首先推导与归纳了图像三维变换中像素深度场的变换规律,同时提出了基于深度场和极线原则的像素可见性别方法,根据上述理论和方法,提出一种基于深度图像的建模与绘制(image-based modeling and rendering,简称IBMR)技术,称为虚平面映射....首先推导与归纳了图像三维变换中像素深度场的变换规律,同时提出了基于深度场和极线原则的像素可见性别方法,根据上述理论和方法,提出一种基于深度图像的建模与绘制(image-based modeling and rendering,简称IBMR)技术,称为虚平面映射.该技术可以基于图像空间内任意视点对场景进行绘制.绘制时,先在场景中根据视线建立若干虚拟平面,将源深度图像中的像素转换到虚平面上,然后通过对虚平面上像素的中间变换,将虚平面转换成平面纹理,再利用虚平面的相互拼接,将视点的成像以平面纹理映射的方式完成.新方法还能在深度图像内侧,基于当前视点快速获得该视点的全景图,从而实现视点的实时漫游.新方法视点运动空间大、存储需求小,且可以发挥图形硬件的纹理映射功能,并能表现物体表面的三维凹凸细节和成像视差效果,克服了此前类似算法的局限和不足.展开更多
In this paper, the basic principles and mathematical process of the Second-order Imaginary Plane Method (IPM) for modeling the radiative heat transfer are analysed and proved in detail. Through the numerical computati...In this paper, the basic principles and mathematical process of the Second-order Imaginary Plane Method (IPM) for modeling the radiative heat transfer are analysed and proved in detail. Through the numerical computation for the real process of the radiative heat transfer using the Second-order IPM,the previous IPM (the first-order), the Analytic Method and the Zone Method, it was shown that the calculation accuracy of the Secondr-order IPM is much higher than that of the first-order IPM, and its demand to computer capacity and time consuming is much lower than that of the Zone Method or the Analytic Method. It is verilied that the method is more effective and has a higher accuracy for modeling radiative heat transfer in engineering.展开更多
The ability of 3D ultrasound volume contrast imaging in C-plane （VCI-C） in the assessment of female levator hiatus was analyzed in eighty normal nullipaxas. Interoperator variability in levator hiatus measurements w...The ability of 3D ultrasound volume contrast imaging in C-plane （VCI-C） in the assessment of female levator hiatus was analyzed in eighty normal nullipaxas. Interoperator variability in levator hiatus measurements was analyzed. The comparison of the axial image of magnetic resonance imaging （MRI） and C-plane image of volume contrast imaging （VCI） in thirty normal nulliparas was also done. It shows that VCI-C can clearly demonstrate the structure and accurately quantitates the size of the levator hiatus. It is reliable, convenient and without contraindication in assessment of female levator hiatus. The technology opens up entirely new modality for assessing female pelvic floor.展开更多
基金the National Natural Science Foundation of China under Grant No.60473105(国家自然科学基金)the National Basic Research Program of China under Grant No.2002CB312102(国家重点基础研究发展计划(973))the Studentship Grant of University of Macao(澳门大学研究生奖学金)
文摘首先推导与归纳了图像三维变换中像素深度场的变换规律,同时提出了基于深度场和极线原则的像素可见性别方法,根据上述理论和方法,提出一种基于深度图像的建模与绘制(image-based modeling and rendering,简称IBMR)技术,称为虚平面映射.该技术可以基于图像空间内任意视点对场景进行绘制.绘制时,先在场景中根据视线建立若干虚拟平面,将源深度图像中的像素转换到虚平面上,然后通过对虚平面上像素的中间变换,将虚平面转换成平面纹理,再利用虚平面的相互拼接,将视点的成像以平面纹理映射的方式完成.新方法还能在深度图像内侧,基于当前视点快速获得该视点的全景图,从而实现视点的实时漫游.新方法视点运动空间大、存储需求小,且可以发挥图形硬件的纹理映射功能,并能表现物体表面的三维凹凸细节和成像视差效果,克服了此前类似算法的局限和不足.
文摘In this paper, the basic principles and mathematical process of the Second-order Imaginary Plane Method (IPM) for modeling the radiative heat transfer are analysed and proved in detail. Through the numerical computation for the real process of the radiative heat transfer using the Second-order IPM,the previous IPM (the first-order), the Analytic Method and the Zone Method, it was shown that the calculation accuracy of the Secondr-order IPM is much higher than that of the first-order IPM, and its demand to computer capacity and time consuming is much lower than that of the Zone Method or the Analytic Method. It is verilied that the method is more effective and has a higher accuracy for modeling radiative heat transfer in engineering.
基金the Scientific Research Project of Shanghai Municipal Health Bureau (No. 2008083)
文摘The ability of 3D ultrasound volume contrast imaging in C-plane （VCI-C） in the assessment of female levator hiatus was analyzed in eighty normal nullipaxas. Interoperator variability in levator hiatus measurements was analyzed. The comparison of the axial image of magnetic resonance imaging （MRI） and C-plane image of volume contrast imaging （VCI） in thirty normal nulliparas was also done. It shows that VCI-C can clearly demonstrate the structure and accurately quantitates the size of the levator hiatus. It is reliable, convenient and without contraindication in assessment of female levator hiatus. The technology opens up entirely new modality for assessing female pelvic floor.
