【正文】 a smoothing。譜數(shù)據(jù)的漲落使譜數(shù)據(jù)處理產(chǎn)生誤差。數(shù)字濾波器是指完成信號濾波處理的功能，用有限精度算法實(shí)現(xiàn)的離散時間線性非時變系統(tǒng)，其輸入是一組（由模擬信號取樣和量化）數(shù)字量，其輸出是經(jīng)過變換的另一組數(shù)字量。數(shù)字濾波器是數(shù)字信號中最重要的組成部分之一，幾乎出現(xiàn)在所有的數(shù)字信號處理系統(tǒng)中。 由于射線和探測器中固有的統(tǒng)計(jì)漲落、電子學(xué)系統(tǒng)的噪聲影響，譜數(shù)據(jù)有很大的統(tǒng)計(jì)漲落。 關(guān)鍵詞 ： 數(shù)字濾波器； 數(shù)據(jù)平滑；語料庫；線性插值平滑； 統(tǒng)計(jì)漲落 ii Research and implementation of spectral data smoothing algorithm based on the digital filtering Abstract:Current is in the digital information age, digital signal processing technology is widespread attention, its theory and algorithm along with the development of the puter technology and microelectronic technology obtained the rapid development and be widely applied in voice and image processing, digital munications, spectrum analysis, pattern recognition, automatic control and other fields. Digital filter is one of the most important part of digital signal, almost appeared in all digital signal processing systems. Filtering processing of digital filter is refers to the plete function, with limited accuracy algorithm of discrete time linear timeinvariant system, its input is a set of (by the analog signal sampling and quantization) digital quantity, its output is another digital quantity after transforming. Data smoothing is the key technology of statistical language modeling, It not only can improve the performance of language modeling, it Can also improve speech recognition and Application areas such as language identification system recognition rate. Different data smoothing method should be at the contrast between the different scale of operation on the training set. A variety of smoothing algorithms, To GoodTuring estimate, linear interpolation smoothing, Katz’s backofftype is most typical and monly used smoothing. In this paper, various methods of data smoothing empirical parison, and discussed the impact of these data smoothing method performance of relevant factors. Due to inherent statistical fluctuation and the electronics system of noise influence in the rays and the probe, Spectral data has a lot of fluctuations. Spectral data fluctuation spectrum data processing error is produced. In gamma energy spectrum analysis, if the analysis of nuclide activity is very low, or is the analysis of the emission of radiation by gamma rays nuclide more weak branches, or the measuring time is too short, so, because of the statistical fluctuation count, may make the adjacent word count in the spectral dispersion larger and lead to the peak fuzzy. In order to reduce the spectrum measurement data of statistical fluctuation, and keep all the important feature of spectral peak to facilitate analysis of the spectral , must be smooth to the measured gamma spectrometry original data. KeyWords： Digital filter。 Statistical fluctuation iii 目 錄 摘要 ....................................................................... i ABSTRACT. .................................................................. i 目錄 ..................................................................... iii 1 緒論 .................................................................... 1 譜數(shù)據(jù)的平滑處理概念 及方法 ..........................................1 濾波器的選用 ........................................................ 1 常用的數(shù)字濾波算法 與選擇原則 ........................................ 3 2 能譜平滑算法的研究 ...................................................... 5 幾種能譜平 滑算法 .................................................... 5 其他算法的基本思想 ..................................................5 算數(shù)滑動平均法基本思想 ..........................................5 重心法基本思想 ..................................................5 傅里葉變換法基本思想 ............................................6 指數(shù)平滑法基本思想 ..............................................6 最小二乘 移動平滑 法 ..................................................7 SavitzkyGolay 濾波 .............................................7 最小二乘移動平滑法基本思想 與方法 ................................8 移動最小二乘法與最小二乘法比較 .................................12 小波變換 方法 .......................................................13 小波 算法 原理 ...................................................13 小波 算法 去噪的基 本方法 .........................................14 連續(xù)小波變換與局部時域分析 .....................................16 3 能譜平滑算法的實(shí)現(xiàn) .....................................................18 系統(tǒng)的實(shí)現(xiàn) .........................................................18 四種 平滑法 的仿真 ...............................................18 兩種仿真的結(jié)果分析以及比較 .....................................22 譜 平滑的幾個具體問題 ...........................................23 本章小結(jié) ...........................................................26 4 未來展望與全文總結(jié) ..................................................... 28 未來展望 ........................................................... 28 全文總結(jié) ........................................................... 28 iv 參考文獻(xiàn) .................................................................. 30 致謝 ...................................................................... 31 參考附錄 .................................................................. 32 1 1 緒論 譜數(shù)據(jù)的平滑處理的概念 及方法 在放射性測量中，由于存在統(tǒng)計(jì)漲落 ，使得測量數(shù)據(jù)的規(guī)律不顯著，尤其在能譜分析工作中，當(dāng)被分析的放射性核素的活度很低時，在有限的測量時間內(nèi)，每道計(jì)數(shù)較少，峰面積 統(tǒng)計(jì)漲落較大，給測量結(jié)果帶來較大的誤差。 對譜數(shù)據(jù)進(jìn)行平滑處理可以減少譜數(shù)據(jù)的統(tǒng)計(jì)漲落，從而減少凈面積的計(jì)算誤差。第二步是放射性核素的活度或樣品中元素濃度的計(jì)算，即由峰位所對應(yīng)的能量識別出被測樣品中含有哪些放射性核素或被激發(fā)的元素，并且由峰的凈面積計(jì)算出放射性核素的活度或元素在樣品中的濃度。 數(shù)字 濾波器 是對 數(shù)字 信號 進(jìn)行 濾波 處理以得到期望 的響應(yīng)特性的 離散時間系統(tǒng) 。 數(shù)字濾波器有低通、高通、帶通、帶阻和全通等類型。 平滑的本質(zhì)實(shí)際上就是對譜曲線進(jìn)行低通濾波，去掉高頻成分，保留有用的低頻信號。濾波技術(shù)是信號消噪的基本方法。當(dāng)噪聲的頻率處于信號的頻率范圍時，應(yīng)選用帶阻濾波器。 圖 畫出了 SAVITZKY濾波器在道域和頻域中的響應(yīng)函數(shù) 圖 SAVITZKY 濾波器在道域中的響應(yīng)函數(shù)； Figure The response function of the SAVITZKY filter in the domain； 圖 SAVITZKY 濾波器 在頻域中的響應(yīng)函數(shù)； Figure The response function of the SAVITZKY filter in frequency domain； g x/2 x/3 x/6 X35 0 X32 x w g(f)