共查询到20条相似文献,搜索用时 156 毫秒
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提出了一种改进的单相限实数Fourier-Mellin 变换(SRFMT)相位校正稳像算法,提高了稳像实时性,解决了因图像局部遮挡而引起的错误估计问题.分析了基于Fourier-Mellin 变换估计抖动图像序列尺度因子、旋转、平移向量引起的计算堵塞,然后利用傅里叶变换共轭对称性,改进实数傅里叶变换,并以查表方式访问wi 因子,提升了计算性能;最后采用统计直方图方法处理块运动向量,通过局部运动向量集中度判定,去除伪全局运动向量.实验结果表明,与未改进的算法相比,采用改进的SRFMT 相位校正稳像算法处理512×512 的灰度图像序列,稳像的实时性提高了42%,满足实时性要求,有效的去除了因局部遮挡而引起的错误估计,鲁棒性进一步增强. 相似文献
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在详细分析用斑点成像消除目标图像中随机扰动影响的基础上,提出了在有像差光学系统中,应用斑点成像消除图像中像差影响的方法。通过在光学系统的光路中引入随机相位屏,采集物的短曝光像,用斑点成像处理,恢复目标图像的功率谱和相位谱,可以得到目标近衍射极限的图像。实验结果表明,这种方法可以消除图像中光学系统像差的影响。 相似文献
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《IEEE transactions on instrumentation and measurement》1975,24(3):248-255
The passive detection of velocities of objects moving transverse to the optical viewing axis is discussed from the standpoint of the spatial Fourier transform of the image. A simple algorithm is developed which yields the velocity, as a function of time, of an object moving against a complicated background. This algorithm relies on monitoring magnitude and phase of two prominent spatial Fourier components. Measurement of the Fourier components is most simply accomplished with the direct electronic Fourier transform (DEFT) sensor. This device employs coupling between the image intensity, surface acoustic waves, and electron current in a CdS film to decompose the image into Fourier components. Experimental results show strong confirmation between theory and experiment. The paper concludes with a brief comparison of the DEFT implementation versus other systems in terms of speed, sensitivity, and cost. 相似文献
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余弦变换广泛应用于图像和视频的压缩编码以及模式识别之中。余弦变换为实偶对称的傅里叶变换,把实偶对称物体传送到位于傅里叶变换透镜前焦面的空间光调制器上,采用单色均匀平面激光光波照射,则在后焦面上为光波复振幅分布为实偶对称物体的傅里叶变换,即为物体的余弦变换。由于余弦变换谱系数既有正实数又有负实数,提出了采用傅里叶变换同轴数字全息方法记录余弦变换谱系数,通过把数字全息图减去参考光光强和物光光强而得到余弦变换系数。理论推导和实验结果表明了该方法的可行性,该方法可应用于图像的快速余弦变换。 相似文献
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动态图像运动目标检测是图像处理中的热点,但动态图像的识别范围却成了目标检测的限制,针对此问题,本文提出了一种利用图像拼接技术扩展图像识别范围、并在此基础上完成运动目标检测的方法。在图像拼接中采用了SURF图像匹配算法,运动目标识别利用背景差分法,实验中使用的是开源的Linux操作系统、以及为图像处理提供了大量算法和函数的Open CV软件开发库。针对不同分辨率、不同角度采集的图像进行了实验研究,结果表明,可以在较好满足图像识别范围的同时,明确地检测出运动目标的相关信息。同时,本文提出一种通过图像拼接实现扩展运动目标检测的方法,满足了实时性要求,达到了增加图像清晰度的目的,但是,在摄像设备与场景之间的相对运动方面还存在着有待解决的问题,这将成为今后研究的重点方向。 相似文献
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利用傅里叶变换提取图像纹理特征新方法 总被引:9,自引:0,他引:9
研究发现,由图像傅里叶周向谱传统算法得到的频谱分布不能够真正反映其频率特性。因此,根据傅里叶变换的共轭对称性,提出了更具有一般性的长方环傅里叶周向谱能量百分比新算法。该算法均匀地把图像功率谱分成20个等间距同心长方环,计算每一个长方环内功率谱能量占总能量的比值作为图像频率分布特征。实验证明,新算法能更好地反映具有一般性的不同频率图像的纹理特征。在对作物缺乏营养元素诊断识别研究中,新算法提取的特征有效性远远高于传统算法,使识别的准确率达到82%以上。 相似文献
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The frequency content of a photographic image can be considerably modified by using a suitable optical system. The Fraunhofer diffraction pattern (the Fourier transform) of a transparency is produced by using parallel light from a laser. This spatial frequency spectrum can be differentially filtered to produce a reconstructed image of arbitrary frequency content. The radiographic image is a convolution of the X-ray source with the object under examination. The filtering operation lessens the degrading effect of penumbra by means of a deconvolution with a filter that is representative of the Fourier transform of the X-ray source.Manufacture of the spatial filter is described and results showing enhancement of detail in radiographs by reduction of penumbra are presented. 相似文献
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抗打印扫描彩色图像水印算法 总被引:2,自引:2,他引:0
目的设计一种适用于彩色打印扫描图像的鲁棒性盲水印算法。方法结合四元数傅里叶变换及离散小波变换的优点,提出了一种双变换域全息水印算法。利用四元数傅里叶变换及离散小波变换,将全息水印信息分散嵌入到彩色宿主图像3个色彩分量的低频小波系数区域,而不引起大的图像失真,同时,算法实现了盲提取。结果算法满足不可见性要求,同时打印扫描实验证明,该算法具有抵抗打印扫描攻击的能力。结论结合四元数傅里叶变换及离散小波变换的双变换域水印算法,保留了2种变换域在处理彩色图像中的优点,在应用于打印扫描彩色图像时,效果比现有算法更好。 相似文献
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《IEEE transactions on instrumentation and measurement》1978,27(3):215-219
A new type of Fourier transform system proposed by the author was realized in hardware and applied to the moving vehicle size detection. CdS photo-sensor array (9 cell units) was used to pick up the moving vehicle image which was transformed into spatial frequency domain. The experimental results showed the peak value of the fundamental component corresponded to the vehicle size. 相似文献
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The use of different kinds of nonlinear filtering in a joint transform correlator are studied and compared. The study is divided into two parts, one corresponding to object space and the second to the Fourier domain of the joint power spectrum. In the first part, phase and inverse filters are computed; their inverse Fourier transforms are also computed, thereby becoming the reference in the object space. In the Fourier space, the binarization of the power spectrum is realized and compared with a new procedure for removing the spatial envelope. All cases are simulated and experimentally implemented by a compact joint transform correlator. 相似文献
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Phase wraps in a 2D wrapped phase map can be completely eliminated or greatly reduced by frequency shifting. But it usually cannot be optimally reduced using conventional fast Fourier transform (FFT) because the spectrum can be shifted only by a integer number in the frequency domain. In order to achieve a significant phase wrap reduction, we propose a fast and precise two-step method for phase wraps reduction in this paper, which is based on the iterative local discrete Fourier transform (DFT). Firstly, initial estimate of the frequency peak is obtained by FFT. Then sub-pixel spectral peak with high resolution is determined by iteratively upsampling the local DFT around the initial peak location. Finally, frequency shifting algorithm that operates in the spatial domain is used to eliminate phase wraps. Simulations and experiments are conducted to demonstrate the superb computing efficiency and overall performance of the proposed method. 相似文献