Fuzzy homogeneity and scale-space approach to color image segmentation

Image segmentation is the procedure in which the original image is partitioned into homogeneous regions, and has many applications. In this paper, a fuzzy homogeneity and scale-space approach to color image segmentation is proposed. A color image is transformed into fuzzy domain with maximum fuzzy entropy principle. The fuzzy homogeneity histogram is employed, and both global and local informations are considered when we process fuzzy homogeneity histogram. The scale-space filter is utilized for analyzing the fuzzy homogeneity histogram to find the appropriate segments of the homogeneity histogram bounded by the local extrema of the derivatives. A fuzzy region merging process is then implemented based on color difference and cluster sizes to avoid over-segmentation. The proposed method is compared with the space domain approach, and experimental results demonstrate the effectiveness of the proposed approach.     

Linear color segmentation and its implementation

A framework for color image segmentation is presented, which combines color histogram analysis and region merging approach. Its main goal is to segment an image at material boundaries (i.e., discontinuities of reflectance properties) while ignoring spatial color inhomogeneities of uniformly pigmented (colored) objects, caused by accidents of illumination and viewing geometry. Theoretical examination of light spectrum transformations upon light reflection from material surfaces and upon interaction with a sensor system shows that in a wide variety of viewed scenes (even containing interreflections and highlight areas) uniformly pigmented objects are projected to the color space of the sensor as planar, linear, or point-like clusters, depending on lighting and viewing conditions and object geometry. To detect such clusters in the color space, three methods are suggested: Generalized Hough Transform method, gradient descent method, and eigenvectors method. A framework algorithm of color segmentation based on region merging approach is developed, which can use any of these methods. Testing this algorithm with both artificially generated and real images shows quite reliable results.     

Color image segmentation—an innovative approach

In this paper we describe a color image segmentation system that performs color clustering in a color space and then color region segmentation in the image domain. For color segmentation, we developed a fuzzy clustering algorithm that iteratively generates color clusters using a uniquely defined fuzzy membership function and an objective function for clustering optimization. The fuzzy membership function represents belief value of a color belonging to a color cluster and the mutual interference of neighboring clusters. The region segmentation algorithm merges clusters in the image domain based on color similarity and spatial adjacency. We developed three different methods for merging regions in the image domain. Unlike many existing clustering algorithms, the image segmentation system does not require the knowledge about the number of the color clusters to be generated at each stage and the resolution of the color regions can be controlled by one single parameter, the radius of a cluster. The color image segmentation system has been implemented and tested on a variety of color images including satellite images, car and face images. The experiment results are presented and the performance of each algorithm in the segmentation system is analyzed. The system has shown to be both effective and efficient.     

Text extraction in complex color documents

Text extraction in mixed-type documents is a pre-processing and necessary stage for many document applications. In mixed-type color documents, text, drawings and graphics appear with millions of different colors. In many cases, text regions are overlaid onto drawings or graphics. In this paper, a new method to automatically detect and extract text in mixed-type color documents is presented. The proposed method is based on a combination of an adaptive color reduction (ACR) technique and a page layout analysis (PLA) approach. The ACR technique is used to obtain the optimal number of colors and to convert the document into the principal of them. Then, using the principal colors, the document image is split into the separable color plains. Thus, binary images are obtained, each one corresponding to a principal color. The PLA technique is applied independently to each of the color plains and identifies the text regions. A merging procedure is applied in the final stage to merge the text regions derived from the color plains and to produce the final document. Several experimental and comparative results, exhibiting the performance of the proposed technique, are also presented.     

Bounded irregular pyramid: a new structure for color image segmentation

This paper presents a new segmentation technique for color images. It relies on building an irregular pyramid into a regular one, presenting only nodes associated to homogeneous color regions. Hence, the size of the irregular pyramid is bounded. Segmentation is performed by rearranging the set of links among pyramid nodes. Unlike other hierarchical methods based on relinking procedures, our algorithm does not operate in an iterative way and it preserves region connectivity.     

基于K均值聚类与区域合并的彩色图像分割算法

提出一种基于K均值聚类与区域合并的彩色图像分割算法。首先,对图像运用mean shift算法进行滤波,在对图像进行平滑的同时保持图像的边缘;然后,运用K均值算法对图像在颜色空间进行聚类,得到初始分割的结果;最后,给出了一种区域合并策略,对初始分割获得的区域进行合并,得到最终的分割结果。仿真结果表明,算法的分割结果和人的主观视觉感知具有良好的一致性。     

一种基于区域分级合并的彩色图像分割方法

在区域合并过程中,手工设置颜色相似性和边界距离的权重极大地影响了分割的精度和自动化.针对这一问题,提出了一种新的基于区域分级合并的彩色图像分割算法.该方法能够根据邻接区域的边界特点设置权重因子,从而自适应地融合区域的颜色相似性和边界距离.使用均值漂移算法对图像进行初始分割,将原图像分割为具有较好边界的同质区域;通过计算区域相似度对区域进行分级合并.多幅彩色图像的分割实验结果证明,所提算法优于传统的基于区域合并的方法.     

一种融合颜色和空间信息的彩色图像分割算法

提出了一种基于图像颜色和空间信息的彩色图像分割算法.该算法首先根据所提出的颜色粗糙度概念对图像进行颜色量化,并在此基础上使用增量式的区域生长算法发现颜色相近的像素之间的空间连通性,形成图像的初始分割区域.然后,根据融合了颜色和空间信息的区域距离,对初始分割区域进行分级合并,直到系统满足了所提出的停止区域合并的准则.最后,利用形态学的有关算法对分割区域的边缘进行平滑.实验证明,算法的分割结果与人的主观视觉感知具有良好的一致性.     

Interactive image segmentation by matching attributed relational graphs

A model-based graph matching approach is proposed for interactive image segmentation. It starts from an over-segmentation of the input image, exploiting color and spatial information among regions to propagate the labels from the regions marked by the user-provided seeds to the entire image. The region merging procedure is performed by matching two graphs: the input graph, representing the entire image; and the model graph, representing only the marked regions. The optimization is based on discrete search using deformed graphs to efficiently evaluate the spatial information. Note that by using a model-based approach, different interactive segmentation problems can be tackled: binary and multi-label segmentation of single images as well as of multiple similar images. Successful results for all these cases are presented, in addition to a comparison between our binary segmentation results and those obtained with state-of-the-art approaches. An implementation is available at http://structuralsegm.sourceforge.net/.     

Color image segmentation based on multiobjective artificial bee colony optimization

This paper presents a new color image segmentation method based on a multiobjective optimization algorithm, named improved bee colony algorithm for multi-objective optimization (IBMO). Segmentation is posed as a clustering problem through grouping image features in this approach, which combines IBMO with seeded region growing (SRG). Since feature extraction has a crucial role for image segmentation, the presented method is firstly focused on this manner. The main features of an image: color, texture and gradient magnitudes are measured by using the local homogeneity, Gabor filter and color spaces. Then SRG utilizes the extracted feature vector to classify the pixels spatially. It starts running from centroid points called as seeds. IBMO determines the coordinates of the seed points and similarity difference of each region by optimizing a set of cluster validity indices simultaneously in order to improve the quality of segmentation. Finally, segmentation is completed by merging small and similar regions. The proposed method was applied on several natural images obtained from Berkeley segmentation database. The robustness of the proposed ideas was showed by comparison of hand-labeled and experimentally obtained segmentation results. Besides, it has been seen that the obtained segmentation results have better values than the ones obtained from fuzzy c-means which is one of the most popular methods used in image segmentation, non-dominated sorting genetic algorithm II which is a state-of-the-art algorithm, and non-dominated sorted PSO which is an adapted algorithm of PSO for multi-objective optimization.     

基于改进分水岭算法的熏烤肉图像分割

针对传统分水岭算法容易产生过度分割的问题,提出一种改进分水岭算法,并用来分割熏烤肉表面颜色。算法先对熏烤肉原始图像作滤波预处理,然后作传统分水岭变换,对产生的过度分割区域,在RGB颜色空间中进行自动种子选取及种子区域生长,最后对剩余小区域进行合并得到分割图像。实验表明,该方法减少了过度分割现象,成功地分割熏烤肉表面颜色,为之后的分析工作奠定了基础。     

基于HSV色彩空间的自适应肤色检测

针对复杂背景彩色图像提出了一种基于HSV色彩空间的自适应肤色检测算法。该算法首先使用阈值在HSV空间对人体肤色区域进行肤色分割,然后对分割出的肤色区域使用相对重要性滤波和自适应区域归并,最后将归并后的肤色区域使用人眼定位进行验证,将多人脸检测转化为单人脸检测。实验结果表明,该算法复杂度较小,对光照变化具有很好的鲁棒性。     

Generalized Hough Transform Using Regions with Homogeneous Color

A novel generalized Hough transform algorithm which makes use of the color similarity between homogeneous segments as the voting criterion is proposed in this paper. The input of the algorithm is some regions with homogeneous color. These regions are obtained by first pre-segmenting the image using the morphological watershed algorithm and then refining the resultant outputs by a region merging algorithm. Region pairs belonging to the object are selected to generate entries of the reference table for the Hough transform. Every R-table entry stores a relative color between the selected region pairs. This is done in order to compute the color similarity and in turn generate votes during the voting process and some relevant information to recover the transformation parameters of the object. Based on the experimental results, our algorithm is robust to change of illumination, occlusion and distortion of the segmentation output. It recognizes objects which were translated, rotated, scaled and even located in a complex environment.     

基于语义的图像物体提取的新方法

在图像语义研究中,提取图像中的语义物体或区域是重要的.本文首先对图像预处理,通过颜色空间的转换,在空间对图像进行K-均值分类,提取出具有语义性质的物体和区域.实验结果表明该方法是可行的,而且很有效的.     

融合颜色和深度信息的图像物体分割算法*

当图像中存在阴影、低对比度边缘和模糊区域时,传统算法仅利用外观信息难以准确提取物体轮廓,而深度不连续性为辨识物体边界提供有用信息。文中提出基于颜色和深度信息的图像物体分割算法,首先利用mean-shift算法对图像进行适度的过分割,然后融合颜色和深度信息充分描述过分割区域的特性,根据深度信息自动选取目标和背景的种子区域,最后基于最大相似度进行区域合并,得到图像物体分割结果。在Middlebury和NYU-V2数据库上的实验表明,相比当前通用算法,文中算法简单有效,能提高分割的准确性,改善分割图像的视觉效果。     

基于颜色分布的图像检索系统

基于内容的图像检索日益成为当今图像检索研究的热点。该论文在论述基于颜色直方图的图像检索方法的基础上,将图像重叠分块,提出了基于颜色分布的图像检索方法。最后实现了基于颜色直方图与基于颜色分布的两种图像检索方法的图像检索原型系统,并对实验结果进行了详细的分析和比较。     

Color image segmentation using adaptive unsupervised clustering approach

This paper presents the Region Splitting and Merging-Fuzzy C-means Hybrid Algorithm (RFHA), an adaptive unsupervised clustering approach for color image segmentation, which is important in image analysis and in understanding pattern recognition and computer vision field. Histogram thresholding technique is applied in the formation of all possible cells, used to split the image into multiple homogeneous regions. The merging technique is applied to merge perceptually close homogeneous regions and obtain better initialization for the Fuzzy C-means clustering approach. Experimental results have demonstrated that the proposed scheme could obtain promising segmentation results, with 12% average improvement in clustering quality and 63% reduction in classification error compared with other existing segmentation approaches.     

Segmentation of natural scenes

A new simple and computationally efficient approach to image segmentation via recursive region splitting and merging is presented. Unlike other techniques the criterion for splitting is based on a generalization of a two-class gradient relaxation method and merging uses a test for mean gray level equivalency for adjacent regions. The technique is illustrated by providing results for both synthetic and natural scenes.     

一种基于HSV颜色空间的车辆牌照提取方法

给出了一种根据车牌底的彩色信息,利用HSV颜色空间对输入的含有汽车牌照的彩色图像直接进行处理,从而快速提取车牌照的方法。该方法的主要思想是通过选取合适的彩色空间将输入的彩色图像直接转换为二值图像,再用空问聚类技术进行滤波消噪,最后利用二值图像的水平垂直投影来分割提取车牌区域。     

Color recovery of black-and-white halftoned images via categorized color-embedding look-up tables

A new method of recovering the original colors of black-and-white (B&W) halftoned images with homogeneous dot patterns is proposed. The conventional inverse halftoning method, which uses a look-up table (LUT), can establish the relation between the halftoned patterns and the corresponding gray levels, while the conventional reversible color to gray conversion method can recover the original colors from a given color-embedded gray image. To accomplish our goal of original color recovery from B&W halftoned patterns, an approach of combining the conventional inverse halftoning and reversible color to gray conversion is presented in this paper. Differently from the conventional method of inverse halftoning via LUT, four LUTs categorized according to the red, green, blue, and gray reference colors are designed to more accurately map a specific B&W halftone pattern into the corresponding color-embedded gray level based on the observation that the shapes of the halftone patterns depend on input colors, thereby increasing the color recovery accuracy. Also, a color mapping method based on a linear regression which models the relation between the recovered colors and the original colors is introduced to adjust the initially recovered colors more closely to the original colors. Experimental results show that unknown original colors can be recovered from B&W halftoned images via the proposed method.