The Research Of Key Controlling Technology Of Continuous Zooming System

Continuous zooming lens is widely used in aviation industry,photoelectric reconnaissance,unmanned aerial vehicles and so forth,because of its good quality and high stability for long distance imaging.Optical zooming achieved by the stepping motor drive mechanism outperforms the traditional cam drove lens with severe vibration,drastic attrition,large size and low efficiency.In the continuous zooming system,the movement of the zooming and supplementary lens can precisely fall into specific pattern controlled by the algorithm inputted,as a result the quality and stability of the imaging can be guaranteed,at the meanwhile,the output focal length is precise enough to meet the requirement for precise measurement.In this thesis an introduction of the necessary background of continuous zooming lens is presented to help the reader understand the lens supplementary methodology,the automatic focus theory,the focus evaluation function,and the working mechanism of the stepping drive motor as well as its controlling techniques.International and domestic(china)literatures are also reviewed to allow the reader to get an overall idea about the current state and the most recent advance of this area.The objective of this work is to realize the photoelectric reconnaissance of the xxx unmanned aerial vehicles.The driving circuit of the stepping motor and the hardware platform are designed and built respectively according to the specific characteristics of the zooming lens and stepping motors investigated in this study.The algorithm of the zooming length controlling algorithm has been studied to meet the requirement for real-timing and stability of the continuous zooming system by applying the calibrating method.This work further investigated the widely used focus evaluation function of the automatic focus technique.A customized evaluation function is developed for our system.The real time captured images has been compared and evaluated with the function,based on which the zooming length of the lens has been re-evaluated to get the optimal results.Finally,this paper summarized the research process and achievements,imagined the following research content.