共查询到19条相似文献,搜索用时 46 毫秒
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当有参考噪声信号时,自适应噪声抵消的实质就是求参考噪声输入通路的逆滤波器,LMS自适应滤波问题就是一个多变量函数的极值问题。LMS算法因其具有算法简单,容易实现的优点而为常用,但是算法的收敛特性和失调量受到步长参数μ的影响。而步长参数μ和最优值不易确定。遗传算法是一种应用于大规模搜索空间的有效方法,它不要求函数的解析表达式,只根据已知的测量数据便可以求得全局极值。本文以FIR滤波器为例。采用改进的实值编码遗传算法,将遗传算法用于逆滤波器的求解。计算机仿真结果表明该算法对噪声抵消取得了较满意的效果。 相似文献
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传统的中值滤波和均值滤波通常被分别用来滤除椒盐噪声和高斯噪声.但是当图像同时存在高斯噪声和椒盐噪声时,单独使用哪种滤波方法都不会达到最好的去噪效果.为了能同时滤除两种不同性质的噪声,提出了一种新的自适应混合噪声滤波算法.该算法采用了一种基于自适应阈值的方法对滤波系数加以优化,使其既可以有效地减少噪声,又可以较好的保持图像的边缘细节信息,仿真结果表明该算法能较好的滤除混合噪声,且滤波效果优于传统的滤波算法. 相似文献
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介绍车用发电机噪声的测试方法和特点,应用自适应滤波方法对车用发电机试验过程中所测得的发电机噪声与试验台背景噪声的混合信号进行分离研究,同时与独立分量分析(ICA)方法进行了比较。实验结果表明,用自适应滤波的方法能很好地把发电机噪声和背景噪声分离开来,从而使发电机生产厂家不必为控制噪声测试过程中的背景噪声而对其发电机试验平台进行改造,有效地解决了其产品噪声测试的难题。 相似文献
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针对传统中值滤波算法在图像去噪过程中造成较多图像细节信息丢失的问题,提出了一种基于噪声点多级检测的自适应中值滤波算法。该算法根据像素的空间相关性,逐级检测不同空间特征的噪声点。首先根据滤波窗口中相近像素点的数量来检测空间孤立的单个噪声点;然后通过扩展邻近窗口的方式检测空间连续的两个噪声点;接着进一步增加约束条件对空间连续的三个及以上的噪声点进行检测;最后对判断为噪声的像素用滤波窗口的中值替换。此外,该算法还能通过自适应地调整像素空间相关性判别阈值来处理不同分布特征的噪声。实验结果表明,与现有中值滤波算法相比,算法在有效滤除图像噪声的同时能更好地保护图像细节信息。 相似文献
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针对图像中的椒盐噪声,基于模糊理论设计了一种滤波算法。首先分析了椒盐噪声的特点,给出了自适应的噪声检测方法,并对噪点设计了自适应的噪声消除方法,最后采用几幅图像进行实验,定性和定量分析结果表明该方法对于椒盐噪声的消除可行、有效。 相似文献
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A novel switching median filter integrated with a learning-based noise detection method is proposed for suppression of impulse noise in highly corrupted colour images. Noise detection employs a new machine learning algorithm, called margin setting (MS), to detect noise pixels. MS detection is achieved by classifying noise and clean pixels with a decision surface. MS detection yields very high detection accuracy, i.e. a zero miss detection rate and a fairly low over detection rate for a wide range of noise levels. After noise detection, a new filter scheme called the noise-free two-stage (NFTS) filter is triggered. NFTS corrects the noise pixels using the median of the noise-free pixels in two stages. The results of experiments have demonstrated that the MS based NFTS (MSN) filter is superior to the support vector machine and neural network for denoising highly corrupted images, in terms of noise suppression and detail preservation. 相似文献
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Switching vector median filters based on non-causal linear prediction for detection of impulse noise
A new group of switching vector filters based on the non-causal linear prediction for the detection of impulse noise from colour images is presented. The proposed filters utilise the non-causal linear prediction coefficients obtained from the block-by-block autocorrelation function to find prediction vector pixel value at the centre of the filter window. Thirteen prediction coefficients are selected from the autocorrelation matrix obtained from a block of an image, and these coefficients are used to predict all pixels in that block. The difference between the predicted pixel and the original decides whether the pixel is corrupted with impulse noise. Extensive simulation experiments indicate that the new vector filters outperform the other vector filters currently used to eliminate impulse noise from colour images. 相似文献
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基于阈值判断的自适应中值滤波算法 总被引:1,自引:0,他引:1
针对标准的中值滤波算法在去除噪声与保留图像细节方面难以取舍的缺陷,在自适应中值滤波算法的基础上提出了一种改进的基于噪声点检测的自适应中值滤波算法.该算法在进行噪声点检测时采用了一种阈值判断法,充分利用了当前像素点与邻域像素点的灰度值之间的关系.结果表明,在噪声浓度较高时仍然可以区分噪声点与边缘点,滤波的同时有效地保护了图像的细节. 相似文献
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噪声概率快速估计的自适应椒盐噪声消除算法 总被引:1,自引:0,他引:1
提出一种可识别噪声概率自动调节滤波窗口的自适应椒盐噪声消除算法。对非理想椒盐噪声污染图像随机区域进行变窗口中值滤波,将结果与滤波前比对获得噪声点数,滤波区域即按此点数排序。然后取每种滤波窗口下的中间三组数据,该数据平均加权获取图像噪声概率初估计,对初估计平均加权即得图像噪声概率。滤波前首先采用阈值法排除明显噪声点,剩余像素中再以离窗口中心像素距离平方的倒数为权值估计中心像素。最后由噪声概率按照T-S模糊规则对不同模型的输出估计值进行融合。实验证明,与传统中值滤波等算法相比,该算法具有噪声自动估计和自适应窗口调节能力,滤波后标准均方差可减少20%以上,速度可提高一倍多。 相似文献
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M. Sindhana Devi M. Soranamageswari 《International journal of imaging systems and technology》2019,29(4):465-475
Impulse noise (IN) affects the digital image, during transmission, digital storage, and image acquisition. IN removal from an image is necessary as it retains the quality of the image. This work concentrates on the IN. A neuro-fuzzy (NF) system based on a fuzzy technique which is trained by a learning algorithm derived from neural network theory was implemented for the removal of noise. A NF network for noise filtering in grayscale images that combines two NF filters with a postprocessor to produce the output was presented. However, Sugeno-type is not intuitive technique and it also less accurate. To overcome these problems, a hybrid NF filter with optimized intelligent water drop (IWD) technique is introduced, where hybridized Sugeno–Mamdani-based fuzzy interference system is implemented in both the NF filters to obtain more efficient noise removal system. To improve the accuracy of the assignment of membership values to each input pixels, the optimized IWD technique is utilized, as the choice of membership function decides the efficiency of the noise removal in the images. Here, Fuzzy rules have been used to obtain the filtered output. The Hybrid method maintains the accuracy of the Sugeno model and also the interpretable capability of the Mamdani model. This method is robust against the IN and it is flexible, efficient, and accurate than existing filtering method in both noise attenuation and detail preservation and it has a great scope for better real-time applications. 相似文献
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传统D类功率放大器因特有的开关噪声对水下电子设备的信号接收、通信控制和信号传输等电信号产生很大的干扰,限制了D类功率放大器在水下电子设备中的广泛应用针对这一现象,首先阐明了Σ-Δ调制的D类功率放大器降低开关噪声的原理,然后对传统调制方式和Σ-Δ调制方式的D类功率放大器进行原理分析,并在Simulink软件中进行仿真对比。仿真结果表明,传统D类功率放大器在开关频率处的开关噪声能量高,Σ-Δ调制的D类功率放大器的开关噪声能量分散在一定的带宽内,并且开关噪声能量峰值低于传统D类功率放大器。 相似文献
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