对Welsh灰度图像彩色化算法的改进

把灰度图像变成彩色图像可以增强视觉效果和识别能力,因此研究灰度图像的彩色化,寻找更好的算法具有重要意义.分析Reinhard的颜色传输算法和Welsh的灰度图像彩色化算法,发现了其处理速度慢的缺点.基于图像的空间相关性,提出一种新的搜索策略,实现像素的快速匹配,提高了处理速度.使用该匹配方法,对Welsh算法进行改进,并利用分块处理的方法实现了基调相近图像的彩色化.通过仿真分析,该改进算法在提高处理速度的同时,得到了很好的彩色化效果.     

基于稀疏表示和色彩传递的图像融合与彩色化

针对红外图像和微光图像的特点,提出一种基于稀疏表示和色彩传递的双波段图像融合与彩色化方法。该方法首先采用改进的基于K_SVD的分块稀疏表示获得红外与微光图像的稀疏融合图像,然后在YUV空间采用基于色彩传递的自然感彩色夜视处理技术,对红外与微光图像进行彩色化融合,最后用稀疏融合图像的灰度值代替彩色融合图像的Y分量,从而实现双波段图像的融合与彩色化。实验表明,本文提出的彩色融合算法能够综合红外与微光特征信息,且使图像具有最佳的亮度对比和细节信息,图像色彩更易于人眼观察。     

一种基于SOFM网络图像分割的彩色化方法

本文采用了SOFM神经元网络对图像进行分割,通过分割区域的外轮廓的提取,保证了种子点在扩散时的终止条件,采用局部线性映射的方法进行彩色化处理,能够完成快速、准确的彩色化处理.     

灰度图像彩色化的效果评价研究

灰度图像彩色化的效果评价是目前图像彩色融合和增强急需解决的问题之一。从彩色化图像与原灰度图像比较和彩色化图像之间比较两方面对灰度图像的彩色化效果评价进行研究,提出了相应的主观评价方法和客观评价参数。     

基于再生核空间的自适应图像彩色化算法

针对传统的图像彩色化算法中彩色化结果质量不佳、参数设置不合理等问题,提出一种新的基于再生核空间的自适应灰度图像彩色化算法.该方法通过求泛函极值建立非线性方程,设置与图像像素亮度相关的自适应再生核,用最小二乘法对方程进行数值求解得到彩色化结果.与其他灰度图像彩色化技术相比,该方法能在自适应选择参数的同时,有效提高图像彩色化质量.     

基于颜色扩展的图像彩色化技术研究进展

分析图像彩色化的病态性,按照解决病态问题的规整化形式将彩色化分为基于颜色转移和利用颜色扩展的两类方法.颜色扩展彩色化方法的核心在于对颜色扩展过程的合理控制,分析比较了基于总体控制和局部控制的两类颜色扩展方法,探讨了不同控制形式之间的关系、对初始涂色的设置要求及颜色模型的选择问题.可操作性和有效性是此类方法的优势,进一步改善处理效果的真实性并增强处理纹理图像的能力,有望发展成为真正实用的彩色化技术.     

色度与亮度特征相融合的彩色人脸识别算法

在存在色度与亮度差异性的条件下,彩色人脸的识别准确度不高,为了提高彩色人脸的识别性能,提出基于色度与亮度特征相融合的彩色人脸识别算法。对采集的原始彩色人脸图像进行色度均衡处理,采用特征提取方法进行人脸的关键特征点定位,提取人脸图像的色度和亮度特征。对提取的特征量根据眼睛和眉毛等关键点的差异性进行信息融合,对提取的眼部区域色度信息进行二值化分离和信息增强处理,提高对彩色人脸图像的特征识别能力,实现彩色人脸识别算法的改进设计。仿真结果表明,采用该方法进行彩色人脸识别的准确识别率较高,抗色度和亮度的局部干扰能力较强。     

HSV空间和形态学处理相结合的车牌定位方法

车牌定位是实现车牌自动识别的前提.在传统的基于RGB彩色空间的形态学定位方法的基础上进行改进,提出了一种HSV彩色空间和图像形态学处理相结合的车牌定位方法.在HSV彩色空间中将车牌图像分割为H,S,V这3个单通道灰度图像,分别进行去噪和二值化处理,然后将这3幅二值图像做“与”运算得到一幅能有效去除背景干扰的二值图像,再运用形态学的闭运算和开运算进行处理,得到车牌候选区域,最后利用车牌宽高比属性进行验证以确定真实的车牌位置.实验结果表明,该方法相对传统方法实现简单,车牌定位准确、高效.     

基于改进的2-D Otsu方法和YCgCr空间的肤色分割

为了弥补基于固定阈值的肤色分割方法存在的缺陷,在对多种彩色空间和肤色模型进行分析的基础上,提出采用改进的2-D Otsu方法和YCgCr彩色空间进行肤色分割。首先将光照补偿之后的肤色样本图像从RGB彩色空间转换到YCgCr彩色空间,并利用样本图像上的179221个肤色点建立2维高斯模型;进而将待分割的图像进行光照补偿并转换到YCgCr彩色空间,利用已经建立的高斯模型计算图像的肤色相似度,得到肤色相似度图像;最后,结合像素的空间邻域信息,使用改进的2-D Otsu方法对肤色相似度图像进行2值化处理。对这种方法进行了理论分析和实验验证。结果表明,该肤色分割算法有效地克服了使用固定阈值法进行图像分割时缺乏针对性和抗噪性的缺陷,该算法是可行的。     

红外焦平面阵列图像的伪彩色编码和处理

红外焦平面阵列成的热图像的伪彩色编码有利于人眼识别和获取图像中的有用信息。本文所描述的软件可对红外图像进行16种伪彩色编码，以中值滤波、直方图均匀化等处理，同时显示图像中每点的温度。文中描述了伪彩色编码原理，给出了软件实现的方法和所开发的热像仪原理框图。     

Image Registration Using Adaptive Polar Transform

Image registration is an essential step in many image processing applications that need visual information from multiple images for comparison, integration, or analysis. Recently, researchers have introduced image registration techniques using the log-polar transform (LPT) for its rotation and scale invariant properties. However, it suffers from nonuniform sampling which makes it not suitable for applications in which the registered images are altered or occluded. Inspired by LPT, this paper presents a new registration algorithm that addresses the problems of the conventional LPT while maintaining the robustness to scale and rotation. We introduce a novel adaptive polar transform (APT) technique that evenly and effectively samples the image in the Cartesian coordinates. Combining APT with an innovative projection transform along with a matching mechanism, the proposed method yields less computational load and more accurate registration than that of the conventional LPT. Translation between the registered images is recovered with the new search scheme using Gabor feature extraction to accelerate the localization procedure. Moreover an image comparison scheme is proposed for locating the area where the image pairs differ. Experiments on real images demonstrate the effectiveness and robustness of the proposed approach for registering images that are subjected to occlusion and alteration in addition to scale, rotation, and translation.     

Salient edge and region aware image retargeting

The purpose of image retargeting is to automatically adapt a given image to fit the size of various displays without introducing severe visual distortions. The seam carving method can effectively achieve this task and it needs to define image importance to detect the salient context of images. In this paper we present a new image importance map and a new seam criterion for image retargeting. We first decompose an image into a cartoon and a texture part. The higher order statistics (HOS) on the cartoon part provide reliable salient edges. We construct a salient object window and a distance dependent weight to modify the HOS. The weighted HOS effectively protects salient objects from distortion by seam carving. We also propose a new seam criterion which tends to spread seam uniformly in nonsallient regions and helps to preserve large scale geometric structures. We call our method salient edge and region aware image retargeting (SERAR). We evaluate our method visually, and compare the results with related methods. Our method performs well in retargeting images with cluttered backgrounds and in preserving large scale structures.     

Robust blind image watermarking scheme based on Redundant Discrete Wavelet Transform and Singular Value Decomposition

Copyright protection and proof of ownership are two of the main important applications of the digital image watermarking. The challenges faced by researchers interested in digital image watermarking applications lie in the creation of new algorithms to serve those applications and to be resistant to most types of attacks, especially the geometrical attacks. Robustness, high imperceptibility, security, and large capacity are four essential requirements in any watermarking scheme. This paper presents a new image watermarking scheme based on the Redundant Discrete Wavelet Transform (RDWT) and the Singular Value Decomposition (SVD). The gray scale image watermark was embedded directly in the singular values of the RDWT sub-bands of the host image. The scheme achieved a large capacity due to the redundancy in the RDWT domain and at the same time preserved high imperceptibility due to SVD properties. Embedding the watermarking pixel's values without any modification inside the wavelet coefficient of the host image overcomes the security issue. Furthermore, the experimental results of the proposed scheme showed a high level of robustness not only against the image processing attacks but also against the geometrical attacks which are considered as difficult attacks to resist.     

遥感图像中云雾干扰的消除

本文是在O.R.Mitchell(1977)关于滤除卫星照片中云的掩盖一文的基础上,对去云的问题进行了进一步的研究。本文的发展有以下三点:(1)重新推导了关于云层失真的数学模型;(2)以新推出的数学模型为基础提出了两级滤波的处理方案;(3)提出了一种噪声抵消法和一种三维处理方案。对以上设想做了部分实验验证,在微型机上做了计算机模拟实验,还在S101图像处理系统上进行了正式实验,取得了初步有效的实验结果。     

Hue-preserving color image enhancement without gamut problem

The first step in many techniques for processing intensity and saturation in color images keeping hue unaltered is the transformation of the image data from RGB space to other color spaces such as LHS, HSI, YIQ, HSV, etc. Transforming from one space to another and processing in these spaces usually generate a gamut problem, i.e., the values of the variables may not be in their respective intervals. We study enhancement techniques for color images theoretically in a generalized setup. A principle is suggested to make the transformations gamut-problem free. Using the same principle, a class of hue-preserving, contrast-enhancing transformations is proposed; they generalize existing grey scale contrast intensification techniques to color images. These transformations are also seen to bypass the above mentioned color coordinate transformations for image enhancement. The developed principle is used to generalize the histogram equalization scheme for grey scale images to color images.     

A new class of chromatic filters for color image processing. theory and applications

This paper advances a new framework for chromatic filtering of color images. The chromatic content of a color image is encoded in the CIE u'v' chromaticity coordinates whereas the achromatic content is encoded as CIE Y tristimulus value. Within the u'v' chromaticity diagram, colors are added according to the well-known center of gravity law of additive color mixtures, which is generalized here into a nonlinear filtering scheme for processing the two chromatic signals u' and v'. The achromatic channel Y can be processed with traditional filtering schemes, either linear or nonlinear, depending on the specific task at hand. The most interesting characteristics of the new filtering scheme are: 1) the elimination of color smearing effects along edges between bright and dark areas; 2) the possibility of processing chromatic components in a noniterative fashion through linear convolution operations; and 3) the consequent amenability to computationally efficient implementations with fast Fourier transform. The paper includes several examples with both synthetic and real images where the performance of the new filtering method is compared with that of other color image processing algorithms.     

EdgeFlow: a technique for boundary detection and image segmentation

A novel boundary detection scheme based on "edge flow" is proposed in this paper. This scheme utilizes a predictive coding model to identify the direction of change in color and texture at each image location at a given scale, and constructs an edge flow vector. By propagating the edge flow vectors, the boundaries can be detected at image locations which encounter two opposite directions of flow in the stable state. A user defined image scale is the only significant control parameter that is needed by the algorithm. The scheme facilitates integration of color and texture into a single framework for boundary detection. Segmentation results on a large and diverse collections of natural images are provided, demonstrating the usefulness of this method to content based image retrieval.     

高速图像处理系统中DDR2-SDRAM接口的设计

为了满足高速图像处理系统中需要高接口带宽和大容量存储的目的,采用了FPGA外接DDR2-SDRAM的设计方法,提出一种基于VHDL语言的DDR2-SDRAM控制器的方案,针对高速图像处理系统中的具体情况,在Xilinx的ML506开发板上搭建了简单的图像处理系统平台并进行了连续读/写标准VGA格式图像数据的实验,在显示端得到了清晰不掉帧的图像结果,具有结构简单和高速存取图像的特点。     

面向机载分布式光电的图像拼接算法

随着航空无人系统技术的迅猛发展,分布式机载图像拼接技术已成为备受瞩目的研究领域。本文针对分布式机载图像拼接中存在的视差大和空间几何变换关系复杂等问题,在APAP图像拼接算法基础上提出了一种改进算法。该算法采用变形处理、线性化单应平滑外推至全局性变换以及网格划分法等方法,有效消除了模糊重影、减少边缘处投影失真,提高算法运行效率。在多个场景下的实验中,该算法表现出更小的对齐误差和更高的图像质量指标,包括均方根误差、峰值信噪比、结构相似度和图像熵等。在进行大规模图像拼接时,该改进算法能够实现154张图像的大规模拼接,得到10 k×10 k的高分辨率全景图像,拼接耗时为138 s。因此,该改进算法具有重要的实际应用价值,可用于分布式机载图像拼接的实际应用中。     

Multiresolution morphological fusion of MR and CT images of thehuman brain

A hierarchical image fusion scheme is presented which preserves the details of the input images regardless of their scale. The technique is demonstrated by fusing images of the human brain derived from magnetic resonance (MR) and computed tomography (CT) scanners. Results are given to show that fused images preserve a more complete representation of anatomical and pathological structures, providing information that cannot be obtained by processing the images at a single scale