一种无须预指定分割区域数的自适应多阈值图像分割方法

为解决多阈值图像分割中分割区域数较难确定的问题,提出一种基于可逆跳跃马尔可夫链蒙特卡罗(RJMCMC)的自适应多阈值图像分割方法.基于图像直方图的多阈值分割的本质是寻找直方图各峰间的谷底,但其个数较难确定且各局部峰并非都是高斯分布.因此文中用更具普适性的混合α稳定分布拟合直方图,建立包含局部峰个数及各分布元参数的分层贝叶斯概率模型.采用RJMCMC后验概率推理自适应确定混合α稳定分布的分布元个数及各自参数,从而获得分割区域数和多阈值参数.针对单晶炉拉晶图像、人脑核磁共振图像及国际标准测试图进行测试,结果表明该方法准确地建立图像分割模型,得到满意的多阈值分割结果.     

在分布式虚拟现实的环境中数据传输的研究

分布式虚拟现实技术可以在分布式环境下满足多人实时参与虚拟环境的要求．较好地实现了信息的交互、文中从分布式虚拟现实的特征、网络模型以及数据的传输进行了分析和讨论，减少网络通讯负载一直是分布式虚拟现实致力解决的问题，本文基于分布式虚拟环境介绍了兴趣管理技术，并提出了多阈值DR技术的思想。多阈值DR技术为解决大规模分布式虚拟环境的通讯负载提供了新的思路。     

多阈值和标记分水岭相融合的肺部CT图像分割方法

针对肺部CT图像因各组织灰度不均匀、结构复杂等因素造成双肺边界难以准确分割的问题,提出了一种多阈值和标记分水岭相融合的肺部分割方法。首先采用多阈值法对肺部CT图像进行粗分割,并去除图像中气管与主支气管;然后采用标记控制分水岭方法进行精分割,并利用形态学运算对肺实质边缘修补,最后采用临床肺CT图像在Matlab 2012平台上对算法性能进行仿真测试。结果表明,本文方法可以较好保留肺部CT图像的边界信息,提高了肺部CT图像分割精度,误分和错分概率大幅度下降,取得了十分理想的分割结果,为肺部疾病临床医学诊断提供了有价值的参考信息。     

基于灰度直方图拟合曲线的数字图像多阈值分割技术研究

在数字图像处理中,图像分割技术能够对待处理部分进行分割处理,以突出显示所要研究的目标对象.在对数字图像灰度直方图进行高次样条函数曲线拟合之后,通过求取若干个局部最小值作为图像的分割阈值,对图像像素进行多阈值分割,最后采用区域背景像素点增长合并法进行背景区域合并,从而获得完整清晰反映图像各个组成部分的分割结果.实验结果证明,此方法能准确表达图像各个灰度组成部分,克服了传统单阈值分割所带来的缺陷与不足.     

改进的混合蛙跳算法及其在多阈值图像分割中的应用

针对混合蛙跳算法(Shuffled Frog Leaping Algorithm,SFLA)存在的计算复杂度高、优化效率不理想等问题,提出了一种改进的混合蛙跳算法(Improved Shuffled Frog Leaping Algorithm,ISFLA)。在原始 SFLA的基础上进行如下改进:首先,将其中每次只更新组内最差青蛙的方式改为更新组内所有青蛙的方式,这既增大了获得优质解的概率,又省去了调整组内迭代次数的步骤,从而提升了优化效率和可操作性;其次,将基于局部最优更新的方法和基于全局最优更新的方法融合为一种混合扰动更新方法,从而避免了复杂条件的选择步骤,进一步提升了优化效率;最后,去掉随机更新方式,以免优质解被破坏,从而提高了整体的优化性能。将 ISFLA 用于 CEC2005和CEC2015连续基准函数的优化测试和基于Renyi 熵的灰度和彩色图像分割的多阈值选择实验中,结果表明,与 SFLA 和state-of-the-art的LSFLA 相比,ISFLA 具有更高的优化效率,更适用于多阈值图像分割的阈值选择。     

Introduction of a new technique for simultaneous reduction of the delay and leakage current in digital circuits

By the reduction in the size of transistors and the development of submicron technology, as well as the construction of more integrated circuits on chips, leakage power has become one of the main concerns of electronic circuit designers. In this article, we first review techniques presented in recent years to reduce leakage power and then present a new technique based on the gate-level body biasing technique and the multi-threshold CMOS technique to minimize leakage power in digital circuits. Afterward, we develop another new method by improving the first proposed technique to achieve higher efficiency and simultaneously reduce leakage power and propagation delay in digital circuits. In the proposed technique, we use two dynamic threshold MOSFET transistors to reduce leakage current. In this paper, the body biasing generator structure is applied to reduce propagation delay. The proposed technique has been successfully validated and verified by post-layout simulation with Cadence Virtuoso based on the 32 nm process technology.We evaluate the efficiency of the proposed techniques by examining factors including power, delay, area, and the power delay product. The simulation results using HSPICE software and performance analysis to process corner variations based on the 32 nm process technology show that the proposed technique, in addition to having proper performance in different corners of the technology, significantly reduces leakage power and propagation delay in logic CMOS circuits. In general, the proposed technique has a very successful performance compared to previous techniques.     

多门限随机早期丢弃及仿真研究

CIOQ交换结构通常在输入端口侧采用基于VOQ结构的输入排队,为了实现VOQ队列报文的优先级区分丢弃,文章在实验的基础上给出了一种支持DiffServ结构中QoS的多门限随机早期丢弃（MTRED）队列管理机制。并通过大规模业务流量下的仿真对不同丢包门限的设置进行了深入的研究,最后给出了相关结论。     

带噪图像的多阈值零树编码方法

零树编码利用一固定量化阈值对系数进行扫描,而多阈值零树编码将小波分解后各子带的最大系数作为该子带的扫描阈值,将扫描阈值大于量化阈值的子带作为重要子带,反之作为次要子带。只在重要子带中判断其是否存在重要系数。针对含有高斯白噪声的图像,引入混合降噪模型对各子带的扫描阈值进行修正,有效地提高了编码图像质量和编码效率。     

Low-power multi-threshold MCML: Analysis, design, and variability

The increasing demand on low-power applications is adding pressure on circuit designers to come out with new circuit styles that can decrease power dissipation while making use of the performance improvement of the new CMOS technologies. Multi-threshold MOS current mode logic (MTMCML) appears to be a solution to this problem by making use of the high-performance of MOS current mode circuits while minimizing power dissipation with the help of multi-threshold CMOS technologies. In this work, analytical formulations, based on the BSIM3v3 model, are proposed for MTMCML performance measures with an error within 10% compared to HSPICE. The formulation helps designers to efficiently design MTMCML circuits without undergoing the time-consuming HSPICE simulations. Furthermore, it provides design guidelines and aids for designers to fully understand the different tradeoffs in MTMCML design. In addition, the analysis is extended to study the impact of technology scaling and parameter variations on MTMCML. It is shown that the worst case variation in the minimum supply voltage of MTMCML is 1.16%, thus suggesting maximal power saving.     

改进布鸟搜索算法最大熵值的医学图像分割

研究医学图像分割问题.医学图像是医学影像的分析基础,医学图像由于组织边缘模糊和灰度不均匀含噪声等特点,导致最大熵值分割医学图像算法难以进行准确分割,分割精度低,为了提高医学图像分割的准确性,提出一种改进布鸟搜索算法优化最大熵值的医学图像分割方法.首先由最大熵法找到医学图像分割目标函数,然后采用改进布谷鸟搜索算法对目标函数进行优化,找到医学图像的最佳分割点,实现医学图像分割,最后采用多幅医学图像进行仿真,以测试算法性能.结果表明,改进方法不仅解决了传统最大熵值医学图像分割算法存在的缺陷,同时提高医学图像分割的精度,并且具有较好的鲁棒性,具有较好的实际应用价值.