空间频率

CR系统空间频率处理对影像质量影响的探讨

The exploring of the effect of spatial frequency processing upon imaging quality in CR system

空间频率在窄带DOA估计中的应用

The Application of Spatial Frequency in Narrowband DOA Estimation

利用白光信息处理系统，对X射线底片采用空间频率假彩色编码技术处理，使射线底片假彩色化，以提高对缺陷的辨认能力。

Radiographic film is processed by artificial color encoding technique with a light information processing system to improve defect recognition ability .

该算法使用钝化模糊影像来增加对选择空间频率的响应，以增强CR图像的结构边缘和细节。

The arithmetic adapts the unsharp masking to enhance select frequency response in order to enhance CR image edge details ;

依据傅里叶变换的相似性定理和空间频率的标度变换，研究了n平面线性相干光处理系统的一般性质。

We consider the property of the n-plane linear coherent optical-processing system in term of the similarity theorem of Fourier transform and the spatial frequency scaling transform .

光学实验给出了由光学塑料制成的空间频率为10lp／mm的柱面透射光栅的衍射光强分布。

The diffractive light intensity distributions for cylindrical transmissive grating with 10 lp / mm spatial frequency made by optical plastics are given by optical experiments .

Kerr型介质的增益与光束小扰动空间频率的关系

Relation between Spatial Frequency Due to Small Perturbation of Optical Beam and Gain of Kerr Medium

方法对临床怀疑肋骨骨折512例患者的肋骨CR影像应用谐调处理与空间频率处理的方法进行技术处理。

Methods The fractures of the ribs of 512 patients were suspected in clinic , and those CR images were processed with gradation and spatial frequency technology .

空间频率域的张量ABCD定律

Tensor ABCD Law in Spatial-Frequency Domain

基于对视觉系统定量描述其随空间频率明暗变化的视觉特性；探讨视觉系统MTF的测量。

Based on the vision characteristic of space frequency which changing with light and shade , discuss MTF measurement of vision system .

它们多数仅在较低的空间频率时（或较高运动速度时）呈现方向敏感性，其敏感性强度明显低于W型细胞。

Most of them exhibited their direction sensitivity only to gratings at lower spatial frequency ( or higher moving velocity ) . Their direction bias was significantly lower than that of W cells .

对同一双胶合透镜在不同空间频率下的MTF值进行了测量，所得结果与实际值基本吻合。

The MTF of the same lens in the different space frequency is measured , the results agree well with the practical results .

由于参考空间频率的引入，大体消除了CMOS图像传感器本身MTF对测量结果的影响，从而使测量结果更接近理论运算结果。

The reference frequency can eliminate most of the impact CMOS imager sensor itself makes to the system MTF and therefore make the MTF values more accurate .

Gabor变换可以提取图像特定区域多尺度、多方向的空间频率特征，对人脸变化具有较强的鲁棒性。

Gabor transform can extract multi-scale and multi-dimensional spatial frequency characteristics of specific area of the image , and it is robust to the changes of face .

采用FFT（快速傅立叶变换）对针织物进行图像处理，并利用提取的针织线圈的空间频率信息来测量针织物的密度。

The FFT ( Fast Fourier Transform ) technique is applied to process the image of knitted fabrics to get the frequency of needle loops in order to measure the density .

Gabor滤波器组通过提取具有空间频率、空间位置和取向选择性的特征，较好克服了实际中由于表情和光照不同带来的变化；

The Gabor features characterized by spatial frequency , spatial locality , and orientation selectivity can do with the variations due to changes in illumination and facial expression .

根据知觉学习的特异性和迁移性，设计了Gabor的识别训练，在训练中改变Gabor光栅的方向，对比度和空间频率。

According to the specificity and transfer of perceptual learning , designed the gabor identify training and change the direction , contrast and spatial frequency during the training .

所有患者术后远近立体视锐度及在各空间频率下对比敏感度均较术前有不同程度的提高，与术前相比差异均有统计学意义（P0.05）。

All patients with postoperative distance stereoacuity and contrast sensitivity compared with surgery in the spatial frequency improved to varying degrees , compared with preoperative differences were statistically significant ( P0.05 ) . Conclusion : 1 .

本文介绍两种新的电视测试图，可供电视工程技术人员检测、校准CCD摄象系统的二维空间频率特性，尼奎斯特效应，滤波线路的缺陷以及光学系统的校准都是非常方便的。

This article introduces two new TV test charts which can be conveniently used to detect and align two-dimensional frequncy response , Nyquist effect , defect of filtering circuits and optical systems in CCD camera systems .

本研究结合空间频率滤波技术和ERP技术，对经特征信息和结构信息变化的人脸图片进行高、低通滤波处理，旨在考察特征信息和结构信息在人脸加工过程中的脑电机制。

In the present study , with spatial-frequency filtering technique , the ERP properties of featural and configural information processing in face recognition were investigated by manipulating featural or configural information under high pass or low pass condition .

应用光折变效应动力学方程，导出了在Fe∶LiNbO3中对光折变全息图热定影所需的最小H+浓度，以及H+浓度与光栅空间频率的关系。

By application of kinetic equations for photorefractive effect , the minimal H + concentration for thermal fixing the photorefractive holograms in Fe ∶ LiNbO 3 and the relationship between H + concentration and spatial frequency of holograms are derived .

空间频率域中的柯林斯公式和张量ABCD定律直接给出了像散光束的空间傅里叶频谱的传输规律。

The Collins formula and tensor ABCD law in spatial frequency domain provide the relation between the input spatial Fourier spectrum and the output spectrum directly .

采用反射式光学元件设计记录光路，制作满足特定空间频率的全息光栅，并利用质心法计算得到CCD采集面上光斑的中心坐标。

The holographic grating with specifically spatial frequency is fabricated using a record beam path composed of reflecting optical element . The coordinate of the center of the laser spot on the CCD collection plane is obtained using mass center method .

运用小波分解提取LFP的响应频带Gamma频带，研究了Gamma频带对空间频率和朝向视觉特征的响应特性，并且与同一电极记录到的spike信号进行了对比。

We studied the response characteristics for spatial frequency and orientation according to the Gamma band of LFP which extracted by wavelet decomposition , and the spike recorded from the same electrode was compared .

根据光学传递函数、调制度和空间频率视觉及对物象的感知程度，制作TIFF格式透视灰度图。

According to optical transfer function , degree of modulation and apperceive degree of space frequency vision vs object image , TIFF grayscale scenograph is made .

具体来说，本文主要完成了以下工作：（1）提出用于计算二维非正弦图像空间频率的等效MSE方法。

The main contributions and specific work of this thesis are shown as following : ( 1 ) An Eq-MSE method is proposed for calculating the spatial frequency of non-sine picture .

波前功率谱密度PSD（PowerSpectralDensity）能定量给出波前畸变的空间频率分布、限定波纹度和粗糙度指标，全面反映ICF驱动器对高功率激光光学元件加工质量的特殊要求。

The wavefront power spectral density ( PSD ) can give the spatial frequency distribution of wavefront aberration , limit the waviness and the roughness , and specify the large components employed in high power density solid state laser for inertial confinement fusion ( ICF ) .

方法：在实验室搭建实验装置，分别利用矩形光栅法的实验装置和平板法视网膜MTF测量仪器，来测定正视眼组和屈光不正组的不同空间频率条纹分辨的阈值，算出并分析比较所测MTF值。

· METHODS : Retina MTF of two groups of people with emmetropia and ametropia were measured by means of a grating and parallel plate respectively . Then the measured MTF were compared and analyzed .

当刺激由倾斜45°的某一空间频率的正弦条纹变化为另一空间频率的竖直正弦条纹时，RT主要由两者中较低的空间频率决定。

It is discovered in our experiments that the RTs to the change of the stimulus from the 45 degrees tilted grating of one spatial frequency to the vertical grating of another spatial frequency is determined by the lower spatial frequency .

成像干涉光刻技术（IIL）利用多次曝光分别记录物体空间频率的不同部分，极大地提高了成像质量，其中大角度倾斜照明是对OAI的扩展。

Imaging interferometric lithography ( IIL ) uses multiple exposure to record different portions of the spatial frequency space of mask and greatly increases resolution .