CN109520941A - The receptance function bearing calibration of online spectrum measurement instruments - Google Patents
The receptance function bearing calibration of online spectrum measurement instruments Download PDFInfo
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Abstract
The disclosure provides a kind of receptance function bearing calibration of online spectrum measurement instruments.Utilize standard substance linear data of standard spectrum in the database, the linear of standard substance in the compounding substances spectral signal obtained in experiment measurement is compared, to realize the multidimensional information linear using small-molecule substance spectrum, compounding substances signal integral linear and special shape spectrum are corrected, to realize the correction to spectrum measurement instruments receptance function, without extras and error it is small, it is adaptable.
Description
Technical field
This disclosure relates to spectral measurement analysis technical field more particularly to a kind of receptance function of online spectrum measurement instruments
Bearing calibration.
Background technique
Spectrum measurement instruments be it is a kind of can analyze light to obtain the common measuring device of spectral information, be now widely used in
Various fields, such as gas detection, biotechnology, laser technology field.But due to spectrum measurement instruments or the response letter of system
The factors such as non-linear of the noises of several power swing, environment or instruments and system with input signal, detector and signal path
It is closely related, so as to cause spectral signal there are baseline drift and the fluctuation of amplitude or distortion, cause to detection accuracy and
The influence of sensitivity etc..Thus it is guaranteed that and improve the detection accuracy and sensitivity of spectrum measurement instruments or system, need pair
Its receptance function is corrected.But due to the receptance function of spectrum measurement instruments cannot directly be obtained and school only,
Utilize the correction realized to the linear correction of measure spectrum to the receptance function of spectrum measurement instruments.
Present most bearing calibration needs to be arranged some empirical parameters, and this reduces correction side to a certain extent
The generality and adaptability of method, and be unable in correction signal influence spectrum bring due to the non-linear of detector itself, it is difficult
To meet to the high-precision demand of spectrum.For example, Fast Fourier Transform (FFT) method needs artificial determining bound, and spend a large amount of
Time calculated.Under many real-time applications, it is difficult to handle original spectrum one by one in face of a large amount of data.
Common polynomial fitting assumes that baseline can be approximated to lower order polynomial expressions form, goes to intend with a suitable multinomial
Data are closed, gives up any point for being greater than a specific criteria difference in matched curve, iterates to remaining point, until not having
There are data point needs to be rejected, and this method effect in the case where low signal-to-noise ratio or low signal background ratio is poor；In addition, very
In more application processes, the spectral line of spectrum is rendered as various shapes.The method of simple fitting of a polynomial is not able to satisfy special spectrum
Baseline fitting requirement.The automatic Iterative method of moving average is in the case where multimodal or overlap peak, and effect not smooth enough to baseline correction
Fruit is not fine；ALS method and air PLS method are all based on the smooth baseline correction of Whittaker, baseline correction effect compared with
It is good, but parameter optimization is required, and adjusting optimized parameter is the process for needing experience；And traditional Rubber-
If spectrum is divided into stem portion by band method, the minimum point of each part is considered as the position of baseline, then by with linearly
Interpolation or spline interpolation combine these points to complete the baseline of estimation, and this method needs artificial adjusting segmentation width, corrects result
Quality to a certain extent depend on operator experience.
And existing patent and paper have and are much referred to different spectral correction methods.For example, Taiwan super-micro optical
Hong Jianxiang of company et al. (108318137 A of CN) establishes stray light data bank using the response of more narrow frequency spectrographic pulse, with
It is established afterwards using the data in data bank and repairs the spectrum that formula removes amendment spectroradio standard light, to obtain measure spectrum number
According to generate correction coefficient formula.Although this method effectively, needs to establish database, therefore heavy workload and need by
It is gradually perfect, it is not used to online real-time measurement and application range receives the limitation of database.Hangzhou distant place photoelectric information is public
The advanced spectroscope function that Pan Jiangen et al. (1021559971 A of CN) calculates spectral instrument using photoradiometer is taken charge of, the letter is utilized
Number can be modified spectral instrument measurement result.This method can effectively improve that precision, speed are fast, design is simple and user
Just, but it is only limitted to the calibration spectrum measurement of the free wave band of shortwave, application range limitation is big.The auspicious environmental science and technology company of Shenzhen Kapp
Ou Yangbin et al. (107607144 A of CN) obtains functional relation using aiding sensors and carries out school to the baseline drift of sensor
Just.This method is only capable of the influence of baseline drift in removal measurement result and needs additional aiding sensors during processing
It assists.Cyrillic Bo Dibu gas of university, Bordeaux et al. (107076664 A of CN) in multiple absorption spectrums using absorbing
The interval spectral coverage for the position that amount is zero determines baseline correction curve.This method uses signal self-correcting, is only capable of preferably removing width
Baseline problem caused by the apparent fluctuation of value.Therefore in the prior art, there are no can handle spectral signal simultaneously in real time online
Middle noise, baseline drift and detector or signal path cause the bearing calibration of nonlinear influence.
Disclosure
(1) technical problems to be solved
Based on above-mentioned technical problem, the disclosure provides a kind of receptance function bearing calibration of online spectrum measurement instruments, real
Now to the correction of the receptance function of spectrum measurement instruments, spectrum can not be handled simultaneously in real time online in the prior art to alleviate
The technical issues of noise, baseline drift and detector or signal path cause nonlinear influence in signal.
(2) technical solution
The disclosure provides a kind of receptance function bearing calibration of online spectrum measurement instruments, by adding in measured matter
Standard substance after screening realizes the response letter of spectrum measurement instruments using the correction linear to measure spectrum Plays substance
Several correction, comprising: step A: using photodetector acquisition absorption signal and background signal, and make in two groups of spectral signals
It include one section of signal segment without laser emitting；Wherein, in the absorption signal comprising sample to be tested spectral signal and with this
The spectral signal for the standard substance that sample to be tested does not chemically react；Step B: using in the absorption signal and the background signal
Signal segment and photodetector without laser emitting eliminate environmental background light without the output signal under laser input state
Fluctuate the influence to spectroscopic data；Step C: being respectively weighted fitting to step B treated absorption signal and background signal,
And the optical stripe in absorption signal is eliminated using the regression criterion in background signal；Step D: the standard substance acquired is utilized
Spectral signal is matched with the spectral information in database, and to step C, treated that absorption signal is corrected, and is corrected
The spectral signal of sample to be tested afterwards.
In some embodiments of the present disclosure, the step A includes: step A1: known concentration being added in sample to be tested
Standard substance；Wherein, the concentration of the standard substance, so that its feature peak amplitude is less than or equal to the amplitude of sample to be tested
It is quasi-；Step A2: it is mixed with the spectral signal of the sample to be tested of standard substance using photodetector acquisition, and utilizes identical system
Nitrogen data of the parameter acquisition without absorption of uniting are as background signal；It wherein, include laser tuning in two groups of spectral signals
Current threshold output signal below；And step A3: multicycle signal is used to the two groups of spectral signals acquired in step A2
Average method is smoothed.
In some embodiments of the present disclosure, in the step A1: the standard substance contains in tested absorption bands
Characteristic peak that is independent and not interfered mutually with measured matter, and have detailed spectrum parameter in the database.
In some embodiments of the present disclosure, the database includes: HITRAN database, PNNL database or NIST number
According to library.
In some embodiments of the present disclosure, the step B includes: step B1: determining two groups of spectrum letters on a timeline
Number start position, and be aligned two groups of spectral signals on a timeline on the basis of the start position of absorption signal；Step B2: it adopts
Collect output signal of the photodetector under no laser input state and calculates signal averaging；Step B3: background signal is calculated
With absorption signal laser tuning current threshold output signal below average value；Step B4: step B3 is resulting flat
Mean value makes the difference with the resulting average value of step B2 respectively, and using respective difference as offset, moves background signal and suction respectively
Position of the collection of letters number on y direction, makes background signal and absorption signal and photodetector under no laser input state
The aligned in position of output signal.
In some embodiments of the present disclosure, the step C includes: step C1: to background signal entire data segment into
Row weight is 1 fitting；Step C2: the fitting that weight is 0, nothing are carried out to the data segment in absorption signal containing characteristic information
The data segment of characteristic information carries out the fitting that weight is 1；Step C3: the regression criterion after step C1 and step C2 fitting is carried out
Comparison matching, so that mutually be overlapped with the regression criterion of background signal without the corresponding regression criterion of characteristic information data section in absorption signal
It closes；Step C4: the regression criterion of absorption signal and background signal is made the difference, and removes the influence of optical stripe in absorption signal.
In some embodiments of the present disclosure, in the step D: utilize following updating formula, to step C treated inhale
The collection of letters number carries out a baseline correction:
I′0(v)=WI0(v)+Q(v)
Wherein, I '0(v) indicate that the spectrum after baseline correction is linear, second order polynomial fitting are as follows: I '0(v)=c+bv+
av2, I0(v) indicate that the spectrum before baseline correction is linear, second order polynomial fitting are as follows: I0(v)=m+nv+tv2,For
The gamma correction factor, For deviation constant matrix.
In some embodiments of the present disclosure, the step D includes: step D1: setting W initial value is the initial square of 1, Q (v)
Battle array value is all 0；Step D2: the spectral signal and number of the standard substance that Beer-Lambert law acquires photodetector are utilized
Linear matching is carried out according to the spectral signal in library, until the variance yields of the two is minimum；Step D3: when acquisition variance yields minimum
The gamma correction factor W and deviation constant matrix Q (v).Step D4: minimum two is carried out to deviation constant matrix Q (v) using following formula
Multiplication iteration acquires deviation constant Q:
N=Σ (Qi-Qj)2
Wherein, when N obtains minimum value, the spectral signal for the standard substance that deviation constant Q acquires photodetector
And the linear deviation of the spectral signal in database is minimum；
Step D5: gamma correction factor W and deviation constant Q are brought into updating formula, and using updating formula to light
Spectrum signal is corrected.
In some embodiments of the present disclosure, the step D2 includes: step D2a: obtaining absorption signal Plays substance
Spectrum it is linear；Step D2b: the database shape difference linear with the spectrum of absorption signal Plays substance is calculated；Step D2c:
The variance of the shape difference obtained in step D2b is calculated, and judges whether variance yields is minimum at this time, if variance is minimum, carries out step
Otherwise D3 carries out step D2d；Step D2d: updating the value of gamma correction factor W, is got the bid using updating formula to absorption signal
The linear carry out baseline correction of the spectrum of quasi- substance, and return step D2b.
In some embodiments of the present disclosure, in which: the receptance function bearing calibration institute of the online spectrum measurement instruments
Applicable spectrum includes: absorption spectrum, emission spectrum, molecular spectrum, atom spectrum；The response of the online spectrum measurement instruments
The project that function correction method can correct includes: the non-linear, dry of baseline drift, channel existing for spectral signal and detector
It disturbs and noise.
(3) beneficial effect
It can be seen from the above technical proposal that the receptance function bearing calibration for the online spectrum measurement instruments that the disclosure provides
It one of has the advantages that or in which a part:
(1) disclosure realizes the correction to spectrum measurement instruments receptance function by the correction linear to measure spectrum,
This bearing calibration is not necessarily to extras and error is small, and linear correction can be carried out to special shape spectrum, adaptable；
(2) the receptance function bearing calibration for the online spectrum measurement instruments that the disclosure provides directly utilizes standard substance in number
Linear according to the linear standard substance in the compounding substances spectral signal that obtains in experiment measurement of library Plays spectrum carries out pair
Than amendment, to realize the school using the linear multidimensional information of the spectrum of small-molecule substance to compounding substances signal integral linear
Just, to remove the non-linear and baseline drift in signal, the total regression to the entire signal path including spectrum baseline is realized
It corrects, reaches correction while realizing multiple measurement parameters using correction course of a standard substance；
(3) the receptance function bearing calibration for the online spectrum measurement instruments that the disclosure provides is simple and convenient for operation, effective,
There is wide applicability in the fields of measurement such as molecular spectrum measurement and content of material.
Detailed description of the invention
Fig. 1 is the step flow chart of the receptance function bearing calibration for the online spectrum measurement instruments that the disclosure provides.
Fig. 2 is spectroscopic data correcting process in the receptance function bearing calibration for the online spectrum measurement instruments that the disclosure provides
Figure.
Fig. 3 is the direct absorption spectrum measuring system schematic diagram based on TLAS technology.
Fig. 4 is the initial data schematic diagram of photodetector acquisition.
Fig. 5 is the weighted fitting result and residual error comparison diagram of background signal and absorption signal.
Fig. 6 be using the disclosure provide line spectrum measurement instruments receptance function bearing calibration correction after baseline with
Baseline comparison diagram before correction.
Fig. 7 is the comparison diagram and correcting value before and after spectrum correction.
Specific embodiment
The receptance function bearing calibration for the online spectrum measurement instruments that the disclosure provides directly utilizes standard substance in data
Plays spectrum linear the linear of standard substance in the compounding substances spectral signal obtained in experiment measurement in library compares
Amendment is not necessarily to extras and error is small to realize the correction to spectrum measurement instruments receptance function, adaptable.
For the purposes, technical schemes and advantages of the disclosure are more clearly understood, below in conjunction with specific embodiment, and reference
The disclosure is further described in attached drawing.
The disclosure provides a kind of receptance function bearing calibration of online spectrum measurement instruments, by adding in measured matter
Standard substance after screening realizes the response letter of spectrum measurement instruments using the correction linear to measure spectrum Plays substance
Several corrections, as shown in Figure 1 to Figure 2, comprising:
Step A: using photodetector acquisition absorption signal and background signal, and make include in two groups of spectral signals
One section of signal segment without laser emitting；
Wherein, in the absorption signal comprising sample to be tested spectral signal and do not chemically reacted with the sample to be tested
Standard substance spectral signal；
Step B: using in the absorption signal and the background signal without laser emitting signal segment and photodetector without
Output signal under laser input state eliminates influence of the fluctuation of environmental background light to spectroscopic data；
Step C: fitting is respectively weighted to step B treated absorption signal and background signal, and is believed using background
Regression criterion in number eliminates the optical stripe in absorption signal；
Step D: it is matched using the spectral signal of the standard substance of acquisition with the spectral information in database, to step
Treated that absorption signal is corrected by C, the spectral signal of the sample to be tested after being corrected.
In some embodiments of the present disclosure, step A includes:
Step A1: the standard substance of known concentration is added in sample to be tested；
Wherein, the concentration of the standard substance, so that its feature peak amplitude is less than or equal to subject to the amplitude of sample to be tested；
Step A2: it is mixed with the spectral signal of the sample to be tested of standard substance using photodetector acquisition, and utilizes phase
Same nitrogen data of the system parameter acquisition without absorption are as background signal；
It wherein, include laser tuning current threshold output signal below in two groups of spectral signals；
Step A3: the two groups of spectral signals acquired in step A2 are smoothly located using the method for multicycle signal averaging
Reason.
In some embodiments of the present disclosure, step A1: standard substance in tested absorption bands containing it is independent and not with
The characteristic peak that measured matter mutually interferes, and have detailed spectrum parameter in the database.
In some embodiments of the present disclosure, database includes: HITRAN database, PNNL database or NIST database.
In some embodiments of the present disclosure, as shown in " signal alignment " part in Fig. 2, step B includes:
Step B1: the start position (s and r) of two groups of spectral signals is determined, and on a timeline with the starting point of absorption signal
Two groups of spectral signals are aligned on the basis of the r of position on a timeline；
Step B2: in acquisition longer period of time, output signal and meter of the photodetector under no laser input state
Signal averaging is calculated, d is denoted as；
Step B3: background signal and absorption signal being averaged in laser tuning current threshold output signal below are calculated
Value, is denoted as f and e respectively；
Step B4: the resulting average value f and e of step B3 is made the difference with the resulting average value d of step B2 respectively, and with respective
Difference be offset, move the position of background signal and absorption signal on y direction respectively, make background signal and absorption
The aligned in position of the output signal of signal and photodetector under no laser input state.
In some embodiments of the present disclosure, step C includes:
Step C1: the fitting that weight is 1 is carried out in entire data segment to background signal；
Step C2: carrying out the fitting that weight is 0 to the data segment in absorption signal containing characteristic information, no characteristic information
Data segment carries out the fitting that weight is 1；
Step C3: the regression criterion after step C1 and step C2 fitting is compared into matching, so that nothing in absorption signal
The regression criterion of the corresponding regression criterion of characteristic information data section and background signal coincides；
Step C4: the regression criterion of absorption signal and background signal is made the difference, and removes the shadow of optical stripe in absorption signal
It rings.
In some embodiments of the present disclosure, step D: following updating formula is utilized, to step C treated absorption signal
Carry out baseline correction:
I′0(v)=WI0(v)+Q(v)
Wherein, I '0(v) indicate that the spectrum after baseline correction is linear, second order polynomial fitting are as follows: I '0(v)=c+bv+
av2, It(v) indicate that the spectrum before baseline correction is linear, second order polynomial fitting are as follows: I0(v)=m+nv+tv2,For
The gamma correction factor, For deviation constant matrix.
In some embodiments of the present disclosure, step D includes:
Step D1: setting W initial value is that 1, Q (v) initial matrix value is all 0；
Step D2: the spectral signal and data of the standard substance that Beer-Lambert law acquires photodetector are utilized
Spectral signal in library carries out linear matching, until the variance yields of the two is minimum；
Step D3: the gamma correction factor W and deviation constant matrix Q (v) when variance yields minimum are obtained.
Step D4: least square method iteration is carried out to deviation constant matrix Q (v) using following formula and acquires deviation constant Q:
N=Σ (Qi-Qj)2
Wherein, when N obtains minimum value, the spectral signal for the standard substance that deviation constant Q acquires photodetector
And the linear deviation of the spectral signal in database is minimum；
Step D5: gamma correction factor W and deviation constant Q are brought into updating formula, and using updating formula to light
Spectrum signal is corrected.
In some embodiments of the present disclosure, as shown in " extension Internal standard correction methods " part in Fig. 2, step D2 includes:
Step D2a: the spectrum for obtaining absorption signal Plays substance is linear；
Step D2b: the database shape difference linear with the spectrum of absorption signal Plays substance is calculated；
Step D2c: calculating the variance of the shape difference obtained in step D2b, and judges whether variance yields is minimum at this time, if side
It is poor minimum, step D3 is carried out, step D2d is otherwise carried out；
Step D2d: the value of gamma correction factor W is updated, using updating formula to the light of absorption signal Plays substance
Spectral line shape carries out baseline correction, and return step D2b.
In some embodiments of the present disclosure, in which: the receptance function correction for the online spectrum measurement instruments that the disclosure provides
The spectrum that method is applicable in includes: absorption spectrum, emission spectrum, molecular spectrum, atom spectrum；The disclosure provide in line spectrum
The project that the receptance function bearing calibration of measuring instrument can correct includes: baseline drift, channel existing for spectral signal and inspection
Survey the non-linear of device, interference and noise.
Below with a specific embodiment, the receptance function bearing calibration for the online spectrum measurement instruments that the disclosure provides is verified
Validity:
As shown in figure 3, being based on tunable laser absorption spectrum (Tunable Laser
AbsorptionSpectroscopy, TLAS) technology constructs spectral measurement system, and SG is signal generator in Fig. 3, and LDC is sharp
CD-ROM driver, DFB-ICL are distributed Feedback interband cascade lasers, and PD is photodetector, and DAQ is data collecting card, PC
Acetonitrile (CH is selected according to the existence conditions that experiment has for computer3CN it) is used as measured matter, and is swashed in Binding experiment system
The scanning range of light device determines that detection wave band is 3037.5-3043cm-1。
Step 1: screening criteria substance: the requirement of combination technology scheme, the standard substance finally chosen are methane.
Step 2: preparing sample to be tested: for the validity for verifying bearing calibration, being mixed with the calibrating gas of known concentration
Close the proportion of gaseous sample.Experiment utilizes 10.2ppm methane (CH4) as a kind of standard substance addition 160.8ppm CH3CN sample
In product.
Step 3: acquisition data: by proportioned mixed gas sample under conditions of normal temperature and pressure (23.6 DEG C, 1atm)
It is passed through in the gas cell of 10.24455m light path, and absorbs information containing mixed gas using what capture card acquired 20 periods
Signal It.Then, the pure nitrogen gas for being passed through enough time blows mixed gas, and is believed using identical sampling parameter acquisition nitrogen
Number as background signal such as.Collected original signal is as shown in figure 4, without absorption peak be background signal I0, contain absorption peak
Be mixed gas absorption signal It。
Step 4: noise reduction process: two groups of signals will be obtained in step 3 and carry out monocycle signal extraction respectively, then to 20
The cycle data progress period is average, to realize signal smoothing.
Step 5: signal alignment: as shown in " signal alignment " part in Fig. 2, determining that two groups of signals are each on a timeline first
From initial point position (s and r), and be aligned two signals on a timeline on the basis of the start position r of absorption signal.Then,
Background signal I is obtained respectively0With absorption signal ItWhen below laser tuning current threshold (in 0.002 second), output signal
Average value be respectively f and e.Then, the photodetector in one hour is acquired under the natural working condition that no laser inputs
Output signal and calculate signal averaging be d.Later, background signal I is utilized0With absorption signal ItResulting average value f, e points
The average value d not obtained with photodetector makes the difference, and using respective difference as offset, moves background signal I respectively0And suction
Collection of letters ItPosition on y direction, so that background signal I0With absorption signal ItIt is inputted with photodetector in no laser
Natural working condition under output signal aligned in position, to eliminate the influence of background light beats.
Step 6: weighted fitting: to by step 5 treated background signal I0With absorption signal ItIt is respectively weighted quasi-
It closes.To background signal I0After entire data segment carries out the fitting that weight is 1, the available complete light in regression criterion
Striped and noise are learned, as shown in Fig. 5 (a), due to absorption signal ItIt is middle to there is absorption information, therefore using sectionally weighting fitting
Method will be set as 1 without the position weight for absorbing information, other positions 0, to curve matching be come out, such as Fig. 5 (b) institute
Show, then, by background signal I0With absorption signal ItRegression criterion compare, it can be found that background signal from Fig. 5 (c)
I0With absorption signal ItOptical stripe can be well matched with, so as to utilize background signal I0In regression criterion disappear
Except absorption signal ItMiddle optical stripe.
Step 7: baseline correction: will be by the absorption signal I of step 6 removal optical stripetCarry out baseline correction, processing stream
Journey sets 1 for gamma correction factor W first, utilizes the mixed of experiment acquisition as shown in " extension Internal standard correction methods " part in Fig. 2
Close gas absorption signal Plays substance C H4Absorption lineshape matched with the linear of CH4 in HITRAN database.Correction is calculated
Method is iterated by least square method, when the value of W is adjusted to the two variance minimum, acquires the final gamma correction factor
W and deviation constant matrix Q (v), since Q (v) is an array, it contain between two curves with all independent variable v phases
Corresponding offset.Therefore, the smallest offset of variance that can make two curves is obtained by the iteration of least square method
Constant Q, i.e., when quadratic sum N is minimum, corresponding QiThe deviation of two curves can be made minimum, Q=Qi, after corrected
For baseline as shown in fig. 6, top curve is before correcting, lower curve is after correcting.Finally, utilizing the resulting gamma correction factor
W and deviation constant Q combines the signal expression before correction, the signal after correction can be obtained, as shown in Figure 7 the mixing of correction front and back
The absorption spectrum of gas has obvious gap, and can intuitively find out the value of correcting value.
In conclusion the receptance function bearing calibration for the online spectrum measurement instruments that the disclosure provides can remove in signal
Non-linear and baseline drift, realization the total regression of the entire signal path including spectrum baseline is corrected, reach and utilize one
Correction course of a standard substance corrects while realizing multiple measurement parameters, and final realize responds letter to spectrum measurement instruments
Several corrections.
It should also be noted that, the direction term mentioned in embodiment, for example, "upper", "lower", "front", "rear", " left side ",
" right side " etc. is only the direction with reference to attached drawing, not is used to limit the protection scope of the disclosure.Through attached drawing, identical element by
Same or similar appended drawing reference indicates.When may cause understanding of this disclosure and cause to obscure, conventional structure will be omitted
Or construction.
And the shape and size of each component do not reflect actual size and ratio in figure, and only illustrate the embodiment of the present disclosure
Content.In addition, in the claims, any reference symbol between parentheses should not be configured to the limit to claim
System.
Similarly, it should be understood that in order to simplify the disclosure and help to understand one or more of each open aspect,
Above in the description of the exemplary embodiment of the disclosure, each feature of the disclosure is grouped together into single implementation sometimes
In example, figure or descriptions thereof.However, the disclosed method should not be interpreted as reflecting the following intention: i.e. required to protect
The disclosure of shield requires features more more than feature expressly recited in each claim.More precisely, such as front
Claims reflect as, open aspect is all features less than single embodiment disclosed above.Therefore,
Thus the claims for following specific embodiment are expressly incorporated in the specific embodiment, wherein each claim itself
All as the separate embodiments of the disclosure.
Particular embodiments described above has carried out further in detail the purpose of the disclosure, technical scheme and beneficial effects
Describe in detail it is bright, it is all it should be understood that be not limited to the disclosure the foregoing is merely the specific embodiment of the disclosure
Within the spirit and principle of the disclosure, any modification, equivalent substitution, improvement and etc. done should be included in the guarantor of the disclosure
Within the scope of shield.
Claims (10)
1. a kind of receptance function bearing calibration of online spectrum measurement instruments, by adding the standard after screening in measured matter
Substance realizes the correction of the receptance function of spectrum measurement instruments using the correction linear to measure spectrum Plays substance, packet
It includes:
Step A: using photodetector acquisition absorption signal and background signal, and make to include one section in two groups of spectral signals
Signal segment without laser emitting；
Wherein, the spectral signal in the absorption signal comprising sample to be tested and the mark not chemically reacted with the sample to be tested
The spectral signal of quasi- substance；
Step B: using in the absorption signal and the background signal without laser emitting signal segment and photodetector without laser
Output signal under input state eliminates influence of the fluctuation of environmental background light to spectroscopic data；
Step C: fitting is respectively weighted to step B treated absorption signal and background signal, and using in background signal
Regression criterion eliminate absorption signal in optical stripe；
Step D: it is matched using the spectral signal of the standard substance of acquisition with the spectral information in database, at step C
Absorption signal after reason is corrected, the spectral signal of the sample to be tested after being corrected.
2. the receptance function bearing calibration of online spectrum measurement instruments according to claim 1, the step A include:
Step A1: the standard substance of known concentration is added in sample to be tested；
Wherein, the concentration of the standard substance, so that its feature peak amplitude is less than or equal to subject to the amplitude of sample to be tested；
Step A2: it is mixed with the spectral signal of the sample to be tested of standard substance using photodetector acquisition, and utilizes identical
System parameter acquires the nitrogen data without absorption as background signal；
It wherein, include laser tuning current threshold output signal below in two groups of spectral signals；
Step A3: the two groups of spectral signals acquired in step A2 are smoothed using the method for multicycle signal averaging.
3. the receptance function bearing calibration of online spectrum measurement instruments according to claim 2, in the step A1: described
Standard substance contains characteristic peak that is independent and not interfering mutually with measured matter in tested absorption bands, and has in the database in detail
Thin spectrum parameter.
4. the receptance function bearing calibration of online spectrum measurement instruments according to claim 3, the database include:
HITRAN database, PNNL database or NIST database.
5. the receptance function bearing calibration of online spectrum measurement instruments according to claim 1, the step B include:
Step B1: the start position of two groups of spectral signals is determined on a timeline, and on the basis of the start position of absorption signal
It is aligned two groups of spectral signals on a timeline；
Step B2: output signal of the acquisition photodetector under no laser input state simultaneously calculates signal averaging；
Step B3: background signal and absorption signal are calculated in the average value of laser tuning current threshold output signal below；
Step B4: the resulting average value of step B3 is made the difference with the resulting average value of step B2 respectively, and is with respective difference
Offset moves the position of background signal and absorption signal on y direction respectively, makes background signal and absorption signal and light
The aligned in position of output signal of the electric explorer under no laser input state.
6. the receptance function bearing calibration of online spectrum measurement instruments according to claim 1, the step C include:
Step C1: the fitting that weight is 1 is carried out in entire data segment to background signal；
Step C2: the fitting that weight is 0, the data of no characteristic information are carried out to the data segment in absorption signal containing characteristic information
The fitting that Duan Jinhang weight is 1；
Step C3: the regression criterion after step C1 and step C2 fitting is compared into matching, so that without feature in absorption signal
The regression criterion of the corresponding regression criterion of information data section and background signal coincides；
Step C4: the regression criterion of absorption signal and background signal is made the difference, and removes the influence of optical stripe in absorption signal.
7. the receptance function bearing calibration of online spectrum measurement instruments according to claim 3, in the step D: utilizing
Following updating formula carries out baseline correction to step C treated absorption signal:
I′0(v)=WI0(v)+Q(v)
Wherein, I '0(v) indicate that the spectrum after baseline correction is linear, second order polynomial fitting are as follows: I '0(v)=c+bv+av2, I0
(v) indicate that the spectrum before baseline correction is linear, second order polynomial fitting are as follows: I0(v)=m+nv+tv2,It is non-linear
Correction factor, For deviation constant matrix.
8. the receptance function bearing calibration of online spectrum measurement instruments according to claim 7, the step D include:
Step D1: setting W initial value is that 1, Q (v) initial matrix value is all 0；
Step D2: in the spectral signal and database of the standard substance acquired using Beer-Lambert law to photodetector
Spectral signal carry out linear matching, until the variance yields of the two is minimum；
Step D3: the gamma correction factor W and deviation constant matrix Q (v) when variance yields minimum are obtained.
Step D4: least square method iteration is carried out to deviation constant matrix Q (v) using following formula and acquires deviation constant Q:
N=∑ (Qi-Qj)2
Wherein, when N obtains minimum value, the spectral signal and number of the standard substance that deviation constant Q acquires photodetector
It is minimum according to the linear deviation of the spectral signal in library；
Step D5: gamma correction factor W and deviation constant Q are brought into updating formula, and are believed using updating formula spectrum
It number is corrected.
9. the receptance function bearing calibration of online spectrum measurement instruments according to claim 8, the step D2 include:
Step D2a: the spectrum for obtaining absorption signal Plays substance is linear；
Step D2b: the database shape difference linear with the spectrum of absorption signal Plays substance is calculated；
Step D2c: calculating the variance of the shape difference obtained in step D2b, and judges whether variance yields is minimum at this time, if variance is most
It is small, step D3 is carried out, step D2d is otherwise carried out；
Step D2d: the value of gamma correction factor W is updated, using updating formula to the spectrum line of absorption signal Plays substance
Shape carries out baseline correction, and return step D2b.
10. the receptance function bearing calibration of online spectrum measurement instruments according to any one of claim 1 to 9, in which:
The spectrum that the receptance function bearing calibration of the online spectrum measurement instruments is applicable in include: absorption spectrum, emission spectrum,
Molecular spectrum, atom spectrum；
The project that the receptance function bearing calibration of the online spectrum measurement instruments can correct includes: base existing for spectral signal
Line drift, channel and the non-linear of detector, interference and noise.
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