Burgess A E
Invest Radiol. 1977 Jan-Feb;12(1):36-43. doi: 10.1097/00004424-197701000-00011.
Focal spot models have been based on the implicit assumption that the two dimensional MTF is mathematically separable in the form P(u, v) = P(u)P(v). Experimental results for nine foci are presented. It is concluded that the assumption of separability can be used without introducing a large error. As a consequence of this property, considerable simplification is brought to the measurement and mathematical description of the two dimensional focal distribution.
焦点模型一直基于这样一个隐含假设，即二维调制传递函数在数学上可分离为P(u, v) = P(u)P(v)的形式。文中给出了九个焦点的实验结果。得出的结论是，可分离性假设在不引入较大误差的情况下可以使用。由于这一特性，二维焦点分布的测量和数学描述得到了相当大的简化。
