Fast image retrieval using color-spatial information

In this paper, we present an image retrieval system that employs both the color and spatial information of images to facilitate the retrieval process. The basic unit used in our technique is a single-colored cluster, which bounds a homogeneous region of that color in an image. Two clusters from two images are similar if they are of the same color and overlap in the image space. The number of clusters that can be extracted from an image can be very large, and it affects the accuracy of retrieval. We study the effect of the number of clusters on retrieval effectiveness to determine an appropriate value for “optimal' performance. To facilitate efficient retrieval, we also propose a multi-tier indexing mechanism called the Sequenced Multi-Attribute Tree (SMAT). We implemented a two-tier SMAT, where the first layer is used to prune away clusters that are of different colors, while the second layer discriminates clusters of different spatial locality. We conducted an experimental study on an image database consisting of 12,000 images. Our results show the effectiveness of the proposed color-spatial approach, and the efficiency of the proposed indexing mechanism. Received August 1, 1997 / Accepted December 9, 1997     

Integrated spatial and feature image query

We present a new system for querying for images by regions and their spatial and feature attributes. The system enables the user to find the images that contain arrangements of regions similar to those diagrammed in a query image. By indexing the attributes of regions, such as sizes, locations and visual features, a wide variety of complex joint spatial and feature queries are efficiently computed. In order to demonstrate the utility of the system, we develop a process for the extracting color regions from photographic images. We demonstrate that integrated spatial and feature querying using color regions improves image search capabilities over non-spatial content-based image retrieval methods.     

序列化颜色直方图的分析与应用

在许多基于颜色的图像检索系统中,图像的颜色属性通过颜色直方图来描述。基于颜色直方图的搜索,对规模较大的颜色直方图往往很低效。因此论文将介绍一种新方法,这种方法能有效的表示颜色直方图和两个颜色直方图的区别。这种方法是基于以下的观察:最大的20%的颜色直方图能占到图像的90%的像素;当颜色直方图用一个阀值过滤后,主成分颜色数量MCCC(maincomponentcolorusedcount)代表这幅图像的复杂性,在第一阶段的检索中被用来快速索引,主成分颜色序列MCCS(maincomponentcolorsequence)能够用来在检索的第二阶段比较图像的颜色信息。使用该方法,总的颜色索引信息将比传统的颜色直方图节省存储空间。试验结果基于包含1000张图像的图像数据库。     

Efficient Content-Based Image Retrieval through Metric Histograms

This paper presents a new and efficient method for content-based image retrieval employing the color distribution of images. This new method, called metric histogram, takes advantage of the correlation among adjacent bins of histograms, reducing the dimensionality of the feature vectors extracted from images, leading to faster and more flexible indexing and retrieval processes. The proposed technique works on each image independently from the others in the dataset, therefore there is no pre-defined number of color regions in the resulting histogram. Thus, it is not possible to use traditional comparison algorithms such as Euclidean or Manhattan distances. To allow the comparison of images through the new feature vectors given by metric histograms, a new metric distance function MHD( ) is also proposed. This paper shows the improvements in timing and retrieval discrimination obtained using metric histograms over traditional ones, even when using images with different spatial resolution or thumbnails. The experimental evaluation of the new method, for answering similarity queries over two representative image databases, shows that the metric histograms surpass the retrieval ability of traditional histograms because they are invariant on geometrical and brightness image transformations, and answer the queries up to 10 times faster than the traditional ones.     

NeTra: A toolbox for navigating large image databases

We present here an implementation of NeTra, a prototype image retrieval system that uses color, texture, shape and spatial location information in segmented image regions to search and retrieve similar regions from the database. A distinguishing aspect of this system is its incorporation of a robust automated image segmentation algorithm that allows object- or region-based search. Image segmentation significantly improves the quality of image retrieval when images contain multiple complex objects. Images are segmented into homogeneous regions at the time of ingest into the database, and image attributes that represent each of these regions are computed. In addition to image segmentation, other important components of the system include an efficient color representation, and indexing of color, texture, and shape features for fast search and retrieval. This representation allows the user to compose interesting queries such as “retrieve all images that contain regions that have the color of object A, texture of object B, shape of object C, and lie in the upper of the image”, where the individual objects could be regions belonging to different images. A Java-based web implementation of NeTra is available at http://vivaldi.ece.ucsb.edu/Netra.     

Image retrieval using efficient local-area matching

We present an efficient and accurate method for retrieving images based on color similarity with a given query image or histogram. The method matches the query against parts of the image using histogram intersection. Efficient searching for the best matching subimage is done by pruning the set of subimages using upper bound estimates. The method is fast, has high precision and recall and also allows queries based on the positions of one or more objects in the database image. Experimental results showing the efficiency of the proposed search method, and high precision and recall of retrieval are presented. Received: 20 January 1997 / Accepted: 5 January 1998     

Robust image retrieval based on color histogram of local feature regions

Color histograms lack spatial information and are sensitive to intensity variation, color distortion and cropping. As a result, images with similar histograms may have totally different semantics. The region-based approaches are introduced to overcome the above limitations, but due to the inaccurate segmentation, these systems may partition an object into several regions that may have confused users in selecting the proper regions. In this paper, we present a robust image retrieval based on color histogram of local feature regions (LFR). Firstly, the steady image feature points are extracted by using multi-scale Harris-Laplace detector. Then, the significant local feature regions are ascertained adaptively according to the feature scale theory. Finally, the color histogram of local feature regions is constructed, and the similarity between color images is computed by using the color histogram of LFRs. Experimental results show that the proposed color image retrieval is more accurate and efficient in retrieving the user-interested images. Especially, it is robust to some classic transformations (additive noise, affine transformation including translation, rotation and scale effects, partial visibility, etc.).     

Spatial Color Indexing Using Rotation,Translation, and Scale Invariant Anglograms

As color plays an essential role in image composition, many color indexing techniques have been studied for content-based image retrieval. This paper examines the use of a computational geometry-based spatial color indexing methodology for effective and efficient image retrieval. In this scheme, an image is evenly divided into a number of M * N non-overlapping blocks, and each individual block is abstracted as a unique feature point labeled with its spatial location and dominant colors. For each set of feature points labeled with the identical color, we construct a Delaunay triangulation and then compute the feature point histogram by discretizing and counting the angles produced by this triangulation. The concatenation of all these feature point histograms serves as the image index, the so-called color anglogram. An important contribution of this work is to encode the spatial color information using geometric triangulation, which is rotation, translation, and scale invariant. We have compared the proposed approach with two of the best performing of recent spatial color indexing schemes, Color-WISE and the color correlogram approaches, respectively, at image block and pixel levels of different granularity. Various experimental results demonstrate the efficacy of our techniques.     

一种基于颜色聚合向量的图像检索方法

颜色直方图被广泛地应用在基于内容的图像检索中，其优点是效率高，对于视点细微的变化不敏感。然而直方图只是图像的一个粗糙特征，对于视觉上完全不相似的图像，其直方图有可能非常相似。该文在颜色直方图的基础上进行了改进，采用一种基于颜色聚合向量的图像检索方法，极大地提高了检索精度。     

彩色图象的联合分布表示及检索技术

随着图象数据的大量涌现,基于内容的图象检索技术已成为图象数据库领域的研究热点,在图象检索系统中,由于颜色直方图方法简单方便,所以它已成为CBIR系统中最常用的一种技术方法,然而,经典的颜色直方图方法存在诸多缺陷,例如它不能表示图象中的空间分布信息。为此,人们提出了直方图细化技术,即将图象的颜色分布表示扩充成为颜色和其他相关特征的联合分布。为了进一步提高图象检索能力,在分析图象特征的基础上,给出了两种加权直方图模型;其一是将图象的颜色分布和细节信号能量的分布集成到单个直方图之中;另一种模型是将图象颜色及其边界强度的联合分布集成到一个直方图中。这两种方法不仅保持了经典直方图简单方便的特点;同时又有效地将空间信息集成到直方图中,实验结果表明,这些加权直方图表示均具有较强的图象辨别能力。     

Cell Histograms Versus Color Histograms for Image Representation and Retrieval

This paper presents a new approach for content-based image retrieval, which is based on the well-known and widely used color histograms. Previous approaches have used a single global color histogram (GCH) for the whole image, or local color histograms (LCHs) for cells within a grid of fixed size. Our approach is also based on a grid of cells, but unlike the latter it uses a cell histogram for each of the colors actually present in the images, representing how that color is distributed among the image cells -- hence the name Cell/Color Histograms. Our experiments have shown that the actual number of colors present in images is often low. Thus we are able to achieve performance comparable to using LCHs within a grid, but with a much smaller space overhead. Furthermore, the proposed approach is very flexible in the sense that the user has alternative ways to calibrate the trade-off between space overhead and retrieval effectiveness. In fact, we have been able to outperform GCHs (typically a compact representation) in terms of effectiveness requiring less storage space.     

Color indexing for efficient image retrieval

Content based image retrieval is an active area of research. Many approaches have been proposed to retrieve images based on matching of some features derived from the image content. Color is an important feature of image content. The problem with many traditional matching-based retrieval methods is that the search time for retrieving similar images for a given query image increases linearly with the size of the image database. We present an efficient color indexing scheme for similarity-based retrieval which has a search time that increases logarithmically with the database size.In our approach, the color features are extracted automatically using a color clustering algorithm. Then the cluster centroids are used as representatives of the images in 3-dimensional color space and are indexed using a spatial indexing method that usesR-tree. The worst case search time complexity of this approach isOn _q log(N^* n_avg)), whereN is the number of images in the database, andn _q andn _avg are the number of colors in the query image and the average number of colors per image in the database respectively. We present the experimental results for the proposed approach on two databases consisting of 337 Trademark images and 200 Flag images.     

图像相似模式挖掘中的颜色-位置直方图方法

颜色直方图计算简单快捷 ,对大小、方向、物体移动和视点等不敏感而在基于内容的图像检索中得到了广泛的应用 .然而 ,由于它只包含颜色的总体信息而没有反映其相对位置 ,检索精度受到了一定的限制 .针对这个问题 ,提出了一种颜色 -位置直方图 ,该直方图在不失传统直方图鲁棒性的前提下 ,将颜色和位置信息有机地融合起来 ,同时考虑它们对图像内容的表征作用 .由于该直方图在反映颜色频率的同时也记录其分段虚拟边界的位置信息 ,因而较好地解决了传统直方图存在的问题 .对合成图像和实际图像所做的实验结果表明 ,该方法是有效的 ,具有一定的实用价值 .     

The analysis and applications of adaptive-binning color histograms

Histograms are commonly used in content-based image retrieval systems to represent the distributions of colors in images. It is a common understanding that histograms that adapt to images can represent their color distributions more efficiently than do histograms with fixed binnings. However, existing systems almost exclusively adopt fixed-binning histograms because, among existing well-known dissimilarity measures, only the computationally expensive Earth Mover’s Distance (EMD) can compare histograms with different binnings. This paper addresses the issue by defining a new dissimilarity measure that is more reliable than the Euclidean distance and yet computationally less expensive than EMD. Moreover, a mathematically sound definition of mean histogram can be defined for histogram clustering applications. Extensive test results show that adaptive histograms produce the best overall performance, in terms of good accuracy, small number of bins, no empty bin, and efficient computation, compared to existing methods for histogram retrieval, classification, and clustering tasks.     

Visual information retrieval system via content-based approach

In this paper a content-based image retrieval method that can search large image databases efficiently by color, texture, and shape content is proposed. Quantized RGB histograms and the dominant triple (hue, saturation, and value), which are extracted from quantized HSV joint histogram in the local image region, are used for representing global/local color information in the image. Entropy and maximum entry from co-occurrence matrices are used for texture information and edge angle histogram is used for representing shape information. Relevance feedback approach, which has coupled proposed features, is used for obtaining better retrieval accuracy. A new indexing method that supports fast retrieval in large image databases is also presented. Tree structures constructed by k-means algorithm, along with the idea of triangle inequality, eliminate candidate images for similarity calculation between query image and each database image. We find that the proposed method reduces calculation up to average 92.2 percent of the images from direct comparison.     

Integrating symbolic images into a multimedia database system using classification and abstraction approaches

Symbolic images are composed of a finite set of symbols that have a semantic meaning. Examples of symbolic images include maps (where the semantic meaning of the symbols is given in the legend), engineering drawings, and floor plans. Two approaches for supporting queries on symbolic-image databases that are based on image content are studied. The classification approach preprocesses all symbolic images and attaches a semantic classification and an associated certainty factor to each object that it finds in the image. The abstraction approach describes each object in the symbolic image by using a vector consisting of the values of some of its features (e.g., shape, genus, etc.). The approaches differ in the way in which responses to queries are computed. In the classification approach, images are retrieved on the basis of whether or not they contain objects that have the same classification as the objects in the query. On the other hand, in the abstraction approach, retrieval is on the basis of similarity of feature vector values of these objects. Methods of integrating these two approaches into a relational multimedia database management system so that symbolic images can be stored and retrieved based on their content are described. Schema definitions and indices that support query specifications involving spatial as well as contextual constraints are presented. Spatial constraints may be based on both locational information (e.g., distance) and relational information (e.g., north of). Different strategies for image retrieval for a number of typical queries using these approaches are described. Estimated costs are derived for these strategies. Results are reported of a comparative study of the two approaches in terms of image insertion time, storage space, retrieval accuracy, and retrieval time. Received June 12, 1998 / Accepted October 13, 1998     

一种基于彩色边缘综合特征的图像检索算法

图像特征的提取与表达是基于内容的图像检索技术基础。边缘是重要的视觉感知信息,也是图像最基本的特征之一,其在图像分析和理解中有重要价值。文中以视觉重要的图像边缘轮廓为基础,提出一种基于彩色边缘综合特征的图像检索算法。该算法首先利用Canny检测算子提取出原始图像的彩色边缘轮廓。然后构造出能全面反映边缘轮廓内容的3种直方图,即加权颜色直方图、角度直方图和梯度方向直方图。最后综合利用上述3种彩色边缘直方图计算图像间的内容相似度,并进行彩色图像检索。仿真实验表明,该算法能够准确和高效地查找出用户所需内容的彩色图像,并且具有较好的查准率和查全率。     

基于位平面颜色直方图的图像检索新方法

为了解决现有颜色直方图检索技术所存在的鲁棒性较差、特征维数过高等问题,本文提出了一种基于位平面颜色直方图的图像检索新方法.该方法首先结合噪声攻击特点(对高位影响较小),提取出重要的位平面图像并确定其视觉权值;然后构造出位平面图像颜色直方图;最后以位平面图像颜色直方图为特征,计算图像间内容的相似度并进行检索.仿真实验表明,本文方法不仅能够准确检索出用户所需图像,而且对光照、锐化、模糊等噪声攻击均具有较好的鲁棒性.     

一种鲁棒的多特征彩色图像检索新方法

为了提高彩色图像检索的准确性,以回归型支持向量机(SVR)理论为基础,结合重要的图像边缘信息,提出了一种鲁棒的多特征彩色图像检索新方法。该方法首先利用回归型支持向量机(SVR)理论,对原始图像进行去噪处理及彩色边缘提取;然后将整个彩色边缘划分成局部网格区域,并分别计算出每个网格区域的颜色直方图和纹理直方图;最后综合利用上述网格区域的颜色直方图和纹理直方图来计算图像间内容的相似度,并进行彩色图像检索。实验结果表明,该方法不仅能够准确、快速的检索出用户所需图像,而且对光照、锐化、模糊等噪声攻击均具有较好的鲁棒性。