A transceiving integrated non-contact laser speckle vibration measurement system and method

Abstract

This invention discloses a non-contact laser speckle vibration measurement system integrating transceiver, comprising: a light source, a speckle control module, a first beam splitter, a light absorber, a narrowband filter, an imaging lens, a second beam splitter, and a light detection module. The light source, the speckle control module, and the first beam splitter are arranged sequentially along the light transmission direction. The initial beam emitted from the light source enters the first beam splitter through the speckle control module. The first beam splitter splits the received initial beam into two beams; one beam enters the light absorber; the other beam passes through the narrowband filter and illuminates the object under test. The speckle beam generated by diffuse reflection from the object under test returns to the first beam splitter through the narrowband filter. The speckle beam received by the first beam splitter enters the second beam splitter through the imaging lens. The speckle beam received by the second beam splitter enters the light detection module for detection. This invention also discloses a non-contact laser speckle vibration measurement method integrating transceiver, which improves the accuracy and reliability of the measurement.

Description

Technical Field

[0001] This invention relates to the field of laser speckle vibration measurement technology, and in particular to a non-contact laser speckle vibration measurement system and method integrating transceiver. Background Technology

[0002] Laser speckle-based micro-vibration measurement is a new approach that has recently emerged, distinct from traditional laser Doppler and interferometry methods. It offers advantages such as simple system, easy operation, and non-contact measurement of the object being measured. The speckle pattern caused by laser irradiation of the object remains largely unchanged. When the distance between the object and the detection system is relatively far, the changes in speckle caused by vibration are usually reflected as a translation of the speckle pattern on the observation plane.

[0003] The non-contact, pinpoint measurement of minute vibrations of distant, diffusely reflecting, non-cooperative targets using lasers has significant applications in fields such as bridge and building health monitoring, security systems, reconnaissance and counter-terrorism, and disaster search and rescue.

[0004] In existing technologies, the light source used to transmit light to the object under test and the speckle beam generated by diffuse reflection from the object under test are implemented using different components. Since the receiving and transmitting optical paths of the object under test are separate, when a slight change occurs during the measurement process, the transmitting and receiving optical paths will not change in the same direction at the same time, which will affect the signal reception at the detection end and affect the accuracy and reliability of the measurement. Summary of the Invention

[0005] In view of this, the purpose of this invention is to propose a non-contact laser speckle vibration measurement system that integrates transceiver and receiver. The system uses an integrated optical path structure for detection. When a slight change occurs during the measurement process, the transmitting and receiving optical paths will change in the same direction simultaneously, which will not affect the signal reception at the detection end and avoid the problems of optical path instability and error accumulation. Furthermore, the receiving end uses a combination of photoelectric detection unit and image detection unit to fuse and process data, thereby improving the accuracy and reliability of the measurement.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by this invention is as follows:

[0007] This invention provides a non-contact laser speckle vibration measurement system integrating transceiver, comprising: a light source, a speckle control module, a first beam splitter, a light absorber, a narrowband filter, an imaging lens, a second beam splitter, and a light detection module;

[0008] The light source, the spot control module, and the first beam splitter are arranged sequentially along the light transmission direction. The initial beam emitted from the light source enters the first beam splitter through the spot control module.

[0009] The first beam splitter splits the received initial beam into two beams. One beam enters the light absorber, and the other beam passes through a narrowband filter and illuminates the object under test. The speckle beam generated by the diffuse reflection of the object under test returns to the first beam splitter through the narrowband filter.

[0010] The speckle beam received by the first beam splitter enters the second beam splitter through the imaging lens;

[0011] The speckle beam received by the second beam splitter enters the photodetector module for detection.

[0012] Furthermore, the optical detection module includes a photoelectric detection unit and an image detection unit. The second beam splitter splits the received speckle beam into two beams. One beam enters the photoelectric detection unit to detect the change in luminous flux caused by the vibration of the object under test; the other beam enters the image detection unit to display the spatial speckle image.

[0013] Furthermore, the photoelectric detection unit is a PD detector, a photodiode, an avalanche diode, or a photomultiplier tube.

[0014] Furthermore, the image detection unit is a CCD detector, an area array image sensor, or an array detector.

[0015] Furthermore, the light spot control module includes a set of combined lenses, which includes an input lens and an output lens arranged sequentially along the light transmission direction, and the input lens and the output lens have different focal lengths.

[0016] Furthermore, the light source is a laser.

[0017] This invention also provides a transceiver integrated non-contact laser speckle vibration measurement method, which requires the aforementioned transceiver integrated non-contact laser speckle vibration measurement system and includes the following steps:

[0018] Step 1: The initial beam emitted by the light source passes through the spot control module and is split by the first beam splitter to illuminate the object under test; the speckle beam generated by the object under test returns through the first beam splitter and is then transmitted by the second beam splitter to the photoelectric detection unit and the image detection unit for detection.

[0019] Step 2: The photoelectric detection unit and the image detection unit process the speckle beam to obtain detection information;

[0020] Step 3: Calculate the signal-to-noise ratio based on the detection information, and determine whether the speckle beam needs to be readjusted based on the magnitude of the signal-to-noise ratio.

[0021] Furthermore, step 1 specifically includes:

[0022] Step 11: The initial beam emitted by the light source is transmitted to the beam spot control module. After the beam spot size of the initial beam is adjusted by the beam spot control module, it enters the first beam splitter.

[0023] Step 12: The first beam splitter splits the adjusted initial beam into two beams. One beam is absorbed by the light absorber, and the other beam is filtered out by a narrow-band filter before illuminating the object under test.

[0024] Step 13: After the object under test is illuminated, diffuse reflection occurs, resulting in a speckled beam. The speckled beam is then filtered out by a narrow-band filter before returning to the first beam splitter.

[0025] Step 14: The first beam splitter transmits the speckle beam to the imaging lens, and the imaging lens performs a focusing transformation on the speckle beam. The transformed speckle beam then enters the second beam splitter.

[0026] Step 15: The second beam splitter splits the transformed speckle beam into two beams. One beam enters the photoelectric detection unit for processing, and the other beam enters the image detection unit for processing.

[0027] Furthermore, step 2 specifically includes:

[0028] Step 21: The photoelectric detection unit detects the change in light flux caused by the vibration of the object under test based on the received speckle beam, converts it into a change in photocurrent, and calculates the photoelectric micro-vibration information of the object under test.

[0029] Step 22: The image detection unit acquires the received speckle beam, converts it into a spatial speckle image for display, and inputs it into a computer for analysis and processing to obtain image micro-vibration information;

[0030] Step 23: The photoelectric micro-vibration information and the image micro-vibration information are fused to obtain the detection information.

[0031] Furthermore, step 3 specifically includes:

[0032] Step 31: Calculate the signal-to-noise ratio based on the detection information, and determine whether the signal-to-noise ratio is lower than a preset threshold. If yes, proceed to step 32; otherwise, do not process.

[0033] Step 32: Adjust the distance between the input lens and the output lens of the combined lens in the spot control module to readjust the spot size of the initial beam; and / or adjust the distance between the imaging lens and the object under test to readjust the focusing transformation of the speckle beam.

[0034] Step 33: During the adjustment process, observe the spatial speckle image displayed by the image detection unit and make corresponding adjustments based on the observation results.

[0035] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0036] 1. By using an integrated transceiver optical path structure design, problems such as optical path instability and error accumulation can be avoided. In the case of integrated transceiver, even if there are slight changes during the measurement process, the transmitting and receiving optical paths will change in the same direction simultaneously, without affecting the signal reception at the detection end, thus improving the accuracy and reliability of the measurement.

[0037] 2. The image detection unit and the spot control module work together to provide feedback, enabling visual control of the speckle particle size during the detection process.

[0038] 3. The combination of the image detection unit and the photoelectric detection unit can realize the visual alignment of the object under test and the laser speckle. The photoelectric micro-vibration information detected by the photoelectric detection unit and the image micro-vibration information detected by the image detection unit are fused and processed to improve the vibration measurement accuracy.

[0039] 4. Adaptability to different environments: Due to the improved stability of the optical path, it can adapt to harsher environmental conditions, such as changes in temperature and humidity.

[0040] 5. Reduce signal loss: Since the signal does not need to travel through a long transmission path, signal attenuation and loss can be reduced, thus improving signal strength and quality. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the structure of a non-contact laser speckle vibration measurement system integrating transceiver provided by the present invention.

[0043] Figure 2 This is an execution flowchart of a non-contact laser speckle vibration measurement method integrating transceiver provided by the present invention.

[0044] Explanation of the labels in the diagram:

[0045] 1. Light source, 2. Spot control module, 21. Input lens, 22. Output lens, 3. First beam splitter, 4. Light absorber, 5. Narrowband filter, 6. Imaging lens, 7. Second beam splitter, 8. Light detection module, 81. Photoelectric detection unit, 82. Image detection unit, 9. Object under test. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the invention. Similarly, the following embodiments are only some, not all, embodiments of the present invention, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Please see Figure 1 The present invention provides a non-contact laser speckle vibration measurement system integrating transceiver, comprising: a light source 1, a speckle control module 2, a first beam splitter 3, a light absorber 4, a narrowband filter 5, an imaging lens 6, a second beam splitter 7, and a light detection module 8;

[0048] The light source 1, the light spot control module 2, and the first beam splitter 3 are arranged sequentially along the light transmission direction. The initial beam emitted from the light source 1 enters the first beam splitter 3 through the light spot control module 2.

[0049] The first beam splitter 3 splits the received initial beam into two beams. One beam enters the light absorber 4, and the other beam illuminates the object under test 9. The speckle beam generated by the diffuse reflection of the object under test 9 returns to the first beam splitter 3 through the narrow band filter 5.

[0050] The speckle beam received by the first beam splitter 3 enters the second beam splitter 7 through the imaging lens 6;

[0051] The speckle beam received by the second beam splitter 7 enters the photodetector module 8 for detection.

[0052] The functions of each component are as follows:

[0053] The function of the light source 1 is to provide an illumination beam to illuminate the object 9 being measured for measurement.

[0054] The function of the light spot control module 2 is to receive the light beam sent by the light source and control the size of the light spot when the light beam is output, thereby controlling the size of the light spot illuminating the object 9 being measured.

[0055] The function of the first beam splitter 3 is to split the light beam emitted by the light source into different optical paths and transmit them to the light absorber 4 and the object under test 9; at the same time, it receives the speckle beam generated by the object under test 9. That is, the first beam splitter 3 can realize the light irradiating the object under test 9 and the speckle beam loop generated after the object under test 9 is irradiated, forming an integrated transmit and receive optical path structure. In the case of integrated transmit and receive, even if there are slight changes during the measurement process, the transmitting and receiving optical paths will change in the same direction at the same time, which will not affect the signal reception at the detection end, thus improving the accuracy and reliability of the measurement.

[0056] The function of the light absorber 4 is to absorb the stray light that is split from the first beam splitter 3, so as to prevent stray light interference.

[0057] The function of the narrowband filter 5 is to filter the returned light beam, filter out ambient stray light, and increase the signal-to-noise ratio of the measurement system.

[0058] The imaging lens 6 is used to focus the returning speckle beam.

[0059] The function of the second beam splitter 7 is to split the received speckle beam into two paths for detection.

[0060] The function of the optical detection module 8 is to receive the speckle beam generated by the diffuse reflection of the object under test 9 and output the signal to the microcomputer for processing.

[0061] Preferably, the light detection module 8 includes a photoelectric detection unit 81 and an image detection unit 82. The second beam splitter 7 splits the received speckle beam into two beams. One beam enters the photoelectric detection unit 81 to detect the change in light flux caused by the vibration of the object under test; the other beam enters the image detection unit 82 to display the spatial speckle image.

[0062] This invention utilizes a second beam splitter 7 to achieve dual-path reception. One path, via an image detection unit 82, receives the speckle pattern generated by diffuse reflection of the light beam from the object under test 9, forming a speckle image and video, which are then input into a computer for algorithmic processing to derive micro-vibration information, achieving real-time, high-sensitivity, and high-precision measurement of micro-vibrations. The other path, via a photoelectric detection unit 81, receives and detects changes in the speckle light flux in real time, thereby causing changes in photocurrent. The micro-vibration signal of the object under test 9 is obtained through calculation and processing of the photocurrent. This invention also combines the image detection unit 82 and the photoelectric detection unit 81, enabling visual alignment of the object under test 9 and the laser speckle pattern. The photoelectric micro-vibration information detected by the photoelectric detection unit 81 and the image micro-vibration information detected by the image detection unit 82 are fused and processed, thereby improving the accuracy of vibration measurement.

[0063] Preferably, the photoelectric detection unit 81 is a PD detector, a photodiode, an avalanche diode, or a photomultiplier tube.

[0064] Preferably, the image detection unit 82 is a CCD detector, an area array image sensor, or an array detector.

[0065] Preferably, Example 1:

[0066] The light spot control module 2 includes a set of combined lenses, which includes an input lens 21 and an output lens 22 arranged sequentially along the light transmission direction. The input lens 21 and the output lens 22 have different focal lengths.

[0067] Preferably, the light source 1 is a laser.

[0068] like Figure 2 As shown, the present invention also provides a transceiver integrated non-contact laser speckle vibration measurement method, which requires the aforementioned transceiver integrated non-contact laser speckle vibration measurement system and includes the following steps:

[0069] Step 1: The initial beam emitted by the light source 1 passes through the spot control module 2 and is split by the first beam splitter 3, then shines onto the object under test 9; the speckle beam generated by the object under test 9 returns through the first beam splitter 3 and is then transmitted by the second beam splitter 7 to the photoelectric detection unit 81 and the image detection unit 82 for detection.

[0070] In this embodiment, before step 1, the method further includes turning on the light source 1, the light absorber 4, and the light detection module 8.

[0071] In this embodiment, step 1 specifically includes:

[0072] Step 11: The initial beam emitted by the light source 1 is transmitted to the spot control module 2. After the spot size of the initial beam is adjusted by the spot control module 2, it enters the first beam splitter 3.

[0073] Step 12: The first beam splitter 3 splits the adjusted initial beam into two beams. One beam is absorbed by the light absorber 4, and the other beam is filtered by the narrow-band filter 5 to remove stray light before illuminating the object under test 9.

[0074] Step 13: After the object being tested 9 is illuminated, diffuse reflection occurs, resulting in a speckled beam. The speckled beam is then filtered out by the narrow-band filter 5 before returning to the first beam splitter 3.

[0075] Step 14: The first beam splitter 3 transmits the speckle beam to the imaging lens 6, and the imaging lens 6 performs focusing transformation on the speckle beam. The transformed speckle beam then enters the second beam splitter 7.

[0076] Step 15: The second beam splitter 7 splits the transformed speckle beam into two beams. One beam enters the photoelectric detection unit 81 for processing; the other beam enters the image detection unit 82 for processing. The first beam splitter 3 can realize the illumination of the object under test 9 and the speckle beam loop generated after illumination by the object under test 9, forming an integrated transceiver optical path structure. In the case of integrated transceiver, even if there are slight changes during the measurement process, the transmitting and receiving optical paths will change in the same direction simultaneously, without affecting the signal reception at the detection end, thus improving the accuracy and reliability of the measurement.

[0077] Step 2: The photoelectric detection unit 81 and the image detection unit 82 process the speckle beam to obtain detection information;

[0078] In this embodiment, step 2 specifically includes:

[0079] Step 21: The photoelectric detection unit 81 detects the change in light flux caused by the vibration of the object under test 9 based on the received third beam, converts it into a change in photocurrent, and calculates the photoelectric micro-vibration information of the object under test 9.

[0080] Step 22: The image detection unit 82 acquires the received speckle beam, converts it into a spatial speckle image for display, and inputs it into a computer for analysis and processing to obtain image micro-vibration information; signal processing can be performed using methods such as grayscale value method and cross-correlation coefficient calculation.

[0081] Step 23: The photoelectric micro-vibration information and the image micro-vibration information are fused to obtain the detection information; this can improve the vibration measurement accuracy and efficiency. By using a coordinated feedback mechanism between the image detection unit and the spot control module, the size of the speckle particles during the detection process can be visualized and controlled.

[0082] Step 3: Calculate the signal-to-noise ratio based on the detection information, and determine whether the speckle beam needs to be readjusted based on the magnitude of the signal-to-noise ratio.

[0083] In this embodiment, step 3 specifically includes:

[0084] Step 31: Calculate the signal-to-noise ratio (SNR) based on the detection information and determine whether the SNR is lower than a preset threshold. If so, proceed to step 42; otherwise, do not process. Calculate the SNR by fusing photoelectric micro-vibration information and image micro-vibration information. The closer the photoelectric micro-vibration information and image micro-vibration information are, the higher the SNR, indicating that the optical path design is reasonable.

[0085] Step 32: Adjust the distance between the input lens 21 and the output lens 22 of the combined lens in the spot control module 2 to readjust the spot size of the initial beam. The combined lens acts as a beam expander (beam reducer) system, which proportionally enlarges (reduces) the diameter of the collimated input beam; and / or adjust the distance between the imaging lens 6 and the object under test 9, and adjust the parameters of the imaging lens 6 to readjust the focus of the speckle beam.

[0086] Step 33: During the adjustment process, the spatial speckle image displayed by the image detection unit 82 is observed, and corresponding adjustments are made based on the observation results. This includes changing the speckle beam focusing transformation and real-time adjustment of the spot control module 2 to achieve a suitable spot size for easy detection and improved measurement accuracy. By combining the image detection unit with the photoelectric detection unit, visual alignment of the measured object and the laser speckle can be achieved. The photoelectric micro-vibration information detected by the photoelectric detection unit and the image micro-vibration information detected by the image detection unit are fused and processed, thereby improving vibration measurement accuracy.

[0087] The above description is only a part of the embodiments of the present invention and does not limit the scope of protection of the present invention. Any equivalent device or equivalent process transformation made based on the content of the present invention specification and drawings, or direct or indirect application in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A non-contact laser speckle vibration measurement method integrating transceiver, characterized in that, This method provides a non-contact laser speckle vibration measurement system integrating transceiver, comprising: a light source, a speckle control module, a first beam splitter, a light absorber, a narrowband filter, an imaging lens, a second beam splitter, and a light detection module; the light source, the speckle control module, and the first beam splitter are arranged sequentially along the light transmission direction; an initial beam emitted from the light source enters the first beam splitter via the speckle control module; the first beam splitter splits the received initial beam into two beams, one of which enters the light absorber; the other beam passes through the narrowband filter and illuminates the object under test, and the speckle beam generated by diffuse reflection from the object under test returns to the first beam splitter via the narrowband filter; the speckle beam received by the first beam splitter enters the second beam splitter via the imaging lens; the speckle beam received by the second beam splitter enters the light detection module for detection; the method includes the following steps: Step 1: The initial beam emitted by the light source passes through the spot control module and is split by the first beam splitter, illuminating the object under test. The speckled beam generated by the object under test returns through the first beam splitter and is then transmitted by the second beam splitter to the photoelectric detection unit and the image detection unit for detection. Specifically, this includes: Step 11: The initial beam emitted by the light source is transmitted to the beam spot control module. After the beam spot size of the initial beam is adjusted by the beam spot control module, it enters the first beam splitter. Step 12: The first beam splitter splits the adjusted initial beam into two beams. One beam is absorbed by the light absorber, and the other beam is filtered out by a narrow-band filter before illuminating the object under test. Step 13: After the object under test is illuminated, diffuse reflection occurs, resulting in a speckled beam. The speckled beam is then filtered out by a narrow-band filter before returning to the first beam splitter. Step 14: The first beam splitter transmits the speckle beam to the imaging lens, and the imaging lens performs a focusing transformation on the speckle beam. The transformed speckle beam then enters the second beam splitter. Step 15: The second beam splitter splits the transformed speckle beam into two beams, one of which enters the photoelectric detection unit for processing; the other beam enters the image detection unit for processing. Step 2: The photoelectric detection unit and the image detection unit process the speckle beam to obtain detection information; specifically including: Step 21: The photoelectric detection unit detects the change in light flux caused by the vibration of the object under test based on the received speckle beam, converts it into a change in photocurrent, and calculates the photoelectric micro-vibration information of the object under test. Step 22: The image detection unit acquires the received speckle beam, converts it into a spatial speckle image for display, and inputs it into a computer for analysis and processing to obtain image micro-vibration information; Step 23: The photoelectric micro-vibration information and the image micro-vibration information are fused to obtain the detection information; Step 3: Calculate the signal-to-noise ratio based on the detection information, and determine whether the speckle beam needs to be readjusted based on the magnitude of the signal-to-noise ratio.

2. The non-contact laser speckle vibration measurement method integrating transceiver as described in claim 1, characterized in that, Step 3 specifically includes: Step 31: Calculate the signal-to-noise ratio based on the detection information, and determine whether the signal-to-noise ratio is lower than a preset threshold. If yes, proceed to step 32; otherwise, do not process. Step 32: Adjust the distance between the input lens and the output lens of the combined lens in the spot control module to readjust the spot size of the initial beam; and / or adjust the distance between the imaging lens and the object under test to readjust the focusing transformation of the speckle beam; Step 33: During the adjustment process, observe the spatial speckle image displayed by the image detection unit and make corresponding adjustments based on the observation results.

3. The non-contact laser speckle vibration measurement method integrating transceiver as described in claim 1, characterized in that, The photoelectric detection unit is a photodiode.

4. The non-contact laser speckle vibration measurement method integrating transceiver as described in claim 1, characterized in that, The image detection unit is an area array image sensor.

5. The non-contact laser speckle vibration measurement method integrating transceiver as described in claim 1, characterized in that, The light spot control module includes a set of combined lenses, which includes an input lens and an output lens arranged sequentially along the light transmission direction, and the input lens and the output lens have different focal lengths.

6. The non-contact laser speckle vibration measurement method integrating transceiver as described in claim 1, characterized in that, The light source is a laser.

Images