To achieve full-surface strain measurement of variable curvature objects,a 360°3D digital image correlation(DIC)system is proposed.The measurement system consists of four double-camera systems,which capture the o...To achieve full-surface strain measurement of variable curvature objects,a 360°3D digital image correlation(DIC)system is proposed.The measurement system consists of four double-camera systems,which capture the object’s entire surface from multiple angles,enabling comprehensive full-surface measurement.To increase the stitching quality,a hierarchical coordinate matching method is proposed.Initially,a 3D rigid body calibration auxiliary block is employed to track motion trajectory,which enables preliminary matching of four 3D-DIC sub-systems.Subsequently,secondary precise matching is performed based on feature points on the test specimen’s surface.Through the hierarchical coordinate matching method,the local 3D coordinate systems of each double-camera system are unified into a global coordinate system,achieving 3D surface reconstruction of the variable curvature cylindrical shell,and error analysis is conducted on the results.Furthermore,axial compression buckling experiment is conducted to measure the displacement and strain fields on the cylindrical shell’s surface.The experimental results are compared with the finite element analysis,validating the accuracy and effectiveness of the proposed multi-camera 3D-DIC measuring system.展开更多
乳腺X线摄影技术是早期发现和诊断乳腺肿瘤的首选方法。提取乳腺钼靶图像的感兴趣区域(region of interest,ROI)并利用人工智能算法对其进行模式识别,可有效提高乳腺肿瘤筛查工作的效率。试验图像均来自DDSM乳腺X线钼靶图像公开数据库,...乳腺X线摄影技术是早期发现和诊断乳腺肿瘤的首选方法。提取乳腺钼靶图像的感兴趣区域(region of interest,ROI)并利用人工智能算法对其进行模式识别,可有效提高乳腺肿瘤筛查工作的效率。试验图像均来自DDSM乳腺X线钼靶图像公开数据库,以其中BI-RADS分类为第4类(BI-RADS4)的簇状分布多形性钙化钼靶图像为研究对象,探求在设计乳腺钼靶图像分类器过程中提取ROI的新方法。结果显示,设计出优化的分类器后,可高效地识别试验对象,其测试集上的分类准确率最高可达99.3%。因此,本研究可为医生的临床研判提供辅助信息,并为细分BI-RADS4、进一步精准诊断奠定技术基础。展开更多
基金funded by the National Natural Science Foundations of China(Nos.12272176,U2037603).
文摘To achieve full-surface strain measurement of variable curvature objects,a 360°3D digital image correlation(DIC)system is proposed.The measurement system consists of four double-camera systems,which capture the object’s entire surface from multiple angles,enabling comprehensive full-surface measurement.To increase the stitching quality,a hierarchical coordinate matching method is proposed.Initially,a 3D rigid body calibration auxiliary block is employed to track motion trajectory,which enables preliminary matching of four 3D-DIC sub-systems.Subsequently,secondary precise matching is performed based on feature points on the test specimen’s surface.Through the hierarchical coordinate matching method,the local 3D coordinate systems of each double-camera system are unified into a global coordinate system,achieving 3D surface reconstruction of the variable curvature cylindrical shell,and error analysis is conducted on the results.Furthermore,axial compression buckling experiment is conducted to measure the displacement and strain fields on the cylindrical shell’s surface.The experimental results are compared with the finite element analysis,validating the accuracy and effectiveness of the proposed multi-camera 3D-DIC measuring system.
文摘乳腺X线摄影技术是早期发现和诊断乳腺肿瘤的首选方法。提取乳腺钼靶图像的感兴趣区域(region of interest,ROI)并利用人工智能算法对其进行模式识别,可有效提高乳腺肿瘤筛查工作的效率。试验图像均来自DDSM乳腺X线钼靶图像公开数据库,以其中BI-RADS分类为第4类(BI-RADS4)的簇状分布多形性钙化钼靶图像为研究对象,探求在设计乳腺钼靶图像分类器过程中提取ROI的新方法。结果显示,设计出优化的分类器后,可高效地识别试验对象,其测试集上的分类准确率最高可达99.3%。因此,本研究可为医生的临床研判提供辅助信息,并为细分BI-RADS4、进一步精准诊断奠定技术基础。
