Research On The Design Of Linear CCD Spectrometer And The Spectral Data Processing Method

With the development of spectral measurement technolgy, the spectrometer has beenwidely used in many fields of science and technology; it is the key method to analysis thecompnent and feature of material. The traditional spectral instrument cannot measure the lightintensity of different wavelength simultaneously, also the structure of the old one is complex,large in volume, cannot work in the field and finish the work in real time. So, the research.ofsmall size and easy carry spectral instrument is the key and hot point nowadays.The modern spectral analysis technique can be used to measure the material compositionand ingredient by detecting the distribution of the spectrum. The principle of thismeasurement is the light absorption and emission of the material. The main feature of themodern measurement device is the construction of the spectrometer with linear array CCDand optical fiber. The Y shape optical fiber beam is used as light guider, the plane diffractiongrating as dispersion components, CCD as photoelectric conversion, and data acquisition cardas data transformation set to realize the communication between the linear CCD and PC.The application software is developed according to the process of data capture and dataprocessing for spectrum detection. This software interface has the function of data acquisition,normalized spectral dynamic display, parameter setting, data storage, the preservation ofspectral image, and the light intensity show at any point and so on. It is convenient forspectrum curve observation and analysis.The collected spectral data has been respectively processed by window function method,wavelet threshold value method, median filtering method and the wavelet threshold-medianfiltering method for noise reduce. The filtering effect of different method is compared andanalyzed. The experimental results show that the method given in this thesis has the bestsignal-to-noise ratio, can remove most noise.Through the experiment, the hardware and software system presented in this thesis canrealize the spectrum measurement purposes well. This small fiber spectrometer is feasible,practical, reliable, and can achieve the aim to distinguish the material composition. Thisinstrument has feature of easy operation and low cost. It can quickly identify the jewelry andstone. It can be widely used as the professional jewelry test instrument, and its applicationprospect are very wide.