CN117190905A

CN117190905A - Laser detection sensor and control method thereof

Info

Publication number: CN117190905A
Application number: CN202311177699.4A
Authority: CN
Inventors: 王威; 姚文政
Original assignee: Phoskey Shenzhen Precision Technology Co ltd
Current assignee: Phoskey Shenzhen Precision Technology Co ltd
Priority date: 2023-09-12
Filing date: 2023-09-12
Publication date: 2023-12-08

Abstract

The application discloses a laser detection sensor and a control method thereof. Wherein, laser detection sensor includes: the device comprises a laser light source, a light path adjusting module, a photosensitive imaging module and a control module; the laser light source is used for emitting laser beams; the light path adjusting module comprises a rotatable reflecting structure and a telecentric optical assembly; the rotatable reflection structure is used for rotating according to a control signal output by the control module so as to modulate the laser beam; the telecentric optical assembly is used for adjusting the laser beam reflected by the rotatable reflection structure into a parallel laser beam. According to the technical scheme, the reflecting surface of the rotatable reflecting structure is utilized to continuously reflect the laser beam and sequentially pass through the telecentric optical assembly and the object to be detected to form the edge photosensitive image on the photosensitive imaging module, so that the speckles of the single-frame or multi-frame edge photosensitive image acquired by the photosensitive imaging module are restrained in the exposure time, and the accuracy of the laser detection sensor is improved.

Description

Laser detection sensor and control method thereof

Technical Field

The application relates to the technical field of high-precision detection, in particular to a laser detection sensor and a control method thereof.

Background

At present, a laser detection sensor mainly irradiates the surface of a detected object with laser beams emitted by a laser diode, and the laser beams which are not blocked by the surface of the detected object are projected onto a photosensitive element matrix. And calculating the shape of the object to be measured according to the photosensitive image on the photosensitive element matrix.

In the technology, the actual shape of an object to be measured is determined by a photosensitive image, so that the measurement accuracy is greatly influenced by the quality of the photosensitive image. However, because the laser is a coherent light source, the laser speckle effect is inevitably brought, that is, when the coherent light irradiates the measured object, different optical path differences are caused by reflection or scattering of the incident coherent light by different surface elements, and the reflected or scattered light waves generate interference phenomena when meeting in space, so that spots with random and irregular light intensity distribution can be formed on the surface of the measured object. The laser speckle effect can cause deformation of the photosensitive image, thereby affecting the measurement accuracy of the laser detection sensor.

Disclosure of Invention

The application provides a laser detection sensor and a control method thereof, which aim to solve the problem of low measurement precision of the laser detection sensor caused by a laser speckle effect.

According to an aspect of the present application, there is provided a laser detection sensor including:

the device comprises a laser light source, a light path adjusting module, a photosensitive imaging module and a control module;

the laser light source is used for emitting laser beams;

the light path adjusting module comprises a rotatable reflecting structure and a telecentric optical assembly; the rotatable reflection structure is positioned on the propagation path of the laser beam and is in communication connection with the control module, and is used for rotating according to a control signal output by the control module so as to modulate the laser beam;

the telecentric optical assembly is arranged in the optical path between the rotatable reflection structure and the object to be measured and is used for adjusting the laser beam reflected by the rotatable reflection structure into a parallel laser beam;

the photosensitive imaging module is arranged on the propagation path of the parallel laser beam and is used for receiving the parallel laser beam which is not blocked by the object to be detected and obtaining an edge photosensitive image of the object to be detected according to the parallel laser beam;

the control module is connected with the photosensitive imaging module and is used for determining the shape of the object to be detected according to the light spots of the edge photosensitive image.

Optionally, the telecentric optical assembly comprises at least one lens having optical power.

Optionally, the rotatable reflective structure comprises a rotational drive assembly and a rotatable reflector;

the rotary driving assembly is respectively in communication connection with the control module and the rotatable reflector and is used for controlling the rotatable reflector to rotate according to a control signal of the control module.

Optionally, the rotatable reflector comprises a cylindrical reflector or an N-plane cylindrical reflector, N is more than or equal to 6, and N is an integer;

the cylindrical reflector and the N-plane cylindrical reflector are rotatable about the center of the rotatable reflector.

Alternatively, the rotational drive assembly comprises a microelectromechanical system or a mechanical motor.

Optionally, the reflective surface of the rotatable reflective structure comprises a plurality of reflective particles or a plurality of microlenses.

Optionally, the photosensitive imaging module comprises an imaging lens and a photosensitive element; the imaging lens and the photosensitive element are sequentially positioned on the propagation path of the parallel laser beam after passing through the object to be detected;

the imaging lens is used for receiving the parallel laser beams which are not shielded by the object to be detected and projecting the parallel laser beams onto the photosensitive element;

the photosensitive element is used for receiving the parallel laser beams and obtaining an edge photosensitive image of the object to be detected according to the parallel laser beams.

Optionally, the control module includes a driving circuit and an information processor;

the driving circuit is in communication connection with the rotatable reflecting structure and is used for outputting a control signal to the rotatable reflecting structure to control the rotatable reflecting structure to rotate;

the information processor is in communication connection with the photosensitive element and is used for determining the shape of the object to be detected according to the edge photosensitive image.

According to another aspect of the present application, there is provided a control method of a laser detection sensor for controlling the laser detection sensor, the control method including:

the output control signal controls the rotatable reflecting structure to rotate so as to switch different reflecting surfaces, and the laser beam is modulated by utilizing the reflection, so that the modulated laser beam is modulated again by the telecentric optical assembly to form a parallel laser beam;

acquiring an edge photosensitive image of a parallel laser beam which is not shielded by an object to be detected in a photosensitive element;

and determining the shape of the object to be detected according to the edge photosensitive image.

Optionally, determining the shape of the object to be measured according to the edge sensitive image includes:

and determining the shape of the object to be detected according to the single-frame or multi-frame edge photosensitive image.

According to the technical scheme, the rotatable reflecting structure and the telecentric optical assembly are arranged in the laser detection sensor, the reflecting surface of the rotatable reflecting structure is utilized to continuously reflect laser beams and sequentially pass through the telecentric optical assembly and an object to be detected to form an edge photosensitive image on the photosensitive imaging module in the exposure time of the photosensitive imaging module, the parallel laser beams irradiate on the photosensitive imaging module at different moments in the exposure time of the image, speckle characteristics of the speckle particles are different and random, smoothing of the speckle particles is achieved, uniform light treatment of detection laser is achieved, speckle influence can be eliminated or inhibited through superposition treatment of a plurality of edge photosensitive images acquired based on the speckle characteristics of the speckle, and then edge contours of the object to be detected after speckle inhibition can be obtained, and detection precision of the laser detection sensor is improved.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the application or to delineate the scope of the application. Other features of the present application will become apparent from the description that follows.

Drawings

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

FIG. 1 is a schematic view of the optical principle of a first laser detection sensor according to an embodiment of the present application;

FIG. 2 is a schematic diagram of the optical principle of a second laser detection sensor according to an embodiment of the present application;

FIG. 3 is a flowchart of a control method of a first laser detection sensor according to an embodiment of the present application;

fig. 4 is a flowchart of a control method of a second laser detection sensor according to an embodiment of the present application.

Detailed Description

In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, shall fall within the scope of the present application.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the application described herein may be implemented in sequences other than those illustrated or otherwise described herein.

Fig. 1 is a schematic optical principle diagram of a first laser detection sensor according to an embodiment of the present application, where, as shown in fig. 1, the laser detection sensor includes:

the device comprises a laser light source 1, a light path adjusting module 2, a photosensitive imaging module 3 and a control module 4;

the laser light source 1 is used for emitting laser beams;

the optical path adjustment module 2 includes a rotatable reflecting structure 21 and a telecentric optical assembly 22; the rotatable reflection structure 21 is located on the propagation path of the laser beam and is in communication connection with the control module 4, and is used for rotating according to the control signal output by the control module 4 so as to modulate the laser beam;

a telecentric optical assembly 22 is disposed in the optical path between the rotatable reflection structure 21 and the object 5 to be measured, for adjusting the laser beam reflected by the rotatable reflection structure 21 into a parallel laser beam;

the photosensitive imaging module 3 is arranged on the propagation path of the parallel laser beam and is used for receiving the parallel laser beam which is not blocked by the object 5 to be detected and obtaining an edge photosensitive image of the object 5 to be detected according to the parallel laser beam;

the control module 4 is connected with the photosensitive imaging module 3 and is used for determining the shape of the object 5 to be detected according to the light spots of the edge photosensitive image.

The laser light source 1 may be a semiconductor laser, and the semiconductor laser emits a laser beam. By way of example, a semiconductor laser in the visible light band, such as a 760mm red semiconductor laser, has the advantages of good monochromaticity, high brightness, and the like.

The optical path adjusting module 2 may be used to adjust a propagation path of the laser beam, where the optical path adjusting module 2 includes a rotatable reflecting structure 21 and a telecentric optical assembly 22, and the rotatable reflecting structure 21 and the telecentric optical assembly 22 are sequentially disposed on the propagation path of the laser beam. The rotatable reflective structure 21 may comprise a reflective surface and the control module 4 controls the rotation of the rotatable reflective structure 21 such that the laser beam is reflected at different positions of the reflective surface. For example, the rotatable reflecting structure 21 may be a cylinder rotating at a preset angular velocity, and the sidewall of the cylinder is a torus reflecting surface, when the cylinder rotates at the preset angular velocity, the laser beam is incident on different positions of the torus reflecting surface within a preset time, and is reflected at different positions of the torus reflecting surface, so as to modulate the laser beam. It can be appreciated that the modulation principle of the laser beam is as follows: in consideration of the process errors of the rotatable reflecting structure 21, in practical applications, it is difficult to make the different positions of the toroidal reflecting surface identical, so there are fine differences on the surfaces of the toroidal reflecting surface at the different reflecting positions, which are process errors, such as uneven surfaces of the toroidal reflecting surface, and coarse particles. Because the rotatable reflecting structure 21 rotates, laser beams sequentially pass through different reflecting positions of the annular reflecting surface and pass through the telecentric optical assembly 22 and the object 5 to be detected and then are imaged on the photosensitive imaging module 3 in continuous time, when slight differences exist in different reflecting positions of the annular reflecting surface, the speckle characteristics of light spots on the photosensitive imaging module 3 are different and random after the parallel laser beams pass through the object 5 to be detected in continuous time, so that the smoothing of speckle particles is realized, the uniform light treatment of the laser beams is realized, and the influence caused by the speckle can be eliminated or inhibited by the superposition treatment of single-frame or multi-frame edge photosensitive images acquired based on the light spots with different and random speckle characteristics.

The telecentric optical assembly 22 may be an optical lens combination disposed in a telecentric optical system, where the telecentric optical system refers to an optical system in which the principal ray is parallel to the principal optical axis. Where the chief ray is the centerline of the object ray that participates in the imaging. In some embodiments, telecentric optical assembly 22 includes at least one lens having optical power. The laser beam reflected by the rotatable reflecting structure 21 can be adjusted parallel to the main optical axis by means of a telecentric optical assembly 22. It can be understood that, in the embodiment of the present application, the purpose of the laser detection sensor is to detect the shape and the size of the object 5 to be detected, and the telecentric optical assembly 22 is used to adjust the laser beam to be parallel to the laser beam, so that the beam passing through the object 5 to be detected is parallel, and further, the single-frame or multi-frame edge photosensitive image obtained on the photosensitive imaging module 3 is an edge contour image of the object 5 to be detected along the direction of the parallel laser beam, and then the shape and the size of the object 5 to be detected are determined according to the edge contour image, so that the characteristic that the edge contour image represents the shape and the size of the object 5 to be detected is stronger, the accuracy is higher, and the detection accuracy of the laser detection sensor is improved.

In the photosensitive imaging exposure time of the photosensitive imaging module 3, the gray value of each pixel is the integral of the speckle characteristics of the edge photosensitive image at different moments, so that the single-frame or multi-frame edge photosensitive image actually collected in each exposure time of the photosensitive imaging module 3 is an image formed after speckle suppression.

The control module 4 extracts an edge photosensitive image obtained by the photosensitive imaging module 3, performs spot center calculation based on the edge photosensitive image after speckle suppression, determines an edge contour of the object 5 to be detected according to all spot centers on the edge photosensitive image, and determines a shape of the object 5 to be detected according to the edge contour. Wherein the shape of the object 5 to be measured includes all parameters characterizing the contour of the object 5 to be measured, such as shape and size.

Specifically, the control module 4 controls the rotatable reflection structure 21 to rotate, the laser beam is emitted from the laser light source 1 to different reflection positions of the rotatable reflection structure 21 and reflected at the different reflection positions, the reflected laser beam is adjusted to be parallel laser beam by the telecentric optical assembly 22, and the parallel laser beam forms an edge photosensitive image on the photosensitive imaging module 3 after passing through the object 5 to be detected. In the process, as the speckle characteristics of the light spots on the photosensitive imaging module 3 irradiated by the laser beams through the object 5 to be measured at different moments are different and random, the interference effect of the reflected or scattered light on the photosensitive imaging module 3 can be reduced, and the effect of inhibiting the laser speckle is achieved; in addition, after the rotatable reflection structure 21, a telecentric optical assembly 22 is added, all laser beams are adjusted to be parallel laser beams, so that the parallel laser beams are utilized to form single-frame or multi-frame edge photosensitive images passing through the object 5 to be detected while different and random speckle characteristics of the light spots on the photosensitive imaging module 3 are ensured, the formation of speckles in the edge photosensitive images is inhibited, and the accuracy of the control module 4 in determining the shape of the object 5 to be detected according to the light spots of the edge photosensitive images is improved.

According to the technical scheme, the rotatable reflecting structure and the telecentric optical assembly are arranged in the laser detection sensor, the reflecting surface of the rotatable reflecting structure is utilized to continuously reflect laser beams and sequentially pass through the telecentric optical assembly and an object to be detected to form an edge photosensitive image on the photosensitive imaging module in the exposure time of the photosensitive imaging module, and parallel laser beams at different moments are irradiated on the photosensitive imaging module in different and random speckle characteristics in the single-frame exposure time of the image, so that when the photosensitive imaging module acquires single-frame or multi-frame edge photosensitive images, speckle on the single-frame or multi-frame edge photosensitive images is restrained, the calculation precision of all light spot centers on the edge photosensitive images is improved, the smoothness of speckle particles is realized, and then the edge profile of the object to be detected after speckle restraint can be acquired according to all light spot centers, and the precision of the laser detection sensor is improved.

Optionally, with continued reference to FIG. 1, the rotatable reflective structure 21 includes a rotational drive assembly 211 and a rotatable reflector 212;

the rotary driving assembly 211 is respectively connected with the control module 4 and the rotatable reflector 212 in a communication manner, and is used for controlling the rotatable reflector 212 to rotate according to a control signal of the control module 4.

The rotation driving component 211 may be a central driving shaft of the rotatable reflector 212, and the control module 4 may control the driving shaft to rotate the rotatable reflector 212. In some embodiments, the rotational drive assembly 211 includes a Micro-Electro-Mechanical System (MEMS) or mechanical motor for the purpose of rotating the rotatable reflector 212.

Specifically, the control module 4 outputs a control signal to the rotation driving component 211, the rotation driving component 211 drives the rotatable reflector 212 to rotate at a preset angular speed, when laser beams are incident on the reflecting surface of the rotatable reflector 212 at different moments, reflection occurs at different positions of the reflecting surface, so that speckle characteristics on the photosensitive imaging module 3 are different and random in continuous time, smoothing of speckle particles and light homogenizing treatment of detection laser are achieved, and speckle effects can be eliminated or suppressed through superposition treatment of a plurality of edge photosensitive images acquired based on light spots with different and random speckle characteristics.

Optionally, FIG. 2 is a schematic diagram of an optical principle of a second laser detection sensor according to an embodiment of the present application, and referring to FIG. 1 and FIG. 2, the rotatable reflector 212 includes a cylindrical reflector or an N-plane cylindrical reflector, where N is greater than or equal to 6 and N is an integer;

the cylindrical reflector and the N-plane cylindrical reflector are rotatable about the center of the rotatable reflector 212.

As shown in fig. 1, the rotatable reflector 212 includes a cylindrical reflector, the cylindrical reflector includes an annular reflecting surface, the rotation driving assembly 211 may be disposed on a central axis of the cylindrical reflector, and when the rotation driving assembly 211 rotates at a preset angular velocity, the rotation driving assembly 211 drives the annular reflecting surface to rotate at the preset angular velocity. Specifically, taking the counterclockwise rotation of the cylindrical reflector as an example for illustration, the preset angular velocity ω may be a constant value or a variable value, which is not limited by the embodiment of the present application. The annular reflecting surface is positioned on the optical axis of the laser beam, when the laser beam is incident on the cylindrical reflector at different moments, reflection occurs at different positions of the annular reflecting surface respectively, and as the fine difference exists at different positions of the annular reflecting surface, the laser beam reflected at different positions has difference at the center position of a light spot of the photosensitive imaging module 3, so that speckle characteristics of the light spot formed by the laser beam at different moments are different and random, thereby eliminating or inhibiting speckle influence on an edge imaging image, and improving the detection precision of the laser detection sensor.

As shown in fig. 2, the rotatable reflector 212 includes an N-type cylindrical reflector, the N-type cylindrical reflector includes N reflecting surfaces, the rotation driving assembly 211 may be disposed on a central axis of the N-type cylindrical reflector, and when the rotation driving assembly 211 rotates at a preset angular velocity, the rotation driving assembly 211 drives the N reflecting surfaces to rotate at the preset angular velocity. Specifically, taking the counterclockwise rotation of the N-type cylindrical reflector as an example for explanation, the preset angular velocity ω may be a fixed value or a variable value, and the embodiment of the application is not limited, the N reflecting surfaces are sequentially located on the optical axis of the laser beam, when the laser beam is incident on the N-type cylindrical reflector at different times, the N-plane cylindrical reflector sequentially rotates N-1 times around the central axis of the N-plane cylindrical reflector in a rotation period, the laser beam sequentially enters different reflecting surfaces, and due to the fine difference of the surfaces of the reflecting surfaces, the laser beams reflected by the different reflecting surfaces have differences in the center positions of the light spots of the photosensitive imaging module 3, so that when the subsequent photosensitive imaging module 3 acquires the edge photosensitive images of a single frame or multiple frames, the speckle characteristics of the laser beam formed by the laser beam are different and the speckle characteristics of the outline of the object 5 to be measured are different at each edge photosensitive image, thereby eliminating or inhibiting the influence of the speckle in the edge photosensitive image.

It can be understood that the characteristics of speckle formed by laser beams at different moments are different and random when reflection occurs at different reflection positions due to process errors of the cylindrical reflector or the N-plane cylindrical reflector, and other reflector forms can be adopted in the embodiment of the application, so that the characteristics of speckle formed by laser beams are different and random.

Optionally, the reflective surface of the rotatable reflective structure comprises a plurality of reflective particles or a plurality of microlenses (not shown).

Specifically, in order to further improve the light homogenizing characteristic of the rotatable reflection structure, a plurality of uniformly distributed reflective particles or a plurality of uniformly distributed microlenses may be additionally arranged on the reflection surface of the rotatable reflection structure, the reflective particles may be metal ions or inorganic nonmetallic particles, the microlenses may be a microlens array with smaller size, and the like, and it is emphasized that the sizes of the reflective particles and the microlenses need to be controlled so as to slightly adjust the sizes of the reflective particles and the microlenses to irradiate the laser beam on the spot center position of the photosensitive imaging module.

Optionally, with continued reference to fig. 1, the photosensitive imaging module 3 includes an imaging lens 31 and a photosensitive element 32; the imaging lens 31 and the photosensitive element 32 are sequentially positioned on the propagation path of the parallel laser beam after passing through the object 5 to be measured;

the imaging lens 31 is used for receiving the parallel laser beams which are not blocked by the object 5 to be detected and projecting the parallel laser beams onto the photosensitive element 32;

the photosensitive element 32 is configured to receive the parallel laser beams and obtain an edge photosensitive image of the object 5 to be measured according to the parallel laser beams.

The imaging lens 31 and the photosensitive element 32 form an imaging system in the photosensitive imaging module 3, the imaging lens 31 is used for receiving parallel laser beams which are not blocked by the object 5 to be detected and projecting the parallel laser beams onto the photosensitive element 32, the photosensitive element 32 can adopt a high-width photosensitive matrix, and an edge photosensitive image of the object 5 to be detected can be obtained according to light spots of the parallel laser beams on the photosensitive matrix. For example, a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor or a CCD (charge coupled device, CCD) image sensor is employed.

In some embodiments, a photosensitive element 32 with a larger size can be used, and by increasing the photosensitive surface, more parallel laser beams which are not blocked by the object 5 to be detected are received, so as to generate an edge photosensitive image, improve the accuracy of shape detection of the object 5 to be detected, and improve the accuracy of measurement of the laser detection sensor.

Optionally, the control module includes a driving circuit and an information processor (not shown in the figure);

The driving circuit is in communication connection with the rotatable reflecting structure, outputs a control signal to the rotatable reflecting structure, and controls the rotatable reflecting structure to rotate; the information processor is in communication connection with the photosensitive element and is used for acquiring the centers of all light spots on the edge photosensitive image according to the edge photosensitive image, determining the edge contour of the object to be detected according to the centers of all light spots and further determining the shape of the object to be detected. The information processor can analyze and process the edge sensitive image, extract and calculate the centers of all light spots of the edge sensitive image, and has the functions of inhibiting laser speckle, mapping and outputting distance results and the like.

In summary, the laser detection sensor provided by the embodiment of the application has the advantages of compact structure, convenience for integration and mass production, and capability of inhibiting the laser speckle effect to accurately acquire the shape of an object to be detected, and greatly improves the measurement accuracy of the laser detection sensor by using the optical structure of the laser, the rotatable reflection structure, the telecentric optical assembly and the high-width photosensitive system.

Based on the same inventive concept, the embodiment of the present application further provides a control method of a laser detection sensor, and fig. 3 is a flowchart of a control method of a first laser detection sensor according to an embodiment of the present application, and in combination with fig. 1 and fig. 3, the control method is used for controlling the laser detection sensor, and the control method includes:

s10, outputting a control signal to control the rotatable reflecting structure to rotate so as to switch different reflecting surfaces, modulating the laser beam by utilizing the reflecting surface, and enabling the modulated laser beam to be modulated again by the telecentric optical assembly to form a parallel laser beam.

S11, acquiring an edge photosensitive image of the parallel laser beam which is not shielded by the object to be detected in the photosensitive element.

S12, determining the shape of the object to be detected according to the edge photosensitive image.

Specifically, the laser light source 1 emits a laser beam, the rotatable reflection structure 21 rotates anticlockwise at the angular velocity ω, after the laser beam is reflected by the reflection surface of the rotatable reflection structure 21 and continuously rotates, the laser beam is incident to the telecentric optical assembly 22, the telecentric optical assembly 22 adjusts the reflected laser beam into a parallel laser beam, the parallel laser beam forms an edge photosensitive image on the photosensitive imaging module 3 through the object to be detected 5, and due to process errors of different reflection positions of the reflection surface, the center position of a light spot of the laser beam on the photosensitive imaging module 3 is slightly changed after the laser beam is reflected by the continuously rotating reflection surface, in the exposure time of image acquisition, the speckle characteristics of the laser beam irradiated on the surface of the object to be detected 5 at different moments are different and random, and the parallel laser beam which is not blocked by the light spot speckle characteristics of the object to be detected 5 is received by the photosensitive imaging module 3 in the exposure time, so as to generate the edge photosensitive image of the object to be detected 5. It can be understood that the laser beam passing through the telecentric optical assembly 22 is adjusted into a parallel laser beam, after the parallel laser beam passes through the object 5 to be measured, due to the limitation of the shape of the object 5 to be measured, part of the parallel laser beam is blocked, the rest of the parallel laser beam is imaged in the photosensitive imaging module 3, the edge photosensitive image represents the outline of the object 5 to be measured, and the shape of the object 5 to be measured is judged according to the outline. In the practical application process, the technical scheme of the embodiment of the application can be used for measuring the size of the object 5 to be measured, such as parameters of inner diameter, outer diameter and the like. Further, when the subsequent photosensitive imaging module 3 acquires single-frame or multi-frame edge photosensitive images, in the continuous time corresponding to each frame, each frame of edge photosensitive image has light spots with different speckle characteristics and representing the outline of the object 5 to be detected, so that the influence caused by speckle in the edge photosensitive image is eliminated or inhibited, the imaging of the edge photosensitive image representing the outline of the object 5 to be detected is clearer due to the inhibition imaging of speckle, and the precision of the laser detection sensor is further improved.

According to the technical scheme, the rotatable reflecting structure and the telecentric optical assembly are arranged in the laser detection sensor, the reflecting surface of the rotatable reflecting structure is utilized to continuously reflect laser beams and sequentially pass through the telecentric optical assembly and an object to be detected to form an edge photosensitive image on the photosensitive imaging module in the exposure time of the photosensitive imaging module, and parallel laser beams at different moments are irradiated on the photosensitive imaging module in the single-frame or multi-frame exposure time of the image, so that the single-frame or multi-frame edge photosensitive image acquired by the photosensitive imaging module is an image formed after speckle suppression, the calculation precision of all the spot centers on the edge photosensitive image is improved, the smoothness of speckle particles is realized, the edge contour of the object to be detected after speckle suppression can be acquired according to all the spot centers, and the precision of the laser detection sensor is improved.

On the basis of the above embodiment, fig. 4 is a flowchart of a control method of a second laser detection sensor according to an embodiment of the present application, and in combination with fig. 1 and fig. 4, the control method includes:

s20, outputting a control signal to control the rotatable reflecting structure to rotate so as to switch different reflecting surfaces, modulating the laser beam by utilizing the reflecting surface, and enabling the modulated laser beam to be modulated again by the telecentric optical assembly to form a parallel laser beam.

S21, acquiring an edge photosensitive image of the parallel laser beam which is not shielded by the object to be detected in the photosensitive element.

S22, determining the shape of the object to be detected according to the single-frame or multi-frame edge photosensitive image.

The gray value of each pixel in the single-frame or multi-frame edge photosensitive image is the integral of the speckle characteristic of the parallel laser beam on the photosensitive imaging module 3 at different moments, so that the data quantity and the randomness of the data statistics of the single-frame or multi-frame photosensitive image are increased.

Specifically, when the shape of the object 5 to be measured is determined according to the single-frame edge photosensitive image, the control module 4 is used for extracting and calculating the pixel gray value of the single-frame edge photosensitive image, and determining the edge contour of the object 5 to be measured according to the size of the pixel gray value.

Specifically, when determining the shape of the object 5 to be measured according to the multi-frame edge photosensitive image, the control module 4 obtains the multi-frame edge photosensitive image, performs statistics and superposition on gray data of the multi-frame edge photosensitive image to obtain a superposition mean value of the superimposed gray data, namely, speckle data after speckle suppression and speckle suppressed speckle images, and confirms the edge contour of the object 5 to be measured through the superimposed speckle images

Because the laser beams passing through a plurality of different reflection positions can inhibit the laser speckle effect caused by the fixed light source, in the exposure time, each frame of edge photosensitive image has light spots with different speckle characteristics in the continuous time corresponding to each frame, the gray data of the edge photosensitive image is further overlapped and averaged, the data volume of single frame photosensitive image data is increased, the laser speckle is further inhibited, the light spot center calculation precision of the single frame photosensitive image is improved, and finally the measurement precision is improved.

It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present application may be performed in parallel, sequentially, or in a different order, so long as the desired results of the technical solution of the present application are achieved, and the present application is not limited herein.

The above embodiments do not limit the scope of the present application. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of the present application.

Claims

1. A laser detection sensor, comprising:

the laser light source is used for emitting laser beams;

the optical path adjusting module comprises a rotatable reflecting structure and a telecentric optical assembly; the rotatable reflection structure is positioned on the propagation path of the laser beam and is in communication connection with the control module, and is used for rotating according to a control signal output by the control module so as to modulate the laser beam;

the telecentric optical assembly is arranged in an optical path between the rotatable reflection structure and the object to be measured and is used for adjusting the laser beam reflected by the rotatable reflection structure into a parallel laser beam;

2. The laser detection sensor of claim 1, wherein the telecentric optical assembly comprises at least one lens having optical power.

3. The laser detection sensor of claim 1, wherein the rotatable reflective structure comprises a rotational drive assembly and a rotatable reflector;

4. The laser detection sensor of claim 3, wherein the rotatable reflector comprises a cylindrical reflector or an N-sided cylindrical reflector, N being greater than or equal to 6 and N being an integer;

the cylindrical reflector and the N-plane cylindrical reflector are rotatable about a center of the rotatable reflector.

5. A laser detection sensor as claimed in claim 3 wherein the rotational drive assembly comprises a microelectromechanical system or a mechanical motor.

6. The laser detection sensor of claim 1, wherein the reflective surface of the rotatable reflective structure comprises a plurality of reflective particles or a plurality of microlenses.

7. The laser detection sensor of claim 1, wherein the photosensitive imaging module comprises an imaging lens and a photosensitive element; the imaging lens and the photosensitive element are sequentially positioned on the propagation path of the parallel laser beam after passing through the object to be detected;

the imaging lens is used for receiving the parallel laser beams which are not blocked by the object to be detected and projecting the parallel laser beams onto the photosensitive element;

8. The laser detection sensor of claim 7, wherein the control module comprises a drive circuit and an information processor;

the driving circuit is in communication connection with the rotatable reflecting structure and is used for outputting a control signal to the rotatable reflecting structure so as to control the rotatable reflecting structure to rotate;

9. A control method of a laser detection sensor for controlling the laser detection sensor according to any one of claims 1 to 8, the control method comprising:

the output control signal controls the rotatable reflecting structure to rotate so as to switch different reflecting surfaces, and the laser beam is modulated by utilizing the reflecting surface, so that the modulated laser beam is modulated again by the telecentric optical assembly to form a parallel laser beam;

acquiring an edge photosensitive image of the parallel laser beam which is not shielded by the object to be detected in the photosensitive element;

10. The control method according to claim 9, wherein determining the shape of the object to be measured from the edge-sensitive image includes: