This paper describes the scanning assembly principle and construction of scanning assembly sample.The factors that affect assembly accuracy are analyzed.There are two steps in CCD focal plane scanning assembly.The fir...This paper describes the scanning assembly principle and construction of scanning assembly sample.The factors that affect assembly accuracy are analyzed.There are two steps in CCD focal plane scanning assembly.The first is rough assembly,and the second is accurate assembly.In this paper,the moiré fringe is introduced in judging assembly accuracy directly and accurately.The equation for optical transmission characteristics of CCD Moiré fringes is presented.The measurement of Moiré fringes can be completed when some conditions are satisfied.2D_assembly error can be obtained by using digital correlation filtering technique.Finally,the result of focal plane scanning assembly is presented.The result is in good accordance with theory.展开更多
Various mucin-producing neoplasms originate in different abdominal and pelvic organs.Mucinous neoplasms differ from non-mucinous neoplasms because of the differences in clinical outcome and imaging appearance.Mucinous...Various mucin-producing neoplasms originate in different abdominal and pelvic organs.Mucinous neoplasms differ from non-mucinous neoplasms because of the differences in clinical outcome and imaging appearance.Mucinous carcinoma,in which at least 50%of the tumor is composed of large pools of extracellular mucin and columns of malignant cells,is associated with a worse prognosis.Signet ring cell carcinoma is characterized by large intracytoplasmic mucin vacuoles that expand in the malignant cells with the nucleus displaced to the periphery.Its prognosis is also generally poor.In contrast,intraductal papillary mucinous neoplasm of the bile duct and pancreas,which is characterized by proliferation of ductal epithelium and variable mucin production,has a better prognosis than other malignancies in the pancreaticobiliary tree.Imaging modalities play a critical role in differentiating mucinous from non-mucinous neoplasms.Due to high water content,mucin has a similar appearance to water on ultrasound(US) ,computed tomography(CT) ,and magnetic resonance imaging,except when thick and proteinaceous,and then it tends to be hypoechoic with fine internal echoes or have complex echogenicity on US,hyperdense on CT,and hyperintense on T1and hypointense on T2-weighted images,compared to water.Therefore,knowledge of characteristic mucin imaging features is helpful to diagnose various mucinproducing neoplastic conditions and to facilitate appropriate treatment.展开更多
To evaluate the homogeneity of asphalt mixtures,the images of sections obtained by cutting the asphalt mixtures specimen horizontally or vertically were analyzed with digital image processing techniques,and the partic...To evaluate the homogeneity of asphalt mixtures,the images of sections obtained by cutting the asphalt mixtures specimen horizontally or vertically were analyzed with digital image processing techniques,and the particle area ratio was achieved by applying sector scan for horizontal specimen and vertical scan for vertical one.The research result indicates that the influence of random distribution of aggregates in cutting the specimen can be eliminated by using colored aggregates to distinguish coarse and fine aggregates and using color threshold to segment the images.Choosing three typical gradations,proving particle area ratio obeying normal distribution and using the variability of particle area ratio as an index,it is feasible to quantitatively evaluate the homogeneity of asphalt mixtures.展开更多
文摘This paper describes the scanning assembly principle and construction of scanning assembly sample.The factors that affect assembly accuracy are analyzed.There are two steps in CCD focal plane scanning assembly.The first is rough assembly,and the second is accurate assembly.In this paper,the moiré fringe is introduced in judging assembly accuracy directly and accurately.The equation for optical transmission characteristics of CCD Moiré fringes is presented.The measurement of Moiré fringes can be completed when some conditions are satisfied.2D_assembly error can be obtained by using digital correlation filtering technique.Finally,the result of focal plane scanning assembly is presented.The result is in good accordance with theory.
基金Supported by A grant from the Korea Healthcare Technology R and D Project,Ministry for Health,Welfare,and Family Affairs,South Korea,A091047
文摘Various mucin-producing neoplasms originate in different abdominal and pelvic organs.Mucinous neoplasms differ from non-mucinous neoplasms because of the differences in clinical outcome and imaging appearance.Mucinous carcinoma,in which at least 50%of the tumor is composed of large pools of extracellular mucin and columns of malignant cells,is associated with a worse prognosis.Signet ring cell carcinoma is characterized by large intracytoplasmic mucin vacuoles that expand in the malignant cells with the nucleus displaced to the periphery.Its prognosis is also generally poor.In contrast,intraductal papillary mucinous neoplasm of the bile duct and pancreas,which is characterized by proliferation of ductal epithelium and variable mucin production,has a better prognosis than other malignancies in the pancreaticobiliary tree.Imaging modalities play a critical role in differentiating mucinous from non-mucinous neoplasms.Due to high water content,mucin has a similar appearance to water on ultrasound(US) ,computed tomography(CT) ,and magnetic resonance imaging,except when thick and proteinaceous,and then it tends to be hypoechoic with fine internal echoes or have complex echogenicity on US,hyperdense on CT,and hyperintense on T1and hypointense on T2-weighted images,compared to water.Therefore,knowledge of characteristic mucin imaging features is helpful to diagnose various mucinproducing neoplastic conditions and to facilitate appropriate treatment.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50808087)
文摘To evaluate the homogeneity of asphalt mixtures,the images of sections obtained by cutting the asphalt mixtures specimen horizontally or vertically were analyzed with digital image processing techniques,and the particle area ratio was achieved by applying sector scan for horizontal specimen and vertical scan for vertical one.The research result indicates that the influence of random distribution of aggregates in cutting the specimen can be eliminated by using colored aggregates to distinguish coarse and fine aggregates and using color threshold to segment the images.Choosing three typical gradations,proving particle area ratio obeying normal distribution and using the variability of particle area ratio as an index,it is feasible to quantitatively evaluate the homogeneity of asphalt mixtures.
