Xiaodong Gao

Aerial camera auto focusing system

Before the aerial photographic task, the cameras focusing work should be performed at first to compensate the defocus caused by the changes of the temperature, pressure etc. A new method of aerial camera auto focusing is proposed through traditional photoelectric self-collimation combined with image processing method. Firstly, the basic principles of optical self-collimation and image processing are introduced. Secondly, the limitations of the two are illustrated and the benefits of the new method are detailed. Then the basic principle, the system composition and the implementation of this new method are presented. Finally, the data collection platform is set up reasonably and the focus evaluation function curve is draw. The results showed that: the method can be used in the Aerial camera focusing field, adapt to the aviation equipment trends of miniaturization and lightweight .This paper is helpful to the further work of accurate and automatic focusing.

Calculation of the vignetting distribution caused by the reflective four-sided pyramid

The Reflective Four-Sided Pyramid can be used to divide one light beam into four beams in image space and to achieve the joint purpose of the four CCDs. It also causes the vignetting effect in the joint areas of the image. The calculation of the vignetting distribution caused by the Reflective Four-Sided Pyramid can give us the theoretical basis to guide the further work of image stitching and image luminance processing.