CN114370935B - CCD target surface laser energy distribution measurement system and method based on image fusion - Google Patents
CCD target surface laser energy distribution measurement system and method based on image fusion Download PDFInfo
- Publication number
- CN114370935B CN114370935B CN202210023742.0A CN202210023742A CN114370935B CN 114370935 B CN114370935 B CN 114370935B CN 202210023742 A CN202210023742 A CN 202210023742A CN 114370935 B CN114370935 B CN 114370935B
- Authority
- CN
- China
- Prior art keywords
- image
- laser
- fusion
- energy distribution
- polarized light
- 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.)
- Active
Links
- 230000004927 fusion Effects 0.000 title claims abstract description 60
- 238000005259 measurement Methods 0.000 title claims abstract description 27
- 238000000034 method Methods 0.000 title abstract description 21
- 238000012360 testing method Methods 0.000 claims abstract description 10
- 230000008859 change Effects 0.000 claims abstract description 9
- 230000010287 polarization Effects 0.000 claims description 111
- 230000002238 attenuated effect Effects 0.000 claims description 13
- 238000007781 pre-processing Methods 0.000 claims description 7
- 230000004044 response Effects 0.000 claims description 3
- 230000008569 process Effects 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 17
- 230000005540 biological transmission Effects 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 5
- 101100139907 Arabidopsis thaliana RAR1 gene Proteins 0.000 description 4
- 241000220225 Malus Species 0.000 description 4
- 101100028790 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) PBS2 gene Proteins 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000008030 elimination Effects 0.000 description 3
- 238000003379 elimination reaction Methods 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/02—Details
- G01J1/04—Optical or mechanical part supplementary adjustable parts
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/02—Details
- G01J1/04—Optical or mechanical part supplementary adjustable parts
- G01J1/0407—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/02—Details
- G01J1/04—Optical or mechanical part supplementary adjustable parts
- G01J1/0407—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
- G01J1/0414—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings using plane or convex mirrors, parallel phase plates, or plane beam-splitters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/02—Details
- G01J1/04—Optical or mechanical part supplementary adjustable parts
- G01J1/0407—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
- G01J1/0418—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings using attenuators
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T5/00—Image enhancement or restoration
- G06T5/50—Image enhancement or restoration using two or more images, e.g. averaging or subtraction
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T5/00—Image enhancement or restoration
- G06T5/70—Denoising; Smoothing
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/0002—Inspection of images, e.g. flaw detection
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/10—Image acquisition modality
- G06T2207/10004—Still image; Photographic image
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Theoretical Computer Science (AREA)
- Quality & Reliability (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Abstract
The invention discloses a CCD target surface laser energy distribution measurement system and method based on image fusion, wherein the method firstly sets a series of interference laser powers with step change, and obtains a gray image of a CCD detector under the condition of orthogonal placement under each interference laser power; and then carrying out data fusion on the images under the equal power condition by adopting orthogonal compensation, and finally carrying out compensation superposition on the fused images according to a linear relation to obtain final image distribution information, and obtaining CCD target surface laser energy distribution information according to the final image distribution information. The invention is applied to the technical field of laser energy measurement, and the measurement of the laser energy distribution of the target surface is carried out based on the CCD detector, so that other devices commonly used in the laser interference effect test process are not needed. Meanwhile, the measurement dynamic range is only affected by the damage threshold of the CCD detector, so that the method has strong expansibility and has good practical value in experimental tests of laser interference effects.
Description
Technical Field
The invention relates to the technical field of laser energy measurement, in particular to a CCD target surface laser energy distribution measurement system and method based on image fusion.
Background
Measurement of laser spatial energy distribution is an important research topic in the laser optical field. Since the laser spatial energy distribution contains very rich beam quality information, accurate measurement thereof is a precondition for evaluating the beam quality. Along with the wide application of CCD in image acquisition and photoelectric measurement, the parameter measurement method using an area array CCD as a detector has great advantages.
However, when collecting and analyzing laser spots, the CCD is easy to be saturated, the corresponding measurement dynamic range is limited, and the practical application requirement cannot be met. The laser beam analyzer based on the CCD detector is widely used at present, mainly by attenuating laser to ensure that the CCD does not generate saturation phenomenon, only measures the light intensity distribution of the peak part of the light beam, but cannot measure complex images such as laser diffraction. Therefore, how to increase the measurement dynamic range of the CCD becomes a key for solving the measurement of the laser spot energy distribution.
Meanwhile, since the CCD is easy to generate crosstalk phenomenon under the condition of laser irradiation, such as the most typical crosstalk line, the information of energy distribution is lost. In order to avoid the generation of crosstalk lines, the relative threshold value generated by the crosstalk lines can be increased by prolonging the integration time, but the background signal is enhanced, so that the measurement dynamic range of the CCD is reduced. Therefore, how to eliminate the influence of crosstalk lines is also a problem to be solved in order to realize laser spot measurement.
Disclosure of Invention
Aiming at the problem that the dynamic range is too small in the measurement of the laser energy distribution of the target surface by the CCD detector in the prior art, the invention provides a CCD target surface laser energy distribution measurement system and method based on image fusion.
In order to achieve the above object, the present invention provides a CCD target laser energy distribution measuring system based on image fusion, comprising:
A laser for emitting laser light;
The diaphragm is positioned on the emergent light path of the laser and used for limiting laser;
The adjustable attenuation device is positioned on the emergent light path of the diaphragm and is used for adjusting the power of emergent laser;
The beam splitter is positioned on the emergent light path of the adjustable attenuation device and used for splitting laser into one path of laser and two paths of laser;
the laser power meter is positioned on the emergent light path of one laser and is used for measuring the power of one laser;
The CCD detector is positioned on the emergent light path of the two paths of lasers and is used for obtaining a test image of the lasers;
And the image acquisition computer is electrically connected with the CCD detector and is used for obtaining laser energy distribution information according to a test image of laser.
In another embodiment, the adjustable attenuation device includes:
a polarization beam splitter for splitting the laser beam into s-polarized light and p-polarized light;
the first attenuation unit is positioned on the light path of the s-polarized light, and is used for carrying out energy attenuation on the s-polarized light and outputting the attenuated s-polarized light;
the second attenuation unit is positioned on the light path of the p-polarized light, and is used for carrying out energy attenuation on the s-polarized light and outputting the attenuated p-polarized light;
And the polarization beam combiner is used for combining and outputting the attenuated s-polarized light and p-polarized light.
In another embodiment, the first attenuation unit includes a first rotating polarizing device and a first fixed polarizing device;
The first rotating polarization device has a rotating stroke, and when the polarization direction of the first rotating polarization device is the same as the polarization direction of the s-polarized light, the rotating angle of the first rotating polarization device is 0;
The polarization direction of the first fixed polarization device is the same as the polarization direction of the s-polarized light, and the first rotating polarization device is positioned between the first fixed polarization device and the polarization beam splitter.
In another embodiment, the second attenuation unit includes a second rotating polarizing device and a second fixed polarizing device;
The second rotating polarization device has a rotating stroke, and when the polarization direction of the second rotating polarization device is the same as the polarization direction of the p-polarized light, the rotating angle of the second rotating polarization device is 0;
the polarization direction of the second fixed polarization device is the same as that of the p-polarized light, and the second rotary polarization device is positioned between the second fixed polarization device and the polarization beam splitter.
In order to achieve the above purpose, the invention also provides a CCD target laser energy distribution measuring method based on image fusion, which adopts the CCD target laser energy distribution measuring system, and the CCD target laser energy distribution measuring method comprises the following steps:
Step 1, constructing a CCD target surface laser energy distribution measurement system, and setting a series of interference laser powers with step change as the output power of a laser;
Step 2, under the power of each interference laser, obtaining gray images of the CCD detector under the condition of orthogonal placement in the X direction and the Y direction, namely an image X and an image Y respectively, and obtaining an image X sequence and an image Y sequence;
Step 3, carrying out data fusion on the image X and the image Y under the condition of equal power by adopting orthogonal compensation to obtain a fused image, and obtaining a fused image sequence after completing data fusion under all power conditions;
And 4, compensating and superposing each fusion image in the fusion image sequence according to a linear relation to obtain final image distribution information, and obtaining CCD target surface laser energy distribution information according to the final image distribution information.
In another embodiment, in step 1, the step of setting a series of step-changing interference laser powers as the output powers of the laser is specifically:
step 1.1, a laser is closed to collect a background image under the condition that a CCD detector works normally;
Step 1.2, obtaining background noise threshold gray G b based on a background image, checking saturation threshold gray G s of the CCD, obtaining linear response gray scale range [ G b,Gs ], and further obtaining dynamic range proportion R G＝Gs/Gb;
step 1.3, setting a series of step-changing interference laser powers as P 0、P1、P2、···、Pn and making R Li＝Pi/Pi-1<RG, where n represents the total number of interference laser powers and P i represents the ith interference laser power.
In another embodiment, in step 2, after obtaining the image X and the image Y, the image X and the image Y need to be preprocessed, including removing background noise, removing a saturation region, and removing a crosstalk region, specifically:
Defining gray values of pixels with gray values lower than G b in the images X and Y as 0, defining gray values of pixels with gray values equal to G s in the images X and Y as 0, and defining gray values of pixels in all columns where crosstalk occurs in the images X and Y as 0.
In another embodiment, in step 3, the data fusion is performed on the image X and the image Y under the condition of using the orthogonal compensation peer to peer power, specifically:
and rotating the image Y by 90 degrees to obtain a corrected image Y, and replacing the gray value of the crosstalk zone in the image X by the gray value of the corrected image Y at the corresponding position to obtain a corrected image X, namely a fusion image.
In another embodiment, in step 4, the compensating and superimposing the fused images in the fused image sequence according to a linear relationship specifically includes:
And selecting a fusion image with the interference laser power of P 0 as basic data, replacing the gray value of a saturation region of the fusion image with the interference laser power of P 1 by multiplying the gray value of the fusion image of P 0 at a corresponding position by R L1, and then sequentially carrying out data fusion according to the fusion image with gradually increased power, thus obtaining the final image distribution information.
According to the CCD target surface laser energy distribution measuring system and method based on image fusion, the method is based on the CCD detector to measure the target surface laser energy distribution, and other devices and devices commonly used in the laser interference effect testing process are not needed. Meanwhile, the measurement dynamic range is only affected by the damage threshold of the CCD detector, so that the method has strong expansibility and has good practical value in experimental tests of laser interference effects.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a CCD target laser energy distribution measurement system based on image fusion in an embodiment of the invention;
FIG. 2 is a schematic diagram of an adjustable attenuation device according to an embodiment of the present invention;
FIG. 3 is a schematic diagram illustrating analysis of laser transmission characteristics of a tunable attenuation device according to an embodiment of the present invention;
FIG. 4 is a flowchart of a method for measuring the laser energy distribution of a CCD target surface based on image fusion in an embodiment of the invention;
Fig. 5 is a schematic diagram of a diffraction sequence of a circular diaphragm under different interference laser power conditions in an embodiment of the present invention, where (a) is an example of diffraction of the circular diaphragm under the first interference laser power condition, (b) is an example of diffraction of the circular diaphragm under the second interference laser power condition, and (c) is an example of diffraction of the circular diaphragm under the third interference laser power condition;
FIG. 6 is a schematic diagram of rectangular diffraction images of diaphragms in two directions under a certain interference laser power condition in an embodiment of the present invention, where (a) is an exemplary diagram of rectangular diffraction images of diaphragms in X direction and (b) is an exemplary diagram of rectangular diffraction images of diaphragms in Y direction;
fig. 7 is a schematic diagram of a circular diaphragm diffraction image after preprocessing and data fusion in an embodiment of the present invention, where (a) is an example diagram of a circular diaphragm diffraction image in the X direction after preprocessing, (b) is an example diagram of a circular diaphragm diffraction image in the Y direction after preprocessing, and (c) is an example diagram of a circular diaphragm diffraction image after data fusion;
fig. 8 is a schematic diagram of a rectangular diaphragm diffraction image after preprocessing and data fusion in an embodiment of the present invention, where (a) is an example diagram of a rectangular diaphragm diffraction image in the X direction after preprocessing, (b) is an example diagram of a rectangular diaphragm diffraction image in the Y direction after preprocessing, and (c) is an example diagram of a rectangular diaphragm diffraction image after data fusion;
fig. 9 is a one-dimensional energy distribution comparison schematic diagram of a circular diaphragm diffraction image after data fusion in an embodiment of the present invention.
Reference numerals: the device comprises a laser 1, a diaphragm 2, an adjustable attenuation device 3, a polarization beam splitter 301, a polarization beam combiner 302, a first rotary polarization device 303, a first fixed polarization device 304, a second rotary polarization device 305, a second fixed polarization device 306, a first reflecting mirror 307, a second reflecting mirror 308, a third reflecting mirror 309, a beam splitter device 4, a laser power meter 5, a CCD detector 6, an image acquisition computer 7, a beam conversion unit 8 and a reflecting mirror assembly 9.
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.
Furthermore, descriptions such as those referred to as "first," "second," and the like, are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying an order of magnitude of the indicated technical features in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present invention, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; the device can be mechanically connected, electrically connected, physically connected or wirelessly connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In addition, the technical solutions of the embodiments of the present invention may be combined with each other, but it is necessary to be based on the fact that those skilled in the art can implement the technical solutions, and when the technical solutions are contradictory or cannot be implemented, the combination of the technical solutions should be considered as not existing, and not falling within the scope of protection claimed by the present invention.
Example 1
Fig. 1 shows an image fusion-based CCD target laser energy distribution measuring system disclosed in this embodiment, which mainly includes a laser 1, a diaphragm 2, an adjustable attenuation device 3, a beam splitter 4, a laser power meter 5, a CCD detector 6, and an image acquisition computer 7. Wherein the laser 1 is used for emitting laser light to be subjected to energy distribution measurement; the diaphragm 2 is a rectangular diaphragm 2, a round diaphragm 2 or a diaphragm 2 of other constellations, and the diaphragm 2 is positioned on an emergent light path of the laser 1 and used for playing a role in limiting laser; the adjustable attenuation device 3 is positioned on the emergent light path of the diaphragm 2 and is used for adjusting the power of emergent laser; the beam splitter 4 is a laser beam splitter and is positioned on an emergent light path of the adjustable attenuation device 3 so as to split laser into one path of laser and two paths of laser; the laser power meter 5 is positioned on an emergent light path of one laser and is used for measuring the power of one laser; the CCD detector 6 is positioned on the emergent light path of the two paths of laser and is used for obtaining a test image of the laser; the image acquisition computer 7 is electrically connected with the CCD detector 6 and is used for obtaining laser energy distribution information according to a test image of laser.
In this embodiment, a beam conversion unit 8 is further disposed on the optical path between the laser 1 and the diaphragm 2 for performing beam conversion on the laser light. And a reflecting mirror assembly 9 is arranged on the optical path between the adjustable attenuation device 3 and the beam splitter 4, so as to guide the laser light emitted by the adjustable attenuation device 3 into the beam splitter 4.
Referring to fig. 2, in the present embodiment, the tunable attenuation device 3 includes a polarization beam splitter 301, a first attenuation unit, a second attenuation unit, and a polarization beam combiner 302. The polarization beam splitter 301 is located on the outgoing light path of the diaphragm 2, and is used for splitting laser beams to be subjected to energy distribution measurement into s polarized light and p polarized light; the first attenuation unit is positioned on the light path of the s-polarized light, and is used for carrying out power attenuation on the s-polarized light and outputting the attenuated s-polarized light; the second attenuation unit is positioned on the light path of the p-polarized light and is used for carrying out power attenuation on the s-polarized light and outputting the attenuated p-polarized light; the polarization beam combiner 302 is located on the light path of the attenuated s-polarized light and the p-polarized light, and is configured to combine the attenuated s-polarized light and the p-polarized light and output the combined light to the beam splitter 4. The adjustable attenuation device 3 adopts a structure of simultaneously attenuating two paths of laser based on a polarization beam splitter/combiner, not only can realize higher attenuation precision while realizing a larger attenuation range, but also can realize continuous dynamic attenuation of laser in any polarization direction, and can also realize continuous dynamic attenuation of laser with a polarization state changing along with time.
The first attenuation component comprises a first rotating polarizing device 303 and a first fixed polarizing device 304, and the first rotating polarizing device 303 and the first fixed polarizing device 304 are polarizing prisms. The first rotating polarizing device 303 is disposed on an optical path of the s polarized light output by the polarizing beam splitter 301 through a rotating bracket, that is, the first rotating polarizing device 303 has a travel rotating around the s polarized light transmission direction, and can change its polarization direction during rotation, which is specifically defined as: when the polarization direction of the first rotating polarizing device 303 is the same as the polarization direction of the s-polarized light, the rotation angle of the first rotating polarizing device 303 is 0. The first fixed polarizer 304 is disposed behind the first rotating polarizer 303 by a fixed bracket, and the polarization direction of the first fixed polarizer 304 is the same as the polarization direction of the s-polarized light. That is, when the rotation angle of the first rotating polarizing device 303 is not 0, the s-polarized light is emitted through the polarizing beam splitter 301, and then passes through the first rotating polarizing device 303 and the first fixed polarizing device 304 to be subjected to power attenuation twice.
The second attenuation component comprises a second rotating polarizing device 305 and a second fixed polarizing device 306, and the second rotating polarizing device 305 and the second fixed polarizing device 306 are polarizing prisms. The second rotating polarizing device 305 is disposed on the optical path of the p polarized light output by the polarizing beam splitter 301 through a rotating bracket, that is, the second rotating polarizing device 305 has a travel rotating around the transmission direction of the p polarized light, and can change the polarization direction thereof during the rotation, which is specifically defined as: and when the polarization direction of the second rotating polarizing device 305 is the same as the polarization direction of the p-polarized light, the rotation angle of the second rotating polarizing device 305 is 0. The second fixed polarizer 306 is disposed behind the second rotating polarizer 305 by a fixed mount, and the polarization direction of the second fixed polarizer 306 is the same as that of the p-polarized light. That is, when the rotation angle of the second rotating polarizing device 305 is not 0, p-polarized light is emitted through the polarizing beam splitter 301, and then passes through the second rotating polarizing device 305 and the second fixed polarizing device 306 to be subjected to power attenuation twice.
In the implementation process, the rotation angle of the first rotating polarizer 303 is always equal to the rotation angle of the second rotating polarizer 305. And the first rotating polarizing device 303, the first fixed polarizing device 304, the second rotating polarizing device 305 and the second fixed polarizing device 306 are respectively provided with a light absorbing component. The light absorbing tank can be directly used as a light absorbing component to absorb stray light reflected by the polarizing prism.
In an implementation, the adjustable attenuation device 3 further includes a first mirror 307, a second mirror 308, and a third mirror 309. The polarization beam splitter 301, the first rotating polarization device 303, the second fixed polarization device 306 and the first reflecting mirror 307 are distributed at intervals in a straight line, the first reflecting mirror 307 is located above the polarization beam combiner 302, and s polarized light emitted by the polarization beam splitter 301 is directly emitted into the first rotating polarization device 303 and the first fixed polarization device 304 in sequence, and then is emitted into the polarization beam combiner 302 after passing through the first reflecting mirror 307. The second reflecting mirror 308, the second rotating polarizing device 305, the second fixed polarizing device 306 and the polarization beam combiner 302 are distributed at intervals in a straight line, the second reflecting mirror 308 is located below the polarization beam splitter 301, p-polarized light emitted by the polarization beam splitter 301 is reflected by the second reflecting mirror 308, sequentially enters the second rotating polarizing device 305 and the second fixed polarizing device 306, then exits attenuated p-polarized light, and directly enters the polarization beam combiner 302. A third mirror 309 is positioned in the output light path of the polarization beam combiner 302 to condition the outgoing laser light to be directed the same as the incoming laser light.
When the laser light to be subjected to the energy distribution measurement is a laser light of an arbitrary polarization state, a laser light transmission characteristic analysis diagram of the tunable attenuation device 3 is shown in fig. 3. When the laser power output by the laser 1 at a certain moment is defined as P 0 and decomposed according to polarization characteristics, the laser P 0 can be represented by s-polarized light and P-polarized light, where P 0s is s-polarized light, corresponding to power P 0s＝ηP0,P0p is P-polarized light, and corresponding to power P 0p＝(1-η)P0. The input laser P 0 is divided into two paths of laser after passing through the polarization beam splitter PBS1 (i.e. the polarization beam splitter 301), namely a first path of laser s polarized light P 1 and a second path of laser P polarized light P 2, and the corresponding laser powers are P 1＝P0s＝ηP0 and P 2＝P0p＝(1-η)P0 respectively.
The attenuation change rule of the first path of laser is as follows: after passing through the first path of laser rotating polarizing prism GP1 (i.e. the first rotating polarizing device 303), the laser P 1 outputs the laser with the polarization direction changed, and the corresponding laser power is P 3. When the rotation angle of the polarizing prism GP1 is 0 when the GP1 polarization direction is the same as the P 1 polarization direction, the polarization angle of the laser light P 3 rotated with respect to P 1 is θ when the rotation angle of the polarizing prism GP1 is θ. According to Malus's law, P 3＝P1×cos2. Theta. Can be obtained. After passing through the first path of laser fixed polarizing prism GP3 (i.e. the first fixed polarizing device 304), the laser P 3 outputs laser with changed polarization direction, and the corresponding laser power is P 5. Since the polarization direction of the fixed polarizing prism GP3 is the same as the polarization direction of P 1, the polarization angle by which the laser light P 5 rotates with respect to P 3 is also θ. According to Malus's law, P 5＝P3×cos2. Theta. Can be obtained. The laser P 5 passes through the first laser mirror M1 (i.e., the first mirror 307) and then enters the polarization beam combining prism PBS2 (i.e., the polarization beam combiner 302) as attenuated s-polarized light.
The attenuation change rule of the second path of laser is as follows: the laser P 2 passes through the second laser mirror M2 (i.e. the second mirror 308) and then changes the transmission direction, and enters the second laser rotating polarizing prism GP2 (i.e. the second rotating polarizing device 305) to output the laser with the changed polarization direction, where the corresponding laser power is P 4. When the rotation angle of the polarizing prism GP2 is 0 when the GP2 polarization direction is the same as the P 2 polarization direction, the polarization angle of the laser light P 4 rotated with respect to P 2 is θ when the rotation angle of the polarizing prism GP2 is θ. According to Malus's law, P 4＝P2×cos2. Theta. Can be obtained. After passing through the second path of laser fixed polarizing prism GP4 (i.e. the second fixed polarizing device 306), the laser P 4 outputs laser with changed polarization direction, and the corresponding laser power is P 6. Since the polarization direction of the fixed polarizing prism GP4 is the same as the polarization direction of P 2, the polarization angle by which the laser light P 6 rotates with respect to P 4 is also θ. According to Malus's law, P 6＝P4×cos2. Theta. Can be obtained. The laser light P 6 enters the polarization beam combining prism PBS2 (i.e., the polarization beam combiner 302) as attenuated P-polarized light.
In summary, the change rule of the total combined laser light in the adjustable attenuation device 3 is as follows: the first path of laser P 5 as s polarized light enters the polarization beam combining prism PBS2 and can be totally transmitted, and the second path of laser P 6 as P polarized light enters the polarization beam combining prism PBS2 and can be totally reflected, so that the two paths of laser outputs combined laser P 7 in the direction shown in fig. 3, and the corresponding energy is P 7＝P5+P6＝P0×cos4 theta. The laser P 7 passes through the beam combining laser mirror M3 (i.e., the third mirror 309) and outputs the laser P 8 with changed direction, the laser energy being P 8＝P0×cos4 θ, and the polarization direction being consistent with that of P 0. Compared with the traditional polarization attenuator, the adjustable attenuation device 3 in the embodiment not only can realize higher attenuation precision while realizing larger attenuation range, but also can realize continuous dynamic attenuation of laser in any polarization direction and can also realize continuous dynamic attenuation of laser with the polarization state changing along with time.
Example 2
The embodiment discloses a CCD target laser energy distribution measuring method based on image fusion, which adopts the CCD target laser energy distribution measuring system in the embodiment 1. Referring to fig. 4, the method for measuring the laser energy distribution of the target surface of the ccd comprises the following steps 1 to 4.
Step 1, a CCD target surface laser energy distribution measuring system is built, and a series of interference laser powers with step change are set as output power of a laser. In the specific implementation process, the implementation mode of setting a series of interference laser powers with step changes as the output power of the laser specifically comprises the following steps:
step 1.1, closing a laser, and collecting a background image under the condition that a CCD detector works normally;
Step 1.2, calculating background noise threshold gray G b based on background image statistics background noise information, checking saturation threshold gray G s of CCD to obtain linear response gray scale range [ G b,Gs ], and further obtaining dynamic range proportion R G＝Gs/Gb;
step 1.3, setting a series of step-changing interference laser powers as P 0、P1、P2、···、Pn and making R Li＝Pi/Pi-1<RG, where n represents the total number of interference laser powers and P i represents the ith interference laser power.
And 2, under the power of each interference laser, obtaining gray images of the CCD detector under the condition of orthogonal placement in the X direction and the Y direction, namely an image X and an image Y respectively, and obtaining an image X sequence and an image Y sequence. The specific implementation process is as follows:
and 2.1, turning on a laser, stabilizing light emission, adjusting an adjustable laser attenuation device to enable the power of interference laser to be P 0, judging that no saturated crosstalk phenomenon exists in the obtained laser interference image through an image acquisition computer, and storing image data. Defining the direction of the CCD detector as the X direction at the moment, and obtaining an image X when the power of the interference laser is P 0;
Step 2.2, adjusting an adjustable laser attenuator to obtain the interference laser power P 1, ensuring R L1＝P1/P0<RG, and acquiring and storing image data through an image acquisition computer to obtain an image X when the interference laser power P 1;
Step 2.3, repeating the step 2.2 to obtain a series of interference laser power P i, wherein the corresponding power proportion meets R Li＝Pi/Pi-1<RG until the laser power level under the laser interference experimental condition is reached, and acquiring and storing image data through an image acquisition computer to obtain an image X under the power of all interference lasers; for example, a circular diaphragm diffraction sequence image under different interference laser power conditions is shown in fig. 5;
Step 2.4, rotating the CCD detector by 90 degrees, keeping other conditions of the CCD target laser energy distribution measuring system unchanged, repeating the steps 2.1-2.3, ensuring that the interference laser power is equal, and acquiring and storing image data through an image acquisition computer to obtain an image Y under the power of all interference lasers; for example, rectangular stop diffraction images in two directions for a certain interference laser power condition are shown in fig. 6.
In a specific implementation process, after obtaining the image X and the image Y, the image X and the image Y need to be preprocessed, including removing background noise, removing a saturation region and removing a crosstalk region, specifically:
The background noise elimination is to define gray values of pixels with gray values lower than G b in the image X and the image Y as 0, the saturation area elimination is to define gray values of pixels with gray values equal to G s in the image X and the image Y as 0, and the crosstalk elimination area is to define gray values of pixels of all columns where crosstalk occurs in the image X and the image Y as 0. The circular diaphragm and rectangular diaphragm diffraction images after the pretreatment are shown in fig. 7 (a), 7 (b), 8 (a) and 8 (b), respectively.
And 3, carrying out data fusion on the image X and the image Y under the condition of equal power by adopting orthogonal compensation to obtain a fused image, and obtaining a fused image sequence after completing data fusion under all power conditions. The specific implementation mode is as follows:
and rotating the image Y by 90 degrees to obtain a corrected image Y, and replacing the gray value of the crosstalk zone in the image X by the gray value of the corrected image Y at the corresponding position to obtain a corrected image X, namely a fusion image.
And 4, compensating and superposing each fusion image in the fusion image sequence according to a linear relation to obtain final image distribution information, and obtaining CCD target surface laser energy distribution information according to the final image distribution information. The specific implementation mode is as follows:
And selecting a fusion image with the interference laser power of P 0 as basic data, replacing the gray value of a saturation region of the fusion image with the interference laser power of P 1 by multiplying the gray value of the fusion image of P 0 at a corresponding position by R L1, and then sequentially carrying out data fusion according to the fusion image with gradually increased power, thus obtaining the final image distribution information. The circular diaphragm diffraction image after data fusion is completed is shown in fig. 7 (c) and 8 (c).
And combining the laser power under the laser interference experimental condition and the fused final image distribution information, and calculating to obtain the target surface laser energy distribution information. The one-dimensional distribution image of the laser energy of the round diaphragm diffraction target surface after data fusion is completed at the center position of the light spot is shown in fig. 9, and the dynamic range is improved from 20dB to 40dB.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the description of the present invention and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the invention.
Claims (8)
1. The CCD target surface laser energy distribution measuring system based on image fusion is characterized by comprising:
A laser for emitting laser light;
The diaphragm is positioned on the emergent light path of the laser and used for limiting laser;
The adjustable attenuation device is positioned on the emergent light path of the diaphragm and is used for adjusting the power of emergent laser;
The beam splitter is positioned on the emergent light path of the adjustable attenuation device and used for splitting laser into one path of laser and two paths of laser;
the laser power meter is positioned on the emergent light path of one laser and is used for measuring the power of one laser;
The CCD detector is positioned on the emergent light path of the two paths of lasers and is used for obtaining a test image of the lasers;
The image acquisition computer is electrically connected with the CCD detector and is used for obtaining laser energy distribution information according to a laser test image;
the CCD target laser energy distribution measuring system is adopted to measure the CCD target laser energy distribution, and comprises the following steps:
Step 1, constructing a CCD target surface laser energy distribution measurement system, and setting a series of interference laser powers with step change as the output power of a laser;
Step 2, under the power of each interference laser, obtaining gray images of the CCD detector under the condition of orthogonal placement in the X direction and the Y direction, namely an image X and an image Y respectively, and obtaining an image X sequence and an image Y sequence;
Step 3, carrying out data fusion on the image X and the image Y under the condition of equal power by adopting orthogonal compensation to obtain a fused image, and obtaining a fused image sequence after completing data fusion under all power conditions;
And 4, compensating and superposing each fusion image in the fusion image sequence according to a linear relation to obtain final image distribution information, and obtaining CCD target surface laser energy distribution information according to the final image distribution information.
2. The image fusion-based CCD target laser energy distribution measurement system of claim 1, wherein the adjustable attenuation device comprises:
a polarization beam splitter for splitting the laser beam into s-polarized light and p-polarized light;
the first attenuation unit is positioned on the light path of the s-polarized light, and is used for carrying out energy attenuation on the s-polarized light and outputting the attenuated s-polarized light;
the second attenuation unit is positioned on the light path of the p-polarized light, and is used for carrying out energy attenuation on the s-polarized light and outputting the attenuated p-polarized light;
And the polarization beam combiner is used for combining and outputting the attenuated s-polarized light and p-polarized light.
3. The image fusion-based CCD target laser energy distribution measurement system of claim 2, wherein the first attenuation unit includes a first rotating polarizer and a first fixed polarizer;
The first rotating polarization device has a rotating stroke, and when the polarization direction of the first rotating polarization device is the same as the polarization direction of the s-polarized light, the rotating angle of the first rotating polarization device is 0;
The polarization direction of the first fixed polarization device is the same as the polarization direction of the s-polarized light, and the first rotating polarization device is positioned between the first fixed polarization device and the polarization beam splitter.
4. The image fusion-based CCD target laser energy distribution measuring system according to claim 2 or 3, wherein the second attenuation unit includes a second rotating polarizing device and a second fixed polarizing device;
The second rotating polarization device has a rotating stroke, and when the polarization direction of the second rotating polarization device is the same as the polarization direction of the p-polarized light, the rotating angle of the second rotating polarization device is 0;
the polarization direction of the second fixed polarization device is the same as that of the p-polarized light, and the second rotary polarization device is positioned between the second fixed polarization device and the polarization beam splitter.
5. The system for measuring the laser energy distribution of the CCD target surface based on image fusion according to claim 1, wherein in step 1, a series of step-changing interference laser powers are set as the output powers of the lasers, specifically:
step 1.1, a laser is closed to collect a background image under the condition that a CCD detector works normally;
Step 1.2, obtaining background noise threshold gray G b based on a background image, checking saturation threshold gray G s of the CCD, obtaining linear response gray scale range [ G b,Gs ], and further obtaining dynamic range proportion R G＝Gs/Gb;
step 1.3, setting a series of step-changing interference laser powers as P 0、P1、P2、···、Pn and making R Li＝Pi/Pi-1<RG, where n represents the total number of interference laser powers and P i represents the ith interference laser power.
6. The system for measuring the laser energy distribution of the CCD target surface based on image fusion according to claim 5, wherein in the step 2, after obtaining the image X and the image Y, preprocessing is further required for the image X and the image Y, including removing background noise, removing a saturation region and removing a crosstalk region, specifically comprising:
Defining gray values of pixels with gray values lower than G b in the images X and Y as 0, defining gray values of pixels with gray values equal to G s in the images X and Y as 0, and defining gray values of pixels in all columns where crosstalk occurs in the images X and Y as 0.
7. The image fusion-based CCD target laser energy distribution measuring system according to claim 5 or 6, wherein in step 3, the image X and the image Y under the condition of adopting orthogonal compensation peer-to-peer power are subjected to data fusion, specifically:
and rotating the image Y by 90 degrees to obtain a corrected image Y, and replacing the gray value of the crosstalk zone in the image X by the gray value of the corrected image Y at the corresponding position to obtain a corrected image X, namely a fusion image.
8. The system for measuring the laser energy distribution of the target surface of the CCD based on the image fusion according to claim 7, wherein in the step 4, the compensation and superposition are performed on each fused image in the fused image sequence according to a linear relationship, specifically:
And selecting a fusion image with the interference laser power of P 0 as basic data, replacing the gray value of a saturation region of the fusion image with the interference laser power of P 1 by multiplying the gray value of the fusion image of P 0 at a corresponding position by R L1, and then sequentially carrying out data fusion according to the fusion image with gradually increased power, thus obtaining the final image distribution information.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210023742.0A CN114370935B (en) | 2022-01-10 | 2022-01-10 | CCD target surface laser energy distribution measurement system and method based on image fusion |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210023742.0A CN114370935B (en) | 2022-01-10 | 2022-01-10 | CCD target surface laser energy distribution measurement system and method based on image fusion |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114370935A CN114370935A (en) | 2022-04-19 |
| CN114370935B true CN114370935B (en) | 2024-05-24 |
Family
ID=81144012
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210023742.0A Active CN114370935B (en) | 2022-01-10 | 2022-01-10 | CCD target surface laser energy distribution measurement system and method based on image fusion |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114370935B (en) |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1621787A (en) * | 2003-11-27 | 2005-06-01 | 北京光电技术研究所 | Measuring system and method for wave zone laser energy/power |
| CN102538960A (en) * | 2011-12-14 | 2012-07-04 | 长春理工大学 | Long time exposure-based laser energy distribution detector |
| JP2013242405A (en) * | 2012-05-18 | 2013-12-05 | Fdk Corp | Variable optical attenuator |
| CN103913299A (en) * | 2014-04-10 | 2014-07-09 | 中国人民解放军国防科学技术大学 | Optical resonant cavity mode and loss measurement device and method based on optical cavity ring-down method |
| CN203908683U (en) * | 2014-05-21 | 2014-10-29 | 中国科学院西安光学精密机械研究所 | High-dynamic-range laser far field focal spot measuring apparatus |
| CN104535201A (en) * | 2015-01-05 | 2015-04-22 | 中国工程物理研究院激光聚变研究中心 | Measuring device for contrast ratio of high-power ultrashort laser pulses |
| CN108020179A (en) * | 2017-12-28 | 2018-05-11 | 西安应用光学研究所 | A kind of High-precision angle measuring device and method |
| CN110363786A (en) * | 2019-06-12 | 2019-10-22 | 西安理工大学 | Single crystal growing furnace level sensing laser spot center localization method based on Bayesian Fusion |
| CN110716318A (en) * | 2019-10-25 | 2020-01-21 | 中国科学院长春光学精密机械与物理研究所 | High repetition frequency laser beam splitting synchronous precision attenuator |
| CN113340570A (en) * | 2021-05-17 | 2021-09-03 | 中国科学院上海光学精密机械研究所 | Measuring device and measuring method for dynamic light field and dynamic focal spot of high-power pulse laser |
| CN113465884A (en) * | 2021-06-03 | 2021-10-01 | 中国科学院空天信息创新研究院 | Continuous laser damage threshold testing device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7706069B2 (en) * | 2007-05-14 | 2010-04-27 | Coherent, Inc. | Attenuator for high-power unpolarized laser beams |
-
2022
- 2022-01-10 CN CN202210023742.0A patent/CN114370935B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1621787A (en) * | 2003-11-27 | 2005-06-01 | 北京光电技术研究所 | Measuring system and method for wave zone laser energy/power |
| CN102538960A (en) * | 2011-12-14 | 2012-07-04 | 长春理工大学 | Long time exposure-based laser energy distribution detector |
| JP2013242405A (en) * | 2012-05-18 | 2013-12-05 | Fdk Corp | Variable optical attenuator |
| CN103913299A (en) * | 2014-04-10 | 2014-07-09 | 中国人民解放军国防科学技术大学 | Optical resonant cavity mode and loss measurement device and method based on optical cavity ring-down method |
| CN203908683U (en) * | 2014-05-21 | 2014-10-29 | 中国科学院西安光学精密机械研究所 | High-dynamic-range laser far field focal spot measuring apparatus |
| CN104535201A (en) * | 2015-01-05 | 2015-04-22 | 中国工程物理研究院激光聚变研究中心 | Measuring device for contrast ratio of high-power ultrashort laser pulses |
| CN108020179A (en) * | 2017-12-28 | 2018-05-11 | 西安应用光学研究所 | A kind of High-precision angle measuring device and method |
| CN110363786A (en) * | 2019-06-12 | 2019-10-22 | 西安理工大学 | Single crystal growing furnace level sensing laser spot center localization method based on Bayesian Fusion |
| CN110716318A (en) * | 2019-10-25 | 2020-01-21 | 中国科学院长春光学精密机械与物理研究所 | High repetition frequency laser beam splitting synchronous precision attenuator |
| CN113340570A (en) * | 2021-05-17 | 2021-09-03 | 中国科学院上海光学精密机械研究所 | Measuring device and measuring method for dynamic light field and dynamic focal spot of high-power pulse laser |
| CN113465884A (en) * | 2021-06-03 | 2021-10-01 | 中国科学院空天信息创新研究院 | Continuous laser damage threshold testing device |
Non-Patent Citations (4)
| Title |
|---|
| 周旋风.激光辐照行间转移型CCD的串扰效应.《光学 精密工程》.2021,第29卷(第6期),正文第二节、附图1. * |
| 激光光束分析仪测量系统及其实验研究;刘慧;;科技咨询导报;20070621(18);全文 * |
| 激光对像增强器干扰的实验研究;谢运涛;张玉钧;王玺;孙晓泉;;光电技术应用;20180215(01);全文 * |
| 激光辐照行间转移型CCD的串扰效应;周旋风;《光学 精密工程》;20210630;第29卷(第6期);正文第二节、附图1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114370935A (en) | 2022-04-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7190442B1 (en) | Method of evaluating fiber PMD using POTDR trace | |
| US7426021B2 (en) | Interferometric optical analyzer and method for measuring the linear response of an optical component | |
| Zhu et al. | A comparison of wavelength dependent polarization dependent loss measurements in fiber gratings | |
| CN107462900B (en) | Gas component detection laser radar based on wavelength tunable laser source | |
| JPH07301580A (en) | Measuring method of noise level | |
| JPS63309825A (en) | Direction deciding apparatus for light concurrently serving for detection of light | |
| CN110716207A (en) | Laser ranging system based on single photon modulation spectrum measurement | |
| CN104180892A (en) | Optical interferometer and vibrometer comprising such an optical interferometer | |
| CN110031093B (en) | Large-range laser power transmission detection device | |
| CN113538381A (en) | Method and system for rapidly detecting Mueller matrix of sample in weak light field | |
| CN114370935B (en) | CCD target surface laser energy distribution measurement system and method based on image fusion | |
| Frankel et al. | Two-dimensional fiber-optic control of a true time-steered array transmitter | |
| CN109696418B (en) | Heterodyne balance detection system and detection method applied to TDLAS direct absorption method under low signal-to-noise ratio | |
| US6504604B1 (en) | In situ polarization mode dispersion measurement | |
| US20040165192A1 (en) | Device and method for determining the chromatic dispersion of optical components | |
| EP0953846A2 (en) | Electro-optic sampling oscilloscope | |
| CA2219286A1 (en) | Measurement of polarization mode dispersion | |
| CN108107020B (en) | Device and method for measuring nonlinear refractive index coefficient of material | |
| CN110243477A (en) | A kind of spectrographic pulse laser polarization analyzer complete in real time | |
| CN114152578A (en) | Vortex wave plate-based spatial modulation polarization detection method | |
| CN207263419U (en) | A kind of Cable's Fault detecting system based on Rayleigh scattering technology | |
| CN112398545A (en) | Quantum signal modulation variance control and calibration method and system for CVQKD system | |
| CN115979967A (en) | Ultrafast single-pixel polarization imaging system | |
| CN115250144B (en) | Visual coupling and large dynamic range crosstalk testing method and device for multi-core optical fiber | |
| Baney et al. | Elementary matrix method for dispersion analysis in optical systems |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |