从几何光学理论出发，详细推导了斐索型光学合成孔径成像系统的近轴非相干成像条件，即子望远系统的角放大率等于系统的线性缩放因子。对于焦平面上的像点而言，合成孔径成像系统可等效为一个带有特殊形状孔径光阑的望远系统，这要求该孔径光栏的开口形状和位置分布与合成孔径成像系统各子系统孔径大小和位置分布相一致。我们由此得到了斐索型合成孔径成像系统的主要约束条件。

Proceedings from the theory of geometric optics,the condition adaxial noncoherent imaging of Fizeau opticalsynthetic aperture imaging system is derived to achieve diffracion limited performance over a finite field of view,and the conclusion is that the angular magnification of the individual telescope must be equal to the linear demagnification factor.So telescope with a special aperture diaphragm so as to teproduce exactly the ensemble of a collecting telescope.Then,the constraint to Fizeau optical synthetic aperture imaging system is achieved.