CN105067226B - A kind of pulse laser far field optical axis stable detection method - Google Patents
A kind of pulse laser far field optical axis stable detection method Download PDFInfo
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Abstract
The invention discloses a kind of pulse laser far field optical axis stable detection method, setting is acquired by display control program first, sets laser pulse period, shooting number, the orientation of whole system is adjusted by turret systems, bornb sight, display control program start to gather image；By collection optical system to light spot image number reach it is default shooting number after, collection terminates；The light spot image of collection is analyzed, so as to obtain the stability information of laser optical axis.The present invention solves the problems, such as synchronous acquisition representation of laser facula so that acquisition system can automatically, in real time, completely collect continuous light spot image.
Description
Technical field
The invention belongs to laser remote field optical axis to carry out stability inspection technology, particularly a kind of pulse laser far field optical axis
Detection of Stability method.
Background technology
Laser has the characteristics of good brightness height, monochromaticjty and good directionality, therefore the application of laser has spread all over science and technology, warp
Ji, the military and other development fields of society.Laser is typically limited to short-range indoor application at present, and remote outdoor
Can there are atmospheric turbulance and the uneven influence of air index under environment, on laser emission path, along with laser in itself
The influence that cavity temperature changes during the vibrations of resonator and laser produce, can ultimately result in the shake of laser emitting optical axis
And laser beam extension effect (change of the angle of divergence).
In actual applications, the presence of optical jitter and beam spread effect can cause hot spot of the laser in target to be trembled
It is dynamic so that the actual envelope size of hot spot is more than preset area, this may and can cause such as laser ranging, laser guidance,
In the application of technique of laser range gated imaging etc., the echo strength for the laser that detector receives every time differs, or even occurs
Because amount of jitter is excessive, the situation of test leakage is caused to occur.The presence of such case, measurement accuracy, the laser of laser ranging can be influenceed
Accuracy of guidance etc., cause the appearance of mistake information, so, before laser is integrated into various systems, to laser
Device carries out the analysis of far field optical axis stable, i.e., the quantitative optical jitter amount for providing laser and angle of divergence amount of jitter just become
It is particularly important.
At present, the main flow for testing measurement is the CCD class laser beam analyzers developed based on videographic measurment theory, and foreign countries are
There are multiple commercial vendors to release the commercialized laser analysis instrument for completing closely optical axis stable analysis, such as Thorlabs companies
BC106 series and Duma Optronics companies of Israel BeamOnHR.
Also than later for foreign countries, domestic at present is ripe for domestic Laser Beam Quality Analysis work starting
The commercialization laser beam analyzer of independent research is also difficult to see, also rest on mostly laboratory internal research and development state, as Beijing with
Track and Research on Communication Technology institute (far-field laser Optical spot measurement system exploitations of [1] Zhang Yingxin, Wang Yunping, the Wang Yu based on CCD with
Using [J] photoelectric technology applications, 2011,04:11-13+52.), China People's Liberation Army General Armament Department Ordnance Technology Research Institute
(" laser spot collector with low frequency and narrow pulse ", the patent No. 200910074771.4) passes through to home and abroad laser beam quality point
The investigation of analysis system is compared with it can be found that external Laser Beam Quality Analysis instrument is either in structure, principle, or in work(
Energy and cost will conveniently be far superior to the Laser Beam Quality Analysis instrument of domestic independent research, but either the country is gone back at present
External, existing Laser Beam Quality Analysis system can be only applied to the fairly simple interior of short distance, environment mostly, for away from
From farther out, the more complicated outdoor environment of environment, almost do not study too much also, this is allowed for applied to far field outdoor environment
Laser beam stability analysis become abnormal difficult.
The content of the invention
It is an object of the invention to provide a kind of pulse laser far field optical axis stable detection method, far field can be swashed
The optical axis stable of light device is analyzed and detected.
The technical solution for realizing the object of the invention is：A kind of pulse laser far field optical axis stable detection method,
Step is as follows：
The first step, setting is acquired by display control program, sets laser pulse period, shooting number, pass through
Turret systems adjust the orientation of whole system, bornb sight, and display control program starts to gather image；
Second step, laser form laser facula after far field transmission in diffusing reflection target, and optical system is collected and is diffusely reflected
The laser energy that target reflects, the time of origin of laser pulse is detected by APD detectors in real time, and exports real-time response arteries and veins
Punching；Known laser pulse frequency, it is contemplated that the next laser pulse closed on reaches the time of optical system, utilizes FPGA board
Line delay is entered to the response impulse of APD detectors output, and delay pulse is accurately arrived in next laser pulse
Produce before；Near Infrared CCD camera imaging is triggered using delay pulse, collects the hot spot figure of the laser pulse of next arrival
Picture, display control program is transferred to, after the light spot image number collected reaches default shooting number, collection terminates；
3rd step, the light spot image of collection is analyzed, first, first image pre-processed, i.e., regional choice, in
Value filtering, opening and closing operation, edge extracting, to reduce the interference of background, the influence of atmospheric perturbation, the influence of CCD intrinsic noises；Its
It is secondary, it is different according to the gray scale of each pixel of image obtained by Near Infrared CCD camera after pretreatment, calculate the center of gravity of hot spot, i.e., it is strong
Degree center；Again, carry out hot spot fitting with least square method circle fitting algorithm, calculate the centre of form of individual light spot image, i.e., it is several
What center；Finally, after the geometry of one group of light spot image being continuously shot, center intensity is calculated, corresponding line chart is generated,
Abscissa is figure sequence number, and ordinate is the geometric center of hot spot or the X values or Y value of center intensity coordinate, passes through display control
System shows, can reflect glossing up geometric center or center intensity in the horizontal direction or vertical direction variation tendency,
And one group of light spot image geometry, the standard deviation of center intensity, average deviation and the average angle of deviation are calculated, if being less than institute
The maximum of permission, then meet the stability requirement of laser, if more than the maximum allowed, do not meet the steady of laser
Qualitative requirement, so as to obtain the stability information of laser optical axis.
The present invention compared with prior art, its remarkable advantage：(1) CCD camera combination Synchronization Control acquisition technique pair is utilized
Laser facula is gathered in real time, then hot spot data are analyzed, so as to obtain the stability information of laser remote field optical axis,
Solve the problems, such as synchronous acquisition representation of laser facula so that acquisition system can automatically, in real time, completely collect continuous light
Spot image.(2) for the optical system of far-field measurement design, it can adapt to wild environment remote, that background is complicated.
The present invention is described in further detail below in conjunction with the accompanying drawings.
Brief description of the drawings
Fig. 1 is the composition frame chart of pulse laser far field optical axis stable detecting system of the present invention.
Fig. 2 is the camera imaging area schematic of the present invention.
Fig. 3 is the object lens imaging relations figure of the present invention (laser beam axis is stable).
Fig. 4 is the object lens imaging relations figure (laser beam axis shake) of the present invention.
Fig. 5 is the timing diagram of the Synchronization Control acquisition system of the present invention：(a) light pulse that laser is sent, (b) generation are represented
The response impulse of Table A PD detectors output, (c) represent response impulse and inputted to being counted during FPGA board to this pulse
Delay figure.
Fig. 6 is the system principle diagram of the present invention.
Fig. 7 is the workflow diagram of pulse laser far field optical axis stable detection method of the present invention.
Fig. 8 is original light spot image.
Fig. 9 be it is smooth after light spot image.
Figure 10 is the light spot image after opening and closing operation.
Figure 11 is the light spot image edge that Canny operators detect.
Figure 12 is least square method circle fitting algorithm fitting circle design sketch.
Embodiment
With reference to Fig. 1 and Fig. 6, pulse laser far field optical axis stable detecting system of the present invention, optical system, synchronization are included
Acquisition system, display control program and turret systems are controlled, optical system, Synchronization Control acquisition system, display control program are all
On turret systems；The turret systems are mainly made up of the U-shaped turntable of two dimension and support tripod.
The Synchronization Control acquisition system includes APD (avalanche diode) detector, Near Infrared CCD camera, FPGA circuitry
Plate, wherein FPGA board include time delay module, and APD detector outputting standard Transistor-Transistor Logic level signals are to FPGA board, through FPGA
Output controls when it exposes (time for exposure) to Near Infrared CCD camera after time delay module delay in circuit board.
The optical system corresponds to optical lens including APD detectors, Near Infrared CCD camera corresponds to optical lens and two
Narrow band filter slice, wherein two same optical axises of optical lens, and narrow band filter slice is placed respectively after two optical lens, suppression
The light pulse that the influence of bias light processed, wherein APD detectors correspond to optical lens collection passes through aperture after narrow band pass filter
Diaphragm inputs APD detectors.
The display control program is connected with Near Infrared CCD camera, sets acquisition parameter and the reception of Near Infrared CCD camera
Near Infrared CCD camera acquired image data, and light spot image is analyzed and processed.Display control program can be to touch
Formula tablet personal computer.Touch tablet personal computer is connected by gigabit network cable with Near Infrared CCD camera.Touch tablet personal computer can be with
Turret systems are communicated by RS485 serial ports to control the rotation of turntable, or turret systems to adjust manually.
The Near Infrared CCD camera of pulse laser far field optical axis stable detection method of the present invention corresponds to Jiao of optical lens
Away from for：One is to ensure that the areas imaging of Near Infrared CCD camera will include the scope of hot spot and its shake；Second, in order to ensure foot
Enough detection accuracies, it is desirable to which hot spot often shakes 0.01mrad on target, and hot spot is at least mobile 3 on infrared CCD camera target surface
Pixel.Determine that the focal length process that Near Infrared CCD camera corresponds to optical lens is：
As shown in Fig. 2 a-quadrant is target scope, B area is camera for the areas imaging requirement of Near Infrared CCD camera target surface
Target surface coverage, C regions are hot spot scopes, and the region between B (black region) and C (white portion) region is hot spot shake
Scope.
If spot radius are R, reception objective focal length is f, and radius of the hot spot on target is H, between target and detection object lens
Distance is l, and when hot spot is stable, then imaging relations are as shown in Figure 3.From imaging relations：
When hot spot is shaken, its imaging relations can become as shown in Figure 4.From new imaging relations, the radius of new hot spot
Scope H1And H2：
Δ R refers to the amount of hot spot shake, then displacement Δ H of the hot spot on infrared CCD camera target surface is：
Mobile pixel count cnt of the hot spot on infrared CCD camera target surface be：
In above formula, a is single pixel length of side of infrared CCD camera；
If laser divergence angle is θ, target is the square that the length of side is A, and the distance of laser transmitting system to target is L,
Hot spot maximum jitter angle is β, then is analyzed more than, and the relation between parameters should meet following a few formulas：
X, Y are the length and width of infrared CCD camera target surface respectively in above formula, and n is that hot spot often shakes Δ θ, infrared CCD on target
Corresponding mobile pixel count on camera target surface, a are the camera list pixel length of side.
Three formulas more than, can obtain focal length should meet：
If X >=Y,
θ is the angle of divergence of laser, and θ maximum is 0.5mrad, and n is integer (can be more than or equal to 3).If set L
It=2000m, A=2m, β=0.05mrad, can be calculated after bringing concrete numerical value into, meet the camera lens focal length f of requirement model
Enclose for 480mm to 640mm.
Areas imaging corresponding to the APD detector target surfaces of pulse laser far field optical axis stable detection method of the present invention with
The areas imaging of infrared CCD camera is consistent, and the focal length that APD detectors correspond to optical lens meets following formula：
In above formula, r is APD detector target surface diameters.
It if setting L=2000m, A=2m, β=0.05mrad, can be calculated after bringing concrete numerical value into, meet the APD of requirement
The lens focus scope of detector is 75mm to 125mm.
With reference to Fig. 5, in pulse laser far field optical axis stable detection method of the present invention, Fig. 5 (a) represents laser and sent
Light pulse, its reach APD detectors target surface after, after response time t, APD detectors output response impulse, such as
In Fig. 5 shown in (b).This response impulse is inputted to FPGA board, acted on through time delay module, and counting is carried out to this pulse and prolonged
When, in Fig. 5 shown in (c), delay time T2Afterwards, FPGA board output prediction pulse, this pulse is Near Infrared CCD camera
Trigger signal, its frequency is consistent with laser pulse frequency, but it has an advanced phase T relative to laser pulse1, i.e.,
The trigger pulse of Near Infrared CCD camera produces before the arrival of each laser pulse, and between trigger pulse and laser pulse
Time interval T1Immobilize.
Delay time T2With leading phase T1Specific size should integrate laser frequency and Near Infrared CCD camera it is minimum
Time for exposure determines.In general, the minimum exposure time T of Near Infrared CCD camera at presentminAll more than Microsecond grade, this is long-range
In the pulsewidth of laser pulse, so the time for exposure of Near Infrared CCD camera is arranged into minimum, air so can be effectively reduced
Back scattering and the influence of veiling glare.
The cycle of laser pulse is T, sets laser facula time of occurrence to be in the centre bit of Near Infrared CCD time for exposure
Put, then the set counting delay time T for APD explorer response pulses in FPGA board2For：
Synchronization Control acquisition system is Synchronization Control acquisition technique, can not only be collected exactly with this technology continuous
, complete light spot image, the back scattering of air and the influence of bias light can also be reduced.
It is as follows the step of pulse laser far field optical axis stable detection method of the present invention with reference to Fig. 7：
The first step, setting is acquired by display control program, sets laser pulse period, shooting number, pass through
Turret systems adjust the orientation of whole system, bornb sight, and display control program starts to gather image.
Second step, laser form laser facula after far field transmission in diffusing reflection target, and optical system is collected and is diffusely reflected
The laser energy that target reflects, the time of origin of laser pulse is detected by APD detectors in real time, and exports real-time response arteries and veins
Punching；Known laser pulse frequency, it is contemplated that the next laser pulse closed on reaches the time of optical system, utilizes FPGA board
Line delay is entered to the response impulse of APD detectors output, and delay pulse is accurately arrived in next laser pulse
Produce before；Near Infrared CCD camera imaging is triggered using delay pulse, collects the hot spot figure of the laser pulse of next arrival
Picture, display control program is transferred to, after the light spot image number collected reaches default shooting number, collection terminates；Not yet
Have and reach setting number, continue to gather.
3rd step, first, the light spot image of collection is analyzed, first image pre-processed, i.e., regional choice, in
Value filtering, opening and closing operation, edge extracting, to reduce the interference of background, the influence of atmospheric perturbation, the influence of CCD intrinsic noises.
Regional choice：Due to there may be other scenery in the visual field of Near Infrared CCD camera, subsequent treatment can be influenceed, is passed through
Regional choice is crossed, processing region is reduced in target, the degree of purity of image handled by raising.
Medium filtering：Many of original image independently of the pixel outside hot spot main part, these pixels
In the presence of causing the edge of hot spot to thicken, this can cause the reduction of follow-up profile extraction accuracy, so by these noise spots
Removed from light spot image so that the edge clear of image is visible.Medium filtering is a kind of nonlinear smothing filtering method, with picture
The intermediate value of grey scale pixel value in vegetarian refreshments neighborhood substitutes current grayvalue, and two dimension median filter mathematic(al) representation is as follows：
Fi,j=MedA{Xi,j}
In above formula, A is filter window, Xi,jFor the grey scale pixel value in A, Fi,jFor the gray scale of current filter window center point
Value.Medium filtering can be eliminated such as the isolated noise spot of the hot spot edge in Fig. 8.Meanwhile medium filtering can also be protected
The marginal information of image, and have good smooth effect to image.Fig. 9 is the light spot image after median filter smoothness of image.
Opening and closing operation：Assuming that E represents a two-dimentional theorem in Euclid space, image A is E a subset, and structural element B is also E
A subset, b is a point in E, and erosion operation is defined as：
Dilation operation is defined as：
Opening operation is that A is opened B, i.e. A is first corroded by B, then the result expanded by B, is defined as follows：
Closed operation is that A closes to B, i.e. A is first expanded by B, then the result corroded by B, is defined as follows：
Structural element is used to carry out an opening operation and closed operation, result to figure respectively for 5 × 5 square
As shown in Figure 10, opening and closing operation can eliminate noise well, fill up hole and smooth edges.
Edge extracting：The extraction of marginal information is carried out using Canny operators, (specific method is shown in Zhou Xiaoming etc. to Canny operators
A kind of improved Canny operator edge detections algorithm [J] Surveying Engineering, 2008,17 (1):28-31) utilize Gaussian function
First differential, preferable balance is obtained between noise suppressed and rim detection, there is good rim detection performance, Canny
The hot spot edge that operator detects is as shown in figure 11.
Secondly, after pretreatment when center intensity (calculate without edge treated) according to scheming obtained by Near Infrared CCD camera
As the gray scale difference of each pixel, the center of gravity for calculating hot spot (calculates the method for the center of gravity of hot spot referring to Sun Aixian etc. laser light
Spot barycenter test Precision Theory analyzes [J] laser technologies, 2004,28 (6):667-672.), i.e. center intensity.
Assuming that light spot image is in two-dimensional coordinate system, image size is M*N, and F (i, j) is image at pixel (i, j)
The gray value at place, then grey scale centre of gravity calculation formula be：
Again, carry out hot spot fitting with least square method circle fitting algorithm, calculate the centre of form of individual light spot image, i.e., it is several
What center.Least square method circle fitting algorithm is to approach laser according to the principle of least square (i.e. the flat method of residual error and minimum) with circle
Light spot profile.
Round general equation is：
(x-A)2+(y-B)2=R2
It can be written as again：
R2=x2-2Ax+A2+y2-2By+B2
Wherein (A, B) is the central coordinate of circle of circle, and R is the radius of circle.
Make a=-2A, b=-2B, c=A2+B2-R2, then circle another form be：
x2+y2+ ax+by+c=0
{(Xi,Yi), i ∈ (1,2,3......N) } be point on the hot spot edge extracted, then it is to the distance in the center of circle
di：
di 2=(Xi-A)2+(Yi-B)2
Point (Xi,Yi) arrive the square distance in the center of circle and the poor σ of radius squarediFor：
σi=di 2-R2=Xi 2+Yi 2+aXi+bYi+c
If σiQuadratic sum be Q (a, b, c), to make the circle that fits and the circle of reality closest, it is suitable to seek to take
A, b, c value so that Q (a, b, c) value minimum[40]。
Q (a, b, c)=∑ σi 2=∑ (Xi 2+Yi 2+aXi+bYi+c)2
From mathematical theory, Q (a, b, c) minimum point is also necessarily extreme point, therefore as shown in following three formula, use Q
(a, b, c) seeks local derviation to a, b, c respectively, and makes local derviation be equal to 0, it can be found that a, b, c solution are unique, i.e., extreme point is unique, therefore
The a now solved, b, c can exactly make the minimum parameter of Q (a, b, c) value.
By three above equation, three unknown numbers a, b, c can be solved, you can obtain the geometric center and radius difference of hot spot
For：
The circle fitted with least square method circle fitting algorithm is as shown in figure 12.
Finally, after the geometry of one group of light spot image being continuously shot, center intensity is calculated, corresponding broken line is generated
Figure, abscissa are figure sequence number, and ordinate is the geometric center of hot spot or the X values or Y value of center intensity coordinate, is controlled by showing
System processed shows, can reflect glossing up geometric center or center intensity in the horizontal direction or the change of vertical direction becomes
Gesture；One group of light spot image geometry, the standard deviation of center intensity, average deviation and the average angle of deviation are calculated, if being less than
The maximum allowed, then meet the stability requirement of laser, if more than the maximum allowed, do not meet laser
Stability requirement, so as to obtain the stability information of laser optical axis.
Claims (6)
1. a kind of pulse laser far field optical axis stable detection method, it is characterised in that step is as follows：
The first step, setting is acquired by display control program, sets laser pulse period, shooting number, pass through turntable
The orientation of system call interception whole system, bornb sight, display control program start to gather image；
Second step, laser form laser facula after far field transmission in diffusing reflection target, and optical system is collected and is diffusely reflected target
The laser energy reflected, the time of origin of laser pulse is detected by APD detectors in real time, and exports real-time response pulse；
Known laser pulse frequency, it is contemplated that the next laser pulse closed on reaches the time of optical system, utilizes FPGA board pair
The response impulse of APD detectors output enters line delay, and enables delay pulse accurately to arrive it in next laser pulse
Preceding generation；Near Infrared CCD camera imaging is triggered using delay pulse, collects the hot spot figure of the laser pulse of next arrival
Picture, display control program is transferred to, after the light spot image number collected reaches default shooting number, collection terminates；
3rd step, the light spot image of collection is analyzed, first, first image pre-processed, be i.e. regional choice, intermediate value filter
Ripple, opening and closing operation, edge extracting, to reduce the interference of background, the influence of atmospheric perturbation, the influence of CCD intrinsic noises；Secondly,
It is different according to the gray scale of each pixel of image obtained by Near Infrared CCD camera after pretreatment, the center of gravity of hot spot is calculated, i.e., in intensity
The heart；Again, hot spot fitting is carried out with least square method circle fitting algorithm, calculates the centre of form of individual light spot image, i.e., in geometry
The heart；Finally, after the geometry of one group of light spot image being continuously shot, center intensity is calculated, corresponding line chart, horizontal seat are generated
Figure sequence number is designated as, ordinate is the geometric center of hot spot or the X values or Y value of center intensity coordinate, passes through display control program
Show, can reflect glossing up geometric center or center intensity in the horizontal direction or vertical direction variation tendency, and count
One group of light spot image geometry, the standard deviation of center intensity, average deviation and the average angle of deviation are calculated, if being less than is allowed
Maximum, then meet the stability requirement of laser, if more than the maximum allowed, do not meet the stability of laser
It is required that so as to obtain the stability information of laser optical axis；
The optical system corresponds to optical lens including APD detectors, Near Infrared CCD camera corresponds to optical lens, two light
The focal length that the same optical axis of camera lens, wherein Near Infrared CCD camera correspond to optical lens determines that method is：
If spot radius are R, reception objective focal length is f, and radius of the hot spot on target is H, and target is with receiving thing distance between mirrors
For l, when hot spot is stable, from imaging relations：
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When hot spot is shaken, from new imaging relations, the radius H of new hot spot1And H2：
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Δ R refers to the amount of hot spot shake, then displacement Δ H of the hot spot on Near Infrared CCD camera target surface is：
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Mobile pixel count cnt of the hot spot on Near Infrared CCD camera target surface be：
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In above formula, a is single pixel length of side of Near Infrared CCD camera；
If laser divergence angle is θ, target is the square that the length of side is A, and the distance of laser transmitting system to target is L, hot spot
Maximum jitter angle is β, then is analyzed more than, and the relation between parameters should meet following a few formulas：
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X, Y are the length and width of Near Infrared CCD camera target surface respectively in above formula, and n is that hot spot often shakes Δ θ, Near Infrared CCD on target
Corresponding mobile pixel count on camera target surface, a are the camera list pixel length of side；
Three formulas more than, can obtain focal length should meet：
If X >=Y,
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<mrow>
<mi>n</mi>
<mi>a</mi>
<mi>l</mi>
</mrow>
<mrow>
<mi>L</mi>
<mi>&Delta;</mi>
<mi>&theta;</mi>
</mrow>
</mfrac>
</mrow>
θ is the angle of divergence of laser, and θ maximum is 0.5mrad, and n is integer.
2. pulse laser far field optical axis stable detection method according to claim 1, it is characterised in that laser is sent out
After the light pulse gone out reaches the target surface of APD detectors, after response time t, APD detectors output response impulse will
This response impulse is inputted to FPGA board, is acted on through time delay module, and counting delay, delay time T are carried out to this response impulse2
Afterwards, FPGA board output prediction pulse, this pulse are Near Infrared CCD camera trigger signal, its frequency and laser pulse frequency
Rate is consistent, but it has an advanced phase T relative to laser pulse1, i.e., the trigger pulse of Near Infrared CCD camera is every
Individual laser pulse produces before arriving, and the time interval T between trigger pulse and laser pulse1Immobilize；
Delay time T2With leading phase T1Specific size should integrate the frequency of laser and the lowest exposure of Near Infrared CCD camera
Time determines：The cycle of laser pulse is T, sets laser facula time of occurrence to be in the centre bit of Near Infrared CCD time for exposure
Put, then the set counting delay time T for APD explorer response pulses in FPGA board2For：
<mrow>
<msub>
<mi>T</mi>
<mn>2</mn>
</msub>
<mo>=</mo>
<mi>T</mi>
<mo>-</mo>
<mi>t</mi>
<mo>-</mo>
<mfrac>
<msub>
<mi>T</mi>
<mrow>
<mi>m</mi>
<mi>i</mi>
<mi>n</mi>
</mrow>
</msub>
<mn>2</mn>
</mfrac>
</mrow>
Wherein, TminFor the minimum exposure time.
3. pulse laser far field optical axis stable detection method according to claim 1, it is characterised in that the optics
System corresponds to optical lens including APD detectors, Near Infrared CCD camera corresponds to optical lens, two same optical axises of optical lens,
Areas imaging is consistent with the areas imaging of Near Infrared CCD camera wherein corresponding to APD detectors target surface, and APD detectors correspond to light
Learn camera lens focal length be：
<mrow>
<mo>(</mo>
<mi>&beta;</mi>
<mo>+</mo>
<mfrac>
<mi>&theta;</mi>
<mn>2</mn>
</mfrac>
<mo>)</mo>
<mo>&times;</mo>
<msup>
<mn>10</mn>
<mrow>
<mo>-</mo>
<mn>3</mn>
</mrow>
</msup>
<mo>&times;</mo>
<mi>L</mi>
<mo><</mo>
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
<mo>&times;</mo>
<mfrac>
<mrow>
<mi>l</mi>
<mi>r</mi>
</mrow>
<mi>f</mi>
</mfrac>
<mo><</mo>
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
<mo>&times;</mo>
<mi>A</mi>
</mrow>
In above formula, r is APD detector target surface diameters.
4. pulse laser far field optical axis stable detection method according to claim 1, it is characterised in that medium filtering
Method be：Current grayvalue, two dimension median filter expression formula institute are substituted with the intermediate value of the grey scale pixel value in neighborhood of pixel points
Show as follows：
Fi,j=MedA{Xi,j}
In above formula, A is filter window, Xi,jFor the grey scale pixel value in A, Fi,jFor the gray value of current filter window center point.
5. pulse laser far field optical axis stable detection method according to claim 1, it is characterised in that opening and closing operation
Method is：Assuming that E represents a two-dimentional theorem in Euclid space, image A is E a subset, and structural element B is also E a subset,
B is a point in E, and erosion operation is defined as：
<mrow>
<mi>A</mi>
<mi>&Theta;</mi>
<mi>B</mi>
<mo>=</mo>
<mo>{</mo>
<mi>Z</mi>
<mo>&Element;</mo>
<mi>E</mi>
<mo>|</mo>
<msub>
<mi>B</mi>
<mi>Z</mi>
</msub>
<mo>&SubsetEqual;</mo>
<mi>A</mi>
<mo>}</mo>
<mo>=</mo>
<mo>&cap;</mo>
<mi>A</mi>
<mi>b</mi>
</mrow>
Dilation operation is defined as：
<mrow>
<mi>A</mi>
<mo>&CirclePlus;</mo>
<mi>B</mi>
<mo>=</mo>
<mo>{</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
<mo>|</mo>
<mi>a</mi>
<mo>&Element;</mo>
<mi>A</mi>
<mo>,</mo>
<mi>b</mi>
<mo>&Element;</mo>
<mi>B</mi>
<mo>}</mo>
<mo>&cup;</mo>
<mi>A</mi>
<mi>b</mi>
</mrow>
Opening operation is that A is opened B, i.e. A is first corroded by B, then the result expanded by B, is defined as follows：
Closed operation is that A closes to B, i.e. A is first expanded by B, then the result corroded by B, is defined as follows：
<mrow>
<mi>A</mi>
<mo>&CenterDot;</mo>
<mi>B</mi>
<mo>=</mo>
<mrow>
<mo>(</mo>
<mi>A</mi>
<mo>&CirclePlus;</mo>
<mi>B</mi>
<mo>)</mo>
</mrow>
<mi>&Theta;</mi>
<mi>B</mi>
<mo>.</mo>
</mrow>
6. pulse laser far field optical axis stable detection method according to claim 1, it is characterised in that calculate hot spot
The method of center of gravity be：Assuming that light spot image is in two-dimensional coordinate system, image size is M*N, and F (i, j) is image in pixel
The gray value at point (i, j) place, then grey scale centre of gravity calculation formula be：
<mrow>
<mfenced open = "{" close = "">
<mtable>
<mtr>
<mtd>
<mi>X</mi>
<mo>=</mo>
<mfrac>
<mrow>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>M</mi>
</munderover>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>j</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>N</mi>
</munderover>
<mi>i</mi>
<mo>&times;</mo>
<mi>F</mi>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>,</mo>
<mi>j</mi>
<mo>)</mo>
</mrow>
</mrow>
<mrow>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>M</mi>
</munderover>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>j</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>N</mi>
</munderover>
<mi>F</mi>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>,</mo>
<mi>j</mi>
<mo>)</mo>
</mrow>
</mrow>
</mfrac>
</mtd>
</mtr>
<mtr>
<mtd>
<mi>Y</mi>
<mo>=</mo>
<mfrac>
<mrow>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>M</mi>
</munderover>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>j</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>N</mi>
</munderover>
<mi>j</mi>
<mo>&times;</mo>
<mi>F</mi>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>,</mo>
<mi>j</mi>
<mo>)</mo>
</mrow>
</mrow>
<mrow>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>M</mi>
</munderover>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>j</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>N</mi>
</munderover>
<mi>F</mi>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>,</mo>
<mi>j</mi>
<mo>)</mo>
</mrow>
</mrow>
</mfrac>
</mtd>
</mtr>
</mtable>
</mfenced>
<mo>.</mo>
</mrow>
3
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| WO2024021063A1 (en) * | 2022-07-29 | 2024-02-01 | 宁德时代新能源科技股份有限公司 | Method and device for detecting stability of vision system |
| CN116625652B (en) * | 2023-07-21 | 2023-10-10 | 武汉斯优光电技术有限公司 | Laser instrument finished product check out test set |
| CN117782313A (en) * | 2024-02-28 | 2024-03-29 | 安徽瑞控信光电技术股份有限公司 | Laser far-field parameter measurement system and method |
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