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灰阶

灰阶的相关文献在1989年到2022年内共计769篇,主要集中在无线电电子学、电信技术、临床医学、自动化技术、计算机技术 等领域,其中期刊论文159篇、会议论文1篇、专利文献609篇;相关期刊99种,包括生物医学工程学进展、中国超声医学杂志、中国医学影像学杂志等; 相关会议1种,包括2013年第十五届全国消费电子技术年会等;灰阶的相关文献由1160位作者贡献,包括王卫、陈黎暄、周国富等。

灰阶—发文量

期刊论文>

论文:159 占比:20.68%

会议论文>

论文:1 占比:0.13%

专利文献>

论文:609 占比:79.19%

总计:769篇

灰阶—发文趋势图

灰阶

-研究学者

  • 王卫
  • 陈黎暄
  • 周国富
  • 张金泉
  • 佐野道明
  • 易子川
  • 王利
  • 何涛
  • 吕博嘉
  • 孔祥梓
  • 期刊论文
  • 会议论文
  • 专利文献

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    • 陈少亮; 张丹江
    • 摘要: 目的:探讨分析对患有下肢深静脉血栓的老年患者采用灰阶及彩色多普勒超声进行诊断的临床应用价值.方法:本次研究对象均为患有下肢深静脉血栓的老年患者,共计118例,收治患者的时间范围介于2018年4月到2019年4月之间.采用灰阶及彩色多普勒超声对患者的病情进行诊断,并对检查结果进行分析.结果:118例患有肢深静脉血栓的老年患者经过检查后,可以确认共有三种类型,分别是中央型(65例)、周围型(39例)、混合型(14例).其中,慢性血栓患者57例,急性血栓患者61例.结论:根据本次研究的结果可以确认,对患有下肢深静脉血栓的老年患者采用彩色多普勒超声进行诊断有着极其显著的价值,不仅能够有效确认患者是或否患有下肢深静脉血栓,还能够准确的判断患者血栓的实际情况,具有临床推广价值.
    • 肖琨
    • 摘要: 目的:研究灰阶和彩色多普勒超声诊断高龄下肢深静脉血栓的价值及临床意义.方法:选取2015年12月至2017年12月在武汉市蔡甸区人民医院治疗的高龄下肢深静脉血栓患者150例为研究组,选取同期健康体检人员150例为对照组.结果:研究组患者的股浅静脉、胫后静脉等的管径均大于对照组(P0.05).结论:在高龄患者下肢深静脉血栓的诊断过程当中,灰阶和彩色多普勒超声可以清楚地将患者的病灶位置与特点显示出来,因此临床上应当进一步的推广应用.
    • 摘要: 针对光伏组件EL测试时出现的明暗差异现象,通过EL测试机理及明暗影响因素解析异常产生的原因,并评估此类组件的质量风险.分析表明,组件EL测试发现的明暗差异问题,既有电池效率失配的原因,也有电流失配的原因.从组件功率衰减方面来看,效率失配对组件功率衰减的影响较大,电流失配对组件功率衰减的影响较小.
    • 江丽; 朱建平; 罗晓莉; 李慧忠
    • 摘要: Objective To analyze the application value of two elastic quantification methods which were virtual touch quantification(VTQ) and virtual touch imaging(VTI) combined with Adobe Photoshop gray quantitative technique in identifying benign and malignant breast solid masses.Methods The VS which represented hardness of the center part in 98 patients with breast tumor(108 breast solid masses) were obtained by VTQ technology.The lesions tissue elastic graphs were obtained in the same patients by VTI technology,then the elastic graphs were imported into Adobe Photoshop image processing system to calculate the lesions overall gray-scale average value,which representing the overall hardness of breast lesions.Compared with the pathological results,the difference between benign and malignant breast lesions of the central local hardness and overall hardness were compared.The best cutoff value of the two indexes in identifying solid benign and malignant breast lesions were obtained,and the diagnostic efficiencies were compared.Results The average VS representing local hardness of malignant lesions was (6.96± 2.50)m/s,while that of the benign lesions was(2.62±1.82)m/s,there was significant difference(P=0.000).The best cutoff value of VS was 2.78 m/s,with sensitivity of 91.18%,specificity of 88.64%,accuracy of 89.74%,which was highly consistent with the pathological result(correctionχ2=0.125,P=0.724,Kappa=0.793,P=0.000).The gray-scale average value representing the overall hardness of malignant lesions was 39.21±16.60,while that of the benign lesions was 63.94±19.42,there was significant difference (P=0.000).The best cutoff value of gray-scale average value was 50.75,with sensitivity of 79.41%,specificity of 77.27%,accuracy of 78.21%,which was moderate consistent with the pathological result(correctionχ2=0.235,P=0.628,Kappa=0.561,P=0.000).Conclusion The diagnostic efficiency of VTQ is higher than that of VTI combined with Adobe Photoshop gray quantitative technique.They are both help to differentiate the benign and malignant breast solid masses.%目的 对比分析声触诊组织量化(VTQ)和声触诊组织成像(VTI)联合Adobe Photoshop灰度定量两种弹性定量方法在鉴别诊断乳腺实性肿块良恶性中的应用价值.方法 选取98例乳腺肿瘤患者(108个乳腺实性肿块),应用VTQ获得代表肿块中央局部硬度的剪切波速度(VS),同时应用VTI联合Adobe Photoshop灰度定量技术计算VTI弹性图中病灶整体灰度平均值,代表乳腺肿块整体硬度.与病理结果对照,分别比较良恶性乳腺肿块中央局部硬度和整体硬度的差异,获得最佳截断值,比较两个指标的诊断效能.结果 恶性和良性乳腺肿块的局部硬度VS值分别为(6.96±2.50)m/s和(2.62±1.82)m/s,差异有统计学意义(P=0.000).ROC曲线获得最佳截断值为2.78 m/s,以肿块中央局部硬度VS>2.78 m/s诊断恶性乳腺肿块的敏感性、特异性及准确率分别为91.18%、88.64%及89.74%,与病理结果高度一致(校正χ2=0.125,P=0.724;Kappa=0.793,P=0.000).恶性和良性乳腺肿块整体硬度灰度平均值分别为39.21±16.60和63.94±19.42,差异有统计学意义(P=0.000).ROC曲线获得最佳截断值为50.75,以肿块整体硬度灰度平均值<50.75诊断恶性乳腺肿块的敏感性、特异性及准确率分别为79.41%、77.27%及78.21%,与病理结果中度一致(校正χ2=0.235,P=0.628;Kappa=0.561,P=0.000).结论 VTQ诊断效能高于VTI联合Adobe Photoshop灰度定量技术,但二者均有助于鉴别乳腺实性肿块性质.
    • 南海燕; 杨洋; 颜林枫; 张欣; 王文; 崔光彬
    • 摘要: 目的 探讨不同纹理模型和灰阶对基于动态对比增强磁共振图像(dynamic contrast enhancement magnetic resonance imaging,DCE-MRI)的支持向量机的胶质瘤自动分级影响.材料与方法 收集经磁共振扫描且经病理证实为胶质瘤Ⅱ、Ⅲ、Ⅳ级的患者共117例,计算DCE-MRI图像血流动力学参数(NordicICE 4.0),利用不同纹理模型和灰阶提取参数图肿瘤区域相应纹理特征.支持向量机递归特征消除算法选择特征后,输入线性SVM对胶质瘤级别进行分类并使用留一法交叉验证.分类结果使用Graphpad Prism 6统计软件分析.结果 灰阶对分类效能的影响差异无统计学意义(P=0.1589),纹理模型对分类效能的影响差异存在统计学意义(P<0.0001).在使用灰度共生矩阵(gray-level co-occurrence matrix,GLCM)提取纹理特征并且灰阶为32和256时,分别选取前22个和前17个特征所得分类正确率最高(正确率=0.79).结论 基于DCE图像纹理对支持向量机胶质瘤分级中,纹理模型GLCM结合特征选择是胶质瘤分级的最优方案,并推荐在后期研究中使用.
    • 李雅怡; 卓文杏; 张雨洁
    • 摘要: 目的:对比研究三维超声断层显像及灰阶定量的灰阶值中位数(GSM)和低灰阶值所占比例(PLGS%)在不同时期慢性乳腺炎的超声特征.方法:收集我院76名病理确诊为慢性乳腺炎的患者,按超声表现分成:炎症初期、脓肿期、炎症后期三型,行二维及三维超声检查,对灰阶值中位数和低灰阶值所占比例进行分析.结果:对三种不同时期慢性乳腺炎的灰阶值中位数及低灰阶值所占比例的数值比较采取单独样本t检验,其中三组的灰阶值中位数有明显差异,P值小于0.05;低灰阶值所占比例无明显差异,P值大于0.05.结论:三维超声的灰阶值中位数对慢性乳腺炎有诊断价值,其诊断与超声分型有关.
    • 王晓春; 计建军; 杨军; 王延群; 周盛
    • 摘要: 目的:研制一套基于现场可编程门阵列(field-programmable gate array,FPGA)的高频超声灰阶血流成像系统,实现浅表器官血流和组织的同时实时成像.方法:该系统主要由超声换能器、超声发射接收模块、上位机成像软件和外围设备组成.超声换能器采用20~50 MHz单阵元聚偏氟乙烯(polyvinylidene fluoride,PVDF)换能器;超声发射接收模块采用高速模数转换器(analog to digital converter,ADC)直接将射频回波信号提前数字化,再由FPGA对数字信号进行多次发射叠加、滤波、检波、对数放大及二次采样等处理,并由USB接口传输至上位机进行实时显示.结果:使用该系统对人手背部静脉距表皮1 mm的血管进行超声扫描检查,可得到各种发射频率对应的血流结果图像.结论:该系统实现了浅表器官血流的实时成像,方案结构简洁清晰,为高频超声灰阶血流成像奠定了实验基础.%Objective To develop a set of high-frequency ultrasound grayscale blood flow imaging system based on field programmable gate array (FPGA) to execute simultaneous imaging of superficial blood flow and tissues.Methods This system was mainly composed of an ultrasonic transducer,an ultrasonic transmission and receiving modules,imaging software in host computer and peripheral equipment.A PVDF transducer with the frequency between 20 and 50 MHz was used for the ultrasonic transducer.In transmission and receiving modules,the radio frequency echo signals were digitized by high-speed A/D.Then the digital signals were transmitted,added,filtered,demodulated,log amplified,double sampled,and lastly transferred to the host computer by USB interface for real-time display.Results A vascular 1 mm far form the surface of the hand skin was examined by this system.Four blood flow images were obtained in corresponding with four transmission frequencies.Conclusion Real-time superficial organ blood flow imaging is realized by this system.The solution has the architecture concise and clear,and lays an experimental foundationfor high-frequency ultrasound gray-scale blood flow imaging.
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