矢量量化用于颜色图像检索的改进方法

为了消除基于颜色的图像检索在颜色空间分布描述方向的不足,提出一种新的基于颜色的检索方法。引入颜色转移矩阵描述颜色的空间分布,再结合颜色直方图和颜色转移矩阵进行复合图像检索。同时通过矢量量化方法量化图像颜色得到颜色直方图和颜色转移矩阵,实现了在压缩领域进行图像检索,减少了额外计算负担。实验表明,该方法能有效提高检索效率和精度。     

基于内容的多特征融合图像检索

提出一种组合颜色、形状和空间信息的图像检索方法,用颜色块的颜色直方图表示图像的颜色特征;使用Zernike矩表示图像的形状特征,通过提取颜色块的质心、分布方差聚散度等特征得到图像的空间特征。为了进一步提高图像检索的精确度,提出一种基于支持向量机的相关反馈方法。实验结果表明,基于组合特征的图像检索方法优于基于单一特征的检索方法。     

采用位平面直方图特征向量的图像检索方法

首先将图像分解为8个位平面,选择前4个重要位平面,求出其灰度码表示,根据每个灰度码位平面的颜色直方图,计算均值、标准偏差、偏斜度、能量、熵;综合这些特征构成名为位平面直方图特征向量的组合特征,进行图像检索。实验中采用Tonimoto相似度量函数计算图像间的相似度。该方法计算速度快,避免了图像量化造成的误检。实验结果显示了该方法的检索性能。     

Extraction of major object features using VQ clustering for content-based image retrieval

An image representation method using vector quantization (VQ) on color and texture is proposed in this paper. The proposed method is also used to retrieve similar images from database systems. The basic idea is a transformation from the raw pixel data to a small set of image regions, which are coherent in color and texture space. A scheme is provided for object-based image retrieval. Features for image retrieval are the three color features (hue, saturation, and value) from the HSV color model and five textural features (ASM, contrast, correlation, variance, and entropy) from the gray-level co-occurrence matrices. Once the features are extracted from an image, eight-dimensional feature vectors represent each pixel in the image. The VQ algorithm is used to rapidly cluster those feature vectors into groups. A representative feature table based on the dominant groups is obtained and used to retrieve similar images according to the object within the image. This method can retrieve similar images even in cases where objects are translated, scaled, and rotated.     

JPEG compressed image retrieval via statistical features

To improve efficiency of compressed image retrieval, we propose a novel statistical feature extraction algorithm in this paper to characterize the image content directly in its compressed domain. The statistical feature extracted is mainly through computing a set of moments directly from DCT coefficients without involving full decompression or inverse DCT. Following the algorithm design, a content-based image retrieval system is implemented especially targeting retrieving joint picture expert group compressed images. Theoretical analysis and experimental results support that the system is robust to translation, rotation and scale transform with minor disturbance, and the system achieves good performances in terms of retrieval efficiency and effectiveness.     

主色调颜色特征的图像检索与分类

颜色是图像检索中应用最为广泛的特征之一。提出一种新的颜色特征提取方法,该方法在HSV空间运用聚类方法得到待分析图像的主色调,通过直方图分析得到整体的图像颜色特征,从而满足图像检索的需要。实验表明,提出的特征分析方法满足人类对图像颜色特征的主观感受。     

基于加权颜色分层和纹理单元的图像检索算法

针对仅使用单一颜色或纹理特征并不能达到较好的图像检索效果的问题,提出了一种结合颜色和纹理特征的图像检索算法。首先,颜色微观部分利用颜色直方图,刻画每种颜色的像素占整个图像的比例;然后,宏观部分应用颜色熵和位平面熵分别对图像处理,其中位平面熵取特征较明显的前4层,并对每层的位平面熵加权;最后,根据定义的五种基本纹理结构基元中各像素点的颜色值和角度值,结合颜色特征,实现图像检索。实验结果表明,加权位平面熵和不加权位平面熵比较,在Corel-1000数据集上平均查准率和平均查全率分别提高10.01个百分点和1.2个百分点。结合颜色和纹理特征的图像检索算法与仅表现纹理特征的结构元素描述(SED)方法相比,在Corel-10000数据集上平均查准率和平均查全率分别提高4.3个百分点和2.1个百分点,有效地提高了图像检索效果。     

基于度量直方图的医学图像检索

研究了医学图像灰度分布的特性,利用相邻灰度的相关性提出了基于度量直方图的医学图像检索方法及其度量空间上的距离函数MHD0;该方法减少了传统直方图特征的维教,克服了SAM索引的缺点。通过对CT图像数据库的检索实验,验证了该方法在性能和速度上都超过了传统直方图检索方法。     

基于多颜色空间的图像检索方法

介绍了HSV在低饱和度和低亮度时的色调奇异性,分析了HSV的色调奇异性对图像检索的影响。在此基础上,提出了基于多颜色空间的图像检索方法,奇异区域的像素点用YUV颜色空间表示,其他像素点用HSV颜色空间表示。实验表明,该算法在一定程度上克服了HSV的色调奇异性对图像检索的影响,提高了检索性能。     

Learning effective color features for content based image retrieval in dermatology

We investigate the extraction of effective color features for a content-based image retrieval (CBIR) application in dermatology. Effectiveness is measured by the rate of correct retrieval of images from four color classes of skin lesions. We employ and compare two different methods to learn favorable feature representations for this special application: limited rank matrix learning vector quantization (LiRaM LVQ) and a Large Margin Nearest Neighbor (LMNN) approach. Both methods use labeled training data and provide a discriminant linear transformation of the original features, potentially to a lower dimensional space. The extracted color features are used to retrieve images from a database by a k-nearest neighbor search. We perform a comparison of retrieval rates achieved with extracted and original features for eight different standard color spaces. We achieved significant improvements in every examined color space. The increase of the mean correct retrieval rate lies between 10% and 27% in the range of k=1-25 retrieved images, and the correct retrieval rate lies between 84% and 64%. We present explicit combinations of RGB and CIE-Lab color features corresponding to healthy and lesion skin. LiRaM LVQ and the computationally more expensive LMNN give comparable results for large values of the method parameter κ of LMNN (κ≥25) while LiRaM LVQ outperforms LMNN for smaller values of κ. We conclude that feature extraction by LiRaM LVQ leads to considerable improvement in color-based retrieval of dermatologic images.     

基于统计特征的DCT压缩域纹理图像检索方法

提出了一种基于离散余弦变换（Discrete Cosine Transfrom,DCT）的纹理图像的检索方法.该方法在DCT压缩域,通过直接对DCT系数计算,获得图像纹理的统计特征,并作为检索的依据.理论分析和实验结果都表明,该方法具有很好的检索准确率和效率,并且对于旋转具有不变性.     

综合文字和非文字区域特征的文档图像检索

提出一种改进的自适应文字区域提取算法,将文档图像分割成文字区域和非文字区域。对文字区域提取连通字符间空白、连通字符高度和宽度等局部特征,以及书写样式、段落特征等全局特征;对非文字区域,提取关键块特征。然后利用检索算法将文字区域特征和非文字区域特征结合起来,提高检索的准确性。同时,在检索算法中引入多维数据检索结构,有效地提高检索速度。通过对大规模文档数据库（包含12 024个文档）的检索,表明该算法具有较高的效率,优于现有的一般文档图像检索算法。     

基于DCT压缩的JPEG图像的快速检索

提出了一种基于离散余弦变换(DCT)压缩的JPEC图像的检索方法。该方法利用JPEG图像数据在DCT压缩域的特性,直接提取特征,而且只需要对JPEC进行部分熵解码。在加速了图像检索的过程的同时也保证了检索结果的精确性,并且具有一定的鲁棒性。     

An adult image identification system employing image retrieval technique

As the development of the Internet, children are easily exposed on the pornography through web browsers. To block adult images, content-based image retrieval technique is employed for adult image identification. First, the background is removed to obtain the rectangular region of interesting based on the detection of skin-like pixels. For each input image, the MPEG-7’s color, texture, and the proposed shape feature is used to retrieve 100 most similar images from the image database which contains both adult and non-adult images. If the retrieved images contains more than T_ad adult images, the input one is identified as an adult image. Otherwise, it is identified as a non-adult image. Experiment results have shown the effectiveness of the proposed method.     

利用聚类算法提高基于内容的图像检索准确率

给出了一种基于内容的图像检索算法,该算法使用了图像的颜色直方图作为图像的检索特征,并且利用了K均值聚类算法以及用户相关反馈技术来提高检索的准确率。     

综合颜色和纹理及SVM相关反馈的图像检索

由于单一特征不足以准确地描述图像特征,提出了一种结合颜色特征和纹理特征的图像检索方法。针对传统颜色直方图中图像对所有像素具有相同重要性的问题进行了改进,提出像素加权的改进颜色直方图方法;然后采用Gabor小波提取纹理特征。为提高图像检索的性能,提出了一种支持向量机的相关反馈方法。实验结果表明,该方法具有较好的检索性能。     

一种基于区域综合特征的图像检索方法

提出一种基于目标区域的图像检索方法,首先采用颜色聚类的分割方法将图像分割成不同的区域,提取每个区域的颜色、位置、形状等低层特征,然后提出一种相似度计算方法实现图像的相似性度量。为了提高图像检索的准确度,最后采用支持向量机（SVM）的相关反馈算法。实验结果表明,基于目标区域的图像检索效果比基于全局图像特征的检索效果有较好的改善。     

融合曲波变换和颜色直方图的图像检索

研究了曲波变换和颜色直方图在图像检索系统中的应用,在此基础之上提出了一种融合Curvelet变换和颜色直方图的彩色图像检索的方法。该方法首先采用Curvelet变换提取彩色图像中的纹理特征,再利用颜色直方图提取颜色特征,最后分别用Manhattan距离和欧几里德距离进行纹理和颜色的相似性匹配。实验结果表明,融合曲波变换和颜色直方图的方法对图像检索非常有效。     

基于色彩和边缘特征的图像检索方法

为了改善基于内容的图像检索的效果和提高其检索效率,提出一种基于色彩和边缘特征的图像检索方法。首先将RGB图像分成几个子图像的形式,然后,对于每一个子图像提取其色彩特征和边缘特征,其中边缘特征的获得采用了瞬时保持（MP）边缘检测技术。将这两种特征结合在一起使用,可以实现准确快捷的图像检索。实验结果表明,该方法在检索精度和检索效率上都高于Cheng的两种方法且所用的时间分别为Cheng的方法的10%和3%,检索精度提高近20%。