基于活动外观模型的人脸表情分析与识别

分析了用活动外观模板(AAM)提取的人脸表情特征来进行人脸表情识别(FER)的可行性,尝试了以此特征向量为基础的FER。根据人脸图像的特点．先用特征眼的方法定位眼睛区域,再采用AAM的优化算法获取新对象的特征,缩短了AAM方法定位新对象的优化时间,提高了定位的准确度。采用秩相关分析和非度量多维标度(nMDS)等多变量统计学方法分析得出AAM方法提取的表情特征能够很好地表达表情的变化,并构造了神经网络分类器对人脸表情图像进行识别实验,得到93．5％的识别率。     

基于改进主动表现模型的人脸面部特征定位

采用主成分分析(PCA)作为统计分析方法的主动表现模型(AAM)是建立二维可形变模型的有效方法.提出一种将改进的AAM用于人脸面部特征定位的新方法,并与传统AAM进行比较,实验证明此方法要优于传统AAM.     

基于纹理特征库的微光图像色彩纹理传递

对微光夜视图像进行了色彩和纹理的传递.在多次实验的基础上,从拍摄的大量微光图像里,提取不同模式的纹理块,构建了天空,道路、草地、树木四类景物的微光图像库,并结合灰度共生矩阵和Gabor滤波器提取图像纹理特征,建立其对应的纹理特征库.然后通过比对目标图像像素点纹理特征与特征库中各向量的相似性,来判定该像素所属类别,实现了微光图像的分割;最后,通过套印算法进行快速的色彩与纹理传递.实验结果表明,该算法实现了对微光图像较为准确的分割,得到了同时具有自然色彩和纹理的彩色夜视图像,更有利于人眼对目标的识别.     

彩色电视机用有源天线分配器的设计

随着数字信号技术的不断发展,数字电视成为未来电视的主流,但在模/数转换相当长时间内,会存在模数信号共存的情况,有源天线分配器根据消费者的使用情况对两种信号起转换作用。同时有源天线分配器的信号平坦度、隔离特性对信号传输有很大影响。通过分析该分配器的产品结构和工作原理,介绍了其设计目标、设计方法、测试结果及对多功能彩色电视机的影响。     

Multi-source Local Color Transfer Based on Texture Similarity

In order to realize automatic region matching between source and target images, a multi-source local color transfer algorithm based on texture similarity is proposed. The source and target images are segmented into a set of regions using an image segmentation algorithm. It computes the texture features of each region through the gray level co-occurrence matrix and then constructs corresponding texture feature vectors. The authors measure the relevance between the target and source regions by computing the Euclidean distance between corresponding tex- ture feature vectors. The source region having the largest relevance with the target region is selected as the transfer source. Complete the color transfer by performing color space transformation and linear conversion on color values. Experimental results concerning on multi-source local color transfer and gray image colorization verify the validity of the proposed algorithm.     

综合利用颜色和纹理特征的图像检索

基于特征的图像检索在多媒体数据库管理和多媒体通信传输中得到越来越多的重视。本文介绍了我们设计的分别基于颜色特征和基于纹理特征的两种图像检索算法。在利用单一特征检索的基础上,我们提出了一种综合利用上述两个特征共同进行检索的方法。对真实图像数据库的检索实验表明,综合特征检索要比单一特征检索更符合人的视觉感受要求,因而检索效果更好。     

基于高斯混合模型的纹理图像的分割

文章提出了使用高斯混合模型对纹理图像分割的方法。该模型考虑到图像纹理的特点，使用二状态的高斯混合分布来对图像各纹理类像素的分布进行拟和。首先对待分割的各类像素寻找与之匹配的最佳模型参数，然后再进行分割。最后，对分割结果进行多尺度综合，得到了各尺度的分割结果。实验表明该算法不仅能够较精确地定位各纹理区域，而且还有运算速度快的优点。     

基于小波概率神经网络的彩色纹理识别

提出了一种将颜色信息融入到纹理识别中的新方法--基于小波概率神经网络的彩色纹理识别.首先将RGB彩色纹理图像转化为HSV彩色模型,用小波变换(WT)进行树形结构小波分解提取彩色纹理的特征,然后使用概率神经网络对测试样本进行分类识别.实验结果证明,该方法的识别效果比较好.     

Efficient Content-Based Image Retrieval Methods Using Color and Texture

In this paper, we propose efficient content-based image retrieval methods using the automatic extraction of the low-level visual features as image content. Two new feature extraction methods are presented. The first one is an advanced color feature extraction derived from the modification of Stricker's method. The second one is a texture feature extraction using some DCT coefficients which represent some dominant directions and gray level variations of the image. In the experiment with an image database of 200 natural images, the proposed methods show higher performance than other methods. They can be combined into an efficient hierarchical retrieval method.     

一种基于纹理和颜色的粒子滤波目标跟踪方法

针对基于颜色的粒子滤波跟踪方法在复杂背景下会导致跟踪失败的问题,提出了一种基于局部二值模式纹理和颜色特征的粒子滤波目标跟踪方法。颜色直方图是对目标在彩色图像中的全局描述,而局部二值模式纹理包含了灰度图像中局部邻近区域的纹理信息,两者可以互为补充。因此同时用颜色直方图和局部二值模式纹理直方图描述目标,在粒子滤波框架下将目标颜色和局部二值模式纹理有机结合起来。实验结果表明,该算法不仅提高了跟踪精度,而且具有较强的稳健性。     

活动轮廓模型综述

基于活动轮廓模型的目标分割、物体跟踪方法是近十几年来图像和视频领域研究的热点,它可以将待处理问题的先验知识与各种图像处理算法有效地融合在一起,比以往的计算机视觉理论有更强的实用性.本文结合图像分割方法从指导思想和所用的数学方法两方面对活动轮廓模型特别是几何活动轮廓模型中基于水平集方法的C-V方法做了一定综述.     

Leaf Image-Based Plant Disease Identification Using Color and Texture Features

Wireless Personal Communications - Identification of plant disease is usually done through visual inspection or during laboratory examination which causes delays resulting in yield loss by the time...     

基于色貌模型CIECAM02和CIECAM16的观察者色觉差异研究

为研究现有CIECAM02和CIECAM16色貌模型对个体观察者颜色分辨的计算性能,选用了5个光谱功率分布不同的照明光源和GretagMacbeth ColorChecker标准色卡的24个颜色,代入208套个体观察者颜色匹配函数,量化计算不同观察者的色觉差异.两个色貌模型中,对于所有选用的照明光源和颜色中心,个体观察者与标准观察者CIE1964的CIECAM-UCS色差平均值相同,均为1.29.同时,两个色貌模型中,观察者间离均色差表现较为一致,在白光LED光源下观察者间差异性相对较大,且在蓝色中心处获得最大值,为2.49(2.32),表明在该观察条件下,不同观察者间颜色感知偏差较大.研究结果可为色貌模型的修正提供基础数据和计算依据.     

基于小波变换和支持向量机的彩色纹理识别

为了提高纹理图像的识别率,提出了一种将颜色信息融入到纹理识别中的新方法--基于小波变换和支持向量机的彩色纹理识别.首先将彩色纹理图像转化到HSV彩色空间,用小波变换进行树形结构小波分解提取彩色纹理的特征,然后用SVM对不同的特征进行纹理分类识别.对不同的彩色自然纹理图像进行了实验,并将结果与已有的进行了比较.实验结果证明,此方法的正确识别率比较高.     

Color Texture Segmentation Based on the Modal Energy of Deformable Surfaces

This paper presents a new approach for the segmentation of color textured images, which is based on a novel energy function. The proposed energy function, which expresses the local smoothness of an image area, is derived by exploiting an intermediate step of modal analysis that is utilized in order to describe and analyze the deformations of a 3-D deformable surface model. The external forces that attract the 3-D deformable surface model combine the intensity of the image pixels with the spatial information of local image regions. The proposed image segmentation algorithm has two steps. First, a color quantization scheme, which is based on the node displacements of the deformable surface model, is utilized in order to decrease the number of colors in the image. Then, the proposed energy function is used as a criterion for a region growing algorithm. The final segmentation of the image is derived by a region merge approach. The proposed method was applied to the Berkeley segmentation database. The obtained results show good segmentation robustness, when compared to other state of the art image segmentation algorithms.     

Computer-Aided Evaluation of Screening Mammograms Based on Local Texture Models

We propose a new approach to diagnostic evaluation of screening mammograms based on local statistical texture models. The local evaluation tool has the form of a multivariate probability density of gray levels in a suitably chosen search window. First, the density function in the form of Gaussian mixture is estimated from data obtained by scanning of the mammogram with the search window. Then we evaluate the estimated mixture at each position and display the corresponding log-likelihood value as a gray level at the window center. The resulting log-likelihood image closely correlates with the structural details of the original mammogram and emphasizes unusual places. We assume that, in parallel use, the log-likelihood image may provide additional information to facilitate the identification of malignant lesions as untypical locations of high novelty.      

基于压电陶瓷的风机叶片模型覆冰主动监测

南方山区高湿低温严酷环境易导致冰灾,风机叶片覆冰会导致发电效率降低甚至停机,因此发展高效可靠的风机叶片覆冰监测技术对防冰、除冰具有重要意义。该文提出了一种基于压电陶瓷应力波测量的风机叶片覆冰主动监测方法。开展叶片模型进行模拟覆冰试验,在叶片表面布置伸缩型和剪切型两种压电陶瓷片,根据波动法原理对驱动器输入正弦扫频电压信号作为激励,记录不同传感器在不同结冰厚度下的响应信号,并对测量信号进行小波包能量分析。结果表明,同一压电陶瓷片接收信号的小波包能量与结冰厚度存在明显关系。     

基于动态时间规整和主动外观模型的动态表情识别

针对静态表情特征缺乏时间信息,不能充分体现表情的细微变化,该文提出一种针对非特定人的动态表情识别方法：基于动态时间规整(Dynamic Time Warping, DTW)和主动外观模型(Active Appearance Model, AAM)的动态表情识别。首先采用基于局部梯度DT-CWT(Dual-Tree Complex Wavelet Transform)主方向模式(Dominant Direction Pattern, DDP)特征的DTW对表情序列进行规整。然后采用AAM定位出表情图像的66个特征点并进行跟踪,利用中性脸的特征点构建人脸几何模型,通过人脸几何模型的匹配克服不同人呈现表情的差异,并通过计算表情序列中相邻两帧图像对应特征点的位移获得表情的变化特征。最后采用最近邻分类器进行分类识别。在CK+库和实验室自建库HFUT-FE(HeFei University of Technology-Face Emotion)上的实验结果表明,所提算法具有较高的准确性。     

Active Contours Guided by Echogenicity and Texture for Delineation of Thyroid Nodules in Ultrasound Images

Thyroid nodules are solid or cystic lumps formed in the thyroid gland and may be caused by a variety of thyroid disorders. This paper presents a novel active contour model for precise delineation of thyroid nodules of various shapes according to their echogenicity and texture, as displayed in ultrasound (US) images. The proposed model, named joint echogenicity–texture (JET), is based on a modified Mumford–Shah functional that, in addition to regional image intensity, incorporates statistical texture information encoded by feature distributions. The distributions are aggregated within the functional through new log-likelihood goodness-of-fit terms. The JET model requires only a rough region of interest within the thyroid gland as input and automatically proceeds with precise delineation of the nodules, revealing their shape and size. The performance of the JET model was validated on a range of US images displaying hypoechoic and isoechoic nodules of various shapes. The quantification of the results shows that the JET model: 1) provides precise delineations of thyroid nodules as compared to “ground truth” delineations obtained by experts and 2) copes with the limitations of the previous thyroid US delineation approaches as it is capable of delineating thyroid nodules regardless of their echogenicity or shape.