variance spectrum 中文意思是什麼
variance spectrum
解釋
方差譜-
And understanding and studying the spectral features and variation rules of geo - targets in the experimental area, raising that it is the basis of geo - targets information collection with imaging spectrometer data to understand spectral features and variation rules of geo - targets, realizing that in a great extent spectral - integrated - form - based classification method can remove the phenomenon of " different spectrum with same objects " resulted from reflection ratio curve translation because of the angle change among sensor, targets and observation direction, and the average and variance images can be introduced to solve the problem of two kinds of geo - target with similar spectral forms and much different values of whole reflection ratio. it is suggested that " red edge " range bands of vegetation, which has close relationship with vegetation cover and biomass, is the main characteristic bands and important basis for careful vegetation classification and quantitative retrieval, and pixel - based derivative spectral analysis is very useful for removing the effects of soil background values and quantitatively retrieving vegetation biomass and cover. the remote sense quantitative retrieval model is developed for main appraisable factors of desertification monitoring assessment with imaging spectrometer data and then the applicability of model is analyzed
研究結果如下：首先針對荒漠化地區的地物特徵，對高光譜數據不同波段的數據質量、波段組合進行了評價，提出了適用於荒漠化監測的基本波段選擇集；初步了解和掌握了研究地區的地物光譜特性及變異規律，進一步明確了掌握地物光譜特徵和變異規律是用成像光譜儀數據提取地物信息的基礎；發現了基於光譜整體形狀的分類方法在很大程度上能夠消除由於傳感器、地物目標觀測方向之間的角度變化引起的反射率曲線整體平移的「同物異譜」現象，對于譜形相似而整體反射率的值相差較大的兩類地物，通過引入均值和方差圖像參與分類得到解決；研究還表明在植被「紅邊」范圍內的波段是進行荒漠化監測的主要特徵波段，這些波段與植被生物量和蓋度都有密切的關系，是開展精細植被分類研究和植被定量反演的重要基礎；像元的導數光譜分析可以消除土壤背景的影響，是進行植被生物量和蓋度定量反演的有力工具；建立了荒漠化監測主要評價因子的定量反演模型，並分析了模型的適用性。 -
53 maize standard samples diffuse reflectance spectra were collected from 4000cm - 1 ~ 10000cm - 1 at 8 cm - 1 resolution on perkin - elmer spectrum one nts near - infrared instrument at different energy level. 3 samples were scanned 10 times repeatedly at 100 %, 76 % and 34 % energy level for energy variance analysis
結果表明，隨著儀器能量降低，模型相對標準偏差（ rsd ）有增大趨勢，儀器相對能量從100衰減到18后，模型預測值rsd從2 . 5增至4 . 72 。 -
The signal process function of the software include these function : digital filter, windowing, auto - correlation function and cross - correlation function, mean and variance, probability density function and probability distribution function statistic ; auto - power spectrum, cross - power spectrum, frequency response function, coherence function, cepstrum analysis based on fft ( fast fourier transfer ) ; joint time - frequency analysis based on stft ( short - time fourier transfer )
軟體的處理功能包括：數字濾波、時域加窗、自相關與互相關處理、均值和方差計算、概率密度和概率分佈函數計算；在快速傅立葉變換（ fft ）基礎上計算自功率譜、互功率譜、頻率響應函數、相干函數、倒頻譜分析；基於短時傅立葉變換（ stft ）的聯合時頻分析等。 -
The statistic of wavelet transform coefficient algorithm can solve the periodic noise, high - energy noise and some non - gauss noise simply and effectively ; bi - spectrum can acquire more information from the original signal than power - spectrum, detect more information except from range and restrain the gauss noise. short - time speech signal can be considered as stationary and with periodic non - gauss signal, so we can make use of bi - spectrum to obtain the speech character and separate the speech and noise and detect morse telegraph signal ; complex number spectrum variance algorithm is put forward based on the deeply observing speech data, it is a new algorithm, experiment show that it is simple, effective
統計演算法在解決周期信號、高能噪聲和高斯信號方面有獨特之處，能簡單有效提取以上噪聲的特徵;雙譜能夠提供比功率譜更多的有用信息，有效地檢測信號幅度之外的其它信息，並能有效抑制高斯噪聲，短時語音信號一般認為是平穩且有一定的周期性的非高斯信號，因而可以利用雙譜來提取語音信號特性並實現信噪分離;復數譜方差演算法是在對語音信號進行深入觀察和分析的基礎上而提出來的一種全新的語音特徵提取方法，此方法簡單而有效的提取了語音、噪聲的特徵以及檢測莫爾斯信號，基於實驗表明，該演算法取得了很好的效果。 -
But the spectrum efficiency of the traditional ofdm system is limited due to variance of channel parameters such as channel response and rms delay spread
但是，決定通信系統調制參數的通道響應和rms時延擴展由於物體的運動或者環境的變化而動態變化，傳統的靜態確定ofdm系統調制參數的方法的頻譜效率不夠高。
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