Spiral scanning was performed after appropriately distended by introduction of air at different body positions, collimation and table pitch and orientation of the colon lumen with respect to the gantry. 结肠适度充气后,在不同体位、层厚和螺距、扫描角度下行螺旋CT扫描,观察CTVC成像效果。
Conclusion: The cone artifact in CT image is related to such scanning parameters as pitch and the characters of the scanned objects. 临床照片中,锥形伪影突出表现在边界明显的部位。结论:锥形伪影与螺距和被扫描物属性存在确定关系。
The tread patterns were processed by scanning with a computer to form matrix A, which was compressed and calculated to identify the periodicity and pitch order law of tread patterns and provide the reference and analysing means in designing low noise tire. 首先通过计算机扫描将轮胎花纹图案处理成[0-1]矩阵A,然后对矩阵A进行压缩计算,用以辨识轮胎花纹的周期性和花纹节距排列规律,为低噪声轮胎设计提供参考和分析工具。
By means of N2 adsorption isotherm, scanning electron microscope ( SEM) and X-ray diffraction ( XRD), the difference between isotropic pitch and mesophase pitch used as the precursors material of ACF are compared from the aspect of microstructure. 通过低温N2气吸附等温线测定、扫描电镜(SEM)观察和X-射线衍射分析等方法,从微观结构上比较了两种沥青作为ACF制备原料的差异性。
In the fractal geometry study, after the three dimensional coordinates are obtained using image processing technology, the true fractal dimensions are calculated, the scanning pitch reaches the accuracy requirements of micrometer level for metallic material. 在分形研究中,利用图象处理技术获取三维坐标后,计算出断口的真实分形维数,扫描间距达到金属材料μm级精度的要求。
The scanning system is controlled by precise stepper motor which can be controlled by computer to sweep over point by point with 1 mm pitch. 扫描系统由精密步进电机控制,进行间距约1mm的逐点扫描。