fourier-domain 中文意思是什麼
fourier-domain
解釋
傅氏域-
2. a frequency extrapolation scheme is developed to effectively predict radar cross section using floating genetic algorithm based on the geometrical theory of diffraction ( gtd ) model. the threshold discrete fourier transform ( tdft ) is introduced for the data compression in angle domain
在目標散射中心建模方面，我們將浮點型遺傳演算法（ fga ）應用於實際人工目標的gtd模型參數的抽取，利用所抽取的模型參數完成了雷達散射截面rcs的頻率擴展以及數據壓縮，並利用擴展的數據提高了距離解析度。 -
In recent years, the worldwide researchers pay much attention to fourier telescopy. it is an active imaging technique that encodes the information in the temporal instead of spatial domain, then receives the speckle and deposed of it to reconstruction the object image. now, the high - resolution technique is under the condition of deeply researched
它是一種主動式干涉成像技術，這一技術通過時域內的相位的調制完成直線條紋對目標的掃描，從而達到對深空目標頻譜的抽樣，然後接收其散射回波，對回波信號進行處理，進而還原出目標的像。 -
At present, the typic harmful current detection methods are the fast fourier transform algorithm in frequency domain and methods based on the instantaneous reactive power theory, these methods all require some transform and quick, real - time calculating, so high precision analog multipliers or high speed dsp chip with fast a / d are needed, this results in complex circuit and high cost ， which have restricted the development of apf
目前畸變電流檢測常用的方法有頻域法的fft和基於瞬時無功理論的畸變電流檢測法。這些方法均有一定的變換，需要快速、實時運算，因此必須使用高速的數字微處理器和高性能a / d轉換器，這必將大大提高系統成本，使得電路結構復雜，在一定程度上限制了有源濾波器的發展。 -
On the basis of study of fractional fourier transform and its digital computation, the main aim in this paper is to study the applications of fractional fourier transform in lfm signal detection and parameter estimation, to research filtering of lfm signal in the fractional fourier domain and the digital image watermarking in the fractional fourier domain
本文以研究分數階fourier變換的基本理論與應用為目標。在深入分析分數階fourier變換原理和數值實現的基礎上，對lfm信號的檢測與參數估計， lfm信號的分數階fourier域濾波，以及二維分數階fourier變換在數字圖像水印中的應用作了研究和模擬實現。 -
Then, based on the theory of discrete fourier transform, discrete cosine transform and discrete wavelet transform, two invisible image watermarking schemes in transform domain are proposed, one is circular symmetric spread spectrum digital image watermarking based on chaotic sequences, the other is the hybrid image watermarking based on wavelet decomposition and discrete cosine transform. finally, the good performance of the two algorithms is verified by some common image processing and attack experiments
在分析了dft 、 dct 、 dwt的理論與演算法的基礎上，提出了兩種基於變換域的圖像隱形水印方案? ?基於混沌序列的圓對稱擴頻水印方案和基於小波分解和餘弦變換結合的水印方案，並通過一些常見的圖像處理及攻擊實驗驗證了這兩種演算法生成水印的性能。 -
In order to investigate the unsteady flow frequency domain performances of an axial flow compressor at different mass flow, rotating speed and blade row spacing, plus inlet flow distortion, and considering aerodynamic characteristics and stability of the compressor, the low speed research compressor ( lsc ) at college of energy and power in nuaa is used to carry out the experiment studies. a large amount of test data has been gained through dynamic pressure transducers embedded in the stator blades at the tip, middle and hub section, then fast fourier transform algorithm ( fft ) is applied to calculate the frequency data
為探討軸流壓氣機在工作流量、工作轉速及動?靜葉排軸向間距變化時的葉片排流場非定常頻譜特性變化規律，並耦合進氣畸變的影響，同時與壓氣機氣動性能和氣動穩定性相關聯，作者利用南京航空航天大學能源與動力學院的低速大尺寸軸流壓氣機（ lsc ）試驗器，採取在靜子葉片表面埋入動態壓力傳感器的實驗方法，對葉尖、葉中和葉根三個截面的動態壓力進行了測量，獲得了大量的可靠的實驗數據。 -
Pulse step return loss from measurement in the frequency domain using the inverse discrete fourier transformation
反向不連續傅里葉傳輸的頻率區域內脈沖分步回損測量 -
In section 4, by making use of the fourier transformation for spatial variables and starting from the nonparaxial propagating equation of ultrashort pulsed beam in temporal frequency domain, the nonparaxial solution basing on the paraxial propagating solution was derived, which come to exact solution by iterative of the paraxial integral solution
在第四節里，通過採用空間變量的傅立葉變換和利用時間頻率域下的非傍軸傳輸方程，我們得出了超短脈沖光束傳輸的非傍軸的修正方法。 -
Advanced mathematical technologies, especially the newly developed wavelet transform and the frame theory, provide a solid foundation for such an effort. the ray - theory based beam - summation method, such as the complex source - generated beam and the gaussian beam methods, and the local phase - space domain ( beamlet domain ) wave field extrapolation methods employing windowed fourier transform ( wft ) or wavelet transform are proposed consequently
基於射線理論的高頻漸近射束（復射束、高斯射束）疊加方法，以窗口富里葉變換（ wft ）以及小波變換為基礎的局部相位-空間域（小波束域）波場外推方法等相繼產生。 -
The numerical method based on the coupling of the finite difference method in time domain with the discrete fast fourier transform is applied to calculate the first four eigenfrequencies and eigenfunctions of the six - cavity with open boundary. the absorbing boundary condition for tem wave is tested numerically, and it is applied to writing the code. the cold testing of the cavity is done and the results are good agreement with the numerical results
計算x波段六腔開放腔前四個模式的場分佈;根據第二章公式分別計算x波段六腔開放腔前四個模式的電子負載電導並總結了這四種工作模式渡越效應的規律，基於這種小信號理論分析了x波段渡越輻射振蕩器，得到了工作模式及可能產生的模式競爭。 -
Lacking of space locality in time domain, fourier analysis can only make certain of the integral singularity of a function or signal. as a result ; it is difficult to detect the spatial position and distribution of broken signal by fourier analysis. wavelet analysis has the characteristic of spatial locality, and its wideness in both windows of the time and the frequency can be adjusted, so it can analyze the details of a signal
小波分析優于傅里葉之處在於，小波分析在時域和頻域同時具有良好的局部化性質，因為小波函數是緊支集，而三角正、餘弦的區間是無窮區間，所以小波變換可以對高頻成分採用逐漸精細的時域或空間域取代步長，從而可以聚焦到對象的任意細節。 -
Under the condition of " comparatively weak correlation between the two noises involved, coherence function is used as a frequency domain amplification factor for improving snr of the output signal to the filter and the speech enhancement effect. meanwhile, a real - time recursive algorithm is put forward in substitute for current algorithms based on short time fourier transform. the new algorithm will simplify computations and will be suited for real - time implementation together with the adaptive systems
接著針對上述nanc系統兩路輸入信號噪聲相關性弱的情況，用相干函數作頻域增益因子來提高輸出信噪比與改善語音增強效果，同時，通過一種實時迭代演算法解決了短時傅氏變換計算量大的問題，簡化了計算，便於實時處理與實際應用。 -
One is to use fourier transformation to convert the source signal from time domain to frequency domain and to discard high frequency harmonious components upwards of 19 ( gb / t14953 - 93 d5. 3 demanding ), then to have static huffman coding to the quantized char array which is composed of reserved direct current component and basic wave and each high frequency " s amplitudes and angles. the other is to use discrete wavelet transformation to convert the source signal from time domain to frequency domain and to set the high frequency coefficients that its absolute value is smaller than the given threshold to zero, then to have dynamic huffman coding to the quantized char array which is composed of multiple, wavelet ' s level, datum length, low frequency coefficients and reserved high frequency coefficients. mass simulinks and analyses under the two circumstances have done to show that data compression ratio is small and the relative error is also small and within the permission of engineering and the compression problem can be solved in theory of measured datum of power system
第一種情況的壓縮方法為：採用傳統的傅立葉變換把原始信號從時間域變換到頻率域，舍棄20次及其以上的高次諧波成分（保證了gb / t14953 ? 93d5 . 3要求） ，然後對保留的直流分量、基波和各次諧波的幅值和相角數據量化后和量化時分別乘以的倍數系數構成一個數組，以字元形式保存，採用靜態huffman編碼對變換數據進行壓縮；採用離散小波變換把原始信號從時間域變換到頻率域，然後對分解得到的高頻系數進行閾值量化處理，對乘以的倍數系數、小波變換的階數、小波變換后的低頻、各級高頻以及原始數據長度、量化后的低頻系數以及保留的高頻系數大小、位置構成一個數組，以字元形式保存，採用動態huffman編碼對這個文件進行壓縮。 -
But the complex analytical signal ( cas ) theory can erase this spatial sigu - larity. in this section, gauss, hyperbolic and lorentz pulsed gaussian beam have been derived and compared svea and cas solution by numerical simulatio n. in section 3, by using fourier transform technique and applying the paraxial approximation in frequency domain, we derive an integral solution for the transverse and longitudinal components of the light field propagating in free space
接著，考慮了幾種特殊的脈沖gauss光束（ pulsedgaussianbeam ） ，結果顯示，在此情況下緩變包絡近似（ slowly - varyingenvelopeapproximation ）理論已不再有效，其失效的原因是，該理論導致了脈沖光束解的空間奇異性，並使脈沖光束不再具有符合物理意義的光束行為，而通過復解析信號的分析方法可以消除這種空間奇異性。 -
Synthetic aperture radiometer applies the interferometric principle to sample in the spatial frequency domain and retrieves the image by fourier or other numerical transformation
綜合孔徑輻射計利用孔徑綜合原理在空間頻率域中采樣，通過傅立葉變換或其他數學變換獲取反演亮溫圖像。 -
From the point of spatial frequency domain the paper applies the spatial frequency transformation to analyze the awg transmission characteristics and probes into the function of fourier transform, the characteristics of coherent system and its application in optical information process domain
論文應用傅立葉光學的空間頻域變換，從空間頻域的角度分析了awg的傳輸特性，探討了awg的傅立葉變換功能及其相干系統特性，以及它在光信息處理領域中的應用。 -
Author, secondly, starts from the approximate expandness of square root operator, perform mathematical calculations for finite difference operator in frequency - space domain, fourier finite difference operator in mixing domain ( frequency - space and frequency - wavenumber domain ) and general screen operator in mixing domain, compare and discuss their precision of their wavefield, adaptability for lateral velocity variations, computation efficiency and stability. thirdly, author, applies the steady variational reference slowness rytov approximation general screen wavefield extrapolation operator ( vrselrf ) in frequency - wavenumber domain, to the prestack and poststack forward modeling and depth migration
第二，從平方根運算元的近似展開出發對頻率?空間域的有限差分運算元、混合域（頻率?空間域；頻率?波數域）的fourier有限差分運算元、混合域的廣義屏運算元進行了推導並對其波場描述精度、對橫向變速的適應性、計算效率和穩定性進行了比較與評述。 -
From 1920s up to now, various techniques and methods for wave field decomposition, propagation and migration / imaging have been well developed, such as the kirchhoff asymptotic method, frequency - wavenumber domain phase - shift and phase - shift - plus - interpolation methods, and the one - way wave equation based phase - screen and generalized screen methods, etc. wave field extrapolation in these methods is implemented based on the expansion of the wave field by sets of basic functions like spatial fourier harmonies, modes, and green ' s functions
自上個世紀二十年代至今，波場分解、傳播與偏移成像技術經歷了將近一個世紀的發展，形成了多種不同的方法，如kirchhoff波動方程高頻近似解方法，頻率-波數域的相移（ phase - shift ）方法和相移-內插（ pspi ）方法，以及在混合域中基於單向波動方程的相位屏、廣義屏方法等。 -
Based on the theory of partial coherent diffraction and frt, an approach for fractional fourier domain filtering is presented as a new wavefront engineering method to improve the image quality in photolithography
基於部分相干成像理論和分數傅立葉變換濾波等理論，我們提出了利用分數傅立葉域濾波改善光刻成像質量的波前工程新思想和新方法。 -
Constancy properties of template matching in fourier domain
頻域相關的恆常性特徵及其演算法研究
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