The Method Of Spectrum Data Processing For Echelle Spectrometer

Both high spectral resolution and whole spectrum direct reading can be realized for Echelle spectrometer by cross dispersion and matrix detector.Compared to the common spectrometers which have the same volume,echelle spectrometer not only has high spectral resolution and whole spectrum direct reading,but also has wide wavelength range,high energy efficiency and no scanning unit.As the technology of grating and detector manufacturing developing,the application of echelle spectrometer changed from astronomy to civil field.Nowadays,echelle spectrometer had been used in chemical analysis,quality inspection,geological exploration,environmental monitoring and many foreign companies have launched a series of echelle spectrometer products,while the domestic is still in the stage of the principle prototype.The bottleneck that restricts the development of the echelle spectrometer in china is the accuracy and speed of the spectrum data processing.Therefore,the spectrum data processing method of echelle spectrometer is intensively studied.The main work is as follows:First,the method for the establishment of spectral reduction model based on geometric optics tracing is proposed.Based on the analysis of the structure characteristics of the echelle spectrometer,the spectral reduction model is established to characterize the relationship between wavelength and coordinates of the spots.The error of the model is less than one pixel by correcting the spectral line bending of the prism.Second,the algorithm of background removal is proposed.By analyzing the characteristic of gray value of original image,the method of morphological soothing and edge detection is used to lock the effective spot and the gray value of the otherpixel are set to zero.This method reduces the amount of data to be processed which not only optimizes the signal to noise ratio but also improves the speed of spectrum data processing.Third,two wavelength extraction algorithm is proposed depend on the different imaging characteristics of the incident light source.Wavelength extraction algorithm based on position acquiring of the spots is used for discrete spectrum light source and wavelength extraction algorithm based on the spectral reduction is used for both the continuous spectrum and the discrete spectrum light source.Choosing the appropriate wavelength extraction algorithm can further improve the speed of spectrum data processing.Fourth,the software of echelle spectrometer is designed which integrated spectrum data processing and camera control.The software makes the operation of the echelle spectrometer more intelligent.Fifth,the method of on-line wavelength calibration is proposed.By acquiring and analyzing the spectral data of mercury lamp,the spectral reduction model will be corrected automatically in a certain tolerance range.The function of automatic on-line wavelength calibration improves the echelle spectrometer a lot.Sixth,a kind of structure that makes the instrument easy to adjust is improved by analysis the tolerance of each optical element.The structure realize the fast loading and adjustment which provides a new idea for the commercialization of the echelle spectrometer.