shift axis meaning in Chinese
移动轴
Examples
- In the terms of interpolation , the image reconstructed from nearest interpolation or linear interpolation has good edge but serious noise ; reconstruction from 4 * 4cubic interpolation or three b - spline or three - order lagrange interpolations has better local character . 2 x 2cubic interpolations which has both better edge and local character is the ideal interpolation , the following is the basic principle during reconstruction : ( 1 ) the more width of interpolation , the more number of summation and the more order of interpolation polynomial , the higher of density resolution ; ( 2 ) the more of interpolation polynomial and width of interpolation , the more of reconstruction time simultaneously , aimed at eliminating the effects of noise contained in projection data , in this paper , author analysis cause and effects of common artifacts . importantly , discusses convolution back - projection reconstruction algorithm with a shift axis of rotation has been derived for correcting images that acquired with a divergence axis of rotation using the fan beam geometry with an angle - equaled detector
在ct图像重建时，选择有限带宽窗有较好的空间分辨率，三角形窗有较好的密度分辨率，选择余弦窗则使得空间分辨率与密度分辨率的折衷；从窗函数的频谱角度来讲，可以用于图像重建的一个良好的卷积窗函数应该具备以下条件： ( ? )小的3db带宽b ，即最小的主瓣宽度； ( ? )最小的旁瓣最大峰值a ； ( ? )最大的旁瓣峰值衰减速度d ；就内插函数而言，临近点内插与线性内插重建图像噪声大，但有较好的边缘与细节； 4 4三次内插、三次b -样条与四次拉格朗日多项式内插图像平滑，局部特性较好。