CN110231308B - A kind of active illumination gas imaging detection method and system - Google Patents
A kind of active illumination gas imaging detection method and system Download PDFInfo
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- CN110231308B CN110231308B CN201910723454.4A CN201910723454A CN110231308B CN 110231308 B CN110231308 B CN 110231308B CN 201910723454 A CN201910723454 A CN 201910723454A CN 110231308 B CN110231308 B CN 110231308B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/38—Investigating fluid-tightness of structures by using light
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers
Abstract
The application provides a kind of active illumination gas imaging detection method and system, and the method first passes through tunable laser and emits laser illuminator to detection zone, and carries out wavelength tuning to laser illuminator；The laser illuminator being detected in region after gas absorption is received by infrared CCD again, generates infrared picture data；And according to laser illuminator parameter and infrared picture data, judge whether contain gas leakage in detection zone；When containing gas leakage, according to the gas leakage concentration that can be calculated detection zone.The method carries out active illumination using gas absorption bands laser, can be in the case where bias light is weaker, and infrared-imaging gas detection sensitivity is still very high.Also, wavelength tuning is carried out while irradiation using Wavelength tunable laser, gas absorption peak is scanned, the contrast of gas imaging can be made to be promoted, so that gas diffusion range and concentration information are easier to be extracted.
Description
Technical field
This application involves gas detection technology field more particularly to a kind of active illumination gas imaging detection method and it is
System.
Background technique
In the fields such as daily life, industrial production and communications and transportation, pernicious gas, such as natural gas, petroleum alkanes are easy
Combustion explosion hazard gases leakage will cause various harm.In order to reduce the harm of gas leakage, need to whether there is in region
Gas leakage phenomenon is detected.Common gas detection mode specifically includes that semiconductor-type, catalytic combustion type and electrochemistry
Formula, infrared-type, i.e., the gas concentration by the sensor under correspondence principle, in search coverage.But these sensors need with
Gas, which carries out contact, just can be carried out detection, so that the detection range of these sensors is small, delay of response, and hence it is also possible to pass through
Optical long-haul mode carries out gas detection.
The method that gas detection is carried out using optical long-haul mode, main spectroscopic analysis methods and active including passive type
Two kinds of the laser radar method of formula.Wherein, the spectroscopic analysis methods of passive type be using precision spectrometer to object gas too
Sunlight or thermal radiation absorption spectrum are acquired analysis, to determine that gas concentration, this detection method are widely used in satellite pair
Atmospheric detection, target area detection accuracy lesser for range is very low, and target is imaged, and needs accurate valuableness
Spectrometer or EO-1 hyperion camera carry out data acquisition, increase testing cost.
Active laser radar method, including difference absorption spectrum technology (DOAS) and tunable semiconductor absorption spectrum
Technology (TDLAS) etc..That is, emitting direct laser light beam using laser, concentration product is carried out to the gas on the way that laser passes through
Point, obtain the gas integral concentration on single locus.As it can be seen that active laser radar detection method only examines single-point
It surveys, if one more wide region of detection needs to carry out point by point scanning, keeps detection speed extremely slow.
In order to improve disadvantages mentioned above, the prior art also passes through IR Thermograph and carries out gas detection.Such as the U.S.
The GasFindIR serial gas imager of FLIR company and the Second Sight gas imaging instrument of Bertin company, France.This
A little imagers work are directed to the difference of detected gas infrared signature absorption peak in heat radiation infrared band, camera lens with it is red
The narrow band filter for covering absorption peak is added between outer focus planar detector, to realize the gas imaging detection of narrow-band.But
Since the radiation energy of narrow-band is less than normal, infrared detector in the low-temperature refrigeration type using highly sensitive plating is needed, so that system is made
Valence is high.Also, in the period that heat radiation is small or the temperature difference is small, such as at night, disappear since temperature is reduced with periphery daylight scattering light
It loses, so that detection sensitivity is poor or even is not available.
Summary of the invention
This application provides a kind of active illumination gas imaging detection method and systems, are being carried on the back with solving traditional detection method
In the weaker situation of scape light, the problem of infrared-imaging gas detection sensitivity difference.
On the one hand, the application provides a kind of active illumination gas imaging detection method, comprising:
Emit laser illuminator to detection zone by tunable laser, and wavelength tune is carried out to the laser illuminator
It is humorous；
The laser illuminator after being absorbed by gas in the detection zone is received by infrared CCD, generates infrared picture data；
According to the central wavelength of the laser illuminator, tuning range, tuned frequency and the infrared picture data, judgement
Whether contain gas leakage in the detection zone；
If containing gas leakage in the detection zone, according to the infrared picture data calculate gas absorb light path and
Center transmitance；
Light path and center transmitance are absorbed according to the gas, calculates the gas leakage concentration of the detection zone.
Optionally, laser illuminator is emitted to detection zone by tunable laser, and the laser illuminator is carried out
The step of wavelength tuning includes:
Obtain the gas leakage type in detection zone；
The absorption peak information of gas leakage is searched according to the gas type of acquisition；
Central wavelength, tuning wavelength and the tuned frequency of tunable laser are set according to the absorption peak information.
Optionally, if containing gas leakage in the detection zone, the method also includes:
The visible images data of the detection zone are obtained by Visible-light CCD；
According to the visible images data and the infrared picture data, the leak position of the gas leakage is positioned
And diffusion position.
Optionally, according to the central wavelength of the laser illuminator, tuning wavelength, tuned frequency and the infrared image number
According to, judge in the detection zone whether containing the step of gas leakage include:
Judgment matrix is generated according to the infrared picture data；
Obtain the continuously corresponding judgment matrix of multiple infrared picture datas；
Judge that the matrix element of continuous multiple judgment matrixs changes over time rule, if present with the tuned frequency
Identical periodicity；
If identical periodicity is presented in the changing rule and the tuned frequency, determines and contain in the detection zone
Gas leakage.
Optionally, light path is absorbed according to the gas and center transmitance, the gas leakage for calculating the detection zone is dense
In the step of spending, the method calculates the concentration of gas leakage according to the following formula:
；
In formula, σ (λ0) be center wavelength under gas absorption line section；Transmitance centered on T；L is gas absorption
Light path.
Optionally, calculating the step of gas absorbs light path and center transmitance according to the infrared picture data includes:
The light intensity data of the infrared picture data center position is obtained, the light intensity data includes central wavelength and tune
The corresponding light intensity data of resonance wave length；
The center transmitance is calculated according to the following formula according to the light intensity data:
；
In formula, I(λ1) it is the light intensity value under tuning wavelength；I(λ0) it is the light intensity value under central wavelength.
Optionally, calculating the step of gas absorbs light path and center transmitance according to the infrared picture data includes:
The infrared picture data is traversed, air mass edge data is generated；
Air mass width is obtained according to the edge data；
Gas, which is calculated, according to the air mass width absorbs light path.
On the other hand, the application also provides a kind of active illumination gas imaging detection system, comprising: tunable laser,
Infrared CCD and optical processing system；Wherein, the tunable laser is used to emit laser illuminator to detection zone；It is described
Infrared CCD is used to receive the laser illuminator after being absorbed by gas in the detection zone, and generates infrared picture data；It is described
Optical processing system connects the tunable laser and infrared CCD, swashs for controlling the tunable laser transmitting illumination
Light and control infrared CCD receive light echo imaging；
The optical processing system is further configured to execute following procedure step:
Emit laser illuminator to detection zone by tunable laser, and wavelength tune is carried out to the laser illuminator
It is humorous；
The laser illuminator after being absorbed by gas in the detection zone is received by infrared CCD, generates infrared picture data；
According to the central wavelength of the laser illuminator, tuning range, tuned frequency and the infrared picture data, judgement
Whether contain gas leakage in the detection zone；
If containing gas leakage in the detection zone, according to the infrared picture data calculate gas absorb light path and
Center transmitance；
Light path and center transmitance are absorbed according to the gas, calculates the gas leakage concentration of the detection zone.
Optionally, the system also includes the Visible-light CCD for connecting the optical processing system, the Visible-light CCD is used
Visible images data are generated in the visible images for obtaining the detection zone；The optical processing system is further configured
To execute following procedure step:
The visible images data of the detection zone are obtained by Visible-light CCD；
According to the visible images data and the infrared picture data, the leak position of the gas leakage is positioned
And diffusion position.
Optionally, the receiving plane of the infrared CCD is equipped with filter plate；The transparency range center of the filter plate is leaking
Gas is in the absorption peak of central wavelength and preset range.
From the above technical scheme, the application provides a kind of active illumination gas imaging detection method and system, described
Method first passes through tunable laser and emits laser illuminator to detection zone, and carries out wavelength tuning to laser illuminator；Lead to again
It crosses infrared CCD and receives the laser illuminator being detected in region after gas absorption, generate infrared picture data；And according to laser illuminator
Central wavelength, tuning wavelength, tuned frequency and infrared picture data, judge whether contain gas leakage in detection zone；
If containing gas leakage in detection zone, gas is calculated according to infrared picture data and absorbs light path and center transmitance；Finally,
Light path and center transmitance are absorbed according to gas, calculates the gas leakage concentration of detection zone.
The method carries out active illumination using gas absorption bands laser, can be red in the case where bias light is weaker
Outer imaging gas detection sensitivity is still very high.Also, wavelength tuning is carried out while irradiation using tunable wave length laser,
Gas absorption peak is scanned, the contrast of gas imaging can be made to be promoted, so that gas diffusion range and concentration information
It is easier to be extracted, solves traditional detection method in the weaker situation of bias light, infrared-imaging gas detection sensitivity difference is asked
Topic.
Detailed description of the invention
In order to illustrate more clearly of the technical solution of the application, letter will be made to attached drawing needed in the embodiment below
Singly introduce, it should be apparent that, for those of ordinary skills, without creative efforts, also
Other drawings may be obtained according to these drawings without any creative labor.
Fig. 1 is a kind of flow diagram of active illumination gas imaging detection method of the application；
Fig. 2 is the flow diagram that laser illuminator parameter is arranged in the application；
Fig. 3 be the application judge detection zone whether the flow diagram containing gas leakage；
Fig. 4 is the flow diagram of the application auxiliary positioning leak position and diffusion position；
Fig. 5 is the flow diagram that the application calculates that gas absorbs light path；
Fig. 6 is a kind of application scenario diagram of active illumination gas imaging detection system of the application；
Fig. 7 is a kind of structural schematic diagram of active illumination gas imaging detection system of the application.
Specific embodiment
Embodiment will be illustrated in detail below, the example is illustrated in the accompanying drawings.In the following description when referring to the accompanying drawings,
Unless otherwise indicated, the same numbers in different drawings indicate the same or similar elements.Implement described in following embodiment
Mode does not represent all embodiments consistent with the application.It is only and be described in detail in claims, the application
The example of the consistent system and method for some aspects.
It is a kind of flow diagram of active illumination gas imaging detection method of the application referring to Fig. 1, as shown in Figure 1, this
The active illumination gas imaging detection method provided is provided, comprising the following steps:
S1: laser illuminator is emitted to detection zone by tunable laser, and wavelength is carried out to the laser illuminator
Tuning.
In technical solution provided by the present application, the implementation of the method depends on corresponding hardware device, i.e. active illumination
Gas imaging detection system.The active illumination gas imaging detection system specifically includes that tunable laser, for generating photograph
Bright laser；Infrared CCD and filter plate, for receiving the laser illuminator after being actually taken up by gas；Visible-light CCD is used for building, pipe
Road etc. is imaged；Optical system, for emitting laser illuminator and receiving light echo imaging.The system can be mounted in the height near workshop
Target area gas and background are imaged on tower, while can be scanned to cover bigger region.System installation and debugging are complete
After finishing, corresponding gas detection process can be carried out by executing the program, that is, first pass through tunable laser to detection zone
Emit laser illuminator, and wavelength tuning is carried out to the laser illuminator.
In the application, tunable laser emit the wavelength X of laser at any time central wavelength lambda 0 and tuning wavelength λ 1 it
Between tune, tuned frequency f, i.e., in the detection process, laser illuminator present cyclically-varying.In order to obtain better photograph
The gap very little of obvious results fruit, central wavelength lambda 0 and tuning wavelength λ 1, generally less than 1nm can shield the overwhelming majority in this way and not exist
Noise jamming within the scope of gas absorption peak.
Further, as shown in Fig. 2, emitting laser illuminator to detection zone by tunable laser, and to described
Laser illuminator carries out the step of wavelength tuning further include:
S101: the gas leakage type in detection zone is obtained；
S102: the absorption peak information of gas leakage is searched according to the gas type of acquisition；
S103: central wavelength, tuning wavelength and the tuning frequency of tunable laser are set according to the absorption peak information
Rate.
In the present embodiment, for different application environments, the pernicious gas type of leakage is different, for example, for stone
The pernicious gas hydro carbons of oiling factory district, leakage is more, and for gas pipeline region, the pernicious gas of leakage is with alkanes
It is more.And different types of gas often has difference for the absorbent core wave band of laser, it therefore, in the present embodiment can be with
The gas leakage type in detection zone is first obtained, specific acquisition methods can derive from the record data in region, further according to letting out
Leakage gas type determines the absorption peak information of the gas, so that the final central wavelength for determining tunable laser transmitting laser,
Tuning wavelength and tuned frequency.The present embodiment can be directed to the type of different gas leakages, customize different Laser emission and tune
Humorous scheme, so that testing result is more accurate.
S2: the laser illuminator after being absorbed by gas in the detection zone is received by infrared CCD, generates infrared image number
According to.
In technical solution provided by the present application, can using infrared CCD as gas detection sensor, in practical application,
Narrow band filter slice can be installed before infrared CCD additional, the transparency range center of filter plate is in gas absorption peak λ0(i.e. central wavelength), thoroughly
Optical range width marker is Δ λf.This transmittance spectrum width Delta λfGenerally there was only several nanometers, is greater than 2(λ0-λ1), it therefore, can be with
Laser illuminator is received by returning to the light of infrared CCD through diffusing reflection after gas.With thousands of nanometers of light of visible light and heat radiation
For spectral width compared to very small, narrow band filter slice can shield most not noise jammings within the scope of gas absorption peak, mention
The precision of high gas detection.
S3: according to the central wavelength of the laser illuminator, tuning wavelength, tuned frequency and the infrared picture data,
Judge whether contain gas leakage in the detection zone.
Since transmission of the laser in gas meets Lambert-beer's law, it may be assumed that a branch of monochromatic light exposure is in an absorbing medium
Surface, after through certain thickness medium, medium can absorb a part of luminous energy, therefore the intensity of transmitted light can weaken.And
The concentration of absorbing medium is bigger, and the thickness of medium is bigger, then the decrease of luminous intensity is more significant, relationship are as follows:
；
Wherein, I is the intensity of emergent light；I0For the intensity of incident light；σ is absorption cross-section；C is gas concentration；L is to absorb
Length (light path).
Absorption line section σ (λ) of gas is generally Gaussian lineshape or Lorentz line shape, wherein a length of λ 0 of cardiac wave, spectrum
Width is Δ λg, spectrum highest point absorption cross-section is σ0.It is lorentzian curve, expression that normal atmosphere, which depresses gas absorption spectrum line,
Formula are as follows:
；
When laser wavelength lambda is in λ0When, absorption coefficient is σ (λ0)=σ0；
As λ-λ0=NΔλgWhen,
；
Therefore, when optical maser wavelength deviates core apart from farther away λ 1, such as deviate central wavelength lambda05 times of spectral lines
When at width, N=5, absorption cross-section will fall to original 1/101, it is believed that not absorb substantially.
Based on above-mentioned analysis, as shown in figure 3, the central wavelength of laser illuminator, tuning wavelength, tune can be passed through in the application
Harmonics rate and the infrared picture data judge whether contain gas leakage in the detection zone, specific method include with
Lower step:
S301: judgment matrix is generated according to the infrared picture data；
S302: the continuously corresponding judgment matrix of multiple infrared picture datas is obtained；
S303: judge that the matrix element of continuous multiple judgment matrixs changes over time rule, if with the tuning frequency
Identical periodicity is presented in rate；
S304: if identical periodicity is presented in the changing rule and the tuned frequency, the detection zone is determined
Inside contain gas leakage.
In the present embodiment, tunable laser emits the wavelength of laserλAt any time in central wavelengthλ 0And tuning wavelengthλ 1It
Between tune, tuned frequency f.The infrared picture data that infrared CCD is collected into laser illumination region is denoted as a judgment matrix S
[m,n].Wherein m, n are the horizontal and vertical resolution ratio of infrared CCD respectively.When there is no gas leakage, tunable laser
Wavelength changes over time λ (t), due to λ0And λ1Difference it is very small, the reflectivity of background will not change with wavelength and time,
Therefore S [m, n, t] is not changed over；And in the presence of having gas leakage, gas part matrix member meeting is corresponded in S [m, n, t]
Generate the cyclically-varying that frequency is f.
In addition, the periodically variable image equal with tunable laser tuned frequency f occurred on infrared CCD,
It can also be identified by image recognition algorithm.If its air mass feature is obvious, can with people, animal action dynamic image into
Row is obvious to be distinguished, thus a possibility that further decreasing gas leakage erroneous judgement.
S4: if containing gas leakage in the detection zone, gas is calculated according to the infrared picture data and absorbs light
Journey and center transmitance；
In the present embodiment, if it is determined that contain gas leakage in detection zone, alarm signal can be generated by warning device
Number, prompting maintenance personnel carry out safe investigation.Also, if infrared image number can be passed through containing gas leakage in detection zone
According to determining light intensity variation, and the volume profile of leakage air mass, so that the concentration of leak position and gas leakage is calculated, thus
Personnel convenient for safeguarding carry out security control and malfunction elimination.
Since the leakage process of gas is generally from one outlet to external diffusion, risen or fallen along with air-flow, height
It is generally unequal with width, but its transverse width can be approximately equal, the i.e. air mass shape of gas leakage diffusion with depth thickness
It can be approximately an elliposoidal.Therefore, by the width D of air mass at image analysis, can approximation obtain its depth thickness L.
Further, as shown in figure 4, the method also includes following if containing gas leakage in the detection zone
Step:
S401: the visible images data of the detection zone are obtained by Visible-light CCD；
S402: according to the visible images data and the infrared picture data, letting out for the gas leakage is positioned
Leak position and diffusion position.
In the present embodiment, building, pipeline etc. can be imaged using Visible-light CCD, to infrared CCD detection image into
Row supplement, the leak position of distinguishable gas and diffusion position.
S5: light path and center transmitance are absorbed according to the gas, calculate the gas leakage concentration of the detection zone.
In technical solution provided by the present application, the signal received on infrared CCD is swashing by tunable laser transmitting
The emitted system of light, gas absorption, backscatter, gas absorb, receive the light intensity that system returns.Emit in tunable laser
When wavelength is tuning wavelength λ 1, it is believed that absorbed without gas.It is directly proportional to transmitting light intensity due to receiving light intensity, it may be assumed that
；
It and is center wavelength X in tunable laser launch wavelength0When, the laser of return will be absorbed through gas twice
Journey, and other losses are constant, it may be assumed that
；
Correspondingly, the Strength Changes amount of laser illuminator are as follows:
；
Therefore gas concentration are as follows:
；
According to the intensity that above formula and infrared CCD image obtain, air mass can get in the concentration information of spatial distribution.And
In the application, due to center transmitance T are as follows:
；
I(λ1) it is the light intensity value under tuning wavelength；I(λ0) it is the light intensity value under central wavelength.Correspondingly, the application
In, calculating the step of gas absorbs light path and center transmitance according to the infrared picture data includes: to obtain the infrared figure
As the light intensity data of data center location, the light intensity data includes central wavelength and the corresponding light intensity data of tuning wavelength.
Therefore, according to the corresponding relationship of above formula, in technical solution provided by the present application, the concentration of gas leakage is calculated according to the following formula:
。
Light path is absorbed due to when calculating gas leakage concentration, needing to obtain gas, therefore is implemented in the part of the application
In example, as shown in figure 5, the step of calculating gas absorption light path and center transmitance according to the infrared picture data includes:
S501: traversing the infrared picture data, generates air mass edge data；
S502: air mass width is obtained according to the edge data；
S503: gas is calculated according to the air mass width and absorbs light path.
In the present embodiment, due to the emitted system of laser illuminator, gas absorption, backscatter, gas absorption, receive system
Corresponding information is finally collected by infrared CCD, therefore, in this application, is absorbed by gas twice, thus may determine that gas
Body absorbs 2 times that light path is air mass width.
It is further illustrated by with methane gas leakage scene.Methane gas has in middle infrared band 3345.83nm
There is absorption peak.According to Hitran database, depressed in a normal atmosphere, the line of this absorption peak is S=1.35 × 10 by force-19cm-1,
High 3 orders of magnitude stronger than near infrared band line.It is σ (λ according to the absorption cross-section that the strong S of line calculates methane gas0)=50cm-1, spectrum
Width is about Δ λg=0.1nm.When concentration of methane gas is c=100ppmm, it is L=100cm that gas, which absorbs light path, when laser peak
When being worth position alignment absorption peak center, transmitance。
If detected using mercury cadmium telluride (HgCdTe) area array CCD as infrared detector.Degree of widening is before detector
The narrow band filter slice of 5nm, filter plate central wavelength are 3346nm.The imaging frame frequency of this infrared CCD is 50Hz.Meanwhile using wave
The Distributed Feedback Laser of a length of 1064nm is mixed Yb ion fiber amplifier and is amplified to seed light as seed light, obtain 20W and
Wavelength is the laser of 1064nm.Optical parametric oscillator (OPO) is pumped using the laser as pump light source, which uses period pole
Changing lithium columbate crystal (PPLN) is non-linear conversion material, generates the mid-infrared laser that 3W wavelength is 3345.83nm.
The size that electric current is fed by adjusting Distributed Feedback Laser, can be finely adjusted seed optical wavelength, to tune generation wave
The laser of a length of 3345.83nm, tuning range are more than 1nm.Select central wavelength lambda0=3345.83nm, tuning wavelength λ1=
3345.5nm tuned frequency 10Hz.Since the sampling frame frequency of infrared CCD is 50Hz, if there is gases did escape,
It can get the gas image light and shade mechanical periodicity in 5 periods within 1 second.If acquiring light intensity variation diagram by infrared CCD
Picture judges that gas diffusion width is about 0.5m by image analysis, then, it is 100cm that gas, which absorbs light path,.It is saturating in conjunction with the center
Rate T=0.4 is crossed, calculating the concentration of methane gas at center is 100ppmm.
As it can be seen that the application carries out active illumination to target acquisition region by the way of active laser illumination, while using face
Formation detector (infrared CCD) carries out imaging detection.Active laser illumination uses narrow line width regulatable laser, and generation wavelength exists
Gas absorption spectra peak value nearby does periodic scan, obtains the cyclically-varying of the pattern contrast on the formation detector of face.
This apparent cyclically-varying image of feature can be such that gas signal is obviously distinguished with generic background signal, and reduction is made an uproar
Sound improves sensitivity, while reducing the difficulty of gas image recognition.
Based on above-mentioned active illumination gas imaging detection method, the application as shown in Figure 6, Figure 7 also provides a kind of active photograph
Bright gas imaging detection system, comprising: tunable laser, infrared CCD and optical processing system；Wherein, described tunable
Laser is used to emit laser illuminator to detection zone；The infrared CCD is absorbed for receiving by gas in the detection zone
Laser illuminator afterwards, and generate infrared picture data；The optical processing system connects the tunable laser and infrared
CCD receives light echo imaging for controlling the tunable laser transmitting laser illuminator and control infrared CCD；The optics
Processing unit is further configured to execute following procedure step:
S1: laser illuminator is emitted to detection zone by tunable laser, and wavelength is carried out to the laser illuminator
Tuning；
S2: the laser illuminator after being absorbed by gas in the detection zone is received by infrared CCD, generates infrared image number
According to；
S3: according to the central wavelength of the laser illuminator, tuning wavelength, tuned frequency and the infrared picture data,
Judge whether contain gas leakage in the detection zone；
S4: if containing gas leakage in the detection zone, gas is calculated according to the infrared picture data and absorbs light
Journey and center transmitance；
S5: light path and center transmitance are absorbed according to the gas, calculate the gas leakage concentration of the detection zone.
Further, the system also includes the Visible-light CCD for connecting the optical processing system, the Visible-light CCDs
Visible images for obtaining the detection zone generate visible images data；The optical processing system is further matched
It is set to and executes following procedure step:
S401: the visible images data of the detection zone are obtained by Visible-light CCD；
S402: according to the visible images data and the infrared picture data, letting out for the gas leakage is positioned
Leak position and diffusion position.
Further, the receiving plane of the infrared CCD is equipped with filter plate；It is letting out at the transparency range center of the filter plate
Gas leakage body is in the absorption peak of central wavelength and preset range, i.e., the transparency range center of the described filter plate is in gas leakage in
Near the long absorption peak of cardiac wave.
In addition, the application section Example in irradiation light removal process, receive CCD before gas absorption peak can be added
Neighbouring narrow band filter slice, reduces the influence of noise of remaining wave band, while also resulting in the low difficult in imaging of radiation energy.Pass through
The tunable laser for irradiating gas absorption bands, improves its environmental suitability and detection accuracy.
From the above technical scheme, the application provides a kind of active illumination gas imaging detection method and system, described
Method first passes through tunable laser and emits laser illuminator to detection zone, and carries out wavelength tuning to laser illuminator；Lead to again
It crosses infrared CCD and receives the laser illuminator being detected in region after gas absorption, generate infrared picture data；And according to laser illuminator
Central wavelength, tuning wavelength, tuned frequency and infrared picture data, judge whether contain gas leakage in detection zone；
If containing gas leakage in detection zone, gas is calculated according to infrared picture data and absorbs light path and center transmitance；Finally,
Light path and center transmitance are absorbed according to gas, calculates the gas leakage concentration of detection zone.
The method carries out active illumination using gas absorption bands laser, can be red in the case where bias light is weaker
Outer imaging gas detection sensitivity is still very high.Also, wavelength tuning is carried out while irradiation using tunable wave length laser,
Gas absorption peak is scanned, the contrast of gas imaging can be made to be promoted, so that gas diffusion range and concentration information
It is easier to be extracted, solves traditional detection method in the weaker situation of bias light, infrared-imaging gas detection sensitivity difference is asked
Topic.
Similar portion cross-reference between embodiment provided by the present application, specific embodiment provided above is only
It is several examples under the total design of the application, does not constitute the restriction of the application protection scope.For those skilled in the art
For member, any other embodiment expanded without creative efforts according to application scheme all belongs to
In the protection scope of the application.
Claims (9)
1. a kind of active illumination gas imaging detection method characterized by comprising
Emit laser illuminator to detection zone by tunable laser, and wavelength tuning is carried out to the laser illuminator；
The laser illuminator after being absorbed by gas in the detection zone is received by infrared CCD, generates infrared picture data；
According to the central wavelength of the laser illuminator, tuning range, tuned frequency and the infrared picture data, described in judgement
Whether contain gas leakage in detection zone, comprising:
Judgment matrix is generated according to the infrared picture data；
Obtain the continuously corresponding judgment matrix of multiple infrared picture datas；
Judge that the matrix element of continuous multiple judgment matrixs changes over time rule, if identical as the tuned frequency presentation
Periodicity；
If identical periodicity is presented in the changing rule and the tuned frequency, determine in the detection zone containing leakage
Gas；
If containing gas leakage in the detection zone, gas is calculated according to the infrared picture data and absorbs light path and center
Transmitance；
Light path and center transmitance are absorbed according to the gas, calculates the gas leakage concentration and leakage gas of the detection zone
Range of scatter.
2. a kind of active illumination gas imaging detection method according to claim 1, which is characterized in that swashed by tunable
Light device emits laser illuminator to detection zone, and the step of carrying out wavelength tuning to the laser illuminator includes:
Obtain the gas leakage type in detection zone；
The absorption peak information of gas leakage is searched according to the gas type of acquisition；
Central wavelength, tuning wavelength and the tuned frequency of tunable laser are set according to the absorption peak information.
3. a kind of active illumination gas imaging detection method according to claim 1, which is characterized in that if the detection
Contain gas leakage in region, the method also includes:
The visible images data of the detection zone are obtained by Visible-light CCD；
According to the visible images data and the infrared picture data, leak position and the expansion of the gas leakage are positioned
Dissipate position.
4. a kind of active illumination gas imaging detection method according to claim 1, which is characterized in that according to the gas
In the step of absorbing light path and center transmitance, calculating the gas leakage concentration of the detection zone, the method is according to the following formula
Calculate the concentration of gas leakage:
；
In formula,σ(λ 0) be center wavelength under gas absorption line section；Transmitance centered on T；L is that gas absorbs light path.
5. a kind of active illumination gas imaging detection method according to claim 1, which is characterized in that according to described infrared
Image data calculates that gas absorbs light path and the step of center transmitance includes:
The light intensity data of the infrared picture data center position is obtained, the light intensity data includes central wavelength and frequency-modulated wave
Long corresponding light intensity data；
The center transmitance is calculated according to the following formula according to the light intensity data:
；
In formula,I(λ 1) it is the light intensity value under tuning wavelength；I(λ 0) it is the light intensity value under central wavelength.
6. a kind of active illumination gas imaging detection method according to claim 1, which is characterized in that according to described infrared
Image data calculates that gas absorbs light path and the step of center transmitance includes:
According to the infrared picture data, air mass edge data is generated；
Air mass width is obtained according to the edge data；
Gas, which is calculated, according to the air mass width absorbs light path.
7. a kind of active illumination gas imaging detection system characterized by comprising tunable laser, infrared CCD and light
Learn processing unit；Wherein, the tunable laser is used to emit laser illuminator to detection zone；The infrared CCD is for connecing
The laser illuminator after being absorbed by gas in the detection zone is received, and generates infrared picture data；The optical processing system
The tunable laser and infrared CCD are connected, it is red for controlling the tunable laser transmitting laser illuminator and control
Outer CCD receives light echo imaging；
The optical processing system is further configured to execute following procedure step:
Emit laser illuminator to detection zone by tunable laser, and wavelength tuning is carried out to the laser illuminator；
The laser illuminator after being absorbed by gas in the detection zone is received by infrared CCD, generates infrared picture data；
According to the central wavelength of the laser illuminator, tuning wavelength, tuned frequency and the infrared picture data, described in judgement
Whether contain gas leakage in detection zone, comprising:
Judgment matrix is generated according to the infrared picture data；
Obtain the continuously corresponding judgment matrix of multiple infrared picture datas；
Judge that the matrix element of continuous multiple judgment matrixs changes over time rule, if identical as the tuned frequency presentation
Periodicity；
If identical periodicity is presented in the changing rule and the tuned frequency, determine in the detection zone containing leakage
Gas；
If containing gas leakage in the detection zone, gas is calculated according to the infrared picture data and absorbs light path and center
Transmitance；
Light path and center transmitance are absorbed according to the gas, calculates the gas leakage concentration and leakage gas of the detection zone
Range of scatter.
8. a kind of active illumination gas imaging detection system according to claim 7, which is characterized in that the system is also wrapped
The Visible-light CCD for connecting the optical processing system is included, the Visible-light CCD is used to obtain the visible light figure of the detection zone
As generating visible images data；The optical processing system is further configured to execute following procedure step:
The visible images data of the detection zone are obtained by Visible-light CCD；
According to the visible images data and the infrared picture data, leak position and the expansion of the gas leakage are positioned
Dissipate position.
9. a kind of active illumination gas imaging detection system according to claim 7, which is characterized in that the infrared CCD
Receiving plane be equipped with filter plate；The transparency range center of the filter plate is in gas leakage in the absorption peak of central wavelength and pre-
If in range.
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| CN113125359A (en) * | 2019-12-31 | 2021-07-16 | 南京南智芯光科技有限公司 | Active multi-component gas imaging device |
| CN111537157A (en) * | 2020-05-11 | 2020-08-14 | 嘉兴极光物联网科技有限公司 | Method and system for efficiently detecting gas leakage by visual qualitative and accurate quantitative cooperation |
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| CN111782887A (en) * | 2020-06-29 | 2020-10-16 | 数量级(上海)信息技术有限公司 | Temperature quantification system and method for leaked gas |
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