Laser radar based on time domain correlated imaging and imaging method

Abstract

The invention is suitable for the field of target imaging detection, and provides a laser radar based on time domain correlated imaging and an imaging method, and the laser radar based on time domain correlated imaging comprises a transmitting device, a modulation device and a receiving device. The transmitting device is used for transmitting pulse laser with a certain frequency to irradiate a to-be-measured target; the modulation device at least comprises a deflection device and a time domain modulation device, the deflection device is arranged on a light path of the pulse laser, and the deflection device can deflect the pulse laser so that the pulse laser can scan a to-be-measured target in a two-dimensional space; according to the invention, the pulse laser or the target light is modulated through the arranged time domain modulator, so that the intensity of the pulse laser or the target light has fluctuation in the time domain; therefore, the receiving device does not need to have a relatively high response speed, and the problem that the cost of the laser radar is increased due to the fact that the existing laser radar based on time domain correlated imaging requires the relatively high response speed is solved.

Description

Technical Field

[0001] The invention belongs to the field of target imaging detection and provides a laser radar based on time domain correlation imaging and an imaging method. Background Art

[0002] LiDAR is a remote sensing technology that uses lasers to perform three-dimensional detection. The distance detection usually uses the time of flight (TOF) method, that is, using pulsed lasers to illuminate objects, the objects reflect or transmit the pulsed lasers, and the longitudinal distance of the objects is calculated by recording the time difference between the transmitted pulse and the received pulse.

[0003] In order to ensure the resolution of longitudinal distance detection, the detector needs to be able to distinguish the reflected light signals of objects at different distances, which puts forward requirements on the response speed of the detector. Generally, expensive and complex detectors are used to meet the requirements. However, it is impossible to take both the equipment cost and imaging requirements of the laser radar into consideration, and a new laser radar needs to be designed urgently. Summary of the invention

[0004] The purpose of an embodiment of the present invention is to provide a laser radar based on time domain correlation imaging, aiming to solve the problem that the laser radar based on correlation imaging in the prior art has high requirements on the response speed of the detector, thereby increasing the equipment cost of the laser radar.

[0005] The embodiment of the present invention is implemented as follows: a laser radar based on time domain correlation imaging, the laser radar based on time domain correlation imaging includes a transmitting device, a modulating device and a receiving device;

[0006] The transmitting device is used to transmit a pulse laser of a certain frequency to irradiate the target to be measured;

[0007] The modulation device at least includes a deflection device and a time domain modulation device, wherein the deflection device is arranged on the optical path of the pulse laser, and the deflection device can deflect the pulse laser so that the pulse laser scans the target to be measured in two-dimensional space;

[0008] The receiving device at least comprises a receiving element and a light detecting element, wherein the receiving element is used to receive the target light generated after the pulse laser irradiates the target to be measured, and the light detecting element is arranged on the light path of the outgoing light of the receiving element, and the light detecting element is used to detect the intensity of the target light emitted by the receiving element;

[0009] The time domain modulation device is used to modulate the pulse laser emitted by the transmitting device in the time domain, or to modulate the target light emitted by the receiving device in the time domain, so that the intensity of the pulse laser or the target light fluctuates in the time domain.

[0010] Another object of an embodiment of the present invention is to provide an imaging method based on time domain correlation imaging, which is used for the laser radar based on time domain correlation imaging as described above, and the method comprises the following steps:

[0011] The pulsed laser of a certain frequency is emitted to the target to be measured.

[0012] The target to be measured reflects the pulsed laser to form target light;

[0013] Input a first signal to perform time domain modulation on the pulse laser so that the intensity of the pulse laser fluctuates in the time domain, or perform time domain modulation on the target light so that the intensity of the target light fluctuates in the time domain;

[0014] The target light is received, and the intensity value of the received target light is obtained. According to the obtained intensity value of the target light and the input first signal, a reconstruction operation is performed on the modulation of the pulse laser in the time domain to obtain the time domain distribution of the target light, thereby calculating the distance of the target to be measured.

[0015] The laser radar based on time domain correlation imaging provided by the embodiment of the present invention modulates the pulsed laser or target light by means of a time domain modulation device so that the intensity of the pulsed laser or target light fluctuates in the time domain; thereby, the receiving device is not required to have a high response speed, thereby solving the problem that the existing laser radar based on time domain correlation imaging is required to have a high response speed, thereby increasing the cost of the laser radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic structural diagram of a laser radar based on time-domain correlation imaging provided by an embodiment of the present invention;

[0017] Figure 2 A schematic diagram of the structure of another laser radar based on time-domain correlation imaging provided by an embodiment of the present invention;

[0018] Figure 3 Schematic diagram of the principle of a laser radar based on time-domain correlation imaging in an embodiment of the present invention;

[0019] Figure 4 Schematic diagram of another principle of a laser radar based on time-domain correlation imaging in an embodiment of the present invention;

[0020] Figure 5 It is a schematic diagram of the time domain modulation principle of the pulsed laser emitted by the laser radar in an embodiment of the present invention;

[0021] Figure 6 Schematic diagram of the structure of a third laser radar based on time-domain correlation imaging in an embodiment of the present invention;

[0022] Fig. 7A ,7B A flowchart of two imaging methods based on time domain correlation imaging provided by embodiments of the present invention;

[0023] Fig. 8A , 8B Workflow diagram of two other imaging methods based on time domain correlation imaging provided by embodiments of the present invention.

[0024] In the attached drawings: 100 - transmitting device; 200 - receiving device; 300 - modulating device; 1 - laser; 2 - transmitting element; 3 - deflecting device; 4 - receiving element; 5 - light detecting element; 6 - light collecting device; 7 - time domain modulating device; 8 - spatial domain modulating device. DETAILED DESCRIPTION

[0025] 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.

[0026] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0027] like Figure 1 , Figure 2 , which is a structural diagram of a laser radar based on time domain correlation imaging provided by an embodiment of the present invention, including a transmitting device 100, a modulating device 300 and a receiving device 200;

[0028] The transmitting device 100 is used to transmit a pulsed laser of a certain frequency to irradiate the target to be measured;

[0029] The modulation device 300 at least includes a deflection device 3 and a time domain modulation device 7. The deflection device 3 is arranged on the optical path of the pulse laser. The deflection device 3 can deflect the pulse laser so that the pulse laser scans the target to be measured in a two-dimensional space.

[0030] The receiving device 200 at least comprises a receiving element 4 and a light detecting element 5, wherein the receiving element 4 is used to receive the target light generated after the pulsed laser irradiates the target to be measured, and the light detecting element 5 is arranged on the light path of the outgoing light of the receiving element 4, and the light detecting element 5 is used to detect the intensity of the target light emitted by the receiving element 4;

[0031] The time domain modulation device 7 is used to modulate the pulse laser emitted by the transmitting device in the time domain, or to modulate the target light emitted by the receiving device 4 in the time domain, so that the intensity of the pulse laser or the target light fluctuates in the time domain.

[0032] In the embodiment of the present invention, the pulsed laser or target light is modulated by the time domain modulation device 7 so that the intensity of the pulsed laser or target light fluctuates in the time domain; thus, the receiving device 200 is not required to have a high response speed, which solves the problem that the existing laser radar based on time domain correlation imaging requires a high response speed, thereby increasing the cost of the laser radar.

[0033] In one example of the present invention, the deflection device 3 can be a reflector, a rotating multi-faceted reflection prism, frosted glass, a spatial light modulator (SLM) or a digital micro-mirror device (DMD), etc.; the modulation of the pulsed laser or the image of the target to be measured by the deflection device 3 can be known; for frosted glass, modulation can be achieved using a pre-calibrated method; the modulation of light by SLM or DMD is controllable, and by inputting different control signals, SLM or DMD modulates the light differently.

[0034] In the above example, "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 only a detector without spatial resolution is needed to image an object, correlation imaging has the advantages of a wide range of application wavelengths and anti-scattering, and has a wide range of application scenarios.

[0035] In another embodiment, Figure 1 As shown, the transmitting device at least includes a laser 1 and a transmitting element 2 , wherein the laser 1 is used to transmit pulsed laser of a certain frequency, and the transmitting element 2 is arranged on the optical path of the pulsed laser emitted by the deflection device 3 .

[0036] In the present embodiment, the deflection device 3 is arranged on the pulse laser optical path emitted by the laser 1. The pulse laser optical path emitted by the laser 1 refers to the path passed by the pulse laser emitted by the laser 1. It is not a physical path, and the optical path is an optical term well known in the art. Similarly, the pulse laser optical path, the pulse laser optical path or the target light optical path emitted by the deflection device 3 all refer to the path passed by the light beam, which will not be described in detail here.

[0037] In an example of this embodiment, the laser 1 can be a pulse laser for emitting pulse laser, and the laser 1 can include a collimator or a beam expander to collimate or expand the laser. The emitting element 2 can be an emitting lens that has a converging effect on light, and the emitting lens is used to emit the light modulated by the deflection device 3 to illuminate the target to be measured, and can be a single lens or a lens group. Afterwards, the light reflected by the target to be measured is collected by the receiving element 4 of the receiving device 200, and converged and detected. The laser 1 can also be other light-emitting bodies, which can be selected according to the design requirements, and the present embodiment is not limited to this.

[0038] like Figure 2 As shown, in another embodiment, the receiving element 4 can be one of a single lens, a lens group and a Fresnel lens, and a single lens can be used optionally; the light detecting element 5 can be a low-speed detector, which is used to receive the target light emitted by the receiving element 4, and calculate the distance of the target to be measured based on the intensity of the target light and the modulation parameters of the time domain modulation device 7.

[0039] In an example of this embodiment, the modulation parameters are loaded and carried by a first signal, that is, the first signal includes the modulation parameters; the first signal is controlled and output by a driver of the laser radar, and can also be communicated by an external communication device; so that the pulse intensity of each pulse laser has fluctuations in the time domain; such as Figure 5 As shown, it is a schematic diagram of the modulation principle of time domain correlation imaging. The light source (i.e., laser 1) emits a pulsed laser, which is time-domain modulated by the time domain modulation device 7. The modulated pulsed laser is used to measure the time domain object, and then the intensity is detected by the low-speed detector. After reconstruction operation, the time domain information of the signal to be measured can be restored. In the reconstruction, correlation algorithms, compressed sensing algorithms, deep learning algorithms, etc. can be used, but this embodiment is not limited to this.

[0040] In this example, the light detection element 5 can realize the time domain detection of the target light by using a low-speed detector. Compared with using a detector with a higher response speed, the use of a low-speed detector can reduce the overall design cost of the laser radar. Of course, the light detection element 5 can also use other types of low-speed detector elements; and the time domain modulation device 7 can use a high-speed modulation device, for example: the low-speed detector can be a photodiode, a photomultiplier tube or an avalanche photodiode, etc., and the time domain modulation device 7 can be an electro-optical modulator, and this embodiment is not limited to this.

[0041] In another preferred embodiment, Figure 2 As shown, the receiving device 200 further includes a light collecting device 6, which is used to collect the target light emitted by the receiving element 4. The light collecting device 6 can be one of a lens, a lens group, a fiber optic light cone, and a concentrator.

[0042] In one embodiment, there are two basic imaging forms of correlation imaging; Figure 3 The optical path shown is called first modulation correlation imaging: the pulse laser is first irradiated on the deflection device 3 for modulation, then emitted by the emitting device 2 and irradiated on the target to be measured; the receiving device 4 receives the target light reflected by the target to be measured and converges it on the low-speed detector. According to the emission speckle and the light intensity value obtained by the low-speed detector, the image of the target to be measured can be reconstructed. Figure 4 The optical path shown is called post-modulation correlation imaging: the pulsed laser is emitted from the transmitter 2 and irradiated on the target to be measured; the receiver 4 receives the target light reflected by the target to be measured and images it on the deflection device 3 for modulation; the modulated target light is collected by the light collecting device 6 and converged onto the low-speed detector. According to the modulated speckle and the light intensity value obtained by the low-speed detector, the image of the object can be reconstructed.

[0043] In another embodiment, the modulation device 300 also includes a spatial domain modulation device 8, which is arranged in the optical path of the pulse laser and is used to spatially modulate the pulse laser modulated by the time domain modulation device 7, so that the pulse laser generates a plurality of emission speckles, and the plurality of emission speckles are sequentially irradiated to each sub-field of view where the target to be measured is located, thereby realizing a small field of view scanning of the target to be measured.

[0044] In this embodiment, the spatial domain modulation device 8 is set at the same time, and cooperates with the time domain modulation device 7 to realize the modulation of the pulse laser in the time domain and the spatial modulation (also called spatial domain modulation); the functions are diverse and can cooperate with each other, and the application field is wide.

[0045] Among them, in an example of this embodiment, time domain modulation takes the first modulation mode as an example: the laser emitted by the laser 1 first passes through the time domain modulation device 7, so that the laser pulse intensity has fluctuations in the time domain; the deflection device 3 deflects the modulated pulse laser in two-dimensional space, and emits it from the transmitting lens, so that the pulse laser illuminates each sub-field of view in turn for detection; the receiving lens collects the target light reflected by the target to be measured, and the low-speed detector detects it. The target light intensity value obtained by the low-speed detector is used to reconstruct the modulation of the laser in the time domain by the time domain modulation device 7, so that the distribution of the target light in the time domain can be obtained, thereby calculating the distance of the target.

[0046] Similarly, in the post-modulation mode: the transmitting device emits a pulsed laser to illuminate the target to be measured, and then the receiving device 4 receives the target light reflected by the target to be measured; the time domain modulation device 7 modulates the target light in the time domain, and the multiple modulation patterns generated correspond to the images of all sub-fields of view of the target to be measured in the time domain modulation device 7; the low-speed detector receives and processes the target light after time domain modulation, and has a slow response speed, and can be a photodiode, a photomultiplier tube or an avalanche photodiode, etc.; the target light intensity value obtained by the low-speed detector is used to reconstruct the modulation of the target in the time domain by the time domain modulation device 7, so that the distribution of the target light in the time domain can be obtained, thereby calculating the distance of the target to be measured.

[0047] Among them, spatial modulation takes the modulation method as an example: the entire field of view within the target range to be measured is divided into multiple sub-fields of view; each sub-field of view is detected with a modulation pattern, and the modulation pattern in each sub-field of view can be changed according to the design; for example, after the detection of the previous sub-field of view is completed, the next sub-field of view is switched to use a small field of view modulated speckle for illumination. Repeat this process until all sub-fields of view are detected. It should be noted that, according to actual needs, the area of ​​each sub-field of view (that is, the corresponding sub-field of view angle) can be unequal or equal, and the modulation resolution and modulation times of each sub-field of view can also be unequal; there is no limitation here.

[0048] In an example of this embodiment, the spatial domain modulation device 8 can be a rotating multi-faceted reflection prism, a MEMS galvanometer, an SLM or a DMD.

[0049] In this embodiment, the spatial domain modulation device 8 can replace the deflection device 3, and of course can also be set up separately, using the same or different structures to achieve different functions, that is, the deflection device 3 achieves the function of two-dimensional space scanning, and the spatial domain modulation device 8 achieves the function of small field of view scanning.

[0050] In an implementation scenario of this example, the spatial modulation device 8 may use a MEMS galvanometer, and after modulating the pulsed laser multiple times, a series of modulated speckles generated correspond to different sub-fields of view of the target to be measured, are reflected by the target to be measured to form target light, and are received and detected by the receiving device 200. In some scenarios, the modulated speckle is often Hadamard speckle, Fourier speckle, or random speckle.

[0051] As described above, in this embodiment, by covering multiple sub-fields of the entire field of view to be measured with emission speckles (also called modulation speckles), the low-speed detector collects light with a relatively strong intensity and a relatively high light intensity fluctuation.

[0052] Therefore, this embodiment does not cover the entire field of view to be measured by emitting modulated speckles, but emits corresponding modulated speckles for illumination respectively, corresponding to each sub-field of view in the entire field of view to be measured. In this way, the low-speed detector in the receiving device 200 collects light with high intensity and high light intensity fluctuation. That is, this embodiment creatively combines the advantages of time-domain correlation imaging and small field of view scanning, and provides a new target detection method.

[0053] In another implementation scenario of this example, the modulation step of the spatial modulation device 8 can also be performed after the receiving device 200 receives the target light, and the specific detection principle of the target to be detected is the same as above. In this example, according to the different setting positions of the spatial modulation device 8, the laser radar can be arranged in a first modulation mode and a post-modulation mode. Which mode to use in actual application can be flexibly selected and is not limited to this.

[0054] In the above embodiment, the laser radar based on time domain correlation imaging creatively combines the imaging principle of time domain correlation imaging and the imaging principle of small field of view scanning, so that when detecting the target to be measured, it can maintain a high light intensity fluctuation while increasing the received light power, thereby improving the accuracy of target detection; and the reception and detection of target light can be achieved by using a low-speed detector with a low response speed, and the structure of the modulation implementation is relatively simple, which is easy to promote and apply.

[0055] In order to facilitate the promotion and better implementation of the above-mentioned laser radar based on time domain correlation imaging, in another embodiment, an imaging method based on time domain correlation imaging is provided, which is used for the above-mentioned laser radar based on time domain correlation imaging, and the method includes the following steps:

[0056] The pulsed laser of a certain frequency is emitted to the target to be measured.

[0057] The target to be measured reflects the pulsed laser to form target light;

[0058] Input a first signal to perform time domain modulation on the pulse laser so that the intensity of the pulse laser fluctuates in the time domain, or perform time domain modulation on the target light so that the intensity of the target light fluctuates in the time domain;

[0059] The target light is received, and the intensity value of the received target light is obtained. According to the obtained intensity value of the target light and the input first signal, a reconstruction operation is performed on the modulation of the pulse laser in the time domain to obtain the time domain distribution of the target light, thereby calculating the distance of the target to be measured.

[0060] In this embodiment, the pulsed laser or target light is modulated so that the intensity of the pulsed laser or target light fluctuates in the time domain; thereby, the receiving device 200 for receiving the target light does not need to have a high response speed, thereby solving the problem that the existing laser radar based on time domain correlation imaging requires a high response speed, thereby increasing the cost of the laser radar.

[0061] In some examples of this embodiment, the imaging method based on time domain correlation imaging has multiple implementation modes; there are multiple modulation modes based on time domain correlation imaging, and there are also multiple correlation imaging based on time domain and space domain; the details are as follows:

[0062] In the first example, if Fig. 7A As shown, a time domain modulation of a pre-modulation mode is performed before a pulse laser irradiates a target to be measured: the imaging method includes:

[0063] S102: emit a pulse laser of a certain frequency to irradiate the target to be measured.

[0064] S104: inputting a first signal to perform time domain modulation on the pulse laser, so that the intensity of the pulse laser has fluctuations in the time domain;

[0065] S106: the target to be measured reflects the modulated pulse laser to form target light;

[0066] S108: receiving the target light and obtaining the intensity value of the received target light, and performing a reconstruction operation on the modulation of the pulsed laser in the time domain according to the obtained intensity value of the target light and the input first signal to obtain the distance of the target to be measured.

[0067] like Figure 7B As shown, the time domain modulation of the post-modulation mode is performed after the pulse laser irradiates the target to be measured. The imaging method includes:

[0068] S202: emit a pulse laser of a certain frequency to irradiate the target to be measured.

[0069] S204: the target to be measured reflects the pulsed laser to form target light;

[0070] S206: receiving the target light, inputting a first signal to perform time domain modulation on the pulse laser, so that the intensity of the pulse laser has fluctuations in the time domain;

[0071] S208: Obtain the intensity value of the target light, and perform a reconstruction operation on the modulation of the pulse laser in the time domain according to the obtained intensity value of the target light and the input first signal to obtain the distance of the target to be measured.

[0072] In the above two examples, the device used can be the above-mentioned laser radar based on time-domain correlation imaging, or a variation of the laser radar based on time-domain correlation imaging. It should be noted that there is no difference between the above two modes, and they can be flexibly selected according to needs during design, and this embodiment is not limited to this.

[0073] Preferably, in some other embodiments, the method further includes: after the pulse laser is emitted, inputting a second signal to perform spatial modulation on the pulse laser, so that the pulse laser generates a plurality of emission speckles, and the plurality of emission speckles are sequentially irradiated to each sub-field of view where the target to be measured is located, so as to achieve small field of view scanning of the target to be measured.

[0074] In actual application of this embodiment, when the pulse laser is spatially modulated, the modulation speckle of each modulation is different; of course, they can also be the same.

[0075] Specifically, Fig. 8A As shown in an exemplary embodiment, the imaging method includes:

[0076] S301: emit a pulse laser of a certain frequency to irradiate the target to be measured.

[0077] S302: Input a first signal to perform time domain modulation on the pulse laser, so that the intensity of the pulse laser fluctuates in the time domain;

[0078] S303: inputting a second signal to spatially modulate the pulsed laser so that the pulsed laser generates a plurality of emission speckles, and the plurality of emission speckles are sequentially irradiated to each sub-field of view where the target to be measured is located;

[0079] S304: the target to be measured reflects the modulated pulse laser to form target light;

[0080] S305: receiving the target light, and obtaining a light intensity value of the received target light, and performing a reconstruction operation on the modulation of the pulsed laser in the time domain according to the obtained light intensity value of the target light and the first signal to obtain a time domain distribution of the target light;

[0081] S306: reconstructing the modulation of the pulsed laser in all sub-fields of view according to the acquired target light intensity value and the second signal, thereby calculating the distance and image of the target to be measured.

[0082] like Figure 8B As shown in another exemplary embodiment, the imaging method includes:

[0083] S401: emit a pulse laser of a certain frequency to irradiate the target to be measured.

[0084] S402: inputting a second signal to spatially modulate the pulsed laser so that the pulsed laser generates a plurality of emission speckles, and the plurality of emission speckles are sequentially irradiated to each sub-field of view where the target to be measured is located;

[0085] S403: the target to be measured reflects the modulated pulse laser to form target light;

[0086] S404: receiving the target light, inputting a first signal to perform time domain modulation on the received target light, so that the intensity of the target light fluctuates in the time domain;

[0087] S405: acquiring a target light intensity value, and performing a reconstruction operation on the modulation of the pulsed laser in the time domain according to the acquired target light intensity value and the first signal, so as to obtain a time domain distribution of the target light;

[0088] S406: reconstructing the modulation of the pulsed laser in all sub-fields of view according to the acquired target light intensity value and the second signal, thereby calculating the distance and image of the target to be measured.

[0089] In the above embodiment, the multiple emission speckles are modulated in sequence by a spatial modulation device 8, and the multiple modulated speckles are respectively irradiated to each sub-field of view, which is also carried out in sequence. The spatial modulation device 8 can be frosted glass, a spatial light modulator (SLM) or a DMD, etc.; the detection of the target light is achieved by a low-speed detector; other components with low response speed can also be selected; the low-speed detector can be a photodiode, a photomultiplier tube or an avalanche photodiode, etc. The spatial modulation device 8 replaces the deflection device 3 to implement the modulation of the emitted light or the image of the target to be measured, and the modulation parameters or the second signal are known. The modulation of light by SLM or DMD is controllable and is a preferred option; by inputting different control signals (second signals), SLM or DMD modulates light differently; in target reconstruction, association algorithms, compressed sensing algorithms, deep learning algorithms, etc. can be used. It should be noted that there is no difference between the above two modes, and they can be flexibly selected according to needs during design, and this embodiment is not limited to this.

[0090] In the above embodiment of the present invention, a laser radar based on time domain correlation imaging is provided, and an imaging method based on time domain correlation imaging is provided based on the laser radar based on time domain correlation imaging. The laser radar based on time domain correlation imaging, through the time domain modulation device 7, cooperates with the low-speed detector of the receiving device 200, utilizes the modulation of the pulse laser in the time domain, and only uses the low-speed detector with a low response speed to achieve the purpose of detecting the target light, so that the equipment cost of the laser radar can be effectively reduced; at the same time, the time domain modulation can also be coordinated with the spatial modulation to realize the combination of time domain correlation imaging and small field of view scanning or detection; wherein the emission speckle formed by modulating the pulse laser or the target light is used for small field of view scanning or detection, and the emission speckle generated is multiple, and corresponds to each sub-field of view of the field of view to be measured, and at the same time, the optical power and light intensity fluctuation are improved, and the correlation algorithm is used for reconstruction to obtain or restore the image of the target to be measured. In this way, not only the detection has better light intensity fluctuation, but also the detection response speed can be reduced; so that the design cost of the laser radar is reduced in many aspects, and the practicality is high.

[0091] 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.

Claims

1. A laser radar based on time domain correlation imaging, characterized in that: The laser radar based on time domain correlation imaging includes a transmitting device, a modulating device and a receiving device. The transmitting device is used to transmit a pulse laser of a certain frequency to irradiate the target to be measured; The modulation device at least includes a deflection device and a time domain modulation device, wherein the deflection device is arranged on the optical path of the pulse laser, and the deflection device can deflect the pulse laser so that the pulse laser scans the target to be measured in a two-dimensional space; The receiving device at least comprises a receiving element and a light detecting element, wherein the receiving element is used to receive the target light generated after the pulse laser irradiates the target to be measured, and the light detecting element is arranged on the light path of the outgoing light of the receiving element, and the light detecting element is used to detect the intensity of the target light emitted by the receiving element; The time domain modulation device is used to modulate the pulse laser emitted by the transmitting device in the time domain, or to modulate the target light emitted by the receiving device in the time domain, so that the intensity of the pulse laser or the target light fluctuates in the time domain.

2. The laser radar based on time domain correlation imaging according to claim 1, characterized in that: The transmitting device at least comprises a laser and a transmitting element. The laser is used to transmit pulse laser of a certain frequency. The transmitting element is arranged on the optical path of the pulse laser emitted by the deflection device.

3. The laser radar based on time domain correlation imaging according to claim 1, characterized in that: The receiving element is one of a single lens, a lens group and a Fresnel lens, and the light detecting element is a low-speed detector, which is used to receive the target light emitted by the receiving element and calculate the distance of the target to be measured based on the intensity of the target light and the modulation parameters of the time domain modulation device.

4. The laser radar based on time domain correlation imaging according to claim 3, characterized in that: The receiving device further comprises a light collecting device, and the light collecting device is used for collecting the target light emitted by the receiving element.

5. The laser radar based on time domain correlation imaging according to claim 1, characterized in that: The modulation device also includes a spatial domain modulation device, which is arranged on the optical path of the pulse laser and is used to spatially modulate the pulse laser modulated by the time domain modulation device, so that the pulse laser generates a plurality of emission speckles, and the plurality of emission speckles are sequentially irradiated to each sub-field of view where the target to be measured is located, thereby realizing small field of view scanning of the target to be measured.

6. The laser radar based on time domain correlation imaging according to claim 1, characterized in that: The time domain modulation device is an electro-optic modulator.

7. The laser radar based on time domain correlation imaging according to claim 1, characterized in that: The deflection device is a rotating multi-faceted reflection prism, a MEMS galvanometer, an SLM or a DMD.

8. An imaging method based on time domain correlation imaging, characterized in that: For a laser radar based on time domain correlation imaging as claimed in any one of claims 1 to 7, the method comprises the following steps: Emit a pulse laser of a certain frequency to irradiate the target to be measured. The target to be measured reflects the pulsed laser to form target light; Input a first signal to perform time domain modulation on the pulse laser so that the intensity of the pulse laser fluctuates in the time domain, or perform time domain modulation on the target light so that the intensity of the target light fluctuates in the time domain; The target light is received, and the intensity value of the received target light is obtained. According to the obtained intensity value of the target light and the input first signal, a reconstruction operation is performed on the modulation of the pulse laser in the time domain to obtain the time domain distribution of the target light, thereby calculating the distance of the target to be measured.

9. The imaging method based on time domain correlation imaging according to claim 8, characterized in that: The method further includes: after the pulse laser is emitted, inputting a second signal to spatially modulate the pulse laser so that the pulse laser generates a plurality of emission speckles, and the plurality of emission speckles are sequentially irradiated to each sub-field of view where the target to be measured is located, thereby realizing small-field scanning of the target to be measured.

10. The imaging method based on time domain correlation imaging according to claim 9, characterized in that: When the pulse laser is spatially modulated, the modulation speckle of each modulation is different.

Images