CN103808267A

CN103808267A - Spectrograph-based optical displacement sensor signal demodulation method

Info

Publication number: CN103808267A
Application number: CN201210451998.8A
Authority: CN
Inventors: 李秉实; 张兵; 王东辉; 包艳; 吴忠
Original assignee: No 618 Research Institute of China Aviation Industry
Current assignee: No 618 Research Institute of China Aviation Industry
Priority date: 2012-11-12
Filing date: 2012-11-12
Publication date: 2014-05-21
Anticipated expiration: 2032-11-12
Also published as: CN103808267B

Abstract

The invention relates to a spectrograph-based optical displacement sensor signal demodulation method. According the scheme, a data processing process of a wavelength encoding type optical displacement sensor comprises (1) reading spectroscopic data of output diffraction light of the sensor through a spectrograph; (2) processing the data through a full width at half maximum peak searching algorithm to obtain central wavelength; (3) performing comprehensive regression interpolation on the central wavelength to obtain displacement information. The spectrograph-based optical displacement sensor signal demodulation method has the advantages of being rapid, not needing a gate code calculation process and shortening data processing time; being accurate, avoiding gate code equation fitting errors and improving the calculation accuracy; being independent, not being influenced by optical grating diffraction angle errors and eliminating machining and assembling errors due to the facts that a former process of obtaining the grate code through a diffraction formula is eliminated and the displacement is directly obtained through the central wavelength.

Description

A kind of optical displacement sensor signal demodulating method based on spectrometer

Technical field

The present invention relates to a kind of optical displacement sensor signal demodulating method based on spectrometer.

Background technology

Along with light passes the development that flies control techniques, the research of optical displacement sensor deepens continuously, optical displacement sensor output signal be treated as research emphasis, in the development of Wavelength-encoding formula optical displacement sensor, most crucial data processing is to be resolved the displacement information of sensor by wavelength, and treatment scheme is: the spectroscopic data of the output diffraction light of (1) spectrometer read sensor; (2) by algorithm, data are processed and obtained centre wavelength; (3) try to achieve grid by diffraction formula close; (4) calculate displacement by the close equation of grating grid.

Due to current preparing grating process technology limit, the close equation of grid, for approximate three distributions, calculates step (3) and solves difficulty increase, and the processing time increases; Error in processing simultaneously, assembling, makes incident light incident angle produce deviation, causes the result of calculation of diffraction formula not conform to the actual conditions, and calculates wrong displacement information.

Summary of the invention

The object of the invention is to propose a kind of optical displacement sensor signal demodulating method based on spectrometer.

The technical scheme that the present invention takes is that a kind of optical displacement sensor signal demodulating method based on spectrometer, comprises the following steps:

Step 1: optical displacement sensor output arrowband diffraction light signal is to spectrometer;

Step 2: spectrometer reads the spectral information of arrowband diffraction light;

Step 3: spectrometer, by the corresponding array data of the wavelength X in spectral information and light intensity I, is input to computing machine;

Step 4: computing machine utilizes halfwidth method to process the corresponding array data of wavelength X and light intensity I, obtains the central wavelength lambda of arrowband diffraction light ₀;

Step 5: to central wavelength lambda ₀carry out interpolation arithmetic, obtain displacement information, complete demodulation.

Preferably, the method for halfwidth described in step 4 is: first utilize point-to-point comparison method to obtain the maximal value I of light intensity I _mAX, after the corresponding array data of light intensity I is deducted to the I of 0.1～0.9 multiple _mAX, obtain the new array data of light intensity I, then by maximal value I _mAXpoint to the left and right both direction point-by-point comparison obtains the absolute value minimum value I of the new array data of light intensity I _mINL, I _mINR, I _mINL, I _mINRtwo corresponding wavelength value λ _mINLand λ _mINRintermediate value λ _mID, be central wavelength lambda ₀.

Preferably, the interpolation arithmetic described in step 5 is: first pass through survey record one group switching centre wavelength X first _markwith displacement X _markcorresponding array data, then in test, try to achieve central wavelength lambda ₀after, search central wavelength lambda ₀at λ _markinterval of living in corresponding array data, then obtains displacement in interval interpolate value.

The advantage that the present invention has and beneficial effect: a) rapidity, without the process of carrying out the close calculating of grid, has shortened data processing time; B) accuracy, has cast aside the error of the close equation models of grid, has improved computational accuracy; C) independence, is not subject to the impact of optical grating diffraction angular error, has eliminated processing and rigging error.

Accompanying drawing explanation

Fig. 1 is the treatment scheme of many information fusion fast resolution algorithm, the linear arrowband diffraction light of wavelength and displacement centered by sensor output signal, by spectrometer, spectral information is read in to computing machine, utilize halfwidth method to calculate centre wavelength, draw displacement by interpolation arithmetic, complete sensor displacement test.

Fig. 2 is the corresponding relation curve of typical light displacement transducer output light wavelength and light intensity.

Fig. 3 is the process example that halfwidth method solves centre wavelength.

Fig. 4 is the process example that method of interpolation solves displacement.

Embodiment

Below in conjunction with Figure of description, the present invention is elaborated, concrete operation step is as follows:

Step 4: computing machine utilizes halfwidth method to process the corresponding array data of wavelength X and light intensity I, obtains the central wavelength lambda of arrowband diffraction light ₀.First utilize point-to-point comparison method to obtain the maximal value I of light intensity I _mAX, after the corresponding array data of light intensity I is deducted to the I of 0.1～0.9 multiple _mAX, obtain the new array data of light intensity I, then by maximal value I _mAXpoint to the left and right both direction point-by-point comparison obtains the absolute value minimum value I of the new array data of light intensity I _mINL, I _mINR, I _mINL, I _mINRtwo corresponding wavelength value λ _mINLand λ _mINRintermediate value λ _mID, be central wavelength lambda ₀.；

Step 5: to central wavelength lambda ₀carry out interpolation arithmetic, first pass through survey record one group switching centre wavelength X first _markwith displacement X _markcorresponding array data, then in test, try to achieve central wavelength lambda ₀after, search central wavelength lambda ₀at λ _markinterval of living in corresponding array data, then obtains displacement in interval interpolate value, completes demodulation.

Embodiment

Step 2: spectrometer is chosen the HR4000 type of ocean company, reads the spectral information of arrowband diffraction light;

Step 3: spectrometer, by the corresponding array data of the wavelength X in spectral information and light intensity I, is input to computing machine, the corresponding array of wavelength X and light intensity I is two arrays that comprise 3648 numerical value, its typical corresponding relation is as shown in Figure 2;

Step 4: computing machine utilizes halfwidth method to process the corresponding array data of wavelength X and light intensity I, obtains the central wavelength lambda of arrowband diffraction light ₀.First utilize point-to-point comparison method to obtain the maximal value I of light intensity I _mAX, its light intensity value is 9144; After the corresponding array data of light intensity I is deducted to the I of 0.5 multiple _mAX, obtaining the new array data of light intensity I, the new wavelength X of array and the corresponding relation of light intensity I are as shown in Figure 3; Again by maximal value I _mAXpoint to the left and right both direction point-by-point comparison obtains the absolute value minimum value I of the new array data of light intensity I _mINL, I _mINR, be respectively 5.8 and 14.7; I _mINL, I _mINRtwo corresponding wavelength value λ _mINLand λ _mINRbe respectively 713.4nm and 735.6nm, its intermediate value 724.5nm is central wavelength lambda ₀;

Step 5: to central wavelength lambda ₀carry out interpolation arithmetic, first pass through survey record one group switching centre wavelength X first _markwith displacement X _markcorresponding array data, then in test, try to achieve central wavelength lambda ₀after, search central wavelength lambda ₀at λ _markinterval of living in corresponding array data, then obtains displacement in interval interpolate value, and as shown in Figure 4,724.5nm is at λ for example _markin corresponding array data at λ _{mark 1}(722.2nm), λ _{mark 2}(727.1nm), between, between point (722.2nm, 44mm) and (727.1nm, 46mm), carry out linear interpolation arithmetic and can obtain displacement X ₀for 44.94mm, now complete demodulation.

Claims

1. the optical displacement sensor signal demodulating method based on spectrometer, is characterized in that, comprises the following steps:

2. a kind of optical displacement sensor signal demodulating method based on spectrometer according to claim 1, is characterized in that, the method for halfwidth described in step 4 is: first utilize point-to-point comparison method to obtain the maximal value I of light intensity I _mAX, after the corresponding array data of light intensity I is deducted to the I of 0.1～0.9 multiple _mAX, obtain the new array data of light intensity I, then by maximal value I _mAXpoint to the left and right both direction point-by-point comparison obtains the absolute value minimum value I of the new array data of light intensity I _mINL, I _mINR, I _mINL, I _mINRtwo corresponding wavelength value λ _mINLand λ _mINRintermediate value λ _mID, be central wavelength lambda ₀.

3. a kind of optical displacement sensor signal demodulating method based on spectrometer according to claim 1 and 2, is characterized in that, the interpolation arithmetic described in step 5 is: first pass through survey record one group switching centre wavelength X first _markwith displacement X _markcorresponding array data, then in test, try to achieve central wavelength lambda ₀after, search central wavelength lambda ₀at λ _markinterval of living in corresponding array data, then obtains displacement in interval interpolate value.