Method and equipment for material identification by using multi-wavelength light

Abstract

The invention is applicable to the technical field of laser detection, and provides a method and equipment for material identification by using multi-wavelength light, the method is used for identifying the material of a to-be-detected target, and the method comprises the following steps: N beams of laser with different wavelengths are combined and then emitted from one direction, and N is greater than or equal to 2; the combined laser is diverged and irradiated to a to-be-measured target, and target light is formed after the combined laser is reflected by the to-be-measured target; receiving the target light, and separating the received target light into N beams of target light with different wavelengths; and respectively detecting the N beams of separated target light with different wavelengths so as to determine the material of the target to be detected. When material identification is carried out, the reflectivity of the to-be-detected target in all spectrums does not need to be detected, material identification of the to-be-detected target can be carried out only by detecting light of several wavelengths, the device required by the invention is simple in overall structure, a slit does not need to be added, and the signal-to-noise ratio of a detector signal is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser detection, and particularly relates to a method and device for material identification using multi-wavelength light. Background Art

[0002] LiDAR is a remote sensing technology that uses lasers to complete three-dimensional detection and consists of a transmitting system and a receiving system. The transmitting system is used to emit pulsed lasers to irradiate the target to be measured, and the receiving system is used to receive the reflected light of the target to be measured. By recording the time difference between the transmitted pulse and the received pulse, the longitudinal distance of the target to be measured is calculated, and then the detection of the position of the target to be measured is realized.

[0003] The target to be measured is composed of different elements, and each element has its own characteristic spectral line. Therefore, the composition of the target to be measured can be identified according to the difference in spectral components. However, conventional LiDAR can only detect the position of the target to be measured and cannot obtain the material information of the target to be measured. Therefore, it is urgent to design a laser device that can perform material identification. Summary of the Invention

[0004] The purpose of the embodiment of the present invention is to provide a method for material identification using multi-wavelength light, aiming to solve the problem that the existing LiDAR cannot obtain the material information of the target.

[0005] The embodiment of the present invention is implemented as follows. A method for material identification using multi-wavelength light, which is used to identify the material of the target to be measured, includes the following steps:

[0006] Combine N lasers with different wavelengths and emit them from one direction, where N≥2;

[0007] Diverge and irradiate the combined laser towards the target to be measured, and after being reflected by the target to be measured, form target light;

[0008] Receive the target light and separate the received target light into N target lights with different wavelengths;

[0009] Detect the N target lights with different wavelengths after separation respectively to determine the material of the target to be measured.

[0010] The purpose of the embodiment of the present invention is also to provide a device for material identification using multi-wavelength light, which is used for the method for material identification using multi-wavelength light as described above. The device includes a transmitting system and a receiving system. The transmitting system at least includes a light source, a beam combining prism, and a light emitting component. The receiving system at least includes a light receiving component, a beam splitting prism, and a detector;

[0011] N light sources are arranged around the beam combining prism and are used for emitting N beams of lasers with different wavelengths; the beam combining prism is used for combining the N beams of lasers with different wavelengths and emitting them in one direction.

[0012] The light emitting component is arranged on the light path of the emitted light of the beam combining prism and is used for divergently irradiating the combined laser towards the target to be measured.

[0013] The light receiving component is used for receiving the target light reflected by the target to be measured.

[0014] The beam splitting prism is used for receiving the target light emitted by the light receiving component and separating the received target light into N beams of target light with different wavelengths.

[0015] N detectors are arranged around the beam splitting prism and are used for respectively detecting the N beams of target light with different wavelengths after separation to determine the material of the target to be measured.

[0016] For the method for material identification using multi-wavelength light given in the above embodiments, when performing material identification, it is not necessary to detect the reflectivity of the target to be measured in the entire spectrum. Only by detecting several wavelengths of light can the material identification of the target to be measured be carried out. The overall structure of the device required by the embodiments of the present invention is simple, and there is no need to add a slit, which improves the signal-to-noise ratio of the detector signal; it is convenient for popularization and application. Description of the Drawings

[0017] Figure 1 It is a schematic flowchart of a method for material identification using multi-wavelength light provided by an embodiment of the present invention;

[0018] Figure 2 It is a schematic structural diagram of a lidar for material identification using multi-wavelength light provided by an embodiment of the present invention;

[0019] Figure 3 It is another schematic structural diagram of a lidar for material identification using multi-wavelength light provided by an embodiment of the present invention;

[0020] Figure 4 It is an optical path structure diagram of a spectrometer in an embodiment of the present invention;

[0021] Figure 5 It is a response curve diagram of three types of human eye cone cells in the visible light spectrum in an embodiment of the present invention;

[0022] Figure 6 It is another schematic flowchart of a method for material identification using multi-wavelength light provided by an embodiment of the present invention.

[0023] In the accompanying drawings: 100 - emission system; 101 - first light source; 102 - second light source; 103 - beam - combining prism; 104 - light - emitting component; 200 - receiving system; 201 - light - receiving component; 202 - beam - splitting prism; 203 - first detector; 204 - second detector; 300 - light collector; 400 - deflector; 500 - spectrometer; 501 - illumination light source; 502 - first focusing lens; 503 - target to be measured; 504 - second focusing lens; 505 - slit; 506 - light - splitting device; 507 - array detector. Detailed implementation manners

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to 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 used to limit the present invention.

[0025] The following describes the specific implementation of the present invention in detail with reference to specific embodiments.

[0026] Figure 1 The following is a schematic flowchart of a method for material identification using multi - wavelength light provided by an embodiment of the present invention. The method includes the following steps:

[0027] S102: Combine N laser beams with different wavelengths and emit them in one direction, where N≥2;

[0028] S104: Divergently irradiate the combined laser beam onto the target to be measured, and after being reflected by the target to be measured, form target light;

[0029] S106: Receive the target light and separate the received target light into N target lights with different wavelengths;

[0030] S108: Detect the N target lights with different wavelengths after separation respectively to determine the material of the target to be measured.

[0031] In the embodiment of the present invention, when performing material identification, it is not necessary to detect the reflectivity of the target to be measured in the entire spectrum. Only by detecting a few wavelengths of light can the material of the target to be measured be identified. The overall structure of the device required by the embodiment of the present invention is simple, and there is no need to add a slit, which improves the signal - to - noise ratio of the detector signal.

[0032] In an example of this embodiment, the beams for beam combination, separation, and detection correspond one by one. For example, the lasers with wavelengths of 420 nm, 530 nm, and 560 nm are combined, and the wavelengths of the separated lasers are also 420 nm, 530 nm, and 560 nm, and the number of beams is the same. The beam combination of light can be completed by the beam combination prism 103, the separation of light can be completed by the beam splitting prism 202, and the detection of light can be completed by a detector or a detector group. The detector group can be composed of a photodiode, a photomultiplier tube, an avalanche photodiode, etc., as Figure 2 shown.

[0033] In this example, the target to be measured is composed of different elements, and each element has its own characteristic spectral line. Therefore, the composition of the target to be measured can be identified according to the difference in spectral components. The material identification of the target to be measured is based on the response principle of the three types of cone cells in the human eye in the visible light spectrum, as Figure 5 shown, which is the response curve graph of the three types of cone cells in the human eye in the visible light spectrum; Figure 5 In the figure, the abscissa represents the wavelength, and the ordinate represents the relative absorption rate. There are three types of cone cells on the retina of the human eye, which are sensitive to red, green, and blue light respectively. When light of a certain wavelength acts on the retina, the three types of cone cells have different responses to the incident light, and thus each color in the visible light spectrum can be perceived. Therefore, in this embodiment, it is not necessary to detect each wavelength of the light to be measured, but only to detect a specific few wavelengths, such as the light S with a wavelength of 420 nm, the light M with a wavelength of 530 nm, and the light L with a wavelength of 560 nm in the figure, to identify the material. The structure of the overall device is relatively simple and convenient for popularization.

[0034] Therefore, in this example, it is not necessary to measure the target light in the entire spectral range and then use a complex spectral analysis device (such as a spectrometer 500) containing a spectroscopic device 506 and an array detector 507 for processing to achieve identification; instead, the material is identified by measuring the target light of several wavelengths. Of course, in this example, the target light can also be measured in the entire spectral range. At this time, N can be 7, and the 7 target lights with different wavelengths are the seven-color lights, and the combined light is white light or mixed light, but this will increase the complexity of the method implementation process and is not preferred.

[0035] As Figure 4As shown, in one embodiment, to measure the target light over the entire spectral range, a spectrometer 500 is generally used. The spectrometer 500 includes: an illumination light source 501, a first focusing lens 502, a second focusing lens 504, a slit 505, a spectral splitting device 506, and an array detector 507. The illumination light source 501 is used to emit white light or mixed light. The first focusing lens 502, the second focusing lens 504, the slit 505, and the spectral splitting device 506 are sequentially arranged on the optical path of the white light or mixed light emitted by the illumination light source 501. The array detector 507 is arranged on the optical path of the light emitted by the spectral splitting device 506. The target to be measured 503 is located between the first focusing lens 502 and the second focusing lens 504. After the light transmitted or reflected by the target to be measured 503 passes through the spectral splitting device 506, the light of each wavelength is separated in space, and each wavelength is detected separately by the array detector 507. Detection is carried out over the entire spectral range, and then material identification is performed.

[0036] In an example of this embodiment, the illumination light source 501 can be a conventional light source, the spectral splitting device 506 can be a spectral splitting prism or a diffraction grating, and the array detector 507 is composed of multiple CCD cameras. Specifically, the spectrometer 500 focuses the electromagnetic energy from the illumination light source 501 onto the target to be measured 503. Depending on the system configuration of the spectrometer 500, the light is either reflected by the target to be measured 503 or transmitted through the target to be measured 503. After collecting the light from the target to be measured 503, the light is focused onto the slit 505 at the entrance of the spectrometer 500. The spectrometer 500 is used to separate the light by wavelength through the spectral splitting device 506. Then, the light is focused onto the CCD cameras of the electrical array detector 507. The CCD cameras are composed of thousands of independent detectors, so the light intensity of each wavelength can be measured. The data of the CCD cameras is then read out to a computer, and the result is a spectrum showing the light intensity of each wavelength, and the material of the target to be measured 503 is determined through the spectrum.

[0037] As Figure 1 shown, as a preferred embodiment of the present invention, 2 ≤ N ≤ 5.

[0038] In this embodiment, the value of N is 2, 3, or 5. N stipulates the number of wavelengths of light for beam combination, separation, and detection. When actually performing material identification, it can usually be flexibly selected to better balance in terms of time cost, equipment cost, and detection accuracy. For example, when the target to be measured is a specular reflection object such as glass or smooth metal, the number of light beams required to irradiate the object can be less, and thus fewer light sources are arranged, and the types of wavelengths to be detected are also less. That is, as Figure 2As shown, it is only necessary to set the first light source 101 and the second light source 102 to emit lasers of different wavelengths, and set the first detector 203 and the second detector 204 as a detector group to achieve detection; the first detector 203 and the second detector 204 can also use detectors with the same sensitivity. Detectors with the same sensitivity can simplify the complexity of the implementation of this method, reduce the difficulty of post-processing of detection data, and are also convenient for maintenance and promotion.

[0039] In an example of this embodiment, N = 2, or N = 3;

[0040] When N = 2, as Figure 6 shown, the following steps are included:

[0041] S202: Combine two lasers of different wavelengths and emit them from one direction;

[0042] S204: Divergently irradiate the combined laser towards the target to be measured, and after being reflected by the target to be measured, form target light;

[0043] S206: Receive the target light and separate the received target light into two target lights of different wavelengths;

[0044] S208: Detect the two separated target lights of different wavelengths respectively to determine the material of the target to be measured.

[0045] In an example application scenario, when N = 3, the method includes the following steps: Combine three lasers of different wavelengths and emit them from one direction; Divergently irradiate the combined laser towards the target to be measured, and after being reflected by the target to be measured, form target light; Receive the target light and separate the received target light into three target lights of different wavelengths; Detect the three separated target lights of different wavelengths respectively to determine the material of the target to be measured.

[0046] Similarly, when N = 5, the method includes the following steps: Combine five lasers of different wavelengths and emit them from one direction; Divergently irradiate the combined laser towards the target to be measured, and after being reflected by the target to be measured, form target light; Receive the target light and separate the received target light into five target lights of different wavelengths; Detect the five separated target lights of different wavelengths respectively to determine the material of the target to be measured. Among them, combining five lasers of different wavelengths can also be carried out in a single beam-combining grating, or can also be carried out in a prism group composed of two beam-combining prisms. Separating the target light into five target lights of different wavelengths can also be carried out in a beam-splitting grating. The five lights of different wavelengths separated by the beam-splitting grating are detected by five detectors. This embodiment will not be elaborated here.

[0047] As a preferred embodiment of the present invention, the method further includes: before the combined laser is divergently irradiated onto the target to be measured, deflecting the combined laser so that the laser irradiated onto the target to be measured can be scanned in a two-dimensional space.

[0048] In this embodiment, by adding the step of deflecting the combined laser, detection with a larger field of view can be achieved. Moreover, under the conditions that the target to be measured is large in size and complex in shape, by scanning the target to be measured in a two-dimensional space, detection data can be better obtained, so as to more accurately identify the material of the target to be measured.

[0049] In another embodiment, the method further includes: modulating the received target light before separating the received target light into N target lights with different wavelengths.

[0050] By modulating the target light, detection of a target to be measured that is large in size and complex in shape can be achieved. Furthermore, when performing target light detection, detection data can be better obtained, so as to more accurately identify the material of the target to be measured.

[0051] Furthermore, the method further includes: after modulating the received target light, collecting the modulated target light to facilitate separation. By providing a light collector 300 ( Figure 3 as shown in the figure) to collect the modulated light, the modulated target light can be better detected, avoiding additional light loss, which may affect the material identification result.

[0052] In summary, regardless of whether the detection light is modulated, the total light intensity of the reflected light beams after irradiating the target to be measured with lights of different wavelengths can be detected to determine which wavelengths of light the target to be measured is most sensitive to, and then the material of the target to be measured can be identified. Of course, modulating the detection light can increase the accuracy and real-time performance when detecting the target to be measured, and is also more suitable for objects with more complex sizes, shapes, and components. The pre-modulation mode or the post-modulation mode can be flexibly selected according to the actual production, and this embodiment is not limited thereto.

[0053] As Figure 2 shown, in another embodiment, there is provided a device for material identification using multi-wavelength light for the method of material identification using multi-wavelength light as described above. The device includes a transmitting system 100 and a receiving system 200. The transmitting system 100 at least includes a light source, a beam combining prism 103, and a light emitting member 104. The receiving system 200 at least includes a light receiving member 201, a beam splitting prism 202, and a detector;

[0054] N light sources are arranged around the beam combining prism 103 for emitting N beams of lasers with different wavelengths; the beam combining prism 103 is used for combining the N beams of lasers with different wavelengths and emitting them in one direction.

[0055] The light emitting component 104 is arranged on the light path of the emitted light of the beam combining prism 103 for divergently irradiating the combined laser towards the target to be measured.

[0056] The light receiving component is used for receiving the target light reflected by the target to be measured.

[0057] The beam splitting prism 202 is used for receiving the target light emitted by the light receiving component and separating the received target light into N beams of target light with different wavelengths.

[0058] N detectors are arranged around the beam splitting prism 202 for respectively detecting the N beams of target light with different wavelengths after separation to determine the material of the target to be measured.

[0059] In this embodiment, taking N = 2 as an example: the two light sources can be denoted as the first light source 101 and the second light source 102, corresponding to the first laser and the second laser, both of which are pulsed lasers, respectively emitting lasers with different wavelengths λa and laser λ b , laser λa and laser λ b are combined by the beam combining prism; the 2 detectors can be the first detector 203 and the second detector 204 respectively. The first detector 203 detects laser λa, and the second detector 204 detects laser λ b . Through the cooperation of the first laser, the second laser, the beam combining prism 103, the beam splitting prism 202, the first detector 203 and the second detector 204, the lights with different wavelengths in the target light reflected by the target to be measured are respectively detected, and the material of the target to be measured is identified by using the intensity difference of different wavelengths in the target light; only a few wavelengths need to be detected to carry out material identification, the structure of the device is simple, and there is no need to add a conventional slit, improving the signal-to-noise ratio of the detector signal.

[0060] In an example of this embodiment, the two light sources are arranged around the beam combining prism 103, that is, on the incident surface sides of the two incident lights of the beam combining prism 103. The lasers emitted by the two light sources enter the beam combining prism 103 in a mutually perpendicular relationship and are combined; after the beam combining prism 103 combines N lasers with different wavelengths and emits them from one direction, they enter the light emitting component 104. The light emitting component 104 diverges and irradiates the combined laser towards the target to be measured, and detects the field of view where the target to be measured is located; some lasers will pass through the target to be measured, and some lasers are reflected by the target to be measured to form target light; the light emitting component 104 has a diverging effect on the combined laser and irradiates the diverged laser towards the target to be measured; the light receiving component receives the target light reflected by the target to be measured and propagates towards the beam splitting prism 202. The beam splitting prism 202 separates the received target light into two target lights with different wavelengths; finally, they are detected by two detectors, and the material of the target to be measured is determined according to the information detected by the detectors. The two detectors are arranged around the beam splitting prism 202 means: they are respectively arranged on the sides of the two outgoing surfaces where the two outgoing lights of the beam splitting prism 202 are located; the outgoing light optical path of the beam combining prism 103 means: the central axis of the outgoing surface where the outgoing light of the beam combining prism 103 is located, which is common knowledge and will not be described in detail here.

[0061] In another example, the sensitivities of the first detector 203 and the second detector 204 for detecting the target light can be different.

[0062] In the actual application scenario of this example, the sensitivities of the first detector 203 and the second detector 204 correspond to the wavelengths of the separated light beams. For example: if the wavelengths of the separated light beams are the wavelengths of red and blue lights, then the first detector 203 and the second detector 204 are sensitive to red and blue lights respectively, so that the first detector 203 accurately measures the total light intensity of the red light, and the second detector 204 accurately measures the total light intensity of the blue light. Detecting with two detectors with different sensitivities also reduces the requirements for the dynamic range of the detectors, and thus reduces the cost of equipment implementation.

[0063] In addition, in some example scenarios, the first detector 203 and the second detector 204 can also use detectors with the same sensitivity. Detectors with the same sensitivity can simplify the implementation complexity, reduce the detection difficulty, and are also convenient for maintenance.

[0064] Such as Figure 2 、 Figure 3 As shown, in another embodiment, the device further includes a deflector 400.

[0065] The deflector 400 is arranged on the outgoing light optical path of the beam combining prism 103.

[0066] Alternatively, the deflector 400 is disposed on the optical path of the emitted light of the light receiver 201.

[0067] In this embodiment, through the provided deflector 400, the detection light emitted by the light emitter can be scanned in a two-dimensional space, that is, the emitted detection light forms a dual-wavelength two-dimensional laser scanning array to scan different sub-fields of view (sub-field of view 1, sub-field of view 2, sub-field of view 3 shown in the figure), expanding the field of view range and achieving the balance of detection timeliness and detection accuracy; there is no need to accurately align the target to be measured for detection, improving the adaptability of detection. In addition, the deflector 400 can also be used to modulate the image of the target to be measured. When it is arranged on the optical path of the emitted light of the light receiver 201, the deflector 400 can be a rotating multi-faceted reflecting prism, a MEMS galvanometer, a SLM, a DMD, etc.

[0068] In the first example of this embodiment, the deflector 400 is disposed on the optical path of the emitted light of the beam combining prism 103; so that the emitted detection light forms a dual-wavelength two-dimensional laser scanning array to scan different sub-fields of view.

[0069] In the second example of this embodiment, the deflector 400 is disposed on the optical path of the emitted light of the light receiver 201; to achieve the modulation of the image of the target to be measured.

[0070] In the third example of this embodiment, the deflector 400 can be one of a rotating multi-faceted reflecting prism, a MEMS (micro-electro-mechanical system) galvanometer, and a digital micro-mirror device (DMD); both the light emitter and the light receiver adopt a single lens or a lens group composed of multiple lenses.

[0071] In one embodiment, the receiving system 200 further includes a condenser 300, and the condenser 300 is disposed on the light incident surface side of the beam splitting prism 202.

[0072] In this embodiment, the condenser 300 is used to collect the target light after passing through the deflector 400, and can be a single lens, a lens group composed of a single lens, an optical fiber light cone, a condenser, etc. The specific structures of the deflector 400, the light emitter 104, and the light receiver 201 in this embodiment are not limited thereto. In actual application, those skilled in the art can make flexible selections and adjustments according to needs to facilitate the implementation of this solution, which will not be elaborated here.

[0073] In the fourth example of this embodiment, the emitting system 100 further includes a collimator and a beam expander, and the collimator or the beam expander is disposed on the optical path of the emitted light of the light source; for collimating and expanding the laser emitted by the light source to improve the utilization rate of light.

[0074] In another embodiment, the receiving system 200 further includes: a controller communicatively connected to the detector, the controller is connected to a memory, and the memory stores a pre-calibration database.

[0075] The controller is configured to determine the material of the target to be measured according to the intensity difference of lights with different wavelengths in the target light detected by the detector.

[0076] Alternatively, determine the material of the target to be measured according to the comparison between the intensity difference and the data in the pre-calibration database.

[0077] In this embodiment, the pre-calibration database is formed after pre-calibration according to the material properties of known objects, that is, objects with known materials are used in advance to pre-calibrate the intensity difference of the light detected by the first detector 203 and the second detector 204. The controller generally belongs to the configuration part of the detector.

[0078] The above-mentioned device can be applied to material identification, or other remote sensing detection fields, and can also be used in the field of single-pixel imaging, not limited thereto.

[0079] As Figure 3 shown, when applied to single-pixel imaging, a post-modulation mode can be adopted. Taking N = 2 as an example: two beams of lights with different wavelengths λa and λ b are emitted by the first light source 101 and the second light source 102; the two beams of lights with different wavelengths λa and λ b are incident into the beam-combining prism from mutually perpendicular directions and exit from one direction of the beam-combining prism 103; they are emitted through a light emitting member to form dual-wavelength illumination light; the target to be measured reflects the dual-wavelength illumination light to generate target light, the target light is received and imaged by the light receiving member 201, the image of the target to be measured is modulated by the deflector 400, the modulated target light is converged by the condenser 300, and the different wavelengths λa and λ b in the target light are separated by the beam-splitting prism 202, and the two wavelengths λa and λ b of the target light are respectively detected by the first detector 203 and the second detector 204. According to the intensity difference of the two wavelengths λa and λ b in the detected target light, the material of the target to be measured is identified. In some scenarios, objects with known materials can also be used in advance to pre-calibrate the intensity difference of the light detected by the first detector 203 and the second detector 204. Thus, in actual tests, the material of the target to be measured can be determined according to the intensity difference of the light detected by the first detector 203 and the second detector 204. It should be noted that in some example scenarios, the identification of the material can also adopt a pre-modulation mode, and the specific method is not limited.

[0080] In this embodiment, it is not necessary to detect the reflectivity of the target to be measured in the entire spectrum. Only a few wavelengths need to be detected to perform material identification. Compared with a conventional spectrometer 500 or monochromator, the overall structure is simpler and the detection cost is low. In addition, the method of using multiple wavelengths for material identification can also be applied to other imaging detection fields. In such a scenario where distance detection is not required, the light source can be a non-pulsed source such as a laser or an LED.

[0081] In an example of this embodiment, the deflector 400 may be a digital micromirror array (DMD), which can be configured such that the target light of different sub-fields (sub-field 1, sub-field 2, sub-field 3) generated by illuminating an object with illumination light is imaged on the DMD by the light receiver 201, and the micromirrors at different positions on the DMD reflect the target light corresponding to different sub-fields into the light collector 300 for collection.

[0082] In summary, the method for material identification using multi-wavelength light provided by the above embodiment, and the device for material identification using multi-wavelength light provided based on this method for material identification using multi-wavelength light. When performing material identification, it is not necessary to detect the reflectivity of the target to be measured in the entire spectrum. Only a few wavelength lights need to be detected to perform the material identification of the target to be measured. The overall structure of the equipment required by the method in this embodiment is simple, which is conducive to popularization and application; there is no need to add a slit, which improves the signal-to-noise ratio of the detector signal, and the deflector 400 can use the principle of deflected reflection to perform a two-dimensional field of view scan, expanding the detection field of view, realizing the detection of more complex targets to be measured, and then realizing material identification. Moreover, it can be applied to laser detection and single-pixel imaging, and has a wide range of application fields.

[0083] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for material identification using multi-wavelength light, used to identify the material of a target to be measured, characterized in that: The method comprises the following steps: N laser beams with different wavelengths are combined and emitted from one direction, where N ≥ 2; The combined laser beam is diverged and irradiated toward the target to be measured, and the target light is formed after being reflected by the target to be measured; receiving the target light, and separating the received target light into N beams of target light with different wavelengths; The separated N beams of target light of different wavelengths are detected respectively to determine the material of the target to be measured.

2. The method for material identification using multi-wavelength light according to claim 1, characterized in that: 2≤N≤5。 3. The method for material identification using multi-wavelength light according to claim 2, characterized in that: N=2, or N=3.

4. The method for material identification using multi-wavelength light according to claim 1, characterized in that: The method further includes: before the combined laser beams are diverged and irradiated toward the target to be measured, the combined laser beams are deflected so that the laser beams irradiated toward the target to be measured can be scanned in a two-dimensional space.

5. The method for material identification using multi-wavelength light according to claim 1, characterized in that: The method further includes: modulating the received target light before separating the received target light into N beams of target light with different wavelengths.

6. The method for material identification using multi-wavelength light according to claim 5, characterized in that: The method further includes: after modulating the received target light, collecting the modulated target light for separation.

7. A device for material identification using multi-wavelength light, characterized in that: A method for material identification using multi-wavelength light as described in any one of claims 1 to 6, wherein the device comprises a transmitting system and a receiving system, wherein the transmitting system comprises at least a light source, a beam combining prism and a light transmitting element, and the receiving system comprises at least a light receiving element, a beam splitting prism and a detector; The N light sources are arranged around the beam combining prism and are used to emit N laser beams with different wavelengths; The beam combining prism is used to combine N laser beams with different wavelengths and emit them from one direction; The light emitting element is arranged on the outgoing light path of the beam combining prism, and is used to radiate the combined laser beam toward the target to be measured; The light receiving element is used to receive the target light reflected by the target to be measured; The beam splitting prism is used to receive the target light emitted by the light receiving element and separate the received target light into N beams of target light with different wavelengths; The N detectors are arranged around the beam splitting prism and are used to detect the N separated target lights of different wavelengths respectively, so as to determine the material of the target to be measured.

8. The device for material identification using multi-wavelength light according to claim 7, characterized in that: The device also includes a deflector, The deflector is arranged on the optical path of the outgoing light of the beam combining prism; Alternatively, the deflector is arranged on the optical path of the outgoing light of the light receiving element.

9. The device for material identification using multi-wavelength light according to claim 8, characterized in that: The deflector is one of a rotating multi-faceted reflection prism, a MEMS galvanometer, and a digital micromirror array.

10. The device for material identification using multi-wavelength light according to claim 8, characterized in that: The receiving system further comprises: a controller and / or a light collector; The light collector is arranged on the light incident surface side of the beam splitting prism; The controller is in communication connection with the detector and is used to judge the material of the target to be detected according to the intensity difference of light of different wavelengths in the target light detected by the detector.

Images