpose of the embodiment of the application is also to provide a correlation imaging system, which comprises a transmitting device, a receiving device and a light field correction module.

[0013] The transmitting device is used for emitting detection light to irradiate a target to be measured;

[0014] The receiving device is configured to receive target light generated after the probe light irradiates the target object, and detect the received target light;

[0015] The light field correction module comprises an information acquisition unit, an information processing unit and a correction unit, the information acquisition unit is in communication connection with the emitting device, and is configured to acquire intensity distribution information of the probe light emitted by the emitting device,

[0016] The information processing unit is in communication connection with the receiving device, and is configured to reconstruct an image of the target object according to the light intensity value of the target light detected by the receiving device,

[0017] The correction unit is configured to correct the image of the target object according to the intensity distribution information of the probe light.

[0018] The correlation imaging method for correcting non-uniform light field provided by the embodiment of the present application can correct the deviation of the reconstructed image of the target object caused by non-uniform light field of the emitted light according to the pre-calibration information of the probe light or the emitted speckle before the target object is detected, improve the result accuracy of the reconstructed image of the target object, and has a wide application scenario without improving the complexity of the imaging algorithm. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The correlation imaging method for correcting non-uniform light field provided by the embodiment of the present application is a flow chart;

[0020] Figure 2 The correlation imaging method for correcting non-uniform light field provided by the embodiment of the present application is a flow chart;

[0021] Figure 3 The optical path structure schematic diagram of the correlation imaging system provided by the embodiment of the present application is shown in the figure;

[0022] Figure 4 The optical path structure schematic diagram of the correlation imaging system provided by the embodiment of the present application is shown in the figure;

[0023] Figure 5a The light reflection principle schematic diagram of the DMD in which all micromirrors are flipped to the open state is shown in the figure;

[0024] Figure 5b The light reflection principle schematic diagram of the DMD in which part of the micromirrors are flipped to the open state is shown in the figure;

[0025] Figure 6 The structure block diagram of the correlation imaging system provided by the embodiment of the present application is shown in the figure;

[0026] Figure 7 The connection principle schematic diagram of the light field correction module in the embodiment of the present application is shown in the figure;

[0027] Figure 8 Structure diagram of the light field correction module in the embodiment of the present application.

[0028] In the drawings: 100 - emitting device; 101 - light source; 102 - emitting 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 objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0030] It can be understood that the terms "first", "second", etc. used in the present application can be used herein to describe various elements, but unless specifically stated, 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 application will be described in detail below in combination with specific embodiments.

[0032] As shown in the flowchart of the method for correcting the non-uniformity of the light field provided by the embodiment of the present application, the method comprises the following steps: Figure 1

[0033] S102: Emitting the probe light to irradiate the target to be measured;

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

[0035] S106: Modulating the probe light or the target light by the modulating element;

[0036] S108: Reconstructing the image of the target to be measured according to the modulation information of the modulating element and the light intensity value of the target light;

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

[0038] The related characteristic information comprises the intensity distribution information of the probe light pre-calibrated, or the spatial and intensity distribution information of the emission speckle generated after the probe light is modulated.

[0039] ​In the embodiment of the present application, the deviation of the reconstructed image of the target to be measured caused by the non-uniformity of the light field of the emitted light can be corrected according to the pre-calibration information of the emitted light or the emitted speckle before the target to be measured is detected, the accuracy of the reconstructed image of the target to be measured is improved, and the imaging algorithm complexity is not increased, so the method has a wide range of application scenarios.

[0040] In one example of the embodiment, the correlation imaging system using the method comprises an emitting device and a receiving device, the emitting device is used to emit probe light to irradiate a target to be measured, the receiving device is used to receive target light generated after the probe light irradiates the target to be measured, and the light intensity value of the received target light is detected; meanwhile, the probe light or the target light can be modulated by a modulation member; then, the image of the target to be measured is reconstructed according to the modulation information of the modulation member 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 probe light or according to the pre-calibrated spatial and intensity distribution information of the emitted speckle generated after the probe light is modulated; wherein the modulation information is a control signal received by the correlation imaging system, and includes information for modulating the spatial and intensity distribution of the probe light.

[0041] In one example of the embodiment, the probe light or the target light is modulated by the modulation member, including: the probe light is modulated by the modulation member, as shown in Figure 3 The target light is modulated by the modulation member, as shown in Figure 4 .

[0042] In one example of the embodiment, the intensity distribution of the probe light emitted (or emitted) by the emitting device is pre-calibrated before the target to be measured is detected, so as to determine the intensity distribution information of the probe light, and the image of the target to be measured is corrected in the reconstruction operation; for example, the intensity distribution of the probe light is strong in the middle and weak around, so the middle part of the image of the target to be measured is weakened and the surrounding part of the image of the target to be measured is strengthened in the reconstruction operation, so as to correct the light field uniformity, and the image of the target to be measured is reconstructed by combining the light intensity value of the target light, so that the image of the target to be measured with high accuracy is obtained.

[0043] In one example of the embodiment, the emitted speckle modulated by the modulation member is pre-calibrated before the target to be measured is detected, and the spatial and intensity distribution of the emitted speckle is recorded; the pre-calibrated emitted speckle and the obtained light intensity value of the target light are used for the reconstruction operation in the reconstruction, so as to correct and reconstruct the image of the target to be measured, and the correction and reconstruction steps can be combined.

[0044] In one example of the embodiment, the image of the target to be measured is calculated and reconstructed by the correlation algorithm, and the correlation algorithm satisfies:

[0045]

[0046] where Image(x) represents the image of the object 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 intensity value of the target light detected after N times of modulation; I i (x) represents the emitted speckle, i is the i-th modulation, and x represents the spatial coordinate.

[0047] The emitted speckle in this example can be a Hadamard speckle, a Fourier speckle, or a random speckle. When the emitted speckle is modulated into a Hadamard speckle, a Fourier speckle, or a random speckle, a relevant algorithm can be used for reconstruction, such as a Hadamard transform algorithm, a Fourier transform algorithm, and the like. Therefore, this example is not limited to the correlation algorithm for reconstructing the image of the target to be detected. A person skilled in the art can flexibly select the reconstruction algorithm according to actual needs, thereby achieving the purpose of reducing the cost of detecting the target to be detected.

[0048] In the actual imaging process of the correlation imaging, the emitted speckle I i (x) irradiated on the target to be detected cannot be accurately obtained, and therefore I i (x) is often calculated by modulating the modulation signal I′ i (x) of the modulation member. Therefore, if the intensity distribution of the detection light emitted by the light source is uneven, errors are caused in the process of calculating I i (x) from I′ i (x), thereby affecting the accuracy of the reconstructed image, and this problem needs to be solved.

[0049] In some examples, after the image of the target to be detected is reconstructed, the image of the target to be detected can be corrected 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 the emitted speckle generated by the detection light after modulation.

[0050] Specifically, first, before the detection of the target to be detected, the emitted speckle can be pre-calibrated, so that the distribution of the emitted speckle I i (x) irradiated on the target to be detected is accurately obtained. In the actual detection, the modulation member is sent with the modulation signal I′ i (x), and in the process of reconstructing the image of the target to be detected, the pre-calibrated emitted speckle I i (x) is used, thereby greatly reducing errors and improving the accuracy of reconstruction. Second, 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 detected in the process of reconstructing the image of the target to be detected, thereby improving the accuracy of imaging.

[0051] Furthermore, the correlation imaging method in this embodiment can be applied to both pre-modulation and post-modulation imaging systems. Similarly, if the intensity of the probe light emitted by the light source of the transmitting device is uneven, it will cause uneven intensity distribution of the target image in the receiving device. In this case, no matter how the modulator modulates, the final reconstructed image distribution will be uneven, affecting the accuracy of reconstruction. Likewise, the intensity distribution of the light source can be pre-calibrated, and the image of the target image can be corrected during the reconstruction process. In this way, the selection of the emitted light source is diverse, and it can be applied not only to lidar but also to correlation imaging cameras and other fields, with a wide range of application scenarios.

[0052] In another embodiment, the method further includes: when the probe light is modulated by the modulator, controlling the modulator to correct the probe light according to the intensity distribution information of the probe light, so as to make the emitted light field of the modulator uniformly emit speckle.

[0053] In this embodiment, by controlling the modulator, a uniform emission speckle pattern is achieved in the emitted light field, thus correcting for uneven light field. For example, when the modulator uses a digital micromirror array (DMD), the DMD is composed of a series of micrometer-sized aluminum mirrors arranged periodically. Each micromirror can independently rotate ±12° along its diagonal, where +12° rotation is called the "on state" and -12° rotation is called the "off state." When a control signal is input to the DMD, the corresponding micromirror 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 probe light is a laser, because the cross-section of the laser follows a Gaussian distribution (i.e., the laser intensity is strong in the middle and weak at both ends), the required emission speckle pattern needs to be a uniform intensity spot. If all micromirrors in the DMD rotate to the on state, the emitted light spot will also be strong in the middle and weak at both ends. Figure 5a As shown; therefore, by modifying the micromirrors of the DMD according to the intensity distribution of the laser cross-section, reducing the number of open-state micromirrors in the middle and increasing the number of open-state micromirrors at the edges, the intensity of the emitted light in the middle can be reduced, resulting in a more uniform emission speckle. Figure 5b As shown. Similarly, when the modulator is another micromirror array with modulation function, the above modulation steps can also be used to correct the emission speckle. By optimizing the position of the micromirrors in the open state on the DMD, the incident light is modulated to generate uniform emission speckle that illuminates the target under test, thereby realizing the detection of the target under test.

[0054] In one example, such as Figure 2 As shown, the method specifically includes the following steps:

[0055] S202: Emit probe light to illuminate the target;

[0056] S204: modulating the probe light by the modulating member;

[0057] S206: correcting the probe light according to the intensity distribution information of the probe light;

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

[0059] S210: reconstructing the image of the target to be measured according to the modulation information of the modulating member and the light intensity value of the target light.

[0060] In this example, the correction of the probe light is completed in the modulation stage, rather than in the reconstruction stage of the image of the target to be measured, and the principle is as shown in Figure 5a 、 Figure 5b The intensity distribution information of the outgoing probe light is measured in advance, or can be directly obtained or inferred according to the parameters of the light source. If the intensity distribution information of the probe light measured in advance is intermediate strong and both sides weak, the number of open-state micro-mirrors in the middle position of the modulating member can be reduced, and the number of open-state micro-mirrors in the edge position can be increased, so as to reduce the outgoing light intensity in the middle position and make the outgoing light spot uniform. The accuracy of reconstructing the image of the target to be measured is improved.

[0061] Preferably, the modulation and correction of the probe light are both performed by using a digital micro-mirror array as the modulating member.

[0062] As described above, since the digital micro-mirror array is composed of a series of micro-sized aluminum mirrors arranged periodically, when modulating and correcting, the original control program output control signal of the digital micro-mirror array can be used without complex improvement. It can be known that part of the series of micro-sized aluminum mirrors deflects, while the other part does not deflect, thereby realizing the correction of the probe light as laser light, making the light field of the outgoing laser light uniform, and further irradiating the target to be measured.

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

[0064] The transmitting device 100 is used for transmitting probe light to irradiate a target to be measured.

[0065] The receiving device 200 is used for receiving target light generated after the probe light irradiates the target to be measured, and detecting the received target light.

[0066] The light field correction module 300 comprises an information acquisition unit 301, an information processing unit 302 and a correction unit 303, the information acquisition unit 301 is in communication connection with the emitting device 100, and is used for acquiring the intensity distribution information of the probe light emitted by the emitting device 100,

[0067] The information processing unit 302 is in communication connection with the receiving device 200, and is used for reconstructing the 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 for correcting the image of the target to be measured according to the intensity distribution information of the probe light.

[0069] In the embodiment, by means of the light field correction module 300, the deviation of the image of the target to be measured caused by the non-uniformity of the emission light field can be corrected according to the pre-calibration information of the probe light before detecting the target to be measured or the emission speckle, the result accuracy of the image of the target to be measured is improved, and the imaging algorithm complexity is not improved, so that the application scenarios are wide.

[0070] In one example of the embodiment, one case is to use the pre-calibration information of the probe light before detecting the target to be measured, and the pre-calibration information comprises the intensity distribution of the calibrated probe light, and another case is to use the pre-calibration information of the emission speckle before detecting the target to be measured, the emission speckle can be generated by modulating the probe light by a modulation member; the modulation member can be a spatial light modulator (SLM) or a digital micromirror array (DMD), or can be a reflecting mirror, the reflecting mirror is rotatably installed on the light path of the probe light through linear driving; and the linear driving is electrically connected with a driving control board, the digital angle information is converted into a voltage signal through D / A conversion by the driving control board, and then is output to the linear driving through an operational amplifier, and then the reflecting mirror is deflected through the linear driving to realize the modulation; meanwhile, the reflecting mirror is internally provided with a feedback device, for example, an angle sensor, the angle sensor feeds back corresponding analog angle information to the driving control board, and completes the A / D conversion of the angle information in the driving control board, and then combines with the pre-calibration information of the reflecting mirror to obtain the pre-calibration information of the emission speckle.

[0071] In one embodiment, the emitting device 100 comprises a light source 101 and an emitting member 102, the light source 101 is used for emitting probe light to irradiate the target to be measured, and the emitting member 102 is arranged on the light path of the probe light; the receiving device 200 at least comprises a receiving member 201 and a detector 202, the receiving member 201 is used for receiving the target light, and the detector 202 is arranged on the light path of the target light emitted by the receiving member 201, and the detector 202 is used for detecting the light intensity value of the target light emitted by the receiving member 201;

[0072] Specifically, the light source 101 can be a laser, an LED, etc., the emitting member 102 can be a single lens or a lens group, the receiving member 201 can be a single lens, a lens group or a Fresnel lens, etc., the detector 202 can adopt a single-pixel detector, the single-pixel detector is connected with a matching information processor, for example, an FPGA (Field Programmable Gate Array) or a PLC (Programmable Array Logic) controller, etc., preferably an FPGA; the FPGA is in communication connection with an upper computer, the upper computer can install the light field correction module 300, the light field correction module 300 can obtain the signals of the light source 101, the single-pixel detector, etc. through the FPGA; the upper computer is generally composed of a microcomputer, a portable computer, etc. Therefore, 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 adopt an upper computer, and the correction unit 303 can also be a linear drive for controlling the deflection of the modulation member 103 or a micromirror array drive in the above-mentioned DMD, the FPGA is in communication connection with the light source of the emitting device 100, and the single-pixel detector and the modulation member 103 are connected; used for acquiring the intensity distribution information of the probe light emitted by the light source 101 in the emitting device 100, and acquiring the spatial and intensity distribution information of the modulation member 103 modulating the emitted speckle.

[0073] In one example, the laser can emit a fixed frequency pulsed laser, the emitted laser passes through the modulation member 103 and the emitting member 102 and irradiates on the target to be measured, then the diffuse scattering echo signal (i.e. target light) generated by the target to be measured passes through the receiving member 201 again and is detected in the single-pixel detector, and then is detected by the single-pixel detector. At the same time, the light field correction module 300 in the upper computer completes the collection of the target light intensity value based on the synchronous signal emitted by the laser as a reference, 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 probe 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 probe light.

[0074] In another example, the receiving device 200 further includes a light collector 203; the receiving member 201 is used for receiving the target light generated after the probe light irradiates on the target to be measured; the light collector 203 is arranged on the light path of the target light emitted by the receiving member 201, and is used for collecting the target light; the detector 202 is used for receiving and detecting the target light emitted by the light collector 203.

[0075] As Figures 3-7 As shown in a preferred embodiment, a modulation member 103 is further included, which is arranged on the light path of the probe light, and is capable of modulating the probe light and generating emitting speckle irradiation towards the target to be measured.

[0076] Alternatively, the modulation member 103 is arranged on the light path of the target light, and is capable of receiving the target light and modulating the image of the target to be measured formed in the modulation member 103, to generate receiving speckle irradiation towards the receiving device 200.

[0077] The information acquisition unit 301 is further configured to acquire the spatial and intensity distribution information of the emitting speckle.

[0078] The information processing unit 302 is capable of reconstructing the image of the target to be measured according to the spatial and intensity distribution information of the emitting speckle and the light intensity value of the target light.

[0079] In the first example of the present application, a modulation member 103 is arranged on the light path of the probe light, and is used for modulating the probe light.

[0080] In the present example, the modulation is performed before the probe light irradiates the target to be measured, which is a pre-modulation mode, and the structural diagram is as shown in Figure 3 , wherein the solid line represents the emitted probe light, and the dotted line represents the received target light: the laser emitted by the emitting device 100 irradiates on the modulation member 103, the modulation member 103 performs known and controllable modulation on the incident laser, and performs outgoing irradiation on 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 according to the modulation information of the probe light by the modulation member 103 and the intensity data of the detected target light, to reconstruct the image of the target to be measured.

[0081] As shown in Figure 4 , in the second example of the present application, a modulation member 103 is arranged on the light path of the target light, and is used for modulating the target light.

[0082] In the present example, the receiving device 200 first collects the target light reflected by the target to be measured, and images it on the modulation member 103, the modulation member 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 modulation member 103; and can perform correlation imaging calculation according to the modulation of the target light by the modulation member 103 and the intensity data of the detected target light, to reconstruct the image of the target to be measured.

[0083] In the embodiment, when the modulation is performed before or after the modulation, the modulation of the probe light and the target light can be realized by the movement of the modulation member 103, and different modulation speckles (or emission speckles) are modulated to form a series of modulation speckles, which are respectively irradiated to different sub-visual fields (such as sub-visual field 1, sub-visual field 2, and sub-visual field 3) of the to-be-measured visual field, so as to realize the irradiation of the to-be-measured target. Meanwhile, the modulation speckles can be corrected according to the related characteristic information, and the embodiment is not limited in detail.

[0084] In another example of the embodiment, the modulation member 103 is one of ground glass, a spatial light modulator, and a digital micromirror array. In actual application, the modulation member 103 can be combined with the light field correction module 300 to realize the reconstruction and correction of the image of the to-be-measured target, and the accuracy of the reconstructed image is higher. Taking the digital micromirror array as an example: when the modulated probe light is laser, the cross section of the laser follows Gaussian distribution, that is, the intensity distribution of the laser is strong in the middle and weak at both edges. Therefore, the intensity distribution of the cross section of the laser can be used to modify the micromirrors of the DMD, so that the number of open-state micromirrors in the middle position is small, and the number of open-state micromirrors in the edge position is large. Then, the intensity of the outgoing light in the middle position can be reduced, and the emission speckle can be made uniform. Figure 5a 、 Figure 5b as shown.

[0085] As shown in Figure 8 , in one example of the 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 in communication connection with the emission device 100, and the second acquisition unit 3012 is in communication connection with the modulation member 103.

[0086] Specifically, when the light source 101 in the emission device 100 adopts a laser, and the modulation member 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, so as to realize the transmission of related data, which will not be described in detail herein.

[0087] In one example of the embodiment, the correction unit 303 is further configured to output optimization information according to the intensity distribution information of the probe light, and the optimization information controls the modulation member 103 to correct the probe light, so as to make the emission speckle of the outgoing light field of the modulation member 103 uniform.

[0088] Specifically, taking the case that the modulation member 103 adopts a DMD as an example, the correction unit 303 can be an external drive, or a micro-mirror driving chip of the DMD, or other components or driving programs that control the deflection of the DMD; the pulsed laser is used as the probe light to irradiate the DMD, and the intensity distribution of the probe light is strong in the middle and weak in the periphery; when correction is performed, the "on state" of some micro-mirrors in the middle part of the DMD can be changed, so that the light intensity of the outgoing light of the micro-mirrors in the middle part is uniform with the outgoing light of the micro-mirrors in the periphery, and the purpose of correction is achieved; as shown in FIGS. Figure 5a 、 Figure 5b

[0089] In an example of the present application, the modulation member 103 can be ground glass, a spatial light modulator, etc.; when the modulation member 103 is ground glass, the modulation of the probe light or the image of the target to be detected can be known; for example, for ground glass, the method of pre-calibrating the ground glass modulation pattern can be used to achieve modulation; the modulation of light by the SLM is controllable, and different modulation of light can be achieved by inputting different control signals, i.e., modulation information.

[0090] Therefore, the cooperation of the modulation member 103 and the light field correction module 300 in the present embodiment can achieve the modulation and correction of the probe light and the target light, improve the detection accuracy of the target to be detected, and is not high in operation complexity, and is conducive to implementation; can be applied to an imaging system in a pre-modulation mode, and can be applied to an imaging system in a post-modulation mode, and can be applied not only to a laser radar but also to a correlation imaging camera and other fields, and has a wide range of application scenarios.

[0091] The above-described embodiments of the present application provide a correlation imaging method for correcting non-uniform light field, and based on the correlation imaging method for correcting non-uniform light field, a correlation imaging system is provided, which can correct the deviation of the reconstructed image of the target to be detected caused by non-uniform light field of the emitted light according to the pre-calibration information of the probe light or the emitted speckle before detecting the target to be detected, improve the accuracy of the result of the reconstructed image of the target to be detected, and does not increase the complexity of the imaging algorithm, and has a wide range of application scenarios; and the correlation imaging method for correcting non-uniform light field can be applied not only to a pre-modulation system but also to a post-modulation system, and can be applied not only to a laser radar but also to a single-pixel camera and other fields, and has a wide range of application scenarios; and the design cost of the device is low, and the cost can be effectively reduced under the premise of ensuring the imaging image quality.

[0092] The above only describes the preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.​< / s> < / s>

Claims

1. A method of correlated imaging for correcting light field inhomogeneity, characterized in that, The method comprises the following steps: The probe light is irradiated to the target to be measured; The target light generated after the probe light irradiates the target to be measured is received, and the light intensity value of the received target light is detected; The probe light is modulated by a modulation member; The image of the target to be measured is reconstructed according to the modulation information of the modulation member and the light intensity value of the target light; The image of the target to be measured is corrected according to the related characteristic information; The related characteristic information comprises pre-calibrated intensity distribution information of the probe light, or pre-calibrated spatial and intensity distribution information of the emission speckle generated after the probe light is modulated; The method further comprises: When the probe light is modulated by the modulation member, the intensity distribution information of the probe light is used to control the modulation member to correct the probe light so that the emission speckle with uniform light field is emitted by the modulation member; Both the modulation and the correction of the probe light are performed by using a digital micromirror array as the modulation member.

2. The method of claim 1, wherein, The image of the target to be measured is reconstructed by using a correlation algorithm, and the correlation algorithm satisfies: ， wherein, represents an image of the target to be measured, represents the light intensity fluctuation of the target light, represents the light intensity value of the target light detected after the i-th modulation, is the average light intensity value of the target light detected after N modulations; represents the emitted speckle, i is the i-th modulation, and x represents the spatial coordinate.

3. An associated imaging system characterized by, The correlation imaging method for correcting non-uniform light field according to any one of claims 1-2, the correlation imaging system comprises a transmitting device, a receiving device and a light field correction module; The transmitting device is used to emit probe light to irradiate a target to be measured; The receiving device is used to receive target light generated after the probe light irradiates the target to be measured, and detect the received target light; The light field correction module comprises 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 intensity distribution information of the probe light emitted by the transmitting device, The information processing unit is in communication connection with the receiving device, and is used to reconstruct an image of the target to be measured according to a 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 probe light; The method further comprises: When the probe light is modulated by the modulation member, the intensity distribution information of the probe light is used to control the modulation member to correct the probe light so that the emission speckle with uniform light field is emitted by the modulation member; Both the modulation and the correction of the probe light are performed by using a digital micromirror array as the modulation member.

4. The correlated imaging system of claim 3, wherein, Further comprising a modulation member, the modulation member is arranged on the light path of the probe light, and the modulation member can modulate the probe light and generate an emission speckle to irradiate a target to be measured; The information acquisition unit is further used to acquire 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.

5. The correlated imaging system of claim 4, wherein, The information acquisition unit comprises a first acquisition unit and / or a second acquisition unit, the first acquisition unit is in communication connection with the transmitting device, and the second acquisition unit is in communication connection with the modulation member.

6. The correlated imaging system of claim 5, wherein, The correction unit is further configured to output optimization information according to the intensity distribution information of the probe light, and the optimization information controls the modulation member to correct the probe light so that the modulation member emits a uniform emission speckle.

7. The correlated imaging system of claim 4 or 5 or 6, wherein, The modulation member is one of ground glass, a spatial light modulator, and a digital micromirror array.

8. The correlated imaging system of claim 3, wherein, The emission device includes a light source and an emission member, The light source is configured to emit probe light to irradiate a target to be measured, and the emission member is arranged on an optical path of the probe light. The receiving device includes at least a receiving member and a detector, the receiving member is configured to receive the target light, and the detector is arranged on an exit light path of the receiving member and is configured to detect a light intensity value of the target light emitted by the receiving member.

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