Improved resolution for aerial imaging by retro-reflection with two transparent spheres.

This paper proposes a method to improve the modulation transfer function (MTF) of aerial images by combining an aerial imaging optical system by retro-reflection with conjugated two transparent spheres. In the proposed optical system, the transparent spheres collimate the light incident on the retro-reflector to improve the resolution by making the light shift the same amount. The resolution was greatly improved by introducing conjugate two transparent spheres in the AIRR optical system. The MTF is increased by slightly increasing placement distance of the transparent spheres from the focal length and increasing diameter of the transparent spheres in the AIRR optical system. Changing the diameter of the transparent spheres at the near-axis approximate focal length improved the MTF, but there was no difference in MTF with diameter of the spheres. This indicates that different transparent spheres diameters do not affect the MTF because the parallel process is not modified. However, for distances other than the near-axis approximate focal length, the MTF was most improved when the diameter of the transparent spheres was larger. Thus, the improvement in resolution in the proposed AIRR optical system is confirmed. [ABSTRACT FROM AUTHOR]