centroid frequency 中文意思是什麼
centroid frequency
解釋
形心頻率-
As follow : 1. two solutions of estimating the doppler centroid are put forward. we processe the doppler centroid estimation in the frequency domain and time domain. also this chapter discusses principle of the doppler centroid estimation
本文主要研究了多普勒參數估計及波數域演算法，主要有以下幾個方面: 1 .闡述了多普勒質心估計的兩種方法:頻域估計法和時域估計法。 -
The radar which is embedded on platform sidelooking, but the platform will be disturbed by airflow inevitably. so, the radar will have a small sloping angle, thereby, the doppler centroid that is not zero and doppler frequency rate need to be estimated from the raw echo data in order to focus in azimuth commendably
場景成像的合成孔徑雷達一般是正側視放置，但是載機不可避免的要受到各種擾動影響，雷達會有一定的斜視角，從而導致了多普勒中心頻率不為零，多普勒調頻斜率也隨著雷達斜視角改變。 -
At the doppler centroid aspect, this paper make use of maximum value method ; energy method and autocorrelation function method to estimate doppler centroid. at the doppler frequency aspect, this paper make use of image offset method ; time - frequency method ; minimum entropy and fractional fourier transformation method to estimate doppler frequency rate
在多普勒參數估計中，採用了最大值法、能量法和自相關函數法進行多普勒中心頻率估計;採用了圖像偏移法、時頻分析法、最小熵法和分數階傅里葉變換法進行多普勒調頻斜率估計。 -
As a result, the low - frequency contents increase as the centroid of signal spectrum experiences a downshift, in case that frequency is independent on quality factor, the offset of the centroid frequency is proportional to the integral of attenuation factor along wavepath, thus can he used to reconstruct the attenuation distribution
假設介質的品質因子與頻率無關，地震波主頻的偏移量與吸收系數對傳播路徑的積分成比例，則通過它們之間的關系可以估測介質的吸收系數。 -
The emphasis is put on the spatial angle identification of the unsolved jamming signal in the time and frequency field. two methods of the spatial angle separation is given : the clustering analysis and the power centroid track, and the advantages and the shortcomings of these methods are discussed with the theoretical analysis and the emulational result
本文重點研究了對于多個時域、頻域均不可分辨的干擾信號如何從空間角度上進行分辨，提出了兩種角度分辨的方法，聚類分析法和能量重心跟蹤法，並結合理論分析和模擬的結果，討論了這兩種方法的優缺點。 -
The used value of doppler centroid influence the imaging result very much, so it must be estimated precisely. the estimating methods contain time domain method and frequency domain method. time - frequency analysis method can be used to improve estimating precision
多普勒中心頻率的取值對成像效果有很大影響，必須精確估計，估計方法有時域方法及頻域方法，還可利用時頻分析方法提高估計精度是。 -
Firstly, fourier descriptor used to describe the object ' s shape is introduced to the extraction of feature of apple ' s shape. the boundary of apple is an obturated curve, distance between boundary point and centroid r ( k ) " is used as a function to express the 2 - d boundary in spatial domain. the fourier transform coefficients of the discrete sequences f ( h ) are spectrum values in frequency domain, and they compose feature parameters of shape
首次將圖像分析理論中對形狀的傅立葉描述方法引入到對蘋果形狀的特徵提取中，果實邊界是一條封閉曲線，用邊界點到形心之間的距離長度r （ l ）作為空域中對二維曲線的表達函數，離散的函數值序列r （ k ） ~ l的離散傅立葉變換系數f （ h ）就是頻域中得到的頻譜值，可作為形狀的特徵參數。
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