共查询到20条相似文献，搜索用时 15 毫秒
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手背静脉图像的采集过程中,由于图像采集设备、光照、皮下脂肪厚度等因素的影响,手背静脉图像的对比度比较低,同时图像噪声严重影响静脉提取。针对此问题,本文提出了一种基于静脉灰度值特征的图像分割与对比度增强算法。首先提取ROI(有效的感兴趣区域)和对ROI进行维纳滤波;然后采用新的图像分割算法对静脉图像进行静脉提取,利用8-邻接内边界跟踪方法和形态学处理方法对静脉二值图像进行去噪;最后将ROI与去噪后的图像进行加权叠加得到对比度增强的静脉图像。实验结果表明,通过采用基于静脉灰度值特征的图像分割算法可以很好地获取到静脉脉络,最终可以获得高对比度的静脉图像。 相似文献
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为了解决CT图像主动轮廓分割方法对初始轮廓的敏感和分割不准确的问题,本文提出一种融合加权随机森林的自动3D椎骨CT主动轮廓分割方法WRF-AC。该方法提出加权随机森林算法和包含边缘能量的主动轮廓能量函数。首先,通过提取椎骨CT的3D Haar-like特征值训练加权随机森林获得的椎骨中心作为分割的初始轮廓,然后,求解包含边缘能量的主动轮廓能量函数最小值完成椎骨CT图像的分割。实验结果表明,本方法在相同数据集上能够更加准确、快速地分割脊柱CT图像提取椎骨部分。 相似文献
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This article proposes a new topology optimization method for the design of structures under multiple loading cases. The design is formulated as a multi-objective optimization problem by minimizing a new compliance–volume product, which optimizes the overall stiffness and volume simultaneously to avoid the empirical decision on design constraints and obtain an even lower structural volume. A normalized exponential weighted criterion (NEWC) method is included in the multi-objective optimization problem for the capture of the entire Pareto frontier. A weight evaluation method, in terms of the fuzzy multiple-attribute group decision-making (FMAGDM) theory, is incorporated in the problem to evaluate the weights of the objectives and guarantee the optimal design in an acceptable level. The solid isotropic material with penalty (SIMP) method is used to represent the dependence of elemental densities on material properties. Three typical numerical examples are employed to show the effectiveness of the proposed method. 相似文献
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Abstract This paper combines previously developed techniques for image‐preprocessing and characteristic image‐interpreting together with a newly proposed automated shape‐optimization modeling technique into an integrated topology‐optimization and shape‐optimization system. As a result, structure designers are provided with an efficient and reliable automated structural optimization system (ASOS). The automated shape‐optimization modeling technique, the key technique in ASOS, uses hole‐expanding strategy, interference analysis, and hole shape‐adjusting strategy to automatically define the design variables and side constraints needed for shape optimization. This technique not only eliminates the need to manually define design variables and side constraints for shape optimization, but during the process of shape optimization also prevents interference between the interior holes and the exterior boundary. The ASOS is tested in three different structural configuration design examples. 相似文献
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K-均值聚类具有简单、快速的特点,因此被广泛应用于图像分割领域.但K-均值聚类容易陷入局部最优,影响图像分割效果.针对K-均值的缺点,提出一种基于随机权重粒子群优化（RWPSO）和K-均值聚类的图像分割算法RWPSOK.在算法运行初期,利用随机权重粒子群优化的全局搜索能力,避免算法陷入局部最优;在算法运行后期,利用K-均值聚类的局部搜索能力,实现算法快速收敛.实验表明：RWPSOK算法能有效地克服K-均值聚类易陷入局部最优的缺点,图像分割效果得到了明显改善;与传统粒子群与K-均值聚类混合算法（PSOK）相比,RWPSOK算法具有更好的分割效果和更高的分割效率. 相似文献
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V. V. Fomin A. P. Mikhailovich A. S. Popov N. F. Nizametdinov Yu. V. Shalaumova 《Measurement Techniques》2008,51(2):146-151
A universal approach to the detection of drawbacks in techniques used to perform measurements based on the use of systems for automatic image analysis is considered. A regression model that makes it possible to estimate the contribution of errors characterizing the photography conditions and camera setting adjustment is constructed. The accuracy indicators (correctness and precision indicators) are estimated in accordance with an existing standard. __________ Translated from Izmeritel’naya Tekhnika, No. 2, pp. 25–28, February, 2008. 相似文献
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Solar power has become an attractive alternative source of energy. The multi-crystalline solar cell has been widely accepted in the market because it has a relatively low manufacturing cost. Multi-crystalline solar wafers with larger grain sizes and fewer grain boundaries are higher quality and convert energy more efficiently than mono-crystalline solar cells. In this article, a new image processing method is proposed for assessing the wafer quality. An adaptive segmentation algorithm based on region growing is developed to separate the closed regions of individual grains. Using the proposed method, the shape and size of each grain in the wafer image can be precisely evaluated. Two measures of average grain size are taken from the literature and modified to estimate the average grain size. The resulting average grain size estimate dictates the quality of the crystalline solar wafers and can be considered a viable quantitative indicator of conversion efficiency. 相似文献
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本文针对《深化标准化改革方案》和《中华人民共和国标准化法(修订草案)》中对团体标准制定主体范围的不同规定,分析了国际上对标准制定主体的一般要求;结合《民法总则》中对民事责任主体的要求,指出我国团体标准的制定主体也应是法人;研究了民政部对社会组织管理的要求,对国内外联盟法律地位进行了分析,指出除了社会团体外,基金会和民办非企业也都具有法人地位,也应该纳入团体标准制定主体的范畴. 相似文献
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为了提高在前景和背景颜色相似情况下图像的分割效果,提出了一种基于模糊C均值聚类(FCM)和图割的交互式图像分割方法。首先,利用分水岭算法对图像进行预处理,将图像分成多个小区域,用区域代替像素点进行分析。然后,采用模糊C均值算法对用户标记的前景区域和背景区域分别进行聚类分析,挖掘用户交互所提供的隐藏信息。用未标记区域的颜色分量到前景区域及背景区域类心的最小距离表示相似能量,用未标记区域与其相邻区域的相关性表示先验能量。最后,利用最大流/最小割算法求能量函数的全局最优解。与其他方法相比,该文方法具有较好的分割性能,能从前景背景相似的图像中较精确地提取感兴趣的物体,且用户操作简单。 相似文献
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Fereshteh Yousefi Rizi Alireza Ahmadian Nader Rezaie Seyed Amir Iranmanesh 《International journal of imaging systems and technology》2013,23(1):71-84
Human airway tree segmentation from computed tomography (CT) images is a very important step for virtual bronchoscopic applications. Imaging artifacts or thin airway walls decrease the contrast between the air and airway wall and make the segmented region to leak from inside of the airway to the parenchyma. This in turn begins the leakage phenomenon to build and then large parts of the lung parenchyma might be erroneously marked as the airway tree instead. Unfortunately, existing methods typically do not sufficiently extract the necessary peripheral airways needed to plan a procedure. In this article, we propose a new shape based human airway segmentation scheme to suppress the leakage into surrounding area which is based on fuzzy connectivity (FC) method. Complex medical image features such as weak boundary edges in the CT images of the lung parenchyma have fuzzy properties and can be described by FC in many extents. Our method aims to embed a mathematical shape optimization approach in a FC algorithm. Using the partial derivatives of the image data that is minimized with respect to the polar angle and cylindrical axis direction, a proper cost function based on cylindrical features of the airway branches is proposed. This approach retains the cylindrical properties of the airway branches during the segmentation process. The proposed cost function includes two parts named cylindrical‐shape feature and smoothed final error term. The former term arranges the underlying voxels on a cylindrical shape and the latter term controls and smoothes the final error considering the local minima's problem. To evaluate the efficiency of our proposed optimization technique in term of segmentation accuracy, the cost function is first applied to the simulated data with the spongy shape of leakage and the leakage origin. The impact of each term of the proposed cost function on the final error and the convergence of the algorithm are also evaluated. Then, the cost function with best proper parameters is applied to real image dataset. Comparisons of the results on multidetector CT chest scans show that our segmentation algorithm outperforms the fuzzy region growing algorithm. Quantitative comparisons with manually segmented airway trees also indicate high sensitivity of our segmentation algorithm on peripheral airways. On the basis of the results, it is concluded that the proposed method is able to detect more branches up to the sixth generation with no leakage which provides 2–3 more generations of airways than several other methods do. The extracted airway trees enable image‐guided bronchoscopy to go deeper into the human lung periphery than past studies. The novelty of our proposed method is to apply a shape optimization approach embedded in an efficient FC segmentation algorithm. Hence, our method prevents leakage from its origination in contrast to most previously published works that just set their algorithms to repeat the segmentation steps to reduce leakage. As our results indicate leakage suppression in human airway segmentation instead of readjusting the segmentation parameters, more airway branches can be extracted with correct shape. © 2013 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 23, 71–84, 2013 相似文献
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对于稀疏角度下的投影数据,计算机断层扫描在图像重建中容易出现伪影和噪声较多的问题,难以满足工业及医学诊断要求。本文提出一种基于重叠组稀疏和超拉普拉斯先验的稀疏角度CT迭代图像重建算法。其中重叠组稀疏反映图像梯度稀疏性,从图像梯度的角度考虑相邻元素之间互相重叠交叉的关系。而超拉普拉斯先验能够精确地近似图像梯度的重尾分布,能够使得重建图像整体的质量提升。本文提出的算法模型采用交替方向乘子法,主分量最小化法和梯度下降法求解目标函数。实验结果表明,在稀疏角度CT重建的条件下,本文提出的算法在保留结构细节、抑制图像重建过程中产生的噪声和阶梯伪影方面有着一定的改善。 相似文献
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Doaa Sami Khafaga Amel Ali Alhussan El-Sayed M. El-kenawy Ali E. Takieldeen Tarek M. Hassan Ehab A. Hegazy Elsayed Abdel Fattah Eid Abdelhameed Ibrahim Abdelaziz A. Abdelhamid 《计算机、材料和连续体（英文）》2022,73(1):749-765
One of the most common kinds of cancer is breast cancer. The early detection of it may help lower its overall rates of mortality. In this paper, we robustly propose a novel approach for detecting and classifying breast cancer regions in thermal images. The proposed approach starts with data preprocessing the input images and segmenting the significant regions of interest. In addition, to properly train the machine learning models, data augmentation is applied to increase the number of segmented regions using various scaling ratios. On the other hand, to extract the relevant features from the breast cancer cases, a set of deep neural networks (VGGNet, ResNet-50, AlexNet, and GoogLeNet) are employed. The resulting set of features is processed using the binary dipper throated algorithm to select the most effective features that can realize high classification accuracy. The selected features are used to train a neural network to finally classify the thermal images of breast cancer. To achieve accurate classification, the parameters of the employed neural network are optimized using the continuous dipper throated optimization algorithm. Experimental results show the effectiveness of the proposed approach in classifying the breast cancer cases when compared to other recent approaches in the literature. Moreover, several experiments were conducted to compare the performance of the proposed approach with the other approaches. The results of these experiments emphasized the superiority of the proposed approach. 相似文献
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探究了拓扑优化设计方法在水下耐压结构设计中的应用。与固定载荷作用下结构的优化设计相比,此类问题需要正确地确定压力作用面。在拓扑优化过程中,利用变密度法得到的中间结构拓扑实际上可以看成是灰度图。基于此,提出了基于图像分割技术的压力加载面搜索方法,并利用距离正规化水平集方法(DRLSE)检测图像边界。利用数值算例验证了方法的有效性,并研究了静水压力作用下结构的拓扑优化设计问题。在给定材料约束的前提下,研究了不同边界条件下耐压壳体的最小柔顺度及最优结构拓扑形式。优化结果说明了该方法在多球交接耐压壳结构形式优化设计及复杂边界条件下耐压结构新形式探索中的工程应用价值。 相似文献
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Assessing the age of an individual via bones serves as a fool proof method in true determination of individual skills. Several attempts are reported in the past for assessment of chronological age of an individual based on variety of discriminative features found in wrist radiograph images. The permutation and combination of these features realized satisfactory accuracies for a set of limited groups. In this paper, assessment of gender for individuals of chronological age between 1-17 years is performed using left hand wrist radiograph images. A fully automated approach is proposed for removal of noise persisted due to non-uniform illumination during the process of radiograph acquisition process. Subsequent to this a computational technique for extraction of wrist region is proposed using operations on specific bit planes of image. A framework called GeNet of deep convolutional neural network is applied for classification of extracted wrist regions into male and female. The experimentations are conducted on the datasets of Radiological Society of North America (RSNA) of about 12442 images. Efficiency of preprocessing and segmentation techniques resulted into a correlation of about 99.09%. Performance of GeNet is evaluated on the extracted wrist regions resulting into an accuracy of 82.18%. 相似文献
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Tsuyoshi Nomura Ercan M. Dede Jaewook Lee Shintaro Yamasaki Tadayoshi Matsumori Atsushi Kawamoto Noboru Kikuchi 《International journal for numerical methods in engineering》2015,101(8):571-605
A general topology optimization method, which is capable of simultaneous design of density and orientation of anisotropic material, is proposed by introducing orientation design variables in addition to the density design variable. In this work, the Cartesian components of the orientation vector are utilized as the orientation design variables. The proposed method supports continuous orientation design, which is out of the scope of discrete material optimization approaches, as well as design using discrete angle sets. The advantage of this approach is that vector element representation is less likely to fail into local optima because it depends less on designs of former steps, especially compared with using the angle as a design variable (Continuous Fiber Angle Optimization) by providing a flexible path from one angle to another with relaxation of orientation design space. An additional advantage is that it is compatible with various projection or filtering methods such as sensitivity filters and density filters because it is free from unphysical bound or discontinuity such as the one at θ = 2π and θ = 0 seen with direct angle representation. One complication of Cartesian component representation is the point‐wise quadratic bound of the design variables; that is, each pair of element values has to reside in a given circular bound. To overcome this issue, we propose an isoparametric projection method, which transforms box bounds into circular bounds by a coordinate transformation with isoparametric shape functions without having the singular point that is seen at the origin with polar coordinate representation. A new topology optimization method is built by taking advantage of the aforementioned features and modern topology optimization techniques. Several numerical examples are provided to demonstrate its capability. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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成组技术(Group Technology,GT),作为一种优化技术,主要应用于生产制造业,用于零件的加工制造．作为一种思想方法与手段,本文尝试将其引入物流领域。对入库物料进行分类编码,并对仓库系统进行规划与管理。 相似文献
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Fangming Bi Xuanyi Fu Wei Chen Weidong Fang Xuzhi Miao Biruk Assefa 《计算机、材料和连续体（英文）》2020,62(1):199-216
Aiming at the defects of the traditional fire detection methods, which arecaused by false positives and false negatives in large space buildings, a fire identificationdetection method based on video images is proposed. The algorithm first uses the hybridGaussian background modeling method and the RGB color model to perform fireprejudgment on the video image, which can eliminate most non-fire interferences.Secondly, the traditional regional growth algorithm is improved and the fire imagesegmentation effect is effectively improved. Then, based on the segmented image, thedynamic and static features of the fire flame are further analyzed and extracted in the areaof the suspected fire flame. Finally, the dynamic features of the extracted fire flameimages were fused and classified by improved fruit fly optimization support vectormachine, and the recognition results were obtained. The video-based fire detectionmethod proposed in this paper greatly improves the accuracy of fire detection and issuitable for fire detection and identification in large space scenarios. 相似文献