CN102692395B - Light interference gas detection device and working condition detection method thereof - Google Patents

Abstract

The invention relates to the technical field of gas detection and provides a light interference gas detection device capable of automatically carrying out analysis processing on light interference fringes. The light interference gas detection device comprises a light source, a light path, a gas circuit, an image sensor, an acquiring circuit, a fringe analysis processing module and a working condition detection module, wherein the image sensor is used for converting the light interference fringes into an electric signal; the acquiring circuit is used for acquiring fringe waveform data from data output by the image sensor; the fringe analysis processing module is used for carrying out analysis processing on the fringe waveform data acquired by the acquiring circuit; and the working condition detection module is used for evaluating the working condition according to an analysis processing result of the fringe waveform data. The invention also discloses a working condition detection method of the light interference gas detection device. According to the light interference gas detection device and working condition detection method provided by the invention, the anti-interference capacity, the safety and the reliability of the detection device can be improved.

Description

Light interference gas detection device and its Working condition detecting method

Technical field

It is a kind of interference of light detection gas concentration magnitude device and its Working condition detecting method for being particularly suitable for use in that operating mode self-inspection can be carried out the present invention relates to gas detection technology field.

Background technology

Existing use human eye initiative recognition interference spectrum offset reads interference of light gas (such as methane or carbon dioxide) detection means of detected gas concentration values, due to lacking the effective detection to interference fringe, it is impossible to which the operating mode to device itself makes the judgement of science.

The content of the invention

In view of this, the invention provides a kind of by carrying out the method that analyzing and processing realizes the evaluation of device operating mode self-inspection to interference of light striped.

The purpose of the present invention is achieved through the following technical solutions：Light interference gas detection device, including light source, light path and gas circuit, in addition to

Imaging sensor, interference of light striped is changed into electric signal；

Pick-up slip ripple graphic data in Acquisition Circuit, the data exported from imaging sensor；

Fringe analysis processing module, is analyzed and processed to the striped Wave data that Acquisition Circuit is gathered；

Operating mode detection module, operating mode is evaluated according to the analysis processing result of striped Wave data.

Further, extracted valid data in the striped Wave data that the fringe analysis processing module is gathered to Acquisition Circuit.

Further, the operating mode detection module evaluates operating mode by following formula：

Y in formula_iFor gathered data,For gathered data average value,For the match value calculated by the reference waveform fitting function initially preserved, R²Value is bigger, then shows that equipment working condition is better.

Invention additionally discloses a kind of light interference gas detection device Working condition detecting method, comprise the following steps：

1) interference of light striped is changed into by electric signal by imaging sensor；

2) pick-up slip ripple graphic data in the data exported from imaging sensor by Acquisition Circuit；

3) the striped Wave data that Acquisition Circuit is gathered is handled by processing module, rejects redundant data, obtain valid data；

4) operating mode self-inspection is carried out using the valid data of collection.

Further, step 4) in, evaluate operating mode especially by following formula：

$R^2=1-\frac{\mathrm{\Σ}{(y_i-{\hat{y}}_i)}^2}{\mathrm{\Σ}{(y_i-\stackrel{\‾}{y})}^2}$

Y in formula_iFor gathered data,For gathered data average value,For the match value calculated by reference waveform fitting function, R²Value is bigger, then shows that equipment working condition is better.

Further, R is worked as²When value is less than threshold value, alarm is sent.

The beneficial effects of the invention are as follows：By being improved to traditional interference of light detector, interference of light stripe information is read using imaging sensor, using digital collection method, the analog signal that imaging sensor is exported is converted to data signal, processing module is recycled to carry out all kinds of calculation process to the data signal of collection, interference information is rejected, check device own operating condition is realized, so as to improve the security reliability of detection means.

Other advantages, target and the feature of the present invention will be illustrated in the following description to a certain extent, and to a certain extent, based on will be apparent to those skilled in the art to investigating hereafter, or it can be instructed from the practice of the present invention.The target and other advantages of the present invention can be realized and obtained by following specification and claims.

Brief description of the drawings

Fig. 1 is the structural representation of light interference gas detection device；

Fig. 2 is the schematic flow sheet of light interference gas detection device Working condition detecting method.

Embodiment

The preferred embodiments of the present invention will be described in detail below.It should be appreciated that preferred embodiment is only for the explanation present invention, the protection domain being not intended to be limiting of the invention.

Referring to Fig. 1, light interference gas detection device, including light source, light path and gas circuit, in addition to imaging sensor, interference of light striped are changed into electric signal, preferably array image sensor；

Pick-up slip ripple graphic data in Acquisition Circuit, the data exported from imaging sensor；

Fringe analysis processing module, is analyzed and processed, therefrom middle extracted valid data to the striped Wave data that Acquisition Circuit is gathered；

Operating mode detection module, operating mode is evaluated according to the analysis processing result of striped Wave data.The operating mode detection module evaluates operating mode by following formula：

$R^2=1-\frac{\mathrm{\Σ}{(y_i-{\hat{y}}_i)}^2}{\mathrm{\Σ}{(y_i-\stackrel{\‾}{y})}^2};$

Y in formula_iFor gathered data,For gathered data average value,For the match value calculated by the reference waveform fitting function initially preserved, R²Value is bigger, then shows that equipment working condition is better.

Referring to Fig. 2, light interference gas detection device Working condition detecting method comprises the following steps：

1) interference of light striped is changed into by electric signal by imaging sensor；

2) pick-up slip ripple graphic data in the data exported from imaging sensor by Acquisition Circuit；

3) the striped Wave data that Acquisition Circuit is gathered is handled by processing module, rejects redundant data, obtain valid data；

4) operating mode self-inspection is carried out using the valid data of collection, operating mode is evaluated especially by following formula：

$R^2=1-\frac{\mathrm{\Σ}{(y_i-{\hat{y}}_i)}^2}{\mathrm{\Σ}{(y_i-\stackrel{\‾}{y})}^2}$

Y in formula_iFor gathered data,For gathered data average value,For the match value calculated by reference waveform fitting function, R²Value is bigger, then shows that equipment working condition is better.

Work as R²When value is less than threshold value, alarm is sent.

Curve matching principle：

The mutation situation of imaging sensor output waveform is may determine that by curve matching, its principle is that the corresponding function model of known interference fringe waveform is y=g (x), some dis-crete sample values { (x1, y1), (x2, y2) ... (xn, yn) }, by adjusting some undetermined coefficients in the function so that the difference of the function and known point set is minimum.

Initially set up model of fit.According to principle of interference, two beam monochromatic coherent lights are in image planes certain point M conjunction vibration：

${a_0}^2={a_1}^2+{a_2}^2+2a_1{a}_2\cos 2\mathrm{\π}\frac{\mathrm{\Δl}}{\mathrm{\λ}}---\left(2\right)$

A1 in formula, a2 are respectively the relevant light amplitude through over-sampling air chamber and air chamber, and Δ l is the optical path difference of two coherent lights.From Michelson's interferometer principle and equal thickness interference principle, the optical path difference of two coherent lights：

Δ l=2 (n-1) t+2Xtan θ (3)

θ is the angle of wedge of the equivalent air splitter of whole light path system in formula, and t is air chamber length, and n is tested gas refracting index, and the refractive index of air is that 1, X is any interference fringe and the distance at zero order fringe center.

Because the imaging of each pixel of imaging sensor is actually the process in spatial domain to transform progress energy integral, the timing amplitude of frequency one square is proportional to illumination energy, and generally there is linear relationship between the response current and illumination energy of imaging sensor pixel.

To sum up set monochromatic light interference waveform function as：

$Y=\mathrm{\α}\{{a_1}^2+{a_2}^2+2a_1{a}_2\cos \frac{2\mathrm{\π}}{\mathrm{\λ}}[2(n-1)t+2x\tan \mathrm{\θ}\left]\right\}+\mathrm{\β}---\left(4\right)$

For white light, then have

Y=Y_{It is red}(X)+Y_Orange(X)+Y_{It is yellow}(X)+Y_{It is green}(X)+Y_{It is blue}(X)+Y_Indigo(X)+Y_{It is purple}(X)(5)

If (x, y) is the coordinate value under coordinate system o_xy, (x₀, yx) and be new coordinate value of the origin of coordinate system O_XY where (X, Y) under o_xy, then by X=x-x₀, Y=y-y₀, you can realize the conversion between Two coordinate system.Because sampled point is the coordinate value under o_xy, coordinate system O_XY is to cross zero level fringe center as Y-axis, and Y-axis is parallel and y-axis, it is known that Y-axis is x in o_xy abscissa value₀.From (4) formula, waveform is in Y=α { a₁ ²+a₂ ²+ β places slope sign will change, if now corresponding coordinate value is y₀', it thus can determine that coordinate system O_XY X-axis is located at y under o_xy coordinate systems₀=y₀′-α{a₁ ²+a₂ ²}-β。

It is changed into from upper (4) formula：

$y=2\mathrm{\α}{a}_1{a}_2\cos \frac{2\mathrm{\π}}{\mathrm{\λ}}[2(n-1)t+2(x-x_0)\tan \mathrm{\θ}]+{y_0}^{\′}---\left(6\right)$

By (5), (6), have：

$y=\underset{j=1}{\overset{7}{\mathrm{\Σ}}}{c}_j\cos \frac{2\mathrm{\π}}{{\mathrm{\λ}}_j}[2(n-1)t+2(x-x_0)\tan \mathrm{\θ}]+7{y_0}^{\′}---\left(7\right)$

(7) in formula, c_j, λ_jRed, orange, yellow, green, blue, indigo, the amplitude and wavelength of purple light are represented respectively.

By principle of least square method, there is one group of number and cause

∑|g(x_i)-y_i| 2=min (8)

Wherein, (x_i, y_i) it is sampled value, g (x) is the best fit function of (7) formula.

Above mentioned problem is attributed to the extreme-value problem of the function of many variables, and the necessary condition of extreme value is sought by the function of many variables, and the undetermined coefficient of the implicit function determined to (8) formula seeks local derviation and makes it be zero respectively, substitutes into the data (x of collection_i, y_i), you can solve the undetermined coefficient in function (7).

What is finally illustrated is, the above embodiments are merely illustrative of the technical solutions of the present invention and it is unrestricted, although the present invention is described in detail with reference to preferred embodiment, it will be understood by those within the art that, technical scheme can be modified or equivalent substitution, without departing from the objective and scope of the technical program, it all should cover among scope of the presently claimed invention.

Claims (3)

1. light interference gas detection device, including light source, light path and gas circuit, it is characterised in that：Also include imaging sensor, interference of light striped is changed into electric signal； 

Pick-up slip ripple graphic data in Acquisition Circuit, the data exported from imaging sensor； 

Fringe analysis processing module, is analyzed and processed to the striped Wave data that Acquisition Circuit is gathered； 

Operating mode detection module, operating mode is evaluated according to the analysis processing result of striped Wave data； 

The operating mode detection module evaluates operating mode by following formula： 

Y in formula_iFor gathered data,For gathered data average value,For the match value calculated by the reference waveform fitting function initially preserved, R²Value is bigger, then shows that equipment working condition is better； 

Wherein, R is worked as²When value is less than threshold value, alarm is sent. 

2. light interference gas detection device as claimed in claim 1, it is characterised in that：Extracted valid data in the striped Wave data that the fringe analysis processing module is gathered to Acquisition Circuit. 

3. light interference gas detection device Working condition detecting method, it is characterised in that：Comprise the following steps： 

1）Interference of light striped is changed into by electric signal by imaging sensor； 

2）Pick-up slip ripple graphic data in the data exported by Acquisition Circuit from imaging sensor； 

3）The striped Wave data that Acquisition Circuit is gathered is handled by processing module, redundant data is rejected, valid data are obtained； 

4）Operating mode self-inspection is carried out using the valid data of collection;

Step 4）In, operating mode is evaluated by following formula： 

Y in formula_iFor gathered data,For gathered data average value,For the match value calculated by reference waveform fitting function, R²Value is bigger, then shows that equipment working condition is better； 

Work as R²When value is less than threshold value, alarm is sent.