期刊文献+
共找到359篇文章
< 1 2 18 >
每页显示 20 50 100
Robust Watermarking Algorithm for Medical Images Based on Non-Subsampled Shearlet Transform and Schur Decomposition
1
作者 Meng Yang Jingbing Li +2 位作者 Uzair Aslam Bhatti Chunyan Shao Yen-Wei Chen 《Computers, Materials & Continua》 SCIE EI 2023年第6期5539-5554,共16页
With the development of digitalization in healthcare,more and more information is delivered and stored in digital form,facilitating people’s lives significantly.In the meanwhile,privacy leakage and security issues co... With the development of digitalization in healthcare,more and more information is delivered and stored in digital form,facilitating people’s lives significantly.In the meanwhile,privacy leakage and security issues come along with it.Zero watermarking can solve this problem well.To protect the security of medical information and improve the algorithm’s robustness,this paper proposes a robust watermarking algorithm for medical images based on Non-Subsampled Shearlet Transform(NSST)and Schur decomposition.Firstly,the low-frequency subband image of the original medical image is obtained by NSST and chunked.Secondly,the Schur decomposition of low-frequency blocks to get stable values,extracting the maximum absolute value of the diagonal elements of the upper triangle matrix after the Schur decom-position of each low-frequency block and constructing the transition matrix from it.Then,the mean of the matrix is compared to each element’s value,creating a feature matrix by combining perceptual hashing,and selecting 32 bits as the feature sequence.Finally,the feature vector is exclusive OR(XOR)operated with the encrypted watermark information to get the zero watermark and complete registration with a third-party copyright certification center.Experimental data show that the Normalized Correlation(NC)values of watermarks extracted in random carrier medical images are above 0.5,with higher robustness than traditional algorithms,especially against geometric attacks and achieve watermark information invisibility without altering the carrier medical image. 展开更多
关键词 non-subsampled shearlet transform(NSST) Schur decomposition perceptual hashing chaotic mapping zero watermark
下载PDF
Digital watermarking algorithm based on scale-invariant feature regions in non-subsampled contourlet transform domain 被引量:8
2
作者 Jian Zhao Na Zhang +1 位作者 Jian Jia Huanwei Wang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第6期1310-1315,共6页
Contraposing the need of the robust digital watermark for the copyright protection field, a new digital watermarking algorithm in the non-subsampled contourlet transform (NSCT) domain is proposed. The largest energy... Contraposing the need of the robust digital watermark for the copyright protection field, a new digital watermarking algorithm in the non-subsampled contourlet transform (NSCT) domain is proposed. The largest energy sub-band after NSCT is selected to embed watermark. The watermark is embedded into scaleinvariant feature transform (SIFT) regions. During embedding, the initial region is divided into some cirque sub-regions with the same area, and each watermark bit is embedded into one sub-region. Extensive simulation results and comparisons show that the algorithm gets a good trade-off of invisibility, robustness and capacity, thus obtaining good quality of the image while being able to effectively resist common image processing, and geometric and combo attacks, and normalized similarity is almost all reached. 展开更多
关键词 multi-scale geometric analysis (MGA) non-subsampled contourlet transform (NSCT) scale-invariant featureregion.
下载PDF
Multimodal Medical Image Fusion in Non-Subsampled Contourlet Transform Domain 被引量:3
3
作者 Periyavattam Shanmugam Gomathi Bhuvanesh Kalaavathi 《Circuits and Systems》 2016年第8期1598-1610,共13页
Multimodal medical image fusion is a powerful tool for diagnosing diseases in medical field. The main objective is to capture the relevant information from input images into a single output image, which plays an impor... Multimodal medical image fusion is a powerful tool for diagnosing diseases in medical field. The main objective is to capture the relevant information from input images into a single output image, which plays an important role in clinical applications. In this paper, an image fusion technique for the fusion of multimodal medical images is proposed based on Non-Subsampled Contourlet Transform. The proposed technique uses the Non-Subsampled Contourlet Transform (NSCT) to decompose the images into lowpass and highpass subbands. The lowpass and highpass subbands are fused by using mean based and variance based fusion rules. The reconstructed image is obtained by taking Inverse Non-Subsampled Contourlet Transform (INSCT) on fused subbands. The experimental results on six pairs of medical images are compared in terms of entropy, mean, standard deviation, Q<sup>AB/F</sup> as performance parameters. It reveals that the proposed image fusion technique outperforms the existing image fusion techniques in terms of quantitative and qualitative outcomes of the images. The percentage improvement in entropy is 0% - 40%, mean is 3% - 42%, standard deviation is 1% - 42%, Q<sup>AB/F</sup>is 0.4% - 48% in proposed method comparing to conventional methods for six pairs of medical images. 展开更多
关键词 Image Fusion non-subsampled Contourlet transform (NSCT) Medical Imaging Fusion Rules
下载PDF
Deformation, Phase Transformation and Recrystallization in the Shear Bands Induced by High-Strain Rate Loading in Titanium and Its Alloys 被引量:16
4
作者 Yongbo XU Yilong BAI M.A.Meyers 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2006年第6期737-746,I0003,I0004,共12页
α-titanium and its alloys with a dual-phase structure (α+β) were deformed dynamically under strain rate of about 10^4 s^-1. The formation and microstructural evolution of the localized shear bands were character... α-titanium and its alloys with a dual-phase structure (α+β) were deformed dynamically under strain rate of about 10^4 s^-1. The formation and microstructural evolution of the localized shear bands were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results reveal that both the strain and strain rate should be considered simultaneously as the mechanical conditions for shear band formation, and twinning is an important mode of deformation. Both experimental and calculation show that the materials within the bands underwent a superhigh strain rate (9×10^5 S^-1) deformation, which is two magnitudes of that of average strain rate required for shear band formation; the dislocations in the bands can be constricted and developed into cell structures; the phase transformation from α to α2 within the bands was observed, and the transformation products (α2) had a certain crystallographic orientation relationship with their parent; the equiaxed grains with an average size of 10 μm in diameter observed within the bands are proposed to be the results of recrystallization. 展开更多
关键词 Localized shear bands Microstructure Dislocations TWINNING Phase transformation RECRYSTALLIZATION
下载PDF
Broad-band phase retrieval method for transient radial shearing interference using chirp Z transform technique
5
作者 Fang Xue Ya-Xuan Duan +3 位作者 Xiao-Yi Chen Ming Li Suo-Chao Yuan Zheng-Shang Da 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第8期398-406,共9页
The transient radial shearing interferometry technique based on fast Fourier transform(FFT)provides a means for the measurement of the wavefront phase of transient light field.However,which factors affect the spatial ... The transient radial shearing interferometry technique based on fast Fourier transform(FFT)provides a means for the measurement of the wavefront phase of transient light field.However,which factors affect the spatial bandwidth of the wavefront phase measurement of this technology and how to achieve high-precision measurement of the broad-band transient wavefront phase are problems that need to be studied further.To this end,a theoretical model of phase-retrieved bandwidth of radial shearing interferometry is established in this paper.The influence of the spatial carrier frequency and the calculation window on phase-retrieved bandwidth is analyzed,and the optimal carrier frequency and calculation window are obtained.On this basis,a broad-band transient radial shearing interference phase-retrieval method based on chirp Z transform(CZT)is proposed,and the corresponding algorithm is given.Through theoretical simulation,a known phase is used to generate the interferogram and it is retrieved by the traditional method and the proposed method respectively.The residual wavefront RMS of the traditional method is 0.146λ,and it is 0.037λfor the proposed method,which manifests an improvement of accuracy by an order of magnitude.At the same time,different levels of signal-to-noise ratios(SNRs)from 50 dB to 10 dB of the interferogram are simulated,and the RMS of the residual wavefront is from 0.040λto 0.066λ.In terms of experiments,an experimental verification device based on a phase-only spatial light modulator is built,and the known phase on the modulator is retrieved from the actual interferogram.The RMS of the residual wavefront retrieved through FFT is 0.112λ,and it decreases to 0.035λthrough CZT.The experimental results verify the effectiveness of the method proposed in this paper.Furthermore,the method can be used in other types of spatial carrier frequency interference,such as lateral shearing interference,rotational shearing interference,flipping shearing interference,and four-wave shearing interference. 展开更多
关键词 radial shearing interference chirp Z transform(CZT) phase retrieval
下载PDF
Skin Lesion Classification System Using Shearlets
6
作者 S.Mohan Kumar T.Kumanan 《Computer Systems Science & Engineering》 SCIE EI 2023年第1期833-844,共12页
The main cause of skin cancer is the ultraviolet radiation of the sun.It spreads quickly to other body parts.Thus,early diagnosis is required to decrease the mortality rate due to skin cancer.In this study,an automati... The main cause of skin cancer is the ultraviolet radiation of the sun.It spreads quickly to other body parts.Thus,early diagnosis is required to decrease the mortality rate due to skin cancer.In this study,an automatic system for Skin Lesion Classification(SLC)using Non-Subsampled Shearlet Transform(NSST)based energy features and Support Vector Machine(SVM)classifier is proposed.Atfirst,the NSST is used for the decomposition of input skin lesion images with different directions like 2,4,8 and 16.From the NSST’s sub-bands,energy fea-tures are extracted and stored in the feature database for training.SVM classifier is used for the classification of skin lesion images.The dermoscopic skin images are obtained from PH^(2) database which comprises of 200 dermoscopic color images with melanocytic lesions.The performances of the SLC system are evaluated using the confusion matrix and Receiver Operating Characteristic(ROC)curves.The SLC system achieves 96%classification accuracy using NSST’s energy fea-tures obtained from 3^(rd) level with 8-directions. 展开更多
关键词 Skin lesion classification non-subsampled shearlet transform sub-band coefficients energy feature support vector machine
下载PDF
Phenomenon of transformed adiabatic shear band surrounded by deformed adiabatic shear band of ductile metal
7
作者 王学滨 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第5期1177-1183,共7页
The coexistent phenomenon of deformed and transformed adiabatic shear bands(ASBs) of ductile metal was analyzed using the JOHNSON-COOK model and gradient-dependent plasticity(GDP).The effects of melting point,density,... The coexistent phenomenon of deformed and transformed adiabatic shear bands(ASBs) of ductile metal was analyzed using the JOHNSON-COOK model and gradient-dependent plasticity(GDP).The effects of melting point,density,heat capacity and work to heat conversion factor were investigated.Higher work to heat conversion factor,lower density,lower heat capacity and higher melting point lead to wider transformed ASB and higher local plastic shear deformation between deformed and transformed ASBs.Higher work to heat conversion factor,lower density,lower heat capacity and lower melting point cause higher local plastic shear deformation in the deformed ASB.Three reasons for the scatter in experimental data on the ASB width were pointed out and the advantages of the work were discussed.If the transformed ASB width is used to back-calculate the internal length parameter in the GDP,undoubtedly,the parameter will be extremely underestimated. 展开更多
关键词 隔热剪切带 韧性金属 变形度 JOHNSON-COOK模式 可塑性
下载PDF
基于NSST域像素相关性分析的融合算法在医学图像中的评估
8
作者 肖明尧 《长春师范大学学报》 2024年第10期44-48,共5页
多尺度变换对医学图像融合有较好的效果。针对MRI与CT、SPECT、PET的脑部图像融合,采用基于非下采样剪切波变换(NSST)域像素相关性分析(PCAS)的图像融合算法进行评估,体现出较好的稳定性和鲁棒性。
关键词 多尺度变换 非下采样剪切波变换 图像融合
下载PDF
爆炸加载TC4 ELI钛合金微损伤研究
9
作者 宋雨宸 王琳 +4 位作者 赵登辉 吴江 范丽静 张宇轩 程焕武 《兵器材料科学与工程》 CAS CSCD 北大核心 2024年第6期26-31,共6页
用TNT炸药空中爆炸加载等轴组织TC4 ELI钛合金板材,研究爆炸药量及距靶板中心距离对钛合金显微组织演化的影响,测试了爆炸加载后材料的力学性能。结果表明:爆炸加载后TC4 ELI钛合金显微组织内产生了大量形变带,形变带宽度为10~120μm;... 用TNT炸药空中爆炸加载等轴组织TC4 ELI钛合金板材,研究爆炸药量及距靶板中心距离对钛合金显微组织演化的影响,测试了爆炸加载后材料的力学性能。结果表明:爆炸加载后TC4 ELI钛合金显微组织内产生了大量形变带,形变带宽度为10~120μm;随着爆炸药量从200 g提高到300 g,形变带的数量及总宽度增加,形变带边界更加清晰;随着距靶板中心距离的增加,形变带数量不变,宽度增加。对爆炸加载回收靶板采用分离式霍普金森压杆(SHPB)进行动态压缩再加载试验,随药量和距靶板中心距离的增加,钛合金静动态抗压强度与断裂应变增加。动态再加载后产生了绝热剪切转变带,形变带对转变带的萌生及扩展过程影响较小。 展开更多
关键词 TC4 ELI钛合金 爆炸加载 再加载力学性能 绝热剪切形变带 绝热剪切转变带
下载PDF
一个新的基于3D纹理映射及Shear-warp变换的快速体绘制方法 被引量:3
10
作者 陈寅秋 董金祥 王晓梅 《计算机工程》 CAS CSCD 北大核心 1998年第8期14-15,67,共3页
介绍了一个新的基于纹理映射及Shear-warp变换的快速体绘制方法。所提出的方法吸收了纹理映射方法的长处,通过纹理硬件的加速,并在纹理装载时提出了可适应性的纹理分割方法,使该算法不受纹理内存的限制。在进行纹理映射时,通过剪切... 介绍了一个新的基于纹理映射及Shear-warp变换的快速体绘制方法。所提出的方法吸收了纹理映射方法的长处,通过纹理硬件的加速,并在纹理装载时提出了可适应性的纹理分割方法,使该算法不受纹理内存的限制。在进行纹理映射时,通过剪切(Shear)变换和三维图象的分割,加快给制速度。与多种经典的快速体绘制方法进行测试比较,该方法达到了交互的效果和更高的绘制速度。 展开更多
关键词 体绘制 纹理映射 shear-warp变换 计算机图形学
下载PDF
初级纤毛/鞭毛转运系统介导力学反应性信号通路促骨髓基质干细胞成骨分化
11
作者 马占华 严旭 +7 位作者 姜岩 曹争明 王永魁 李东哲 杨腾越 靳宜楷 付苏 张春霖 《中国组织工程研究》 CAS 北大核心 2024年第25期3937-3941,共5页
背景:目前已证实力学刺激可以促进骨髓基质干细胞成骨分化,但其机制未完全明了。初级纤毛是重要的力学感受器并调控TGF-β1/BMP-2/SMAD等多种信号通路,很可能是骨髓基质干细胞力学调控的重要靶点。目的:探讨流体剪切力对骨髓基质干细胞... 背景:目前已证实力学刺激可以促进骨髓基质干细胞成骨分化,但其机制未完全明了。初级纤毛是重要的力学感受器并调控TGF-β1/BMP-2/SMAD等多种信号通路,很可能是骨髓基质干细胞力学调控的重要靶点。目的:探讨流体剪切力对骨髓基质干细胞成骨分化的影响及机制。方法:将大鼠骨髓基质干细胞分为对照组、力学刺激组(通过摇床施加流体剪切力学干预)、力学刺激+IFT88沉默组(力学刺激+使用siRNA沉默IFT88表达),干预24 h后,采用qRT-PCR检测转化生长因子β1、骨形成蛋白2的表达、Western blot检测磷酸化SMAD2/3蛋白的表达,初级纤毛免疫荧光染色及形态学分析。结果与结论:剪切力刺激可促进骨髓基质干细胞的初级纤毛表达,转化生长因子β1及骨形成蛋白2基因转录激活,提高磷酸化SMAD2/3蛋白表达。siRNA干扰初级纤毛生成后,这一力学反应效应明显减低。骨髓基质干细胞的初级纤毛面积改变比值与转化生长因子β1及骨形成蛋白2基因转录增高比例具有Spearman相关性。结果表明:初级纤毛/鞭毛转运系统介导了流体剪切力反应性的TGF-β1/BMP-2/SMAD信号通路激活,促进骨髓基质干细胞成骨分化。 展开更多
关键词 骨髓基质干细胞 转化生长因子β1 骨形成蛋白2 初级纤毛 鞭毛转运系统 剪切力学刺激
下载PDF
长周期地震动对SRC框架-RC核心筒混合结构协同工作的影响
12
作者 杨柯 王博 +2 位作者 祝超 刘伯权 李红 《振动与冲击》 EI CSCD 北大核心 2024年第12期36-45,共10页
长周期地震动因含有丰富的低频成分易使(超)高层建筑等长周期结构发生严重震害。SRC(steel reinforced concrete)框架-RC(reinforced concrete)核心筒混合结构作为广泛应用于高烈度区的双重抗侧力结构体系,确保其强震下的协同工作是实... 长周期地震动因含有丰富的低频成分易使(超)高层建筑等长周期结构发生严重震害。SRC(steel reinforced concrete)框架-RC(reinforced concrete)核心筒混合结构作为广泛应用于高烈度区的双重抗侧力结构体系,确保其强震下的协同工作是实现多道抗震防线,形成合理破坏模式的关键。该文通过与普通地震动对比,阐明了远场长周期地震动对SRC框架-RC核心筒混合结构协同工作的影响规律,并基于谐振激励下的结构动力分析模型及经验模态分解初步揭示了其内在机理。算例分析结果表明:受低频特性影响,远场长周期地震动作用下结构框架剪力分担率与底层倾覆力矩占比明显大于普通地震动,最大框架剪力分担率所在楼层与普通地震动相比出现下移,且当峰值加速度增至400 gal时,SRC框架中下部楼层剪力分担率超过40%,底部倾覆力矩占比超过70%,按照现行规范设计的SRC框架将难以保证远场长周期地震动作用下结构的抗震安全;激励频率对于SRC框架-RC核心筒混合结构协同工作的影响与振型参与方式有关,低频激励(周期为0.5倍~2.0倍结构基本周期)下结构响应主要受低阶振型主导;远场长周期地震动的卓越分量是导致框架剪力分担率增大的原因。 展开更多
关键词 远场长周期地震动 SRC框架-RC核心筒混合结构 协同工作 剪力分配 希尔伯特-黄变换
下载PDF
OBN资料多分量联合横波噪音衰减技术及在莺歌海盆地某区的应用
13
作者 张敏 孙雷鸣 +2 位作者 史文英 王新领 张兴岩 《物探化探计算技术》 CAS 2024年第2期164-173,共10页
在OBN地震资料处理中,Z分量的横波噪音压制一直是纵波处理的关键环节,横波噪音压制的好坏直接影响Z分量的数据品质,对后续双检合并起着至关重要的作用。横波噪音具有强振幅、相干性、低频、低速等特点,并且三维空间上呈锥形。针对横波... 在OBN地震资料处理中,Z分量的横波噪音压制一直是纵波处理的关键环节,横波噪音压制的好坏直接影响Z分量的数据品质,对后续双检合并起着至关重要的作用。横波噪音具有强振幅、相干性、低频、低速等特点,并且三维空间上呈锥形。针对横波噪音的特点,笔者提出一种利用OBN资料多分量数据进行联合横波噪音衰减技术。首先将XY分量中记录的横波信号与Z分量进行联合匹配得到Z分量的横波噪音模型,并在十字交叉域共检波点道集上对数据和噪音模型进行三维曲波正变换,引入最小平方法对有效信号和横波噪音进行匹配减,最后再进行三维曲波反变换,达到压制此噪音的效果。该方法应用于莺歌海盆地某区OBN实际地震资料中有效地压制了Z分量横波噪声,为后续处理提供了高品质地震数据。 展开更多
关键词 三维曲波变换 OBN多分量 Z分量 横波噪音模型 十字交叉域
下载PDF
基于剪切波变换和脉冲耦合神经网络的图像融合方法研究
14
作者 李春林 李晓峰 任宏 《计算机应用文摘》 2024年第9期133-135,共3页
图像融合的目的是将多个来源的图像合并,从而产生1个包含所有原始图像信息的新图像。传统的图像融合方法可能损失一些重要信息或导致图像失真,因此研究新的图像融合方法具有重要意义。作为新兴技术,剪切波变换和脉冲耦合神经网络在图像... 图像融合的目的是将多个来源的图像合并,从而产生1个包含所有原始图像信息的新图像。传统的图像融合方法可能损失一些重要信息或导致图像失真,因此研究新的图像融合方法具有重要意义。作为新兴技术,剪切波变换和脉冲耦合神经网络在图像融合中的应用潜力尚未被充分发掘。文章致力于研究这2种技术在图像融合中的效果,并提出结合两者的新方法。 展开更多
关键词 剪切波变换 脉冲耦合神经网络 图像融合
下载PDF
基于图像能量和NSST的电力设备发热定位方法
15
作者 潘超 胡梓熊 +2 位作者 钱勇 盛戈皞 周小丽 《电气自动化》 2024年第5期66-68,共3页
为了解决现有红外检测技术中电力设备发热点定位不够准确的问题,基于图像能量和非下采样剪切波变换,提出了一种实时监测方法。结合红外图像灰度与温度的关系,使用了图像能量算法和种子生长算法对红外图像进行分割;同时在分析终端使用非... 为了解决现有红外检测技术中电力设备发热点定位不够准确的问题,基于图像能量和非下采样剪切波变换,提出了一种实时监测方法。结合红外图像灰度与温度的关系,使用了图像能量算法和种子生长算法对红外图像进行分割;同时在分析终端使用非下采样剪切波变换融合可见光与红外图像,提高了发热区域的定位精准度;对发热特征进行分析,减小了误判、漏判情况出现的概率。研究结果表明,所提方法为电力设备故障发热区域定位提供了有效信息,可用于在线监测与故障定位。 展开更多
关键词 红外图像 可见光图像 图像能量算法 种子生长算法 非下采样剪切波变换
下载PDF
含孔洞Cu_(64)Zr_(36)及Cu/Cu_(64)Zr_(36)复合材料拉伸变形的分子动力学研究
16
作者 李泽政 申宏飞 吴文平 《材料导报》 EI CAS CSCD 北大核心 2024年第15期235-240,共6页
本工作采用分子动力学模拟研究了含孔洞Cu_(64)Zr_(36)金属玻璃和Cu/Cu_(64)Zr_(36)晶体/非晶复合材料的拉伸变形行为。结果表明:Cu_(64)Zr_(36)金属玻璃在加载过程中由孔洞引起的应变集中导致剪切转变区(STZ)被激活并诱发剪切带的形成,... 本工作采用分子动力学模拟研究了含孔洞Cu_(64)Zr_(36)金属玻璃和Cu/Cu_(64)Zr_(36)晶体/非晶复合材料的拉伸变形行为。结果表明:Cu_(64)Zr_(36)金属玻璃在加载过程中由孔洞引起的应变集中导致剪切转变区(STZ)被激活并诱发剪切带的形成,而Cu/Cu_(64)Zr_(36)复合材料通过晶体相中的位错滑移有效避免了灾难性剪切局部化,阻碍了剪切带的扩展。应变局部化程度出现台阶式的跳跃主要由位错的成核和发射引起,而应变局部化程度的缓慢增加与STZ的激活有关,一旦剪切带形成会导致应变局部化程度的快速增加。孔洞的存在改变了剪切应变和非仿射平方位移的分布,原子剪切应变和非仿射平方位移最小值D_(min)^(2)的最大值总是分布在孔洞周围,使其成为最有可能位错成核、STZ激活并诱发剪切带形成的位点。大量的位错运动和均匀的STZ激活是提高复合材料整体塑性的主要原因,晶体相中位错密度的变化与非晶相中的剪切带活动密切相关。当剪切带扩展受阻,只出现均匀的STZ激活,位错密度基本保持不变,应力累积。一旦STZ局部化,重新诱发剪切带的扩展,位错密度增加和应力释放,这也是Cu/Cu_(64)Zr_(36)复合材料应力波动的主要原因。 展开更多
关键词 Cu/Cu_(64)Zr_(36)复合材料 剪切带 剪切转变区 位错 分子动力学模拟
下载PDF
Multi-Modal Medical Image Fusion Based on Improved Parameter Adaptive PCNN and Latent Low-Rank Representation
17
作者 Zirui Tang Xianchun Zhou 《Instrumentation》 2024年第2期53-63,共11页
Multimodal medical image fusion can help physicians provide more accurate treatment plans for patients, as unimodal images provide limited valid information. To address the insufficient ability of traditional medical ... Multimodal medical image fusion can help physicians provide more accurate treatment plans for patients, as unimodal images provide limited valid information. To address the insufficient ability of traditional medical image fusion solutions to protect image details and significant information, a new multimodality medical image fusion method(NSST-PAPCNNLatLRR) is proposed in this paper. Firstly, the high and low-frequency sub-band coefficients are obtained by decomposing the source image using NSST. Then, the latent low-rank representation algorithm is used to process the low-frequency sub-band coefficients;An improved PAPCNN algorithm is also proposed for the fusion of high-frequency sub-band coefficients. The improved PAPCNN model was based on the automatic setting of the parameters, and the optimal method was configured for the time decay factor αe. The experimental results show that, in comparison with the five mainstream fusion algorithms, the new algorithm has significantly improved the visual effect over the comparison algorithm,enhanced the ability to characterize important information in images, and further improved the ability to protect the detailed information;the new algorithm has achieved at least four firsts in six objective indexes. 展开更多
关键词 image fusion improved parameter adaptive pcnn non-subsampled shear-wave transform latent low-rank representation
下载PDF
基于图像融合的碳纤维复合材料冲击损伤检测
18
作者 张晓龙 程晓颖 《自动化与仪表》 2024年第10期91-95,共5页
碳纤维复合材料在生产使用过程中,损伤检测一直是关注的一大焦点。锁相热成像检测和超声波C扫描检测是两种常用的检测方式,但各自存在着局限性。超声波C扫描适用于材料内部深层损伤的检测而对浅层损伤信息不敏感,锁相热成像适用于浅层... 碳纤维复合材料在生产使用过程中,损伤检测一直是关注的一大焦点。锁相热成像检测和超声波C扫描检测是两种常用的检测方式,但各自存在着局限性。超声波C扫描适用于材料内部深层损伤的检测而对浅层损伤信息不敏感,锁相热成像适用于浅层损伤信息的检测,难以反映材料深层次的损伤。针对此问题,该文提出一种基于非下采样剪切波变换结合脉冲耦合神经网络图像融合的算法,将锁相热像图和超声C扫描图像进行图像融合。结果表明,融合图像可以显著提高图像的清晰度和感知质量,并且将损伤面积的误差从39.1%降低到23.8%。 展开更多
关键词 锁相热成像 超声波C扫描 图像融合 非下采样剪切波变换 碳纤维复合材料 脉冲耦合神经网络
下载PDF
基于Shear变换的彩色地形图混沌加密算法
19
作者 林琳 王玲芝 《现代电子技术》 2014年第14期120-124,共5页
针对目前研究地形图图像加密算法较少,以及现有图像加密算法易被破解的问题,提出基于Shear变换的彩色地形图混沌加密算法。该算法充分利用了Shear变换的多方向性,能够很好地对地形图的线划要素信息进行置乱的特点,以及Lorenz混沌系统具... 针对目前研究地形图图像加密算法较少,以及现有图像加密算法易被破解的问题,提出基于Shear变换的彩色地形图混沌加密算法。该算法充分利用了Shear变换的多方向性,能够很好地对地形图的线划要素信息进行置乱的特点,以及Lorenz混沌系统具有极强初值敏感性和更大的密匙空间和安全性的特点。通过对彩色地形图的加密和解密实验,以及抗攻击性能对比实验,表明使用该算法加密后的彩色地形图具有更高的安全性,并且载体图像具有较高的抗攻击性能。 展开更多
关键词 shear变换 彩色地形图 ARNOLD变换 LORENZ混沌系统 置乱 加密 解密
下载PDF
新型T-P抗剪连接件承载性能研究
20
作者 储宗瑞 廖文远 +4 位作者 戴必辉 余国伟 张宇瑞 陈智强 周翔 《中国科技论文》 CAS 2024年第3期284-291,299,共9页
为了加强抗剪连接件的抗剪承载性能,在传统PBL开孔钢板端部焊接一块平行钢板,形成类似T字的新型T-P抗剪连接件。考虑贯穿钢筋、孔洞数量、混凝土强度、添加钢板长度4种变量控制下的影响,并与传统PBL进行比较。结果表明:T-P抗剪连接件比... 为了加强抗剪连接件的抗剪承载性能,在传统PBL开孔钢板端部焊接一块平行钢板,形成类似T字的新型T-P抗剪连接件。考虑贯穿钢筋、孔洞数量、混凝土强度、添加钢板长度4种变量控制下的影响,并与传统PBL进行比较。结果表明:T-P抗剪连接件比PBL连接件具有更好的抗剪刚度和抗剪承载力,添加钢板距离加载点较近的T-P连接件的抗剪承载性能更优,T-P连接件的变形能力较PBL连接件要弱。参数变化结果表明:增加贯穿钢筋、加长端部钢板长度、提高混凝土强度等级可明显提高T-P抗剪连接件的抗剪承载力,增加孔洞数量可提高其抗剪承载力但提高幅度不大;添加钢板距离加载点近的T-P连接件的应力分布更分散均匀,变形程度更小;布置贯穿钢筋、增强混凝土强度、加长钢板长度能够提升T-P连接件的抗剪刚度,其中混凝土强度及贯穿钢筋提升效果明显,可提高T-P连接件的变形能力。 展开更多
关键词 钢-混凝土组合结构 T-P抗剪连接件 承载性能 变形能力
下载PDF
上一页 1 2 18 下一页 到第
使用帮助 返回顶部