基于分层遗传算法的双阈值图像分割

图像分割是图像处理中的重要问题,通常的图像分割法包括阈值法、边缘检测法、区域跟踪法等.其中,阈值法是一种通用的方法.本文将分层遗传算法用于阈值的选取,仿真结果表明,在设定了合适的遗传算子后,该算法可以实现正确的图像分割,将分层遗传算法用于图像处理中,是非常有效的.     

VLSI design and implementation of a real-time image segmentation processor

Image segmentation is a crucial part of machine vision applications. In this paper a system to perform real-time segmentation of images is presented. It uses a real-time segmentation VLSI chip that is based on a gradient relaxation algorithm and is designed using the Path Programmable Logic design methodology developed at the University of Utah. The system design considerations, system specifications, and an input/output format for the chip are discussed. The actual design of the chip is given that uses pipeline methodology to achieve real-time performance with a compact VLSI layout. The implementation of the segmentation system is presented and the segmentation chip and the overall system are evaluated with regard to real-time performance and segmentation results.This work was supported in part by Grant ISI-856-0393 from the National Science Foundation.     

基于小波变换和尺度共生矩阵的超声图像分割

超声图像所固有的特性使得图像分割比较困难,尤其是应用计算机实现超声图像的自动分割技术远不能达到实际需要,因此,超声图像的分割是亟待解决的一个难题.文中将图像树型框架小波变换、尺度共生矩阵和自组织神经网络聚类相结合应用于超声图像提出一种分割方法.实验表明,应用所提出的方法可得到比较清晰的分割结果,显著提高分割图像的对比度.     

Segment-based coding of color images

Based on the idea of second generation image coding, a novel scheme for coding still images is presented. At first, an image was partitioned with a pulse-coupled neural network; and then an improved chain code and the 2D discrete cosine transform was adopted to encode the shape and the color of its edges respectively. To code its smooth and texture regions, an improved zero-trees strategy based on the 2nd generation wavelet was chosen. After that, the zero-tree chart was selected to rearrange quantified coefficients. And finally some regulations were given according to psychology of various users. Experiments under noiseless channels demonstrate that the proposed method performs better than those of the current one, such as JPEG, CMP, EZW and JPEG2000. Supported by the Senior University Technology Innovation Essential Project Cultivation Fund Project (Grant No. 706028) and the Natural Science Fund of Jiangsu Province (Grant No. BK2007103)     

一个高效的模糊分裂聚类算法FSC

本文首先给出作者提出的模糊分割的形式定义.在此基础上我们对模糊 c-means 算法进行了修正,提出了模糊分裂一聚类算法:FSC.这个算法能自动确定聚类数目 c;与模糊 c-means 算法相比,FSC 算法还大大地提高了运算速度.我们认为 FSC 算法具有极大的实用价值.     

国与家之间：论上海里弄街区日常生活空间的断裂与统一

以当代城市普遍涌现的社会隔离现象为切入点,引出上海里弄街区中出现的毗邻隔离问题,并以此展开毗邻隔离与居住混合辩证关系的论述。指出,物理空间的接近并不能带来社会层面的混合。在对历史向度的里弄变迁进行梳理之后,选取虹口港里弄街区的日常生活空间作为研究对象。通过对社区认知边界的测定和生活空间利用模式的分析,对里弄街区中有关"三个世界"的日常生活空间异化与毗邻隔离展开讨论。最后,在明确日常生活空间社会意义的基础上,从国与家两个维度对社区融合视角下的日常生活空间组织做出总结。认为基于物质层面的日常生活空间维系,与社会层面的社区参与和居民赋权,是当前语境下上海里弄街区修补毗邻隔离问题,实现公共空间统一的必由之路。     

结合先验稀疏字典和空洞填充的CT图像肝脏分割

针对复杂多变的肝脏图像,提出了一种基于先验稀疏字典和空洞填充的三维肝脏图像分割方法。对腹部CT图像进行Gabor特征提取,并分别在Gabor图像和灰度图像的肝脏金标准边界上选择大小相同的图像块作为两组训练集,利用训练集得到两种查询字典及稀疏编码。将金标准图像与待分割图像配准,并将配准后的肝脏边界作为待分割图像的肝脏初始边界;在初始边界点上的十邻域内选择大小相同的两组图像块作为测试样本,利用测试样本与查询字典计算稀疏编码及重构误差,并选择重构误差最小的图像块的中心作为待分割肝脏的边界点;最后,设计一种空洞填充方法对肝脏边界进行补全和平滑处理,得到最终分割结果。利用医学图像计算和计算机辅助介入国际会议中提供的肝脏数据进行了实验验证。结果表明,该方法对肝脏分割图像具有较好的适用性和鲁棒性,并获得了较高的分割精度。其中,平均体积重叠率误差为(5.21±0.45)%,平均相对体积误差为(0.72±0.12)%,平均对称表面距离误差为(0.93±0.14)mm。     

三次透视投影变换图像拼接

为了减少带有路面信息的建筑物图像的拼接中产生的图像失真并提高拼接速度,基于局部变形方法并结合建筑物和路面纹理信息的不同提出了三次投影变换图像拼接方法。该方法根据图像内容将图像分割成不同子图像,然后拼接图像内容相同的子图像,最后实施总体拼接。为了改善当前全局投影变换带来的图像形状失真或扭曲问题,整个拼接过程采用三次局部的透视投影图像变换方法。由于是在传统的透视投影变换的基础上基于图像内容分割后再拼接,故拼接结果比传统方法更精确、更真实。实验结果表明:采用提出的图像拼接方法克服了路面部分纹理信息过少导致图像失真的缺陷,拼接速度比相关拼接方法提高了20%~40%。该方法能快速得到清晰无缝的拼接图像,基本满足拼接速度快、真实度高的要求。     

Review of free software tools for image analysis of fluorescence cell micrographs

An increasing number of free software tools have been made available for the evaluation of fluorescence cell micrographs. The main users are biologists and related life scientists with no or little knowledge of image processing. In this review, we give an overview of available tools and guidelines about which tools the users should use to segment fluorescence micrographs. We selected 15 free tools and divided them into stand‐alone, Matlab‐based, ImageJ‐based, free demo versions of commercial tools and data sharing tools. The review consists of two parts: First, we developed a criteria catalogue and rated the tools regarding structural requirements, functionality (flexibility, segmentation and image processing filters) and usability (documentation, data management, usability and visualization). Second, we performed an image processing case study with four representative fluorescence micrograph segmentation tasks with figure‐ground and cell separation. The tools display a wide range of functionality and usability. In the image processing case study, we were able to perform figure‐ground separation in all micrographs using mainly thresholding. Cell separation was not possible with most of the tools, because cell separation methods are provided only by a subset of the tools and are difficult to parametrize and to use. Most important is that the usability matches the functionality of a tool. To be usable, specialized tools with less functionality need to fulfill less usability criteria, whereas multipurpose tools need a well‐structured menu and intuitive graphical user interface.