一种基于直方图的加权均值滤波方法

根据图像直方图的特点,针对椒盐噪声,提出了一种基于直方图的加权均值滤波方法。该方法首先通过寻找局部极值确定噪声点,并对图像的所有像素做分类标记。处理过程中只考虑标记为噪声的点,以噪声图像的直方图函数作为滤波器的权值,最后将领域内非噪声点的加权均值作为滤波输出。实验结果表明该方法优于中值滤波方法。     

点检测下的中值滤波器图像去噪算法

在图像去噪过程中,运用已有的自适应中值滤波器去除图像椒盐噪声时,易把非噪声点误判为噪声点,使被处理图像严重失真,影响图像进一步分析。笔者在已有自适应滤波器去噪方法的基础上,针对椒盐噪声,进一步研究了点检测下的中值滤波器图像去噪算法,先对含有脉冲噪声的图像进行检测,判定是否为噪声点来选取自适应中值滤波合适的阈值。最后运用试验仿真结果和熵值对比传统方法,说明改进的算法去除图像椒盐噪声效果更优。     

改进型中值滤波器的实现和性能测试

改进型中值滤波器相对普通中值滤波器,既能有效去除噪声,又能较好的保护图像细节。通过对几种改进型中值滤波器的原理分析、实现和性能指标测试,多重中值滤波和窗口加权滤波性能较好,可用于去除图像椒盐噪声。     

图像去噪算法的研究

主要针对图像的高斯噪声和椒盐噪声的去噪算法进行研究,分别使用到中值滤波、均值滤波和维纳滤波三种滤波算法。实验结果表明中值滤波对于椒盐噪声有更好的去噪效果;维纳滤波对高斯噪声有明显的作用,相比中值滤波和均值滤波,维纳滤波对高斯噪声有很好的抑制效果,与此同时,维纳滤波却容易丢失边缘信息且对椒盐噪声几乎没有去噪作用。     

一种基于中值滤波的图像去噪算法

由于图像噪声会对后续的图像处理结果产生影响,所以在对图像进行其他处理前应先对图像去噪。针对传统中值滤波器在去除均匀分布椒盐噪声时效果并不理想,设计出一种自适应阈值中值滤波器。分别用两种滤波器进行图像去噪实验,通过对比去噪后图像的信噪比、峰值信噪比以及视觉效果发现:较之传统的中值滤波器,新的自适应中值滤波器能更有效地去除椒盐噪声并减少图像失真。     

基于决策分析的高椒盐噪声轮胎痕迹图像滤波方法

决策分析能准确判断出噪声像素与信号像素,均值滤波能较好平滑噪声,而自适应中值滤波能较好地保持原始图像的细节及边缘。为了恢复被高密度椒盐噪声污染的轮胎痕迹图像,提出三者相结合的新算法。该算法结合三者的优点,与传统中值滤波器、自适应中值滤波器等非线性滤波器相比,能得到更好的图像质量。实验表明,算法能有效消除灰度轮胎痕迹图像中的高密度椒盐噪声和彩色轮胎痕迹图像中的中低密度椒盐噪声,较好地保护了图像的细节及边缘信息。     

扩展自适应中值滤波器的原理与实现

在图像处理领域中噪声滤除是图像预处理阶段一项必不可少的工作。在许多场合都会遇到高强度噪声的图像，特别是椒盐噪声的滤除非常困难。本文对空间域的常用噪声滤波技术的不足进行了分析，提出了一种新的滤波器技术——扩展自适应中值滤波器技术。该技术不仅继承了原自适应中值滤波器技术的优点，而且还弥补了它的不足，解决了高强度噪声干扰下图像的滤波问题，滤波效果相当理想。最后，给出了几种滤波技术的滤波效果比较图，验证了本文提出的滤波新方法对椒盐噪声的滤除能力。     

一种新型的混合滤波器的设计与实现

对空间域的常用噪声滤波技术的不足进行了分析,提出了一种线性与非线性混合滤波算法。该算法充分结合了中值滤波器和均值滤波器的优点,比均值滤波器和中值滤波器具有更好的抑制噪声的能力,能较好地保持图像的边缘和几何结构细节。最后给出了几种滤波技术的滤波效果比较图,验证了文中提出的滤波新方法对椒盐噪声和高斯噪声的滤除能力。     

一种基于改进的非对称裁剪中值滤波算法

为了在各种噪声密度条件下,都能恢复椒盐噪声污染的图像并能很好地保持图像的细节,提出了一种基于改进的非对称裁剪中值滤波算法清除椒盐噪声.该方法首先对噪声点进行检测,然后基于滑动窗口中噪声点的数目来自适应改变窗口的大小,最后应用一种改进的非对称裁剪中值滤波器计算中值,结果显示该算法各项指标都要优于其它算法.实验结果表明了在各种的噪声密度条件下,该算法能较好地清除椒盐噪声,而且也能较好地保护图像细节,比现存的一些中值滤波算法清除椒盐噪声的效果更加优秀     

一种新型的混合滤波器的设计与实现

对空间域的常用噪声滤波技术的不足进行了分析,提出了一种线性与非线性混合滤波算法。该算法充分结合了中值滤波器和均值滤波器的优点,比均值滤波器和中值滤波器具有更好的抑制噪声的能力,能较好地保持图像的边缘和几何结构细节。最后给出了几种滤波技术的滤波效果比较图,验证了文中提出的滤波新方法对椒盐噪声和高斯噪声的滤除能力。     

Aggressive region growing for speckle reduction in ultrasound images

Speckle appears in all conventional medical B-mode ultrasonic images and can be an undesirable property since it may mask small but diagnostically significant features. In this paper, an adaptive filtering algorithm is proposed for speckle reduction. It selects a filtering region size using an appropriately estimated homogeneity value for region growth. Homogeneous regions are processed with an arithmetic mean filter. Edge pixels are filtered using a nonlinear median filter. The performance of the proposed technique is compared to two other methods––the adaptive weighted median filter and the homogeneous region growing mean filter. Results of processed images show that the method proposed reduces speckle noise and preserves edge details effectively.     

一种基于SIFT特征光流的运动目标跟踪算法

针对传统光流跟踪算法计算复杂度高、受噪声影响大的问题,提出了一种基于尺度不变特征变换(Scale Invariant Feature Transform,SIFT)和卡尔曼滤波器的特征点光流跟踪算法。首先,利用SIFT算法提取图像中的特征点;然后,根据最小绝对值误差准则对运动目标的特征点进行匹配,建立卡尔曼滤波器方程来计算特征点光流;最后,通过光流特征聚类实现运动目标的识别与跟踪。实验结果表明,算法对自然场景中的运动目标具有良好的跟踪特性,稳定性好,计算量小,易于实现。     

基于图像分割的交通图像快速去雾算法

现有去雾算法较少考虑交通图像的特征,直接应用于交通图像去雾效果和实时性较差。针对这一情况,在充分分析了雾天交通图像特征的基础上,提出一种基于图像分割的交通图像快速去雾算法。算法首先采用改进的均值漂移算法分割出天空区域,然后在天空区域中较准确的估计出大气光强度值,最后采用基于双边滤波器的改进暗原色先验（DCP）算法实现去雾,并结合雾天交通图像的特征对去雾图像进行了后处理,增强了去雾效果。实验结果证明该算法实时性高且去雾效果好,在交通图像去雾方面所提出的算法的综合性能优于现有的同类去雾算法。     

Multi-focus image fusion based on sparse decomposition and background detection

The goal of image fusion is to accurately and comprehensively describe complementary information of multiple source images in a new scene. Traditional fusion methods are easy to produce side-effects which cause artifacts and blurred edges. To solve these problems, a novel fusion algorithm based on robust principal component analysis (RPCA) and guided filter is proposed. The guided filter can preserve the edges effectively, which is often used to enhance the images without distort the details. Considering edges and flat area are treated differently by the guided filter, in this paper, sparse component of the source image is filtered by the guided filter to generate the enhanced image which contains the preserved edges and the enhanced background. And then the focused regions of the source images are detected by spatial frequency map of the difference images between the enhanced image and the corresponding source image. Finally, morphological algorithm is used to obtain precise fusion decision map. Experimental results show that the proposed method improves the fusion performance obviously which outperforms the current fusion methods.     

基于粒子滤波的红外运动目标跟踪

提出一种基于粒子滤波及Mean Shift算法的红外运动目标跟踪方法。该方法首先利用目标区域的灰度分布,建立了一种基于统计直方图的系统观测概率模型,并针对红外目标机动性强,需要大量粒子才能保证算法鲁棒性的问题,将Mean Shift算法引入到粒子更新的过程中,使粒子分布在观测的局部区域内,在利用少量粒子实现分布多样性的同时,有效克服了粒子退化现象。序列图像的实验表明：该算法能够在目标高速运动或发生遮挡的情况下稳健跟踪目标,其总体性能优于传统的粒子滤波算法。     

A model for radar images and its application to adaptive digital filtering of multiplicative noise

Standard image processing techniques which are used to enhance noncoherent optically produced images are not applicable to radar images due to the coherent nature of the radar imaging process. A model for the radar imaging process is derived in this paper and a method for smoothing noisy radar images is also presented. The imaging model shows that the radar image is corrupted by multiplicative noise. The model leads to the functional form of an optimum (minimum MSE) filter for smoothing radar images. By using locally estimated parameter values the filter is made adaptive so that it provides minimum MSE estimates inside homogeneous areas of an image while preserving the edge structure. It is shown that the filter can be easily implemented in the spatial domain and is computationally efficient. The performance of the adaptive filter is compared (qualitatively and quantitatively) with several standard filters using real and simulated radar images.     

变差函数和形态学滤波的图像去雾算法

目的 为解决户外视觉系统在恶劣环境下捕捉图像存在细节模糊、对比度较低等问题,提出一种基于变差函数和形态学滤波的图像去雾算法（简称IDA_VAM）。方法 该算法首先利用变差函数获取较准确的全局环境光值,然后对最小通道图采用多结构元形态学开闭滤波器获取粗略的大气散射图,进而估计大气透射率并进行修正,接着采用双边滤波对其进行平滑操作,最后通过物理模型得到复原图像并进行色调调整,获取明亮、清晰无雾的图像。结果 本文算法与多种图像去雾算法进行对比,在含有雾气的近景图像、远景图像以及有明亮区域的图像均能很好地去除雾气,图像的信息熵值相对提高了38.0%,对比度值相对提高了34.1%,清晰度值相对提高了134.5%,得到较好的复原效果,获取一幅自然明亮的无雾图像。结论 大量仿真实验结果证实,IDA_VAM能够很好地恢复非复杂场景下的近景图像、远景图像以及含有明亮区域图像的色彩和清晰度,获得清晰明亮的无雾图像,细节可见度较高,且算法的时间复杂度与图像像素点个数呈线性关系,具有较好的实时性。     

Parallax correction via disparity estimation in a multi-aperture camera

In this paper, an image fusion algorithm is proposed for a multi-aperture camera. Such camera is a feasible alternative to traditional Bayer filter camera in terms of image quality, camera size and camera features. The camera consists of several camera units, each having dedicated optics and color filter. The main challenge of a multi-aperture camera arises from the fact that each camera unit has a slightly different viewpoint. Our image fusion algorithm corrects the parallax error between the sub-images using a disparity map, which is estimated from the single-spectral images. We improve the disparity estimation by combining matching costs over multiple views using trifocal tensors. Images are matched using two alternative matching costs, mutual information and Census transform. We also compare two different disparity estimation methods, graph cuts and semi-global matching. The results show that the overall quality of the fused images is near the reference images.     

Adaptive noise smoothing filter for images with signal-dependent noise

In this paper, we consider the restoration of images with signal-dependent noise. The filter is noise smoothing and adapts to local changes in image statistics based on a nonstationary mean, nonstationary variance (NMNV) image model. For images degraded by a class of uncorrelated, signal-dependent noise without blur, the adaptive noise smoothing filter becomes a point processor and is similar to Lee's local statistics algorithm [16]. The filter is able to adapt itself to the nonstationary local image statistics in the presence of different types of signal-dependent noise. For multiplicative noise, the adaptive noise smoothing filter is a systematic derivation of Lee's algorithm with some extensions that allow different estimators for the local image variance. The advantage of the derivation is its easy extension to deal with various types of signal-dependent noise. Film-grain and Poisson signal-dependent restoration problems are also considered as examples. All the nonstationary image statistical parameters needed for the filter can be estimated from the noisy image and no a priori information about the original image is required.     

双边滤波和标记分水岭的CT心脏图像分割

由于心脏舒张、收缩以及血液的流动,CT心脏图像易出现弱边界、伪影,传统分水岭算法易产生过分割,为此,提出一种双边滤波和标记分水岭相融合的CT心脏图像分割方法（BF-WS）。采用双边滤波算法对心脏图像进行平滑滤波,并采用形态学对图像进行重构,以消除图像噪声,保留边缘信息,采用改进Otsu算法提取CT心脏图像的内、外标记,并采用分水岭分割算法实现CT心脏图像分割,采用临床CT心脏图像在Matlab平台进行性能测试。结果表明,BF-WS提高了CT心脏图像分割准确率,与专家分割结果十分接近,较好地解决了传统分水岭算法过分割难题,可以为临床医学诊断提供重要依据。