Segmentation of lip region in color images by fuzzy clustering

Extraction of the lip region is essential to lip reading, which is a field of image processing that is used to obtain meaningful information by the analysis of lip movement from human face images. Many conventional methods for extraction of the lip region have been proposed. One is to identify the lip position by using geometric face structure. Another discriminates lip and skin regions by using color information only. The former is more complex than the latter; however, it can analyze black and white images as well as color images. The latter is simpler than the former; however, it is difficult to discriminate lip and skin regions because of the high similarity between these two regions, and it is less accurate than the former. Conventional methods usually analyze color coordinate systems to extract lip regions rather than analyzing the coordinate system itself. In this paper, the best color coordinate system for lip extraction was selected by the analysis of discriminability. Segmentation of the lip region with this coordinate system and a new feature vector are proposed.     

Segmentation of color lip images by spatial fuzzy clustering

In this paper, we describe the application of a novel spatial fuzzy clustering algorithm to the lip segmentation problem. The proposed spatial fuzzy clustering algorithm is able to take into account both the distributions of data in feature space and the spatial interactions between neighboring pixels during clustering. By appropriate pre- and postprocessing utilizing the color and shape properties of the lip region, successful segmentation of most lip images is possible. Comparative study with some existing lip segmentation algorithms such as the hue filtering algorithm and the fuzzy entropy histogram thresholding algorithm has demonstrated the superior performance of our method.     

Unsupervised multiscale segmentation of color images

This paper proposes a new multiresolution technique for color image representation and segmentation, particularly suited for noisy images. A decimated wavelet transform is initially applied to each color channel of the image, and a multiresolution representation is built up to a selected scale 2^J. Color gradient magnitudes are computed at the coarsest scale 2^J, and an adaptive threshold is used to remove spurious responses. An initial segmentation is then computed by applying the watershed transform to thresholded magnitudes, and this initial segmentation is projected to finer resolutions using inverse wavelet transforms and contour refinements, until the full resolution 2⁰ is achieved. Finally, a region merging technique is applied to combine adjacent regions with similar colors. Experimental results show that the proposed technique produces results comparable to other state-of-the-art algorithms for natural images, and performs better for noisy images.     

Protein synthesis profiling in the developing brain: a graph theoretic clustering approach

Mapping regional brain development in terms of protein synthesis (PS) activity yields insight on specific spatio-temporal ontogenetic patterns. The biosynthetic activity of an individual brain nucleus is represented as a time-series object, and clustering of time-series contributes to the problem of inducing indicative patterns of brain developmental events and forming respective PS chronological maps. Clustering analysis of PS chronological maps, in comparison with epigenetic influences of alpha2 adrenoceptors treatment, reveals relationships between distantly located brain structures. Clustering is performed with a novel graph theoretic clustering approach (GTC). The approach is based on the weighted graph arrangement of the input objects and the iterative partitioning of the corresponding minimum spanning tree. The final result is a hierarchical clustering-tree organization of the input objects. Application of GTC on the PS patterns in developing brain revealed five main clusters that correspond to respective brain development indicative profiles. The induced profiles confirm experimental findings, and provide evidence for further experimental studies.     

基于多空间多层次谱聚类的非监督SAR图像分割算法

提出了一种基于多层区域谱聚类的非监督SAR图像分割算法（multi-space and multi-hierarchical region based spectral clustering, MSMHSC）。该算法首先在特征与几何空间求距离, 快速获得初始过分割区域, 然后在过分割区域的谱空间上进行聚类, 最终实现非监督的SAR图像分割。该方法计算复杂度小, 无须训练样本, 使用层次化思想使其能更充分地利用SAR图像各类先验与似然信息。在MSTAR真实SAR数据集上的实验验证了该算法的快速性和有效性。     

Segmentation of small objects in color images

A method for effective segmentation of small objects in color images is presented. It can be used jointly with region growing algorithms. Segmentation of small objects in color images is a difficult problem because their boundaries are close to each other. The proposed algorithm accurately determines the location of the boundary points of closely located small objects and finds the skeletons (seed regions) of those objects. The method makes use of conditions obtained by analyzing the change of color characteristics of the edge pixels along the direction that is orthogonal to the boundaries of adjacent objects. These conditions are generalized for the case of the well-known class of color images having misregistration artifacts. If high-quality seed regions are available, the final segmentation can be performed using one of the region growing methods. The segmentation algorithm based on the proposed method was tested using a large number of color images, and it proved to be very efficient.     

结合区域颜色一致性和图割的复杂场景文本分割方法

针对复杂场景文本难以有效分割的问题, 提出一种复杂场景文本分割方法. 首先, 使用简单的线性迭代聚类(SLIC) 算法将原始图像分割为若干局部区域, 并在其区域邻接图上构建图割模型; 然后, 采用高斯混合模型(GMMs) 和支持向量机(SVM) 后验概率模型对场景文本进行建模, 并引入每个局部区域与模型之间的匹配度用于计算似然能. 为了增强GMMs的鉴别力, 在参数学习中引入模型性能描述子, 自适应地获得模型参数. 实验结果表明,所提出的算法能够较好地处理复杂场景文本分割问题, 文本的识别率得到了明显的提升.

     

A comparison of the stability characteristics of some graph theoretic clustering methods

Assessing the stability of a clustering method involves the measurement of the extent to which the generated clusters are affected by perturbations in the input data. A measure which specifies the disturbance in a set of clusters as the minimum number of operations required to restore the set of modified clusters to the original ones is adopted. A number of well-known graph theoretic clustering methods are compared in terms of their stability as determined by this measure. Specifically, it is shown that among the clustering methods in any of several families of graph theoretic methods, clusters defined as the connected components are the most stable and the clusters specified as the maximal complete subgraphs are the least stable. Furthermore, as one proceeds from the method producing the most narrow clusters (maximal complete subgraphs) to those producing relatively broader clusters, the clustering process is shown to remain at least as stable as any method in the previous stages. Finally, the lower and the upper bounds for the measure of stability, when clusters are defined as the connected components, are derived.     

The synthesis and analysis of color images

I describe a method for performing the synthesis and analysis of digital color images. The method is based on two principles. First, image data are represented with respect to the separate physical factors, surface reflectance and the spectral power distribution of the ambient light, that give rise to the perceived color of an object. Second, the encoding is made efficient by using a basis expansion for the surface spectral reflectance and spectral power distribution of the ambient light that takes advantage of the high degree of correlation across the visible wavelengths normally found in such functions. Within this framework, the same basic methods can be used to synthesize image data for color display monitors and printed materials, and to analyze image data into estimates of the spectral power distribution and surface spectral reflectances. The method can be applied to a variety of tasks. Examples of applications include the color balancing of color images and the identification of material surface spectral reflectance when the lighting cannot be completely controlled.     

Collusion set detection using graph clustering

Many mal-practices in stock market trading—e.g., circular trading and price manipulation—use the modus operandi of collusion. Informally, a set of traders is a candidate collusion set when they have “heavy trading” among themselves, as compared to their trading with others. We formalize the problem of detection of collusion sets, if any, in the given trading database. We show that naïve approaches are inefficient for real-life situations. We adapt and apply two well-known graph clustering algorithms for this problem. We also propose a new graph clustering algorithm, specifically tailored for detecting collusion sets. A novel feature of our approach is the use of Dempster–Schafer theory of evidence to combine the candidate collusion sets detected by individual algorithms. Treating individual experiments as evidence, this approach allows us to quantify the confidence (or belief) in the candidate collusion sets. We present detailed simulation experiments to demonstrate effectiveness of the proposed algorithms.     

Correcting show-through effects on scanned color document images by multiscale analysis

This paper describes a new approach to restoring scanned color document images where the backside image shows through the paper sheet. A new framework is presented for correcting show-through components using digital image processing techniques. First, the foreground components on the front side are separated from the background and backside components through locally adaptive binarization for each color component and edge magnitude thresholding. Background colors are estimated locally through color thresholding to generate a restored image, and then corrected adaptively through multi-scale analysis along with comparison of edge distributions between the original and the restored image. The proposed method does not require specific input devices or the backside to be input; it is able to correct unneeded image components through analysis of the front side image alone. Experimental results are given to verify effectiveness of the proposed method.     

Sub-optimal solutions to track detection problem using graph theoretic concepts

This paper demonstrates how the problem of tracking targets, which appear as either straight or curved lines in two-dimensional display images (or data images) can be formulated in terms of a directed weighted graph model and how dynamic programming techniques can be efficiently applied to reach an optimal or sub-optimal solution. In general, track detection algorithms providing optimal solutions have good detective ability, but most of them suffer from the inability to detect discontinuous lines or to resolve efficiently pairs of crossing lines. A sub-optimal solution is provided that efficiently overcomes these weaknesses. We focus on modeling the track detection problem in terms of a graph, formulating fast sequential/parallel sub-optimal track detection algorithms and testing them on simulated data in order to show their detective ability. Moreover, we specify the conditions under which sub-optimal algorithms can perform at least as well as their corresponding optimal algorithms. This is significant for the track detection problem where fast, accurate and real-time detection is considered a necessity.     

An FPGA implementation of real-time K-means clustering for color images

K-means clustering is a very popular clustering technique, which is used in numerous applications. In the k-means clustering algorithm, each point in the dataset is assigned to the nearest cluster by calculating the distances from each point to the cluster centers. The computation of these distances is a very time-consuming task, particularly for large dataset and large number of clusters. In order to achieve high performance, we need to reduce the number of the distance calculations for each point efficiently. In this paper, we describe an FPGA implementation of k-means clustering for color images based on the filtering algorithm. In our implementation, when calculating the distances for each point, clusters which are apparently not closer to the point than other clusters are filtered out using kd-trees which are dynamically generated on the FPGA in each iteration of k-means clustering. The performance of our system for 512 × 512 and 640 × 480  pixel images (24-bit full color RGB) is more than 30 fps, and 20–30 fps for 756 × 512 pixel images in average when dividing to 256 clusters.

应用色彩空间聚类方法实现道路建模

通过图像对交通事故进行识别、处理,需要将卷入交通事故的车辆等目标从交通事故场景图像中分离出来,因此建立准确的道路模型十分重要.传统的道路建模方法大都基于灰度空间,忽略了图像中的彩色信息,不适合复杂的交通环境.针对道路像素分布的非参数化特点和后续处理中对彩色信息的需求,提出一种基于色彩空间聚类的非参数化道路模型,将道路模型的建立抽象为时间轴上的色彩空间聚类过程.根据颜色变化理论,设置聚类区间为RGB颜色空间中以聚类中心和原点连线为轴的圆柱体,并通过聚类中心特征值的不同自适应来调整聚类半径.同时,对于每个像素位置,根据场景复杂程度和变化频率的不同自适应地选取聚类中心数目,获得较为准确的背景模型,在提高检测精度的同时也保证了检测效率.     

An optimal graph theoretic approach to data clustering: theory andits application to image segmentation

A novel graph theoretic approach for data clustering is presented and its application to the image segmentation problem is demonstrated. The data to be clustered are represented by an undirected adjacency graph 𝒢 with arc capacities assigned to reflect the similarity between the linked vertices. Clustering is achieved by removing arcs of 𝒢 to form mutually exclusive subgraphs such that the largest inter-subgraph maximum flow is minimized. For graphs of moderate size (~ 2000 vertices), the optimal solution is obtained through partitioning a flow and cut equivalent tree of 𝒢, which can be efficiently constructed using the Gomory-Hu algorithm (1961). However for larger graphs this approach is impractical. New theorems for subgraph condensation are derived and are then used to develop a fast algorithm which hierarchically constructs and partitions a partially equivalent tree of much reduced size. This algorithm results in an optimal solution equivalent to that obtained by partitioning the complete equivalent tree and is able to handle very large graphs with several hundred thousand vertices. The new clustering algorithm is applied to the image segmentation problem. The segmentation is achieved by effectively searching for closed contours of edge elements (equivalent to minimum cuts in 𝒢), which consist mostly of strong edges, while rejecting contours containing isolated strong edges. This method is able to accurately locate region boundaries and at the same time guarantees the formation of closed edge contours     

Extraction of spots in biological images using multiscale products

We present a new method to detect and count bright spots in fluorescence images coming from biological immunomicroscopy experiments. It is based on the multiscale product of subband images resulting from the à trous wavelet transform decomposition of the original image, after thresholding of non-significant coefficients. The multiscale correlation of the filtered wavelet coefficients, which allows to enhance multiscale peaks due to spots while reducing noise, combines information coming from different levels of resolution and gives a clear and distinctive chacterization of the spots. Results are presented for the analysis of typical immunofluorescence images.     

Information theoretic clustering using a k-nearest neighbors approach

We develop a new non-parametric information theoretic clustering algorithm based on implicit estimation of cluster densities using the k-nearest neighbors (k-nn) approach. Compared to a kernel-based procedure, our hierarchical k-nn approach is very robust with respect to the parameter choices, with a key ability to detect clusters of vastly different scales. Of particular importance is the use of two different values of k, depending on the evaluation of within-cluster entropy or across-cluster cross-entropy, and the use of an ensemble clustering approach wherein different clustering solutions vote in order to obtain the final clustering. We conduct clustering experiments, and report promising results.     

基于多尺度颜色小波纹理特征的火焰图像分割

火焰图像分割质量对基于数字成像的燃烧监测十分重要。受炉膛背景及燃烧工况的影响,难以同时满足火焰图像分割速度和准确度（即火焰图像分割结果与真实火焰接近程度）的需求。提出一种基于多尺度颜色特征和小波纹理特征（MCWT）的无监督火焰图像分割方法,用于提高火焰图像分割的质量和速度。结合火焰图像颜色特征及小波纹理特征构建特征矩阵,对特征矩阵进行压缩并初步检测压缩尺度火焰区域。根据压缩尺度火焰边缘确定原始尺度火焰边缘区域并构建火焰边缘区域特征矩阵,进一步分割得到准确火焰图像分割结果。采用该方法对某工业煤燃烧实验炉内不同燃烧工况下的火焰图像进行分割,并与传统分割方法对比。实验结果表明与其他传统分割方法相比,提出方法能够更准确且快速地实现不同燃烧工况下火焰图像的分割,并且其对于含有高斯噪声和椒盐噪声的火焰图像都具有更好的分割效果。     

基于模糊连接度的近邻传播聚类图像分割方法

针对现有近邻传播聚类图像分割方法分割精度低的问题,提出一种基于模糊连接度的邻近传播聚类(FCAP)图像分割算法。针对传统模糊连接度算法不能得出任意点对间模糊连接度的不足,结合最大生成树提出了全模糊连接度算法。FCAP算法先使用Normalized Cut超像素技术进行超像素分割,这些超像素可以看作数据点以及它们之间的模糊连接度;然后使用所提出的全模糊连接度算法计算超像素间的模糊连接度,根据模糊连接度和空间信息计算超像素的相似度;最后使用近邻传播(AP)聚类算法完成分割。实验结果表明,FCAP算法明显优于超像素处理后直接使用AP聚类算法进行分割的方法,并且优于无监督图像分割方法。