CN116818081A - Transmit-receive integrated non-contact laser speckle vibration measurement system and method - Google Patents

Abstract

The invention discloses a receiving and transmitting integrated non-contact laser speckle vibration measurement system, which comprises: the device comprises a light source, a light spot control module, a first beam splitter, a light absorber, a narrow-band filter, an imaging lens, a second beam splitter and a light detection module; the light source, the light spot control module and the first beam splitter are sequentially arranged along the light transmission direction, and an initial light beam emitted from the light source enters the first beam splitter through the light spot control module; the first beam splitter splits the received initial beam into two beams, one beam enters the light absorber; the other beam of light irradiates the measured object through the narrow-band filter, and the speckle beam generated by diffuse reflection of the measured object returns to the first beam splitter through the narrow-band filter; the speckle light beam received by the first beam splitter enters the second beam splitter through the imaging lens; the speckle light beam received by the second beam splitter enters the light detection module for detection. The invention also discloses a receiving and transmitting integrated non-contact laser speckle vibration measurement method, which improves the accuracy and reliability of measurement.

Description

Transmit-receive integrated non-contact laser speckle vibration measurement system and method

Technical Field

The invention relates to the technical field of laser speckle vibration measurement, in particular to a transceiver integrated non-contact laser speckle vibration measurement system and method.

Background

The micro-vibration measurement based on laser speckle is a recently-occurring new way of micro-vibration measurement which is different from the traditional laser Doppler and interference, has the advantages of simple system, easy operation, non-contact with the measured object and the like, and the speckle pattern caused by laser irradiation on the measured object is basically unchanged, and when the measured object is far away from a detection system, the change of the speckle caused by vibration is usually reflected as the translation of the speckle pattern of an observation plane.

The non-contact fixed point measurement of the micro vibration of the remote diffuse reflection non-cooperative target by utilizing the laser has very important application significance in the fields of bridge and building health detection, security and protection systems, investigation, anti-terrorism, disaster search and rescue and the like.

In the prior art, the speckle light beams used for transmitting the light source to the measured object and receiving the diffuse reflection of the measured object are realized by adopting different components, and because the receiving light path and the transmitting light path of the measured object are separated, when tiny variation occurs in the measuring process, the transmitting light path and the receiving light path cannot change towards a trend at the same time, thus influencing the signal receiving of the detecting end and the accuracy and the reliability of the measurement.

Disclosure of Invention

In view of the above, the present invention aims to provide a transceiver-integrated non-contact laser speckle vibration measurement system, which adopts a transceiver-integrated optical path structure to detect, and when a tiny variation occurs in the measurement process, the transmitting and receiving optical paths can change towards a trend at the same time, so that the signal receiving of the detection end is not affected, the problems of unstable optical path and error accumulation are avoided, and the photoelectric detection unit and the image detection unit are combined at the receiving end to fuse the data, thereby improving the accuracy and reliability of the measurement.

In order to achieve the technical purpose, the invention adopts the following technical scheme:

the invention provides a receiving and transmitting integrated non-contact laser speckle vibration measurement system, which comprises: the device comprises a light source, a light spot control module, a first beam splitter, a light absorber, a narrow-band filter, an imaging lens, a second beam splitter and a light detection module;

the light source, the light spot control module and the first beam splitter are sequentially arranged along the light transmission direction, and an initial light beam emitted from the light source enters the first beam splitter through the light spot control module;

the first beam splitter splits the received initial beam into two beams, wherein one beam enters the light absorber; the other beam of light irradiates on the measured object through the narrow-band filter, and the speckle beam generated by diffuse reflection of the measured object returns to the first beam splitter through the narrow-band filter;

the speckle light beam received by the first beam splitter enters the second beam splitter through the imaging lens;

and the speckle light beam received by the second beam splitter enters the light detection module for detection.

Further, the light detection module comprises a photoelectric detection unit and an image detection unit, and the second beam splitter splits the received speckle light beam into two beams, wherein one beam of light enters the photoelectric detection unit to detect the luminous flux change caused by the vibration of the detected object; the other beam of light enters the image detection unit to display the spatial speckle image.

Further, the photoelectric detection unit is a PD detector, a photodiode, an avalanche diode or a photomultiplier.

Further, the image detection unit is a CCD detector, an area array image sensor or an array detector.

Further, the spot control module comprises a group of combined lenses, wherein the combined lenses comprise an input lens and an output lens which are sequentially arranged along the light transmission direction, and the input lens and the output lens have different focal lengths.

Further, the light source is a laser.

The invention also provides a receiving and transmitting integrated non-contact laser speckle vibration measurement method, which needs to provide the receiving and transmitting integrated non-contact laser speckle vibration measurement system as set forth in claim 2, comprising the following steps:

step 1, an initial beam emitted by the light source passes through a light spot control module and is irradiated onto a measured object by one beam of light after being split by a first beam splitter; the speckle light beam generated by the measured object returns through the first beam splitter and is respectively transmitted to the photoelectric detection unit and the image detection unit for detection through the second beam splitter;

step 2, the photoelectric detection unit and the image detection unit process the speckle light beam to obtain detection information;

and step 3, calculating a signal-to-noise ratio according to the detection information, and judging whether readjusting the speckle light beam is needed according to the signal-to-noise ratio.

Further, the step 1 specifically includes:

step 11, transmitting an initial light beam emitted by the light source to a light spot control module, adjusting the light spot size of the initial light beam by the light spot control module, and then entering a first beam splitter;

step 12, the first beam splitter splits the adjusted initial beam into two beams, wherein one beam is absorbed by the light absorber, and the other beam is irradiated to the object to be measured after the stray light is filtered by the narrow-band filter;

step 13, generating a speckle beam by the diffuse reflection phenomenon of the object to be measured after being illuminated, filtering stray light by the speckle beam through a narrow-band filter, and returning the stray light to the first beam splitter;

step 14, the first beam splitter transmits the speckle light beam to an imaging lens, the imaging lens focuses and transforms the speckle light beam, and the transformed speckle light beam enters a second beam splitter;

step 15, the second beam splitter splits the converted speckle light beam into two beams, wherein one beam enters a photoelectric detection unit for processing; the other beam of light enters the image detection unit for processing.

Further, the step 2 specifically includes:

step 21, the photoelectric detection unit detects the luminous flux change caused by the vibration of the detected object according to the received speckle light beam, converts the luminous flux change into the change of photocurrent, and calculates the photoelectric micro-vibration information of the detected object;

step 22, the image detection unit collects the received speckle light beam, converts the speckle light beam into a space speckle image for display, and inputs the space speckle image into a computer for analysis and processing to obtain image micro-vibration information;

and step 23, carrying out fusion processing on the photoelectric micro-vibration information and the image micro-vibration information to obtain detection information.

Further, the step 3 specifically includes:

step 31, calculating a signal-to-noise ratio according to the detection information, judging whether the signal-to-noise ratio is lower than a preset threshold value, if so, entering step 32; otherwise, not processing;

step 32, adjusting the distance between the input lens and the output lens of the combined lens in the light spot control module to readjust the light spot size of the initial light beam; and/or adjusting the distance between the imaging lens and the object to be detected to carry out focusing transformation adjustment on the speckle light beam again.

And step 33, in the adjusting process, observing through the space speckle image displayed by the image detection unit, and correspondingly adjusting through an observation result.

By adopting the technical scheme, compared with the prior art, the invention has the beneficial effects that:

1. through the integrative light path structural design of receiving and dispatching, can avoid light path unstable, error accumulation scheduling problem, under the integrative circumstances of receiving and dispatching, even when minute change appears in the measurement process, the transmission can change simultaneously to a trend with the receiving light path, can not influence the signal reception of detecting the end, has improved measuring accuracy and reliability.

2. The image detection unit and the light spot control module perform cooperative feedback, so that visual control of the size of speckle particles in the detection process can be realized.

3. The image detection unit is combined with the photoelectric detection unit, so that the visual alignment of the detected object and the laser speckle can be realized, and 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, thereby improving the vibration measurement precision.

4. Adapt to different environments: the stability of the light path is improved, so that the light path can adapt to more severe environmental conditions such as temperature, humidity and the like.

5. Signal loss is reduced: because the signal does not need to pass through a long transmission path, the signal attenuation and loss can be reduced, and the strength and quality of the signal can be improved.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a transceiver-integrated non-contact laser speckle vibration measurement system provided by the invention.

Fig. 2 is a flowchart of an implementation of a transceiver-integrated non-contact laser speckle vibration measurement method provided by the invention.

The reference numerals in the figures illustrate:

the device comprises a light source 1, a light spot control module 2, an input lens 21, an output lens 22, a first beam splitter 3, a light absorber 4, a narrow-band filter 5, an imaging lens 6, a second beam splitter 7, a light detection module 8, a photoelectric detection unit 81, an image detection unit 82 and an object 9 to be detected.

Detailed Description

The invention is described in further detail below with reference to the drawings and examples. It is specifically noted that the following examples are only for illustrating the present invention, but do not limit the scope of the present invention. Likewise, the following examples are only some, but not all, of the examples of the present invention, and all other examples, which a person of ordinary skill in the art would obtain without making any inventive effort, are within the scope of the present invention.

Referring to fig. 1, the present invention provides a transceiver-integrated non-contact laser speckle vibration measurement system, comprising: the device comprises a light source 1, a light spot control module 2, a first beam splitter 3, a light absorber 4, a narrow-band filter 5, an imaging lens 6, a second beam splitter 7 and a light detection module 8;

the light source 1, the light spot control module 2 and the first beam splitter 3 are sequentially arranged along the light transmission direction, and an initial light beam emitted from the light source 1 enters the first beam splitter 3 through the light spot control module 2;

the first beam splitter 3 splits the received initial light beam into two beams, wherein one beam enters the light absorber 4; the other beam irradiates the measured object 9, and the speckle beam generated by diffuse reflection of the measured object 9 returns to the first beam splitter 3 through the narrow-band filter 5;

the speckle light beam received by the first beam splitter 3 enters a second beam splitter 7 through an imaging lens 6;

the speckle light beam received by the second beam splitter 7 enters the light detection module 8 for detection.

The functions of the components are as follows:

the light source 1 has the functions of: providing an irradiation beam to irradiate the object 9 to be measured for measurement;

the light spot control module 2 has the functions of: receiving the light beam sent by the light source, and controlling the light spot size when the light beam is output, so as to control the light spot size irradiated on the measured object 9;

the first beam splitter 3 has the following functions: splitting light beams emitted by the light source to form different light paths and transmitting the different light paths to the light absorber 4 and the measured object 9; at the same time, receiving a speckle beam generated by the object 9 to be measured; namely, the first beam splitter 3 can realize that light irradiates the measured object 9 and a speckle light beam loop generated after the irradiation of the measured object 9 form a light path structure integrating receiving and transmitting, under the condition of the integration of receiving and transmitting, even if tiny variation occurs in the measuring process, the transmitting and receiving light paths can change towards a trend at the same time, the signal receiving of a detecting end is not influenced, and the measuring accuracy and reliability are improved;

the light absorber 4 functions as: absorbing one path of stray light split from the first beam splitter 3 to prevent the stray light from interfering;

the function of the narrowband filter 5 is: the returned light beam is filtered, the ambient stray light is filtered, and the signal to noise ratio of the measuring system is increased;

the imaging lens 6 functions as: for focusing the returned speckle beam

The second beam splitter 7 has the following functions: carrying out beam splitting treatment on the received speckle beam, and dividing the received speckle beam into two paths of detection;

the function of the light detection module 8 is: the speckle beam generated by the diffuse reflection of the object 9 is received, and the signal is output to the microcomputer for processing.

Preferably, the light detection module 8 includes a photo detection unit 81 and an image detection unit 82, and the second beam splitter 7 splits the received speckle beam into two beams, wherein one beam enters the photo detection unit 81 to detect the light flux change caused by vibration of the measured object; the other beam of light enters the image detection unit 82 to display a spatially speckle image.

The invention realizes two paths of receiving through the second beam splitter 7, and one path of receiving unit 82 is used for receiving speckles generated by diffuse reflection of the light beam through the measured object 9, forming speckle images and inputting video into a computer for algorithm processing to obtain micro-vibration information, so as to realize real-time high-sensitivity and high-precision measurement of micro-vibration; the other route of the photoelectric detection unit 81 receives the change of the real-time detection speckle luminous flux, thereby causing the change of the photocurrent, and the micro-vibration signal of the measured object 9 is obtained through the calculation processing of the photocurrent. The invention combines the image detection unit 82 and the photoelectric detection unit 81 at the same time, can realize the visual alignment of the measured object 9 and the laser speckle, and fuses 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, thereby improving the vibration measurement precision.

Preferably, the photo-detection unit 81 is a PD detector, a photodiode, an avalanche diode or a photomultiplier tube.

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

Preferably, embodiment one:

the spot control module 2 comprises a set of combined lenses comprising an input lens 21 and an output lens 22 arranged in sequence in the light transmission direction, the input lens 21 and the output lens 22 having different focal lengths.

Preferably, the light source 1 is a laser.

As shown in fig. 2, the present invention further provides a method for measuring a transceiver-integrated non-contact laser speckle vibration, which needs to provide the transceiver-integrated non-contact laser speckle vibration measuring system, comprising the following steps:

step 1, an initial beam emitted by the light source 1 passes through the light spot control module 2 and is split by the first beam splitter 3, and then a beam of light irradiates the object 9 to be measured; the speckle light beam generated by the object 9 to be detected returns through the first beam splitter 3, and is transmitted to the photoelectric detection unit 81 and the image detection unit 82 for detection through the second beam splitter 7;

in this embodiment, before the step 1, the method further includes: the light source 1, the light absorber 4 and the light detection module 8 are turned on.

In this embodiment, the step 1 specifically includes:

step 11, transmitting the initial light beam emitted by the light source 1 to the light spot control module 2, adjusting the light spot size of the initial light beam by the light spot control module 2, and then entering the first beam splitter 3;

step 12, the first beam splitter 3 splits the adjusted initial beam into two beams, wherein one beam is absorbed by the light absorber 4, and the other beam is irradiated to the measured object 9 after the stray light is filtered by the narrow-band filter 5;

step 13, after the object 9 to be measured is illuminated, the diffuse reflection phenomenon occurs to generate a speckle beam, and the speckle beam is filtered by the narrow-band filter 5 to remove stray light and then returned to the first beam splitter 3;

step 14, the first beam splitter 3 transmits the speckle light beam to the imaging lens 6, the imaging lens 6 focuses and transforms the speckle light beam, and the transformed speckle light beam enters the second beam splitter 7;

step 15, the second beam splitter 7 splits the transformed speckle beam into two beams, wherein one beam enters the photoelectric detection unit 81 for processing; the other beam of light enters the image detection unit 82 for processing. The first beam splitter 3 can realize that light irradiates the measured object 9 and a speckle light beam loop generated after the measured object 9 irradiates, so as to form a light path structure integrating receiving and transmitting, and under the condition of the integration of receiving and transmitting, even if tiny variation occurs in the measuring process, the transmitting and receiving light paths can change towards a trend at the same time, the signal receiving of a detecting end is not influenced, and the measuring accuracy and reliability are improved.

Step 2, the photoelectric detection unit 81 and the image detection unit 82 process the speckle light beam to obtain detection information;

in this embodiment, the step 2 specifically includes:

step 21, the photoelectric detection unit 81 detects the light flux change caused by the vibration of the detected object 9 according to the received third light beam, converts the light flux change into the change of photocurrent, and calculates the photoelectric micro-vibration information of the detected object 9;

step 22, the image detection unit 82 collects the received speckle light beam, converts the speckle light beam into a space speckle image for display, and inputs the space speckle image into a computer for analysis and processing to obtain image micro-vibration information; the signal processing can be carried out by adopting a gray value method, a method of calculating a cross correlation coefficient and the like;

step 23, carrying out fusion processing on the photoelectric micro-vibration information and the image micro-vibration information to obtain detection information; the vibration measuring precision and efficiency can be improved. The image detection unit and the light spot control module are adopted to carry out cooperative feedback, so that the visual control of the size of speckle particles in the detection process can be realized.

And step 3, calculating a signal-to-noise ratio according to the detection information, and judging whether readjusting the speckle light beam is needed according to the signal-to-noise ratio.

In this embodiment, the step 3 specifically includes:

step 31, calculating a signal-to-noise ratio according to the detection information, judging whether the signal-to-noise ratio is lower than a preset threshold value, if so, entering step 42; otherwise, not processing; and calculating the signal-to-noise ratio after the photoelectric micro-vibration information and the image micro-vibration information are fused, and if the photoelectric micro-vibration information and the image micro-vibration information are closer, the signal-to-noise ratio is higher, so that the optical path design is reasonable.

Step 32, adjusting 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, wherein one group of combined lenses is used as a beam expanding (beam shrinking) system for expanding (shrinking) the diameter of the collimated input beam in proportion; and/or adjusting the distance between the imaging lens 6 and the measured object 9, and adjusting the parameters of the imaging lens 6 to re-perform focusing transformation adjustment on the speckle light beam.

In the adjusting process, the space speckle image displayed by the image detecting unit 82 is observed, and the corresponding adjustment is performed according to the observation result, so as to change the focusing transformation of the speckle beam, and adjust the spot control module 2 in real time, so as to achieve a proper spot size, and facilitate detection, thereby improving the measurement accuracy. The image detection unit is combined with the photoelectric detection unit, so that the visual alignment of the detected object and the laser speckle can be realized, and 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, thereby improving the vibration measurement precision.

The foregoing description is only a partial embodiment of the present invention, and is not intended to limit the scope of the present invention, and all equivalent devices or equivalent processes using the descriptions and the drawings of the present invention or directly or indirectly applied to other related technical fields are included in the scope of the present invention.

Claims (10)

1. A transceiver-integrated non-contact laser speckle vibration measurement system, comprising: the device comprises a light source, a light spot control module, a first beam splitter, a light absorber, a narrow-band filter, an imaging lens, a second beam splitter and a light detection module;

the light source, the light spot control module and the first beam splitter are sequentially arranged along the light transmission direction, and an initial light beam emitted from the light source enters the first beam splitter through the light spot control module;

the first beam splitter splits the received initial beam into two beams, wherein one beam enters the light absorber; the other beam of light irradiates on the measured object through the narrow-band filter, and the speckle beam generated by diffuse reflection of the measured object returns to the first beam splitter through the narrow-band filter;

the speckle light beam received by the first beam splitter enters the second beam splitter through the imaging lens;

and the speckle light beam received by the second beam splitter enters the light detection module for detection.

2. The integrated transceiver non-contact laser speckle vibration measurement system of claim 1, wherein the optical detection module comprises a photoelectric detection unit and an image detection unit, the second beam splitter splits the received speckle beam into two beams, and one beam enters the photoelectric detection unit to detect the luminous flux change caused by vibration of the measured object; the other beam of light enters the image detection unit to display the spatial speckle image.

3. The transceiver-integrated non-contact laser speckle vibration measurement system of claim 2, wherein the photo detection unit is a PD detector, a photodiode, an avalanche diode, or a photomultiplier tube.

4. The transceiver-integrated non-contact laser speckle vibration measurement system of claim 2, wherein the image detection unit is a CCD detector, an area array image sensor, or an array detector.

5. The integrated transceiver-non-contact laser speckle vibration measurement system of claim 1, wherein the spot control module comprises a set of combined lenses comprising an input lens and an output lens disposed sequentially along the optical transmission direction, the input lens and the output lens having different focal lengths.

6. A transceiver-integrated non-contact laser speckle vibration measurement system as set forth in claim 1, wherein said light source is a laser.

7. A method for measuring the vibration of a transceiver-integrated non-contact laser speckle, which is characterized in that the method is to provide a transceiver-integrated non-contact laser speckle vibration measuring system as claimed in claim 2, comprising the following steps:

step 1, an initial beam emitted by the light source passes through a light spot control module and is irradiated onto a measured object by one beam of light after being split by a first beam splitter; the speckle light beam generated by the measured object returns through the first beam splitter and is respectively transmitted to the photoelectric detection unit and the image detection unit for detection through the second beam splitter;

step 2, the photoelectric detection unit and the image detection unit process the speckle light beam to obtain detection information;

and step 3, calculating a signal-to-noise ratio according to the detection information, and judging whether readjusting the speckle light beam is needed according to the signal-to-noise ratio.

8. The method for measuring the vibration of the integrated transceiver non-contact laser speckle as set forth in claim 7, wherein the step 1 specifically includes:

step 11, transmitting an initial light beam emitted by the light source to a light spot control module, adjusting the light spot size of the initial light beam by the light spot control module, and then entering a first beam splitter;

step 12, the first beam splitter splits the adjusted initial beam into two beams, wherein one beam is absorbed by the light absorber, and the other beam is irradiated to the object to be measured after the stray light is filtered by the narrow-band filter;

step 13, generating a speckle beam by the diffuse reflection phenomenon of the object to be measured after being illuminated, filtering stray light by the speckle beam through a narrow-band filter, and returning the stray light to the first beam splitter;

step 14, the first beam splitter transmits the speckle light beam to an imaging lens, the imaging lens focuses and transforms the speckle light beam, and the transformed speckle light beam enters a second beam splitter;

step 15, the second beam splitter splits the converted speckle light beam into two beams, wherein one beam enters a photoelectric detection unit for processing; the other beam of light enters the image detection unit for processing.

9. The method for measuring the vibration of the integrated transceiver non-contact laser speckle as set forth in claim 8, wherein the step 2 specifically includes:

step 21, the photoelectric detection unit detects the luminous flux change caused by the vibration of the detected object according to the received speckle light beam, converts the luminous flux change into the change of photocurrent, and calculates the photoelectric micro-vibration information of the detected object;

step 22, the image detection unit collects the received speckle light beam, converts the speckle light beam into a space speckle image for display, and inputs the space speckle image into a computer for analysis and processing to obtain image micro-vibration information;

and step 23, carrying out fusion processing on the photoelectric micro-vibration information and the image micro-vibration information to obtain detection information.

10. The method for measuring the vibration of the integrated transceiver non-contact laser speckle as set forth in claim 7, wherein the step 3 specifically includes:

step 31, calculating a signal-to-noise ratio according to the detection information, judging whether the signal-to-noise ratio is lower than a preset threshold value, if so, entering step 32; otherwise, not processing;

step 32, adjusting the distance between the input lens and the output lens of the combined lens in the light spot control module to readjust the light spot size of the initial light beam; and/or adjusting the distance between the imaging lens and the object to be detected to carry out focusing transformation adjustment on the speckle light beam again.

And step 33, in the adjusting process, observing through the space speckle image displayed by the image detection unit, and correspondingly adjusting through an observation result.