The Relationship between the Optimal Magnification and the Limit Spatial Resolution in CT System
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摘要: 图像质量是CT系统的核心指标,而空间分辨率又是图像质量评价的重要指标之一。图像的极限空间分辨率由系统的截止频率决定,通过对截止频率与系统的有效射束宽度的关系公式推导发现,工业CT系统放大倍数在不同的范围变化下CT系统有其最佳放大倍数,此时CT系统的有效射束出现最小值,极限空间分辨率达到其最大值。这些规律的发现,为检测人员在检测过程中根据自身CT系统的参数进行有效的调整,从而发挥设备的最佳状态,使图像质量更加清晰,同时为CT系统的设计提供参考依据。Abstract: The faithfulness of a CT image depends on a number of system-level performance factors,with one of the most important being spatial resolution.Spatial resolution refers to the ability of a CT system to resolve small details or locate small feature with respect to some reference point.Spatial resolution is generally quantified in terms of the smallest separation at which two points can be distinguished as separate entities.The limiting value of the spatial resolution is determined by the design and construction of the system.The limit spatial resolution is determined by the cut-off frequency(COF),which is approximately 1/BW.The optimal magnification is derived by the relationship equation in this paper.This discovery of this principle will be helpful to getting the best image for the testing personnel in his work.At the same time it will also provide a theoretical basis for the design of the CT system.
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Keywords:
- CT /
- magnification /
- critical magnification(M0) /
- limit spatial resolution /
- BW
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