Efficient image retrieval through vantage objects

We describe a new indexing structure for general image retrieval that relies solely on a distance function giving the similarity between two images. For each image object in the database, its distance to a set of m predetermined vantage objects is calculated; the m-vector of these distances specifies a point in the m-dimensional vantage space. The database objects that are similar (in terms of the distance function) to a given query object can be determined by means of an efficient nearest-neighbor search on these points. We demonstrate the viability of our approach through experimental results obtained with two image databases, one consisting of about 5200 raster images of stamps, the other containing about 72,000 hieroglyphic polylines.     

Human Face Recognition and the Face Image Set′s Topology

If we consider an n × n image as an n²-dimensional vector, then images of faces can be considered as points in this n²-dimensional image space. Our previous studies of physical transformations of the face, including translation, small rotations, and illumination changes, showed that the set of face images consists of relatively simple connected subregions in image space. Consequently linear matching techniques can be used to obtain reliable face recognition. However, for more general transformations, such as large rotations or scale changes, the face subregions become highly non-convex. We have therefore developed a scale-space matching technique that allows us to take advantage of knowledge about important geometrical transformations and about the topology of the face subregion in image space. While recognition of faces is the focus of this paper, the algorithm is sufficiently general to be applicable to a large variety of object recognition tasks     

Interactive noise-controlled boundary image matching using the time-series moving average transform

In this paper we propose a time-series matching-based approach that provides the interactive boundary image matching with noise control for a large-scale image database. To achieve the noise reduction effect in boundary image matching, we exploit the moving average transform of time-series matching. We are motivated by a simple intuition that the moving average transform might reduce the noise of boundary images as well as that of time-series data. To confirm this intuition, we first propose a new notion of k-order image matching, which applies the moving average transform to boundary image matching. A boundary image can be represented as a sequence in the time-series domain, and our k-order image matching identifies similar boundary images in this time-series domain by comparing the k-moving average transformed sequences. We then propose an index-based method that efficiently performs k-order image matching on a large image database, and formally prove its correctness. We also formally analyze the relationship of orders and their matching results and present an interactive approach of controlling the noise reduction effect. Experimental results show that our k-order image matching exploits the noise reduction effect well, and our index-based method outperforms the sequential scan by one or two orders of magnitude. These results indicate that our k-order image matching and its index-based solution provide a very practical way of realizing the noise control boundary image matching. To our best knowledge, the proposed interactive approach for large-scale image databases is the first attempt to solve the noise control problem in the time-series domain rather than the image domain by exploiting the efficient time-series matching techniques. Thus, our approach can be widely used in removing other types of distortions in image matching areas.     

SIMPLIcity: semantics-sensitive integrated matching for picturelibraries

We present here SIMPLIcity (semantics-sensitive integrated matching for picture libraries), an image retrieval system, which uses semantics classification methods, a wavelet-based approach for feature extraction, and integrated region matching based upon image segmentation. An image is represented by a set of regions, roughly corresponding to objects, which are characterized by color, texture, shape, and location. The system classifies images into semantic categories. Potentially, the categorization enhances retrieval by permitting semantically-adaptive searching methods and narrowing down the searching range in a database. A measure for the overall similarity between images is developed using a region-matching scheme that integrates properties of all the regions in the images. The application of SIMPLIcity to several databases has demonstrated that our system performs significantly better and faster than existing ones. The system is fairly robust to image alterations     

黎曼流形上的保局投影在图像集匹配中的应用

目的提出了黎曼流形上局部结构特征保持的图像集匹配方法。方法该方法使用协方差矩阵建模图像集合,利用对称正定的非奇异协方差矩阵构成黎曼流形上的子空间,将图像集的匹配转化为流形上的点的匹配问题。通过基于协方差矩阵度量学习的核函数将黎曼流形上的协方差矩阵映射到欧几里德空间。不同于其他方法黎曼流形上的鉴别分析方法,考虑到样本分布的局部几何结构,引入了黎曼流形上局部保持的图像集鉴别分析方法,保持样本分布的局部邻域结构的同时提升样本的可分性。结果在基于图像集合的对象识别任务上测试了本文算法,在ETH80和YouTube Celebrities数据库分别进行了对象识别和人脸识别实验,分别达到91.5%和65.31%的识别率。结论实验结果表明,该方法取得了优于其他图像集匹配算法的效果。     

Flexible syntactic matching of curves and its application toautomatic hierarchical classification of silhouettes

Curve matching is one instance of the fundamental correspondence problem. Our flexible algorithm is designed to match curves under substantial deformations and arbitrary large scaling and rigid transformations. A syntactic representation is constructed for both curves and an edit transformation which maps one curve to the other is found using dynamic programming. We present extensive experiments where we apply the algorithm to silhouette matching. In these experiments, we examine partial occlusion, viewpoint variation, articulation, and class matching (where silhouettes of similar objects are matched). Based on the qualitative syntactic matching, we define a dissimilarity measure and we compute it for every pair of images in a database of 121 images. We use this experiment to objectively evaluate our algorithm. First, we compare our results to those reported by others. Second, we use the dissimilarity values in order to organize the image database into shape categories. The veridical hierarchical organization stands as evidence to the quality of our matching and similarity estimation     

Face recognition based on 3D ridge images obtained from range data

In this paper, we present an approach for 3D face recognition from frontal range data based on the ridge lines on the surface of the face. We use the principal curvature, k_max, to represent the face image as a 3D binary image called ridge image. The ridge image shows the locations of the ridge points around the important facial regions on the face (i.e., the eyes, the nose, and the mouth). We utilized the robust Hausdorff distance and the iterative closest points (ICP) for matching the ridge image of a given probe image to the ridge images of the facial images in the gallery. To evaluate the performance of our approach for 3D face recognition, we performed experiments on GavabDB face database (a small size database) and Face Recognition Grand Challenge V2.0 (a large size database). The results of the experiments show that the ridge lines have great capability for 3D face recognition. In addition, we found that as long as the size of the database is small, the performance of the ICP-based matching and the robust Hausdorff matching are comparable. But, when the size of the database increases, ICP-based matching outperforms the robust Hausdorff matching technique.     

Image retrieval by texture similarity

Accuracy and efficiency are the two important issues in designing content-based image retrieval systems. In this paper, we present an efficient image retrieval system with high performance of accuracy based on two novel features, the composite sub-band gradient vector and the energy distribution pattern string. Both features are generated from the sub-images of a wavelet decomposition of the original image. A fuzzy matching mechanism based on energy distribution pattern strings serves as a filter to quickly remove undesired images in the database from further consideration. The images passing the filter will be compared with the query image based on composite sub-band gradient vectors which are extremely powerful for discriminating detailed textures. Through several extensive experiments by exercising our prototype system with a database of 2400 images, we demonstrated that both high accuracy and high efficiency can be achieved at the same time by our approach.     

Application of planar shape comparison to object retrieval in image databases

A similarity measure for silhouettes of 2D objects is presented, and its properties are analyzed with respect to retrieval of similar objects in image databases. To reduce influence of digitization noise as well as segmentation errors the shapes are simplified by a new process of digital curve evolution. To compute our similarity measure, we first establish the best possible correspondence of visual parts (without explicitly computing the visual parts). Then the similarity between corresponding parts is computed and summed. Experimental results show that our shape matching procedure gives an intuitive shape correspondence and is stable with respect to noise distortions.     

Multi-scale fidelity measure for image fusion quality assessment

Image fusion is considered an effective enhancing methodology widely included in high-quality imaging systems. Nevertheless, like other enhancing techniques, output quality assessment is made within small sample subjective evaluation studies which are very limited in predicting the human-perceived quality of general image fusion outputs. Simple, blind, universal and perceptual-like methods for assessing composite image quality are still a challenge, partially solved only in particular applications. In this paper, we propose a fidelity measure, called MS-Q_W with two major characteristics related to natural image statistics framework: A multi-scale computation and a structural similarity score. In our experiments, we correlate the scores of our measure with subjective ratings and state of the art measures included in the 2015 Waterloo IVC multi-exposure fusion (MEF) image database. We also use the measure to rank correctly the classical general fusion methods included in the Image Fusion Toolbox for medical, infra-red and multi-focus image examples. Moreover, we study the scores variability and statistical discrimination power with the TNO night vision database using the Friedman test. Finally, we define a new leave one out procedure based on our fidelity measure that selects the best subset of images (within a collection of distorted and unregistered cell phone type images) that provides a defect-free composite output. We exemplify the procedure with the fusion of a collection of images from Latour and Van Dongen paintings suffering from glass highlights and speckle noise, among other artifacts. The proposed multiscale quality measure MS-Q_W demonstrates improvement over the previous single-scale similarity measures towards a fidelity assessment between quantitative image fusion quality metrics and human perceptual qualitative scores.     

结合支持向量回归和图像自相似的单幅图像超分辨率算法

目的 基于学习的单幅图像超分辨率算法是借助实例训练库由一幅低分辨率图像产生高分辨率图像。提出一种基于图像块自相似性和对非线性映射拟合较好的支持向量回归模型的单幅超分辨率方法,该方法不需使用外部图像训练库。方法 首先根据输入的低分辨率图像建立图像金字塔及包含低/高分辨率图像块对的集合;然后在低/高分辨率图像块对的集合中寻找与输入低分辨率图像块的相似块,利用支持向量回归模型学习这些低分辨率相似块和其对应的高分辨率图像块的中心像素之间的映射关系,进而得到未知高分辨率图像块的中心像素。结果 为了验证本文设计算法的有效性,选取结构和纹理不同的7幅彩色高分辨率图像,对其进行高斯模糊的2倍下采样后所得的低分辨率图像进行超分辨率重构,与双三次插值、基于稀疏表示及基于支持向量回归这3个超分辨率方法重建的高分辨率图像进行比较,峰值信噪比平均依次提升了2.37 dB、0.70 dB和0.57 dB。结论 实验结果表明,本文设计的算法能够很好地实现图像的超分辨率重构,特别是对纹理结构相似度高的图像具有更好的重构效果。     

Robust memory-efficient data level information fusion of multi-modal biometric images

This paper presents a novel multi-level wavelet based fusion algorithm that combines information from fingerprint, face, iris, and signature images of an individual into a single composite image. The proposed approach reduces the memory size, increases the recognition accuracy using multi-modal biometric features, and withstands common attacks such as smoothing, cropping, JPEG 2000, and filtering due to tampering. The fusion algorithm is validated using the verification algorithms we developed, existing algorithms, and commercial algorithm. In addition to our multi-modal database, experiments are also performed on other well known databases such as FERET face database and CASIA iris database. The effectiveness of the fusion algorithm is experimentally validated by computing the matching scores and the equal error rates before fusion, after reconstruction of biometric images, and when the composite fused image is subjected to both frequency and geometric attacks. The results show that the fusion process reduced the memory required for storing the multi-modal images by 75%. The integrity of biometric features and the recognition performance of the resulting composite fused image is not affected significantly. The complexity of the fusion and the reconstruction algorithms is O(n log n) and is suitable for many real-time applications. We also propose a multi-modal biometric algorithm that further reduces the equal error rate compared to individual biometric images.     

Geometry-based image retrieval in binary image databases

In this paper, a geometry-based image retrieval system is developed for multi-object images. We model both shape and topology of image objects using a structured representation called curvature tree (CT). The hierarchy of the CT reflects the inclusion relationships between the image objects. To facilitate shape-based matching, triangle-area representation (TAR) of each object is stored at the corresponding node in the CT. The similarity between two multi-object images is measured based on the maximum similarity subtree isomorphism (MSSI) between their CTs. For this purpose, we adopt a recursive algorithm to solve the MSSI problem and a very effective dynamic programming algorithm to measure the similarity between the attributed nodes. Our matching scheme agrees with many recent findings in psychology about the human perception of multi-object images. Experiments on a database of 13500 real and synthesized medical images and the MPEG-7 CE-1 database of 1400 shape images have shown the effectiveness of the proposed method.     

结合双向相似性变换的重定向图像质量评价

目的 显示设备的多样化使得图像重定向的作用日益凸显。不同的重定向方法产生不同视觉感受的重定向图像,而如何评价重定向图像的质量,优化重定向算法是当前研究的热点与难点,为此,提出一种结合双向相似性变换的重定向图像质量评价方法。方法 首先对原始图像和重定向图像进行像素点双向匹配,利用网格顶点坐标对计算前向变换矩阵和后向变换矩阵。然后由相似性变换矩阵与标准变换矩阵间的距离得到重定向图像的几何失真。由网格面积缺失得到重定向图像的信息损失。最后结合网格的显著性,融合前向匹配与后向匹配的几何失真和信息损失得到重定向图像的质量。结果 该方法在RetargetMe和CUHK数据库上的KRCC（Kendall rank correlation coefficient）和SROCC（Spearman rank-order correlation coefficient）性能分别达到了0.46和0.71,较现有方法有较大提升。在前向匹配与后向匹配测试中,双向匹配的测试结果优于单向匹配。结论 本文方法将图像的重定向处理看做相似性变换过程。实验结果表明,从相似性变换矩阵中提取的相关特征能够较精确度量重定向图像的几何失真,而由此引发的网格面积缺失也能准确反映出重定向图像的信息损失。另外,采用双向匹配机制一定程度上减少了像素匹配误差对实验结果的影响,有效提升了重定向图像质量预测的准确性。该方法对重定向图像的质量评价效果好,适用于重定向图像的质量预测及算法优化。     

A novel rotation/scale invariant template matching algorithm using weighted adaptive lifting scheme transform

This paper presents a novel algorithm for detecting user-selected objects in given test images based on a new adaptive lifting scheme transform. Given an object as a template, we first select a set of coefficients as object features in the wavelet transform domain and then build an adaptive transform based on the selected features. The goal of the new adaptive transform is to vanish the selected features in the transform domain. After applying both non-adaptive and adaptive transforms to a given test image, the corresponding transform domain coefficients are compared for detecting the object of interest. In addition, the proposed detection algorithm is combined with the proper log-polar mapping model in the parametric template space to attain rotation/scale invariance property. Finally, we have verified the properties of our proposed algorithm with experimental results.     

Visual image retrieval by elastic matching of user sketches

Effective image retrieval by content from database requires that visual image properties are used instead of textual labels to properly index and recover pictorial data. Retrieval by shape similarity, given a user-sketched template is particularly challenging, owing to the difficulty to derive a similarity measure that closely conforms to the common perception of similarity by humans. In this paper, we present a technique which is based on elastic matching of sketched templates over the shapes in the images to evaluate similarity ranks. The degree of matching achieved and the elastic deformation energy spent by the sketch to achieve such a match are used to derive a measure of similarity between the sketch and the images in the database and to rank images to be displayed. The elastic matching is integrated with arrangements to provide scale invariance and take into account spatial relationships between objects in multi-object queries. Examples from a prototype system are expounded with considerations about the effectiveness of the approach and comparative performance analysis     

Learning context-sensitive similarity by shortest path propagation

In this paper, we introduce a novel shape/object retrieval algorithm shortest path propagation (SSP). Given a query object q and a target database object p, we explicitly find the shortest path between them in the distance manifold of the database objects. Then a new distance measure between q and p is learned based on the database objects on the shortest path to replace the original distance measure. The promising results on both MEPG-7 shape dataset and a protein dataset demonstrate that our method can significantly improve the ranking of the object retrieval.     

Specific object retrieval based on salient regions

In this paper, we present an image retrieval technique for specific objects based on salient regions. The salient regions we select are invariant to geometric and photometric variations. Those salient regions are detected based on low level features, and need to be classified into different types before they can be applied on further vision tasks. We first classify the selected regions into four types including blobs, edges and lines, textures, and texture boundaries, by using the correlations with the neigbouring regions. Then, some specific region types are chosen for further object retrieval applications. We observe that regions selected from images of the same object are more similar to each other than regions selected from images of different objects. Correlation is used as the similarity measure between regions selected from different images. Two images are considered to contain the same object, if some regions selected from the first image are highly correlated to some regions selected from the second image. Two data sets are employed for experiment: the first data set contains human face images of a number of different people and is used for testing the retrieval algorithm on distinguishing specific objects of the same category; and the second data set contains images of different objects and is used for testing the retrieval algorithm on distinguishing objects of different categories. The results show that our method is very effective on specific object retrieval.