CN111366534A - Laser light intensity self-adaptive adjusting method for active vision measurement in turbid water - Google Patents
Laser light intensity self-adaptive adjusting method for active vision measurement in turbid water Download PDFInfo
- Publication number
- CN111366534A CN111366534A CN202010127459.3A CN202010127459A CN111366534A CN 111366534 A CN111366534 A CN 111366534A CN 202010127459 A CN202010127459 A CN 202010127459A CN 111366534 A CN111366534 A CN 111366534A
- Authority
- CN
- China
- Prior art keywords
- laser
- light intensity
- water
- object model
- turbidity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 70
- 238000005259 measurement Methods 0.000 title claims abstract description 30
- 238000000034 method Methods 0.000 title claims abstract description 19
- 230000000007 visual effect Effects 0.000 claims abstract description 13
- 239000004065 semiconductor Substances 0.000 claims abstract description 10
- 230000000694 effects Effects 0.000 claims abstract description 6
- 230000003044 adaptive effect Effects 0.000 claims description 23
- 238000012546 transfer Methods 0.000 claims description 13
- 238000012545 processing Methods 0.000 claims description 2
- 239000000126 substance Substances 0.000 claims 1
- 230000003287 optical effect Effects 0.000 abstract description 7
- 230000008859 change Effects 0.000 description 4
- 238000013461 design Methods 0.000 description 4
- 239000003570 air Substances 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 238000005034 decoration Methods 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 239000005357 flat glass Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000013178 mathematical model Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000013535 sea water Substances 0.000 description 2
- 101100460704 Aspergillus sp. (strain MF297-2) notI gene Proteins 0.000 description 1
- 101100115215 Caenorhabditis elegans cul-2 gene Proteins 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
Abstract
The invention discloses a laser intensity self-adaptive adjusting method for active visual measurement in turbid water, which is characterized in that a laser adjuster is arranged on a semiconductor laser driven by a current source, the laser adjuster comprises a reference model passage and an object model passage, when the reference intensity input added to the object model passage is simultaneously added to the reference model passage, parameters are changed by a light intensity self-adaptive algorithm arranged in the object model passage according to ideal laser controller parameters calculated by the reference model passage, so that the attenuation effect of water turbidity in the object model passage on the light intensity is counteracted, and the light intensity output of the reference model passage is consistent with that of the object model passage. The invention reduces the attenuation of water to laser by self-adaptively adjusting the light intensity of the laser, prevents the saturation or low signal-to-noise ratio of the optical sensor caused by different water turbidities, and can effectively improve the precision of active visual measurement in turbid water.
Description
Technical Field
The invention relates to the technical field of vision measurement application, in particular to a laser light intensity self-adaptive adjusting method for active vision measurement in turbid water.
Background
The active vision measurement has the characteristics of high detection speed, high measurement precision, strong anti-interference performance and the like, so the active vision measurement is widely applied to the fields of thickness measurement, three-dimensional modeling, mold manufacturing and the like.
Active vision measurement systems are typically comprised of a light source, an imaging light path, and optical sensors, among others. The stability of the light source directly determines the accuracy of the active visual measurement. The most commonly used light source at present is a laser light source. When the active visual measurement is used in turbid water, laser emitted by a laser is attenuated due to the action of the water, so that the light intensity is reduced. The degree of turbidity of water varies, and the degree of attenuation of light intensity also varies. Because the calibration of the active visual measurement system can only be performed in a certain turbidity-determining water (such as zero-turbidity water in a laboratory environment), when the turbidity of the water in the measurement environment is inconsistent with the turbidity in the calibration, an optical sensor for receiving light intensity is saturated or the signal-to-noise ratio is low, thereby adversely affecting the measurement accuracy.
Disclosure of Invention
The invention aims to provide a laser light intensity self-adaptive adjusting method for active visual measurement in turbid water, which aims to overcome the technical defects in the prior art.
The technical scheme adopted for realizing the purpose of the invention is as follows:
a laser intensity adaptive control method for the initiative vision measurement in the turbid water, set up a laser regulator for the semiconductor laser driven by current source, the laser regulator includes reference model access and object model access, the parameter of the reference model access is determined by the turbidity of the specific turbidity water at the time of calibration, used for calculating the ideal laser controller parameter according to the controlled object transfer function in the specific turbidity water at the time of calibration, the object model access sets up the adaptive control algorithm of light intensity; when the reference light intensity input added to the object model passage is also added to the reference model passage, the light intensity self-adaptive algorithm arranged in the object model passage changes parameters according to the ideal laser controller parameters, so that the attenuation effect of the water turbidity in the object model passage on the light intensity is counteracted, and the light intensity output of the reference model passage is consistent with that of the object model passage.
Because the reference model calculates ideal laser controller parameters according to the transfer function of the controlled object in the specific turbidity water during calibration, and the water turbidity of the actual system is different from that during calibration, a laser light intensity self-adaptive control algorithm is designed on the object model passage, so that the light intensity output by the reference model and the light intensity of the object model tend to be consistent through the self-adaptive control algorithm, and the light intensity loss caused by the difference of the water turbidity is offset.
The invention reduces the attenuation of water to laser by self-adaptively adjusting the light intensity of the laser, prevents the saturation or low signal-to-noise ratio of the optical sensor caused by different water turbidities, and can effectively improve the precision of active visual measurement in turbid water.
The method has no special requirements on the performance parameters of the laser and the CCD, has wide application range, simple and quick calculation process, easy realization, strong practical value and wide market prospect, and can be widely applied to the field of active visual measurement in various turbid water.
Drawings
FIG. 1 shows an open-loop mathematical model of a laser intensity adaptive adjustment method for active vision measurement in turbid water;
FIG. 2 shows a simplified open-loop mathematical model;
FIG. 3 is a schematic view of the regulator;
FIGS. 4(a) -4(b) show the original error model and the substituted parameters, respectively;
FIG. 5 shows an example of the application of the adaptive adjustment method for laser intensity in the underwater laser triangulation measurement;
fig. 6 is a circuit diagram showing a semiconductor laser driving circuit;
fig. 7(a) -7(c) show the light spot images on the CCD in the standard nephelometric solution, and fig. 7(a) -7(c) show the light spot images in the 30NTU nephelometric solution, the light spot images in the 50NTU nephelometric solution, and the light spot images in the 80NTU nephelometric solution, respectively.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 3, the adaptive laser intensity adjusting method for active visual measurement in turbid water according to the present invention is to provide a laser adjuster for a semiconductor laser driven by a current source, wherein the laser adjuster comprises a reference model passage and an object model passage, the parameters of the reference model passage are determined by the turbidity of specific turbid water during calibration, and are used for calculating the ideal laser controller parameters according to the controlled object transfer function in the specific turbid water during calibration, and the object model passage is provided with an adaptive light intensity control algorithm; when the reference light intensity input added to the object model passage is also added to the reference model passage, the light intensity self-adaptive algorithm arranged in the object model passage changes parameters according to the ideal laser controller parameters, so that the attenuation effect of the water turbidity in the object model passage on the light intensity is counteracted, and the light intensity output of the reference model passage is consistent with that of the object model passage.
Since the parameters of the reference model path are determined by the turbidity of the water at calibration, the output of the reference model path is the light intensity P _ CCDm in the water at calibration at a specific turbidity. Since the parameters of the object model channel are different from those of the reference model due to the change of the turbidity of water, the light intensity P _ CCDp of the object model channel is deviated from the light intensity P _ CCDm of the reference model, and the deviation changes the parameters through the adaptive algorithm k (t), so that the light intensity output of the reference model and the light intensity output of the object model are consistent, namely, P _ CCDm is equal to P _ CCDp. Because the output of the reference model is the light intensity in the specific turbidity water during calibration, when the outputs of the reference model and the object model are consistent, the attenuation effect of the water turbidity in the object model on the light intensity is counteracted by the adaptive rate algorithm.
In the invention, the reference model passage calculates ideal laser controller parameters according to the transfer function of the controlled object in the specific turbidity water during calibration, the adaptive control algorithm of the laser light intensity is designed in the object model passage, and the light intensity output by the reference model and the light intensity of the object model tend to be consistent through the adaptive control algorithm, thereby counteracting the light intensity loss caused by the water turbidity difference.
Fig. 5 shows the application of the laser intensity adaptive adjustment method of the present invention in underwater laser triangulation measurement, one part of the light path is located in the air of the protective cavity, the other part is located in the water, the middle of the two parts is divided by the window glass 10, the light of the laser 14 with the adjuster passes through the lens 13, the three media of air, glass and seawater and then is directly irradiated to the object surface 12 to be measured, the scattered light passes through the water, the glass, the air and the lens 15 and then is imaged on the CCD16, and the reference surface 11 is arranged between the object surface 12 to be measured and the window glass 10.
The following describes the implementation of the present invention:
1) open-loop model building
As shown in fig. 1, the open-loop model comprises three parts: the sea water solar energy laser device comprises a laser light source, a semiconductor laser device and a CCD3, wherein
s is a complex variable in the Laplace transform, s ═ σ + j ω, K is the gain, TlasIs a time constant;
according to Lambert's law, the attenuation law of monochromatic light beam propagating in water conforms to the following formula (2),
P＝P0e-εb(2)，
in the formula, P0And P is the optical power at transmission distances of 0 and b, respectively, the attenuation coefficient ε, the water turbidity and the light beamWavelength dependent, the wavelength of the laser source has good stability, so the attenuation coefficient is only dependent on the turbidity of the water.
For the same laser, the light intensity after the propagation distance b in the specific turbidity water during calibration is set as
The light intensity at another turbidity, also at transmission distance b, is then:
definition of
Is N, b is the propagation distance, εcIs the attenuation coefficient, ε, of water with a specific turbidity (e.g. zero turbidity water)xIs the attenuation coefficient of other turbidity water, then
Px＝PcN (4)
Since N changes with the turbidity of water, the attenuation of the light intensity by water can be regarded as a disturbance link with a change of proportionality coefficient, which is connected in the forward path of the control system.
The light intensity collected and received by the CCD to the optical signal is PCCD. The dynamic behavior of a CCD can be described by equation (5) according to the reference (F.Rodier.Adaptive optics in Astronomy.Cambridge: Cambridge University Press, 1999).
In the formula TCCDIs the blanking time of the CCD.
s is a complex variable in the lagrange transform, s ═ σ + j ω,
laplace transform, which is a pure hysteresis loop, has significance in
(2) Have different meanings; the expression (5) is an expression of the automatic control principle, and the expression (2) is a symbol in the optical field, and happens to use the letter e.
2) Open-loop model simplification
The blanking time of CCD is usually small, because the laser light source belongs to the slowly changing signal, the simplification processing is carried out to the formula (5), as shown in the formula (6)
s is a complex variable in the lagrange transform, s ═ σ + j ω,
the laplacian transform, which is a pure hysteresis loop, simplifies the open-loop model shown in fig. 1 according to equation (6), as shown in fig. 2.
Because of TCCD>TlasTherefore, G(s) can be further simplified to
N is
G(s) is a transfer function in the principle of autonomous control.
3) Design of regulator
Since N varies with the turbidity of the water, the purpose of the regulator is to keep the light intensity received by the CCD constant under the influence of disturbances, i.e. variations in N. The regulator structure is shown in fig. 3.
In FIG. 3
Is the average value of water turbidity in the calibration process according to the reference (Chengbei electric drive automatic control system)System-motion control System (5 th edition), mechanical Industrial Press 2016. A typical type II system1And
formula (7):
τ1＝hTlas
h is the medium bandwidth of a typical type II system, generally taken as h 5,
as can be seen from FIG. 3, when
When the reference model path is matched with the object model path, K (t) is a time-varying coefficient, and phi (t) is set to k (t) k*Then the error model is shown in fig. 4 (a). Handle
The error model shown in fig. 4(a) is substituted with equation (7) to obtain an error model shown in fig. 4 (b).
The purpose of adaptive control is that the object model path becomes identical to the reference model path, and in order for the two paths to become identical, adjustments are made based on the error model, which means that the two model paths are identical if the error of the two model paths is zero.
Taking L(s) ═ s + a, and adjusting the value of a to make
L(s) s + a is the transfer function, s is the complex variable and a is the parameter to be determined.
then adaptive rate
Can ensure the system to be stable and e1(t) → 0, i.e. PCCDp→PCCDmI.e. even if it is turbidThe light intensity received on the CCD, influenced by the water, is still consistent with that of the reference model.
The system stability verification procedure is as follows.
If it is not
Is strictly true and true, one can find
Corresponding implementations (A, b, c),
the control system has two models, one is a transfer function model, the other is a state space model, and the two models can be mutually converted, and (A, b and c) are state space models corresponding to the transfer function model.
Satisfy the requirement of
When c is going toT(sI-A)-1b is strictly true, and there is a certain vector q, and a matrix L ═ LT>0 and a scalar σ>0, making
This is true.
Selecting Lyapunov function
Then
When in use
When the temperature of the water is higher than the set temperature,
then
Example 1
1) Open-loop model building
The semiconductor laser drive circuit is shown in FIG. 6, TlasThe CCD is a linear CCD with blanking time of 166 μ s, and the turbidity variation range of water is 0-100NTU, i.e. the attenuation rate N of laser intensity is [0.7,1 ]]。
2) Open-loop model simplification
3) Design of regulator
Because the range of the attenuation rate N of the laser intensity is [0.7,1 ]]To thereby obtain
Taking h as 5 as the design requirement of the regulator, obtaining:
τ1＝5×30＝150
if a is 3.5, then
Are strictly positive and solid.
Taking gamma as 0.31 to obtain
System stability and e from regulator design1(t) → 0, i.e. PCCDp→PCCDm。
During operation, the difference between the reference light intensity and the actual light intensity is regulated by the controller and applied to the transfer function of the controlled object to generate light intensity PCCDm. Since the parameters of the reference model are determined by the turbidity of the water at calibration, the output of the reference model is the calibrationTiming light intensity P in specific turbidity waterCCDm. For the object model path, the reference light intensity is adaptively calculated to be L(s), k (t) and applied to the controller, and the output of the controller is applied to the actual system, i.e. the semiconductor laser driving circuit to generate the light intensity PCCDpAs shown in fig. 3. Since the parameters of the object model may be different from those of the reference model due to the change in turbidity of water, the light intensity P of the path of the object modelCCDpLight intensity P to be compared with the reference modelCCDmThere is a deviation between the reference model and the object model, which is then subjected to a parameter change by an adaptive algorithm k (t) to finally match the light intensity outputs of the reference model and the object model, i.e. PCCDm＝PCCDp. Because the output of the reference model is the light intensity in the specific turbidity water during calibration, when the outputs of the reference model and the object model are consistent, the attenuation effect of the water turbidity in the object model on the light intensity is counteracted by the adaptive rate algorithm.
The measurement experiments were performed in standard turbidity solutions of 30NTU, 50NTU and 80NTU, and the resulting spot images on the CCD are shown in fig. 7.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (5)
1. A laser intensity adaptive control method for the initiative vision measurement in the turbid water, characterized by, set up a laser regulator for the semiconductor laser driven by current source, the laser regulator includes reference model access and object model access, the parameter of the reference model access is determined by the turbidity of the specific turbidity water of calibration, used for calculating the ideal laser controller parameter according to the controlled object transfer function in the specific turbidity water of calibration, the object model access sets up the adaptive control algorithm of light intensity; when the reference light intensity input added to the object model passage is also added to the reference model passage, the light intensity self-adaptive algorithm arranged in the object model passage changes parameters according to the ideal laser controller parameters, so that the attenuation effect of the water turbidity in the object model passage on the light intensity is counteracted, and the light intensity output of the reference model passage is consistent with that of the object model passage.
2. The adaptive laser intensity adjustment method for the active visual measurement in turbid water according to claim 1, wherein the controlled object transfer function is expressed as:
wherein the content of the first and second substances,
is the average value of water turbidity in calibration, G(s) is the transfer function in the automatic control principle, K is the gain of the semiconductor laser, TlasFor the time constant, s is a complex variable in the Laplace transform, TCCDIs the blanking time of the CCD.
3. The adaptive laser intensity adjustment method for the active visual measurement in turbid water as claimed in claim 2, wherein the difference between the reference intensity and the actual intensity is adjusted by the following controllers arranged in the reference model path and applied to the transfer function of the controlled object to generate the light intensity PCCDm：
Where h is the medium bandwidth of a typical type II system.
4. The adaptive laser intensity adjustment method for the active visual measurement in turbid water as claimed in claim 1, wherein the adaptive laser intensity control algorithm sequentially comprises a processing unit 1/L(s),
l(s); wherein L(s) ═ s + a is transmissionThe function, s being a complex variable, a being a parameter to be determined,
is the average value of the water turbidity during calibration, and N is the laser intensity attenuation rate.
5. The adaptive laser intensity adjustment method for the active visual measurement in turbid water as claimed in claim 4, wherein the reference light intensity is adaptively calculated
L(s), k (t) act on a controller of the path of the object model whose output acts on the actual system to produce light intensity PCCDp：
Where h is the medium bandwidth of a typical type II system,
is the average value of water turbidity in calibration, K is the gain of the semiconductor laser, TCCDIs the blanking time of the CCD, TlasIs a time constant.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010127459.3A CN111366534A (en) | 2020-02-28 | 2020-02-28 | Laser light intensity self-adaptive adjusting method for active vision measurement in turbid water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010127459.3A CN111366534A (en) | 2020-02-28 | 2020-02-28 | Laser light intensity self-adaptive adjusting method for active vision measurement in turbid water |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111366534A true CN111366534A (en) | 2020-07-03 |
Family
ID=71208275
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010127459.3A Pending CN111366534A (en) | 2020-02-28 | 2020-02-28 | Laser light intensity self-adaptive adjusting method for active vision measurement in turbid water |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111366534A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5157596A (en) * | 1987-07-17 | 1992-10-20 | Hughes Aircraft Company | Adaptive noise cancellation in a closed loop control system |
| US5978025A (en) * | 1995-11-21 | 1999-11-02 | Stmicroelectronics S.R.L. | Adaptive optical sensor |
| CN101231387A (en) * | 2008-01-22 | 2008-07-30 | 长春理工大学 | Light intensity self-adaptive control system based on LCD for atmospheric laser communication system |
| US20120069342A1 (en) * | 2010-04-19 | 2012-03-22 | Fraser Dalgleish | MEMS Microdisplay Optical Imaging and Sensor Systems for Underwater Scattering Environments |
-
2020
- 2020-02-28 CN CN202010127459.3A patent/CN111366534A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5157596A (en) * | 1987-07-17 | 1992-10-20 | Hughes Aircraft Company | Adaptive noise cancellation in a closed loop control system |
| US5978025A (en) * | 1995-11-21 | 1999-11-02 | Stmicroelectronics S.R.L. | Adaptive optical sensor |
| CN101231387A (en) * | 2008-01-22 | 2008-07-30 | 长春理工大学 | Light intensity self-adaptive control system based on LCD for atmospheric laser communication system |
| US20120069342A1 (en) * | 2010-04-19 | 2012-03-22 | Fraser Dalgleish | MEMS Microdisplay Optical Imaging and Sensor Systems for Underwater Scattering Environments |
Non-Patent Citations (2)
| Title |
|---|
| 夏超英: "《交直流传动系统的自适应控制》", 31 May 1998, 机械工业出版社 * |
| 陈曦 等: "用于海上油膜厚度测量的激光光强调节装置设计", 《天津大学学报（自然科学与工程技术版）》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0377678B1 (en) | Industrial control systems | |
| CN111766777B (en) | PID controller and PID control method | |
| CN110676680A (en) | Device for controlling output wavelength of microchip laser pumping source | |
| CN107255925B (en) | Continuous self-adaptive online correction method for galvanometer system | |
| CN113176725B (en) | Laser chip atomic clock based on Kalman filtering and/or DFB and implementation method | |
| CN111366534A (en) | Laser light intensity self-adaptive adjusting method for active vision measurement in turbid water | |
| Alalwan et al. | Extended Kalman filter based linear quadratic regulator control for optical wireless communication alignment | |
| CN109856964B (en) | Moving object control method and system based on miss distance processing | |
| CN116297323A (en) | Method and system for measuring multi-wavelength attenuation coefficient of water body | |
| CN111968183B (en) | Gauge block calibration method for calibrating monocular line laser three-dimensional measurement module | |
| CN111650163B (en) | Method and device for measuring transmittance of high-power laser antireflection film | |
| CN201550125U (en) | Controller realizing rapid convergence of erbium doped fiber amplifier | |
| CN105204168B (en) | It is a kind of based on double wave front calibrator without wave front detector far-field laser beam apparatus for shaping and method | |
| CN206930835U (en) | Telescope focusing system | |
| Rijal et al. | Comparing Depth Estimation of Azure Kinect and Realsense D435i Cameras | |
| CN112260758A (en) | Bidirectional homologous phase-coherent microwave optical fiber phase-stable transmission method | |
| CN116320756B (en) | Single-binocular combined depth perception system and method based on liquid optical regulation and control | |
| CN113300766B (en) | Self-adaptive distortion wavefront corrector based on LQG and method thereof | |
| CN115407663B (en) | Unmanned ship control method, device, equipment and computer storage medium | |
| Cai | Optimal Control Strategies for the Alignment Problem of Optical Communication Systems | |
| CN116907647B (en) | Strong light interference resistant polarization imaging device and imaging method for spatial light modulation | |
| CN107179605A (en) | Telescope focusing system and method | |
| CN111476847B (en) | Virtual instrument device for calibrating structured light parameters and method thereof | |
| Lou et al. | Stabilization of laser beam position based on a closed-loop fast steering mirror system | |
| Dai et al. | A new method of data processing of division-of-amplitude polarization navigation angle sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20200703 |