CN205718875U - A kind of scan-type structure light projection system - Google Patents

Abstract

The utility model provides a kind of scan-type structure light projection system, including: LASER Light Source, torsional micro-mirror, feedback module, and control module, wherein, laser rays is incident along being parallel to torsional micro-mirror rotor shaft direction, after the torsional micro-mirror reflection that this incident laser line is rotated, form the projection of two-dimensional structure light；Feedback module is connected vibration frequency and the position gathering torsional micro-mirror with torsional micro-mirror, the input of control module is connected with the output of feedback module, in order to receive the signal of feedback module, the output of control module is connected with LASER Light Source and torsional micro-mirror, the luminous power of motion and LASER Light Source in order to control torsional micro-mirror, guarantee torsional micro-mirror is in the case of identical torsion angle, and LASER Light Source exports identical luminous power.

Description

A kind of scan-type structure light projection system

[technical field]

The utility model belongs to object fields of measurement, particularly a kind of three-dimensional surface measurement device, be specifically related to based on One-dimension Gradient-index Lens, utilizes MEMS torsional micro-mirror to obtain stable scan-type structured light projection image.

[background technology]

Three-dimensional object surface profile measurement, has weight in fields such as machine vision, biomedicine, industrial detection, CAD/CAM Want meaning, be the important component part in reverse engineering and computer vision.Based on the three-dimensional measurement technology of optics, due to its tool Have noncontact, in high precision, the advantage such as be easy to automatically control and obtain and develop on a large scale very much.Existing optical three-dimensional measuring method is most widely used General is to obtain three-dimensional article dignity shape information by being demodulated system to the space structure light field modulated by three-dimensional article dignity shape, So obtaining the premise that stable structure just realizes that three-dimensional surface profile is accurately measured.

Light degree phase outline technology (PMP) is to use phase-shifting technique and sinusoidal grating to project the three-dimensional measurement side combining Method, simple to equipment requirement, it is current mature and reliable, high accuracy three-dimensional measuring method, but the standard to sinusoidal grating Higher with the accuracy requirement of phase shift, also need to ensure the stability of projective structure light.

Existing structured light projection technology mainly utilizes LCD or DLP projector to produce ad hoc structure light and projects measured object On body, but system complex, bulky, with high costs；Another kind is, utilizes optical grating projection to go out structure light, in projection process Move integrally structured light projecting device or regulation projection focal length realize structure light to the scanning to picture for the projection, but refresh rate is low, surveys Accuracy of measurement is not high yet.

In June, 2013, Intel company proposed a kind of based on MEMS micro-reflector projecting structural optical, utilized cylindrical mirror handle Laser beam generates laser rays, and the inclination of controller control LASER Light Source switch and torsional micro-mirror obtains the structure of binary-coding striped Light；But carrying out 3D measurement with binary-coding striped, spatial resolution is low；And the generation feedback-less control of structure light, it is impossible to ensure Stablizing of structure light.

[utility model content]

The utility model proposes a kind of scan-type structure light projection system, to obtain stable scan-type structure light.

The utility model is by the following technical solutions:

A kind of scan-type structure light projection system, comprising: LASER Light Source, torsional micro-mirror, feedback module, and control mould Block, wherein, laser rays is incident along being parallel to torsional micro-mirror rotor shaft direction, after the torsional micro-mirror reflection that this incident ray is rotated, Form the projection of two-dimensional structure light；Feedback module is connected vibration frequency and the position gathering torsional micro-mirror with torsional micro-mirror, control The input of molding block is connected with the output of feedback module, in order to receive the signal of feedback module, and the output of control module It is connected with LASER Light Source and torsional micro-mirror, the luminous power of motion and LASER Light Source in order to control torsional micro-mirror, it is ensured that micro-torsion Mirror is in the case of identical torsion angle, and LASER Light Source exports identical luminous power.

Further, the laser beam that LASER Light Source sends is changed into laser rays by GRIN Lens.

Further, the input path of laser rays is provided with cross section diaphragm, more weak to limit laser rays both sides light intensity Part continues transmission, improves the uniformity of structure light light intensity.

Further, if laser rays transmission is r to the section radius at the diaphragm of cross section_x、r_y, then size a of cross section diaphragm is full Foot: a < 2r_x, wherein, a is the width dimensions of laser rays.

Further, described torsional micro-mirror is arranged in the near focal point of GRIN Lens, it is ensured that incide swashing of torsional micro-mirror Light hot spot is less than the reflecting surface size of torsional micro-mirror, ensureing that laser rays incides on torsional micro-mirror completely, thus by completely Reflection.

Further, the movable minute surface of torsional micro-mirror is provided with the coat of metal, as reflecting layer.

Further, described feedback module includes collecting unit and arithmetic unit, and described collecting unit is used for gathering micro-torsion The vibration frequency of mirror and position, described arithmetic unit obtains vibration amplitude and the phase of torsional micro-mirror according to the position calculation of torsional micro-mirror Position.

Further, vibration frequency and the position of torsional micro-mirror is obtained by gathering reflected light signal, or torsional micro-mirror Vibration frequency and position are obtained by the sensor arranging on torsional micro-mirror, the position of described sensor response torsional micro-mirror, speed Degree, angular speed, acceleration, angular acceleration；Described sensor includes capacitance sensor, piezoresistance sensor, piezoelectric transducer, or electricity Magnetic Sensor.

Compared with prior art, the utility model at least has the advantages that

The utility model proposes a kind of scan-type structured light projection system based on GRIN Lens and MEMS torsional micro-mirror System, volume is little, low in energy consumption；Structure light refresh rate maximum can be consistent with the vibration frequency of torsional micro-mirror simultaneously, and refresh rate is high；Feedback The position of module Real-time Feedback MEMS torsional micro-mirror mirror surface, control module Synchronization Control MEMS torsional micro-mirror and LASER Light Source Luminous power, can obtain stable structure light.

Further, GRIN Lens is laser-beam transformation point laser rays, and this GRIN Lens is biplane lens, adjusts thoroughly Mirror length i.e. adjustable focal length, focal length can be accomplished very little, can converge on its end face, it is simple to and the optical system collection such as colimated light system Become, it is possible to be greatly simplified and reduce optical-mechanical system volume.

[brief description]

Fig. 1 scan-type structure light projection system figure；

Fig. 2 (a) is diaphragm sectional view；

Fig. 2 (b) laser beam luminous power Gaussian Profile figure；

Fig. 3 (a) is many-valued structure light optical power distribution schematic diagram；

Fig. 3 (b) is two-value structure light optical power distribution schematic diagram；

Fig. 4 structure photogenerated and control schematic diagram；

Fig. 5 is based on the scan-type structure light projection system figure of electro-optical feedback；

Fig. 6 is based on the scan-type structure light projection system figure of capacitive feedback；

Fig. 7 is single high-speed light electric explorer torsional micro-mirror photodetector system schematic diagram；

Fig. 8 is torsional micro-mirror photoelectric detecting signal flow chart；

Fig. 9 is single high-speed light electric explorer photodetector system each several part signal graph, wherein, the motion of (9-a) torsional micro-mirror Figure；(9-b) the sensing signal figure of high-speed photodetector；

Figure 10 is double high-speed light electric explorer torsional micro-mirror photodetector system schematic diagrames；

Figure 11 is double high-speed light electric explorer photodetector system each several part signal graphs, wherein, the fortune of (11-a) torsional micro-mirror Cardon；(11-b) the sensing signal figure of high-speed photodetector；(11-c) the sensing signal figure of high-speed photodetector；

Figure 12 is the another kind of distressed structure schematic diagram of Fig. 7.

[detailed description of the invention]

The utility model proposes a kind of scan-type structure light projection system, to obtain stable scan-type structure light, adopt As follows by technical scheme:

A kind of scan-type structure light projection system, such as Fig. 1, including LASER Light Source the 10th, GRIN Lens 11, the micro-torsion of MEMS Mirror 13, feedback module 16, control module 17.The laser beam that wherein LASER Light Source sends is generated laser rays 12 by GRIN Lens； Laser rays 12 is reflected by MEMS torsional micro-mirror reflecting layer, forms reflection light 14, and then obtains two-dimensional structure light 15；Feedback module The vibration frequency of Real-time Feedback MEMS torsional micro-mirror and mirror surface position；Control module Synchronization Control MEMS torsional micro-mirror moves With LASER Light Source luminous power.

LASER Light Source can be by High Speed Modulation, and its luminous power can be continuously adjusted between zero to its peak power or numeral is adjusted Joint.

GRIN Lens is used for laser beam to generate laser rays, selects the One-dimension Gradient-index Lens of appropriate length, available The laser rays of certain certain angle of divergence of focal length；Preferred One-dimension Gradient-index Lens is cuboid lens.

GRIN Lens is the symmetrical GRIN Lens in a kind of face, i.e. the refractive index of GRIN Lens is symmetrical with regard to median surface, And directly change in gradient on the direction of the plane of symmetry at weight, specially refractive index is gradually reduced from symmetry towards both sides, laser light The laser beam that source sends incides on GRIN Lens along the direction being parallel to the plane of symmetry, thus it is straight in the tool of the plane of symmetry to obtain weight There is the laser rays of the specific angle of divergence.

The movable minute surface of MEMS torsional micro-mirror can realize the torsion of certain frequency certain angle around its rotating shaft (X-axis)；Laser Line is incident along being parallel to MEMS torsional micro-mirror rotor shaft direction, the MEMS torsional micro-mirror reflective surface being reversed around its rotating shaft, from And obtain the projection of two-dimensional structure light.

MEMS torsional micro-mirror, is arranged in GRIN Lens near focal point, it is ensured that incide the laser rays hot spot of torsional micro-mirror Less than its reflecting surface size, ensureing that laser rays incides on MEMS torsional micro-mirror completely, thus can be completely reflected.

MEMS torsional micro-mirror has movable minute surface, and it has the coat of metal (selecting with specific reference to laser source wavelength) conduct Reflecting layer, thus realize the reflection of the high efficiency to incident laser line.

The laser beam that LASER Light Source sends is Gaussian beam, after laser beam is changed into laser rays, and laser rays two ends light work( Rate can be significantly less than mid portion, thus brings the situation that in the middle of 2D structure light luminous power, strong both sides are very weak, optional at this, as Fig. 2, arranges a square-section diaphragm on the propagation path of laser beam or laser rays, if Laser Transmission is to section radius at this For r_x、r_y, then (diaphragm is at the width size a), a < 2r of laser rays in other words to width a for rectangular aperture X_x, to limit laser Light strong and weak part in bundle X-direction both sides continues transmission, thus improves the uniformity of structure light light intensity；Diaphragm height h arranges sufficiently large Or arrange according to real needs.

Feedback module, the position signalling of Real-time Collection MEMS torsional micro-mirror and vibration frequency signal, through its internalarithmetic Obtain vibration amplitude and the phase place of MEMS torsional micro-mirror afterwards in real time, and feed back to controller.

Feedback signal can gather reflected light signal by high-speed photodetector and obtain；Feedback signal also can be carried by the signal of telecommunication Supply: the signal of telecommunication can be by integrated capacitance sensor on MEMS torsional micro-mirror or piezoresistance sensor or piezoelectric transducer or electricity The sensor that Magnetic Sensor etc. can react movable mirror position, (angle) speed, (angle) acceleration etc. provides.

Control module can the vibration of Synchronization Control MEMS torsional micro-mirror and LASER Light Source luminous power.It is micro-that controller can control MEMS Torsional mirror realizes the torsion of certain frequency and amplitude around its torsional axis；Controller can realize the modulation of LASER Light Source, controls laser The power of light source, its power arbitrarily can be arranged between its peak power zero, so the structure light obtaining can be many-valued volume Code-bar line, if luminous power is by the sinusoidal light of sinusoidal rule change, such as Fig. 3 (a)；Can certainly be binary-coding striped, Such as Fig. 3 (b).

The amplitude of the MEMS torsional micro-mirror that control module can obtain according to feedback module, phase place, frequency, control MEMS in real time Torsional micro-mirror and laser light source power, thus ensure that the power of LASER Light Source becomes 1 a pair with the angle position of MEMS torsional micro-mirror Should be related to, obtain stable structure light.Such as Fig. 4, incident laser line 12 keeps constant, and torsional micro-mirror 13 is turned round around its rotating shaft (X-axis) Turning, the projected position of reflection laser rays 14 depends on the concrete torsion angle of MEMS torsional micro-mirror, according to feedback module Real-time Feedback The amplitude of MEMS torsional micro-mirror, phase place, frequency, control the power of each moment LASER Light Source, thus ensure the micro-torsion of MEMS Under the identical torsion angle of mirror, the exportable identical luminous power of LASER Light Source, thus obtain stable structure light.

The scan-type structured light projection system based on GRIN Lens and MEMS torsional micro-mirror that the utility model patent proposes System and control method thereof, volume is little, low in energy consumption；Structure light refresh rate maximum can be consistent with the vibration frequency of torsional micro-mirror simultaneously, Refresh rate is high；Increasing feedback module, the position of Real-time Feedback MEMS torsional micro-mirror mirror surface, controller Synchronization Control MEMS is micro- Torsional mirror and LASER Light Source luminous power, can obtain stable structure light；And LASER Light Source luminous power can not only may be used by High Speed Modulation To the structure light of two-value brightness, also can obtain the structure light of many-valued brightness, such as sinusoidal light according to actual needs, meet high-precision The needs of degree three dimensional optical measuring desired structure light.

Below according to drawings and Examples, the utility model is elaborated:

Embodiment one

The present embodiment is by the following technical solutions:

A kind of scan-type structure light projection system based on electro-optical feedback, such as Fig. 5, including LASER Light Source the 10th, self-focusing is saturating Mirror 11, a MEMS torsional micro-mirror 13, an electro-optical feedback module 46 and control module 17.The laser beam that wherein LASER Light Source sends by GRIN Lens generates laser rays 12；Laser rays 12 is reflected by MEMS torsional micro-mirror reflecting layer, forms reflection light 14, and then obtains To two-dimensional structure light 15；The vibration frequency of electro-optical feedback module Real-time Feedback MEMS torsional micro-mirror and mirror surface position；Control Module synchronization control MEMS torsional micro-mirror motion and LASER Light Source luminous power.

Laser source wavelength 808nm, peak power 100mW, can by High Speed Modulation, its luminous power from 0 to 100mW can It is continuously adjusted or digital regulated.

Selecting cuboid One-dimension Gradient-index Lens at this, being used for laser beam to generate laser rays, GRIN Lens length sets For 2.2mm, focal length 1.8mm, the laser rays of the available angle of divergence 45 °.

The movable minute surface of MEMS torsional micro-mirror can realize about 5KHz around its rotating shaft (X-axis), and the mechanical angle of ± 20 degree reverses, Thus line source is along when being parallel to the incidence of MEMS torsional micro-mirror rotor shaft direction, by around the MEMS torsional micro-mirror of its rotating shaft torsion Reflective surface, obtain two-dimensional structure light projection.

MEMS torsional micro-mirror, is arranged in GRIN Lens near focal point, it is ensured that incide the laser rays hot spot of torsional micro-mirror Less than its reflecting surface size, ensureing that laser rays incides on MEMS torsional micro-mirror completely, thus can be completely reflected.

MEMS torsional micro-mirror has movable minute surface, it has golden film as reflecting layer, and that improves to laser line light source is anti- Penetrate rate.

The laser beam spot diameter that LASER Light Source sends about 0.8mm, uses a=before light beam incides GRIN Lens The square-section diaphragm restriction laser beam of 0.6mm, h=1mm is along the continuation transmission of X less optical power portion to both sides, thus changes The uniformity of the kind structure light obtaining.

Electro-optical feedback module is made up of speculum and high-speed photodetector detection module, and wherein speculum is correspondence position The laser rays of place's outgoing reflexes on high-speed photodetector, and high-speed photodetector produces pulse signal, through its arithmetic unit fortune Vibration amplitude, the phase and frequency of MEMS torsional micro-mirror can be obtained after calculation in real time, and feed back to controller.

Control module can the vibration of Synchronization Control MEMS torsional micro-mirror and LASER Light Source luminous power.Controller can realize laser light The modulation in source, the power of control LASER Light Source, its power arbitrarily can be arranged between 0 to 100mW, so the structure light obtaining can To be multivalued encoding striped, if luminous power is by the sinusoidal light of sinusoidal rule change, such as Fig. 3 (a)；It can certainly be two-value Strip encoding, such as Fig. 3 (b).MEMS micro-twisting vibration information that control module can provide according to feedback module, is driven by controlling it Dynamic signal, makes MEMS torsional micro-mirror realize the torsion stablized frequency and stablize amplitude around its torsional axis.

The amplitude of the MEMS torsional micro-mirror that control module can obtain according to feedback module, phase place, frequency, control MEMS in real time Torsional micro-mirror and laser light source power, thus ensure that the power of LASER Light Source becomes 1 a pair with the angle position of MEMS torsional micro-mirror Should be related to, obtain stable structure light.Such as Fig. 4, incident laser line 12 keeps constant, and torsional micro-mirror 13 is turned round around its rotating shaft (X-axis) Turning, the projected position of reflection laser rays 14 depends on the concrete torsion angle of MEMS torsional micro-mirror, according to feedback module Real-time Feedback The amplitude of MEMS torsional micro-mirror, phase place, frequency, control the power of each moment LASER Light Source, thus ensure the micro-torsion of MEMS Under the identical torsion angle of mirror, the exportable identical luminous power of LASER Light Source, thus obtain stable structure light.

Embodiment two

The present embodiment is by the following technical solutions:

A kind of scan-type structure light projection system based on capacitive feedback, such as Fig. 5, including LASER Light Source the 10th, self-focusing is saturating Mirror 11, a MEMS torsional micro-mirror 13, a capacitive feedback module 46 and control module 17.The laser beam that wherein LASER Light Source sends by GRIN Lens generates laser rays 12；Laser rays 12 is reflected by MEMS torsional micro-mirror reflecting layer, forms reflection light 14, and then obtains To two-dimensional structure light 15；The vibration frequency of feedback module Real-time Feedback MEMS torsional micro-mirror and mirror surface position；Control module The motion of Synchronization Control MEMS torsional micro-mirror and LASER Light Source luminous power.

Laser source wavelength 660nm, peak power 50mW, can by High Speed Modulation, its luminous power from 0 to 50mW can quilt Continuously adjust or digital regulated.

Selecting cuboid GRIN Lens at this, being used for laser beam to generate laser rays, GRIN Lens length is set to 2mm, focal length 2mm, the laser rays of the available angle of divergence 55 °；

The movable minute surface of MEMS torsional micro-mirror can realize about 11KHz around its rotating shaft (X-axis), and the mechanical angle of ± 20 degree is turned round Turn, thus line source is along when being parallel to the incidence of MEMS torsional micro-mirror rotor shaft direction, by around the micro-torsion of MEMS of its rotating shaft torsion The reflective surface of tilting mirror, obtains the projection of two-dimensional structure light.

MEMS torsional micro-mirror has movable minute surface, it has golden film as reflecting layer, improves the reflection to laser line light source Rate.

MEMS torsional micro-mirror self is integrated with capacitance sensor.

The capacitance change signal that capacitive feedback module can provide according to capacitance sensor in MEMS torsional micro-mirror vibration processes, Vibration amplitude, the phase and frequency of MEMS torsional micro-mirror can be obtained in real time after its internalarithmetic, and feed back to control module.

Control module can the vibration of Synchronization Control MEMS torsional micro-mirror and LASER Light Source luminous power.Controller can realize laser light The modulation in source, the power of control LASER Light Source, its power arbitrarily can be arranged between 0-50mW, so the structure light obtaining is permissible It is multivalued encoding striped, if luminous power is by the sinusoidal light of sinusoidal rule change, such as Fig. 3 (a)；Can certainly be that two-value is compiled Code-bar line, such as Fig. 3 (b).MEMS micro-twisting vibration information that control module can provide according to feedback module, is driven by controlling it Signal, makes MEMS torsional micro-mirror realize the torsion stablized frequency and stablize amplitude around its torsional axis.

The amplitude of the MEMS torsional micro-mirror that control module can obtain according to feedback module, phase place, frequency, control MEMS in real time Torsional micro-mirror and laser light source power, thus ensure that the power of LASER Light Source becomes 1 a pair with the angle position of MEMS torsional micro-mirror Should be related to, obtain stable structure light.Such as Fig. 4, incident laser line 12 keeps constant, and torsional micro-mirror 13 is turned round around its rotating shaft (X-axis) Turning, the projected position of reflection laser rays 14 depends on the concrete torsion angle of MEMS torsional micro-mirror, according to feedback module Real-time Feedback The amplitude of MEMS torsional micro-mirror, phase place, frequency, control the power of each moment LASER Light Source, thus ensure the micro-torsion of MEMS Under the identical torsion angle of mirror, the exportable identical luminous power of LASER Light Source, thus obtain stable structure light.

The utility model feedback module produces pulse letter according to MEMS torsional micro-mirror vibration processes high speed photodetector Number or capacitance sensor provide capacitance change signal, shaking of MEMS torsional micro-mirror can be obtained after its internalarithmetic in real time Dynamic amplitude, phase and frequency, realize particular by following system and method:

The first situation: use a photodetector, it is achieved the calculating of torsional micro-mirror vibration amplitude and phase place.

Referring to shown in Fig. 7, system 10 ' mainly includes having the fixed frame 11 ' of transparent area 12 ', near transparent area 12 ' limit The resonant mode torsional micro-mirror that in the fixed frame of edge, side is furnished with a high-speed photodetector 13 ', is fixed in fixed frame 11 ' 14 ' and laser instrument 15 '.

High-speed photodetector 13 ', the torsional micro-mirror 14 ' being fixed in fixed frame and laser instrument 15 ' are each attached to fix On frame 11 ', and ensureing positioning relation and the positioning precision of each assembly, the surrounding of this fixed frame 11 ' transparent area 12 ' is impermeable finish Matter；From the injection after torsional micro-mirror 14 ' reflection of the laser beam of laser instrument 15 ' outgoing, sweep limits is β；High speed optoelectronic detects Device is positioned at the boundary (α < β) that scanning angle in the range of β is α, and on the scanning pattern of torsional micro-mirror, i.e. fixed frame is internal thoroughly Light district and light tight intersection.Specifically, high-speed photodetector 13 ' is arranged in the edge of fixed frame 11 ', and is arranged on micro- In the sweep limits of torsional mirror, but high-speed photodetector 13 ' is not disposed at transparent area 12 '.

Incorporated by reference to shown in Fig. 8 and Fig. 9: the light penetrating when laser instrument 15 ' reflects through torsional micro-mirror 14 ', is scanned across at a high speed During photodetector 13 ', photodetector 13 ' can perceive the position signalling of torsional micro-mirror, control system according to time etc. because of Element computing can get amplitude and the phase place of torsional micro-mirror vibration.

Computing Principle is specific as follows: laser instrument 15 ', torsional micro-mirror 14 ', photodetector 13 ' are fixed on fixed frame In 11 ', locality specific, it is known；With head in two adjacent (time interval is less than T/2) pulse signal that photodetector produces The moment point that individual pulse signal produces is timing starting point, takes a vibration period T, t of torsional micro-mirror 14 '₁Moment and t₂When Carving, the light of torsional micro-mirror reflection is through photodetector 13 ', and now the position amplitude of torsional micro-mirror is d₁, detector senses To the signal of torsional micro-mirror reflected-light scanning process, t₁And t₂The intermediate time in momentTorsional micro-mirror reaches maximum amplitude,Moment scanning mirror is positioned at initial position；The vibration amplitude A of torsional micro-mirror₀And initial phaseComputing as follows:

Amplitude computing:

The timing starting point t1 moment:

The t2 moment:

That is:

As above two formulas are added:

$2arcsin\frac{d_1}{A_0}=\mathrm{\&pi;}-\mathrm{\&omega;}\mathrm{\&Delta;}t;\mathrm{\&omega;}=\frac{2\mathrm{\&pi;}}{T}$

Therefore:

Initial phase:

The second situation: using two photodetectors, wherein, a photodetector is for calculating torsional micro-mirror Vibration amplitude and phase place, another one photodetector is for offsetting assembling because being sealed on fixed frame and micro-torsion The torsional micro-mirror amplitude deviation causing installed by mirror and laser instrument.

System composition such as Figure 10 ', this system 20 ' mainly includes having the fixed frame 11 ' of transparent area 12 ', near transparent area In the fixed frame 11 ' at 12 ' edges, both sides are respectively furnished with a high-speed photodetector 13 ' and 46 ', are fixed in fixed frame 11 ' Resonant mode torsional micro-mirror 14 ' and laser instrument 15 '.

High-speed photodetector 13 ' and 46 ', the torsional micro-mirror 14 ' being fixed in fixed frame 11 ' and laser instrument 15 ' are all solid Being scheduled on fixed frame 11 ', and ensureing positioning relation and the positioning precision of each assembly, the surrounding of this fixed frame 11 ' transparent area 12 ' is Light tight material；From the injection after torsional micro-mirror 14 ' reflection of the laser beam of laser instrument 15 ' outgoing, sweep limits is β；At a high speed Photodetector 13 ' and 46 ' is positioned at the boundary (α < β) that scanning angle in the range of β is α, and at the scanning pattern of torsional micro-mirror On, i.e. the internal transparent area of fixed frame and light tight intersection.

With use compared with a photodetector, add the second high-speed photodetector 46 ', it is therefore intended that can reduce by Error in the vibration amplitude calculating that rigging error is brought.During assembling, two high-speed photodetectors are assembled to fixed frame envelope Covering the torsional micro-mirror vibration amplitude deviation that respective position deviation brings is Δ₁And Δ₂If, the dress between capping and fixed frame Join the torsional micro-mirror vibration amplitude total deviation Δ that error is brought with torsional micro-mirror, laser instrument rigging error: as Figure 10 shows: work as laser The light of device injection reflects through torsional micro-mirror, and when being scanned across high-speed photodetector 13 ' and 46 ', photodetector can perceive The position signalling of torsional micro-mirror, control system can get amplitude and the phase place of torsional micro-mirror vibration according to factor computings such as times, The motion of torsional micro-mirror, signal such as Figure 11 of photodetector perception show.

Laser instrument 15 ', torsional micro-mirror 14 ', photodetector 13 ' and 46 ' are fixed in fixed frame, locality specific, It is known；By photodetector 13 ' or 46 ' one of them (as a example by this sentences photodetector 13 ') produce two adjacent (when Between interval be less than T/2) first pulse signal produces in pulse signal moment point is timing starting point, as Figure 11 shows, takes micro-torsion One vibration period T, t of tilting mirror₁Moment and t₂In the moment, the light of torsional micro-mirror reflection is through photodetector 13 ', now micro- The position amplitude of torsional mirror is d₁, detector 13 ' senses the signal of torsional micro-mirror reflected-light scanning process, and produces pulse letter Number；t₃Moment and t₄In the moment, the light of torsional micro-mirror reflection is through photodetector 46 ', and now the position amplitude of torsional micro-mirror is d₂, detector 46 ' senses the signal of torsional micro-mirror reflected-light scanning process, and produces pulse signal,When Carve scanning mirror and be positioned at initial position；Consider rigging error, the vibration amplitude A of torsional micro-mirror₀Principle of operation is as follows:

For high-speed photodetector 13 ':

T1 time point:

T2 time point:

That is:

As above two formulas are added:

$2arcsin\frac{d_1+{\mathrm{\&Delta;}}_1+\mathrm{\&Delta;}}{A_0}=\mathrm{\&pi;}-\mathrm{\&omega;}(t_2-t_1)=\mathrm{\&pi;}-{\mathrm{\&omega;\&Delta;t}}_1;\mathrm{\&omega;}=\frac{2\mathrm{\&pi;}}{T}$

Therefore:

A₀*cos(πΔt₁/ T)=d₁+Δ₁+Δ

For high-speed photodetector 46 ':

t₃Time point:

t₄Time point:

That is:

As above two formulas are added:

$2arcsin\frac{d_2+{\mathrm{\&Delta;}}_2-\mathrm{\&Delta;}}{A_0}=\mathrm{\&pi;}-\mathrm{\&omega;}(t_4-t_3)=\mathrm{\&pi;}-{\mathrm{\&omega;\&Delta;t}}_2;\mathrm{\&omega;}=\frac{2\mathrm{\&pi;}}{T}$

Therefore:

A₀*cos(πΔt₂/ T)=d₂+Δ₂-Δ

Comprehensive high speed optoelectronic sensor 13 ' and 46 ':

$A_0=\frac{d_1+{\mathrm{\&Delta;}}_1+d_2+{\mathrm{\&Delta;}}_2}{cos({\mathrm{\&pi;At}}_1/T)+cos({\mathrm{\&pi;\&Delta;t}}_2/T)}$

Can be seen that from formula, considering high speed optoelectronic sensor 13 ' and 46 ', the assembling between capping and fixed frame is by mistake Difference is cancelled with the torsional micro-mirror vibration amplitude total deviation Δ that torsional micro-mirror, laser instrument rigging error cause, and reduces crest meter Calculate error.

Use a photodetector, can also have variant, such as at the boundary that torsional micro-mirror scanning angle is α (α < β), and a speculum 66 ' is set on the scanning pattern of 1D torsional micro-mirror, when at torsional micro-mirror scanning is to this, scan light Line is reflected mirror and reflexes on photodetector 13 ', such as Figure 12, can record the phase and amplitude information of torsional micro-mirror equally.

Claims (8)

1. a scan-type structure light projection system, it is characterised in that: include: LASER Light Source (10), torsional micro-mirror, feedback module (16), and control module (17), wherein, laser rays (12) is incident along being parallel to torsional micro-mirror rotor shaft direction, this incident ray After the torsional micro-mirror reflection being rotated, form the projection of two-dimensional structure light；Feedback module is connected with torsional micro-mirror to gather micro-torsion The vibration frequency of tilting mirror and position, the input of control module is connected with the output of feedback module, in order to receive feedback module Signal, the output of control module is connected with LASER Light Source and torsional micro-mirror, in order to control motion and the laser of torsional micro-mirror The luminous power of light source, it is ensured that torsional micro-mirror is under corresponding torsion angle, and LASER Light Source output is consistent with object construction light pattern Luminous power.

2. a kind of scan-type structure light projection system according to claim 1, it is characterised in that: what LASER Light Source sent swashs Light beam is changed into laser rays by GRIN Lens (11).

3. a kind of scan-type structure light projection system according to claim 2, it is characterised in that: at the incident light of laser rays It is provided with cross section diaphragm on road, continue transmission to limit the more weak part of laser rays both sides light intensity, improve the equal of structure light light intensity Even property.

4. a kind of scan-type structure light projection system according to claim 3, it is characterised in that: set laser rays transmission and extremely cut Section radius at the diaphragm of face is r_x、r_y, then size a of cross section diaphragm meets: a < 2r_x, wherein, a is the broad-ruler of laser rays Very little.

5. a kind of scan-type structure light projection system according to claim 3, it is characterised in that: described torsional micro-mirror is arranged Near focal point at GRIN Lens, it is ensured that incide the reflecting surface chi less than torsional micro-mirror for the laser rays hot spot of torsional micro-mirror Very little, it ensureing that laser rays incides on torsional micro-mirror completely, thus is completely reflected.

6. a kind of scan-type structure light projection system according to claim 5, it is characterised in that: the movable mirror of torsional micro-mirror It is provided with the coat of metal, as reflecting layer on face.

7. a kind of scan-type structure light projection system according to any one of claim 1 to 6, it is characterised in that: described Feedback module include collecting unit and arithmetic unit, described collecting unit for gathering vibration frequency and the position of torsional micro-mirror, Described arithmetic unit obtains vibration amplitude and the phase place of torsional micro-mirror according to the position calculation of torsional micro-mirror.

8. a kind of scan-type structure light projection system according to claim 7, it is characterised in that: the vibration frequency of torsional micro-mirror Rate and position are obtained by gathering reflected light signal, or vibration frequency and the position of torsional micro-mirror are passed through to arrange on torsional micro-mirror Sensor obtain, the position of described sensor response torsional micro-mirror, speed, angular speed, acceleration, angular acceleration；Described biography Sensor includes capacitance sensor, piezoresistance sensor, piezoelectric transducer, or electromagnetic sensor.