对数变换

灰色预测模型GM（1,1）主要适合于光滑数据序列的预测，对非光滑数据序列常采用对数变换法、开n次方变换法和指数加权变换法提高数据的光滑度。

The grey forecast model GM ( 1,1 ) fits in with the forecast of smooth data . With regard to non-smooth data , it adopts the logarithm transformation , the extraction of a root and the exponent weighted to improve their smoothness .

稳定性试验指标作对数变换的合理性

The Reasonableness of Stability Test Target as Logarithm Transformation

基于对数变换的灰色GM（1,1）改进模型

An improved grey gm ( 1,1 ) model based on the logarithmic transtormation method

本文通过将SAR图像进行对数变换之后，将乘性噪声转变成加性噪声，再使用本文方法进行图像去噪的。

In this paper , we convert the multiply noise to additional noise through logarithm transform for SAR image .

对于SAR图象的压缩编码，通过一个自然对数变换，使得乘性噪声转变为适于软门限去噪的加性噪声。

Especially for SAR image , a natural logarithm transfors multiplicative noise to additive noise so that SAR image can be suppressed via the soft threshold denoising scheme .

由于SAR影像中speckles是一乘性噪声，文中先对原SAR影像进行对数变换得到一同态影像。

Because ` speckle ' in SAR images is a multiplicative noise , we performed firstly logarithm transform over the two SAR images in preprocessing .

由于通常的数字减影算法效果并不理想，该文提出了一种新的减影算法&基于分段对数变换的DSA算法。

For the usual method of DSA has not good performance , a new algorithm based on subsection logarithm transform is presented in this paper .

其中缓存数据的读取及对数变换均采用自定义组件的方式将硬件单元添加到NIOSii系统中，编程时直接调用。

The data catch reading unit and natural logarithm transform unit were added to NIOS II system as User-defined logic , and could be used directly while programming .

然后对LL分量进行对数变换，对LH、HL和HH分量分别进行衰减。

Secondly , it convert the LL component into logarithmic transformation , the LH , HL and HH components are attenuated respectively .

以Hale法为基础的频率&波数域DMO，通过运用对数变换，导出一系列快速近似方法。

We have derived a set of approximations to Hale 's DMO algorithm in f-k domain via a logarithmic transform .

采用固定相位法，通过对数变换从HaleDMO的tx域解析脉冲响应的结果可以导出精确的对数拉伸DMO算法。

Exact logarithmic stretching DMO algorithm is derived via logarithmic transformation on Hale DMO in tx domain by using stationary phase method .

并引进了均匀分布离散化分析，把对数变换与Ridit作为特例，讨论了它在分布假设检验中的应用。

As a generalization of Ridit and Discrete Entropy , the discrete transform of uniform distribution and its application to test distribution hypothesis is also discussed .

经比较发现，先对图像数据进行对数变换、IHS变换和KL变换后再进行密度分割及图像分类，可以更好地区分和识别水体污染。

Through comparison , it can be found that classification and segmentation image of remote sensing may distinguish and recognize water pollution more effectively after logarithm , IHS and KL transformation .

使用指数变换方法对Burgers方程和边界条件作了处理，然后使用代数变换的方法和对数变换的方法将经过指数变换后的问题的取值范围从无界区域变成有界的，最后使用谱方法求解问题。

First , we deal with Burgers Equation and boundary condition by the exponential transformation ; then through algebraic mapping or logarithmic mapping , we map the semi-infinite into finite one ; at last , we solve it by spectral method .

根据SAR图像斑点噪声的特殊性，首先对影像进行对数变换，并使用àtrous运算法则对变换后的影像进行分解，然后通过贝叶斯原理估计修正小波系数。

According to the particularity of speckle noise in SAR image , logarithmically transformation was first applied , and à trous algorithm was used to decompose the image . Then the manipulation of the wavelet coefficients was performed based on Bayesian estimator .

通过对Arrhenius公式作对数变换，分别计算了Sn及In-Sn合金不同温区的流团体积和黏流激活能，发现熔体的流团体积和黏流激活能均随温度的升高而减小。

With the logarithmic transformation of the Arrhenius formula , the flow volumes and activation energies of Sn and In-Sn alloys at every temperature zone are calculated . The results show that the flow volumes and activation energies decrease with the increasing temperature .

通过对数变换将最优问题的HJB方程转化为半线性偏微分方程，证明了最优投资组合解的存在性，给出了价值函数和最优投资策略。

The HJB equation associated to the optimal investment problem becomes the semilinear partial differential equation by the logarithmic transformation . The existence of optimal portfolios solution is proved and the value function and optimal strategies are given .

对数变换与小波变换用于野外采集植物波谱降噪

Field collected plant spectrum denoising by logarithm transform and wavelet transform

基于对数变换的非高斯噪声几何功率谱特性分析

Geometric Power Density of Non-Gaussian Noise based on Logarithmic Transform

将疲劳寿命经对数变换后可提高模拟精度。

The simulation accuracy of fatigue life can be enhanced through a logarithmic transformation .

对数变换的问题及其改进

Problems in the Logarithmic Transformation and Improvements

非线性对数变换能使润湿图像中润湿区域的细节得到加强同时又能压缩背景区域的灰度（非润湿区域）；

The logarithm transforms can enhance the wetting area and compression the non - wetting area .

发现对有机质含量做对数变换可提高与土壤反射率的相关性。

It was found that logarithm transformation of soil organic matter content could increase their correlation .

通过对分级问题的研究表明，各项指标可依对数变换值按0.1的级差，考虑到标准差大小分为5&9级。

According . to standard deviation every item can be divided into 5 & 9 grades by grade difference of 0.1 .

在光路调节中采用具有对数变换功能的示波器和动态范围较大的探测器，可以提高测量精度。

It is suggested that logarithm transform of oscillograph and large dynamic range of detector should be applied to adjust the optical cavity for improving metrical precision .

针对低照度、大背景、小目标图像，提出了基于对数变换的平台直方图均衡化算法。

In order to enhance the images with low illumination , large background area and dim target , this paper proposes the plateau histogram equalization based on logarithm transform .

首先建立以中值滤波、高帽变换、对数变换和图像拉伸为基础的预处理算法，减轻了图像灰度的不均匀性，降低了图像分割的困难。

An preprocessing algorithm for obtained surface images based on median filtering , top-hat transformation and logarithmic transformations is set up to eliminate uneven lighting disturbance and thus reduces the difficulties of defects segmentation .

对联合变换相关器的功率谱进行对数变换可强化其高频分量，锐化相关峰，但同时也会增强其噪声成分，影响抗噪性能。

The high frequencies of the joint power spectrum ( JPS ) of joint transform correlator ( JTC ) can be emphasized by logarithmic transformation of the JPS , and sharp correlation peaks are obtained .

基于灰度映射如直方图均衡化、对数变换、γ-校正等方法出现效果图层次过渡不自然，缺乏立体感等问题。

The methods based on gray-level mapping , for instance , histogram Equalization , logarithm transform ,γ - Correction , are defective since the resultant images are unnatural in grey level transition and short of three-dimensional sense .

为增强联合功率谱的高频成分，改善其调制程度，可对功率谱进行对数变换，从而有效保留更多的高频成份，压低零级衍射光斑，提高联合变换相关器的识别能力。

Logarithmic Transformation to Joint Power Spectrum can enhance the intensity of high frequency component , improve the modulation degree , weigh down the zero-order diffraction , and increase the recognition efficiency of joint transform correlation system .