数字图像相关方法的变形测量,通常会使用常规双相机进行图像采集,然而由于系统光学结构的限制,应用也受到了一定的制约。本文将光纤传像束和三维数字图像相关方法(Three-Dimensional Digital Image Correction,3D-DIC)相结合,提出一种...数字图像相关方法的变形测量,通常会使用常规双相机进行图像采集,然而由于系统光学结构的限制,应用也受到了一定的制约。本文将光纤传像束和三维数字图像相关方法(Three-Dimensional Digital Image Correction,3D-DIC)相结合,提出一种基于光纤传像束成像的双相机三维数字图像相关方法。旨在充分利用传像束的灵活性,进一步拓宽3D-DIC方法的应用范围。由于系统中的传像束将相机和测量环境隔离,在恶劣环境下可以有效避免相机的损坏。首先,分析了不同滤波方法预处理散斑图像对测量结果的影响;然后,通过平移试验研究了散斑尺寸和密度对测量结果的影响;最后,开展了圆柱体形貌测量试验和304不锈钢单轴拉伸试验。结果表明:散斑直径为21~23pixel且密度为55%时使用该方法可得到最佳的测量结果,同时该方法不仅能够获取圆柱体的三维形貌,还能够准确测量单轴拉伸试验的全场变形,以电子引伸计为基准,相对误差始终保持在小于0.25%的范围内。展开更多
AIM:To explore the feasibility of dual camera capsule (DCC)small-bowel(SB)imaging and to examine if two cameras complement each other to detect more SB lesions.METHODS:Forty-one eligible,consecutive patients underwent...AIM:To explore the feasibility of dual camera capsule (DCC)small-bowel(SB)imaging and to examine if two cameras complement each other to detect more SB lesions.METHODS:Forty-one eligible,consecutive patients underwent DCC SB imaging.Two experienced investigators examined the videos and compared the total number of detected lesions to the number of lesions detected by each camera separately.Examination tolerability was assessed using a questionnaire.RESULTS:One patient was excluded.DCC cameras detected 68 positive findings(POS)in 20(50%)cases.Fifty of them were detected by the"yellow"camera,48 by the"green"and 28 by both cameras;44%(n=22)of the"yellow"camera’s POS were not detected by the"green"camera and 42%(n=20)of the"green" camera’s POS were not detected by the"yellow"camera.In two cases,only one camera detected significant findings.All participants had 216 findings of unknown significance(FUS).The"yellow","green"and both cameras detected 171,161,and 116 FUS,respectively;32%(n=55)of the"yellow"camera’s FUS were not detected by the"green"camera and 28%(n=45)of the"green"camera’s FUS were not detected by the "yellow"camera.There were no complications related to the examination,and 97.6%of the patients would repeat the examination,if necessary.CONCLUSION:DCC SB examination is feasible and well tolerated.The two cameras complement each other to detect more SB lesions.展开更多
Pressure Sensitive Paint(PSP)technique has been increasingly applied to the experimental research of aerodynamics and thermodynamics due to its strengths of non-contact,high resolution results and large coverage area,...Pressure Sensitive Paint(PSP)technique has been increasingly applied to the experimental research of aerodynamics and thermodynamics due to its strengths of non-contact,high resolution results and large coverage area,etc.However,rarely has this technique been successfully used to the study of internal flow such as compressor cascade,since narrow flow passages would heavily restrict the acquisition of PSP images.In this paper,PSP technique was used to study the pressure distribution on a linear compressor cascade with large solidity of 2.3,where the view of recording camera can be heavily blocked due to adjacent blade surfaces.To help get integrated PSP images of the internal flow passage,dual camera system along with image processing tools like 3D reconstruction and image integration were adopted.The results showed that with the aid of such assistance,image results with good quality and readability could be obtained.Meanwhile,pressure data given by PSP were compared with data from traditional way of pressure taps and showed good consistency.Massive results of the entire cascade passage surface were given with different inlet Mach numbers and incidence angles.The results showed that PSP technique can integrally measure cascade tunnel of large solidity with the help of dual-camera system.展开更多
文摘数字图像相关方法的变形测量,通常会使用常规双相机进行图像采集,然而由于系统光学结构的限制,应用也受到了一定的制约。本文将光纤传像束和三维数字图像相关方法(Three-Dimensional Digital Image Correction,3D-DIC)相结合,提出一种基于光纤传像束成像的双相机三维数字图像相关方法。旨在充分利用传像束的灵活性,进一步拓宽3D-DIC方法的应用范围。由于系统中的传像束将相机和测量环境隔离,在恶劣环境下可以有效避免相机的损坏。首先,分析了不同滤波方法预处理散斑图像对测量结果的影响;然后,通过平移试验研究了散斑尺寸和密度对测量结果的影响;最后,开展了圆柱体形貌测量试验和304不锈钢单轴拉伸试验。结果表明:散斑直径为21~23pixel且密度为55%时使用该方法可得到最佳的测量结果,同时该方法不仅能够获取圆柱体的三维形貌,还能够准确测量单轴拉伸试验的全场变形,以电子引伸计为基准,相对误差始终保持在小于0.25%的范围内。
文摘AIM:To explore the feasibility of dual camera capsule (DCC)small-bowel(SB)imaging and to examine if two cameras complement each other to detect more SB lesions.METHODS:Forty-one eligible,consecutive patients underwent DCC SB imaging.Two experienced investigators examined the videos and compared the total number of detected lesions to the number of lesions detected by each camera separately.Examination tolerability was assessed using a questionnaire.RESULTS:One patient was excluded.DCC cameras detected 68 positive findings(POS)in 20(50%)cases.Fifty of them were detected by the"yellow"camera,48 by the"green"and 28 by both cameras;44%(n=22)of the"yellow"camera’s POS were not detected by the"green"camera and 42%(n=20)of the"green" camera’s POS were not detected by the"yellow"camera.In two cases,only one camera detected significant findings.All participants had 216 findings of unknown significance(FUS).The"yellow","green"and both cameras detected 171,161,and 116 FUS,respectively;32%(n=55)of the"yellow"camera’s FUS were not detected by the"green"camera and 28%(n=45)of the"green"camera’s FUS were not detected by the "yellow"camera.There were no complications related to the examination,and 97.6%of the patients would repeat the examination,if necessary.CONCLUSION:DCC SB examination is feasible and well tolerated.The two cameras complement each other to detect more SB lesions.
基金This study was co-supported by the National Natural Science Foundation of China(No.51790512)the Ministry of Education of the People's Republic of China(111 Project,No.B17037).
文摘Pressure Sensitive Paint(PSP)technique has been increasingly applied to the experimental research of aerodynamics and thermodynamics due to its strengths of non-contact,high resolution results and large coverage area,etc.However,rarely has this technique been successfully used to the study of internal flow such as compressor cascade,since narrow flow passages would heavily restrict the acquisition of PSP images.In this paper,PSP technique was used to study the pressure distribution on a linear compressor cascade with large solidity of 2.3,where the view of recording camera can be heavily blocked due to adjacent blade surfaces.To help get integrated PSP images of the internal flow passage,dual camera system along with image processing tools like 3D reconstruction and image integration were adopted.The results showed that with the aid of such assistance,image results with good quality and readability could be obtained.Meanwhile,pressure data given by PSP were compared with data from traditional way of pressure taps and showed good consistency.Massive results of the entire cascade passage surface were given with different inlet Mach numbers and incidence angles.The results showed that PSP technique can integrally measure cascade tunnel of large solidity with the help of dual-camera system.
