Research On Imaging Adaptive Focusing System

In the optical imaging system,clear imaging is the primary problem that must be solved,and secondly,the problem of variable imaging size of the target in the field of view needs to be solved.As a core technology of the optical imaging system,automatic focusing technology has been widely used in various fields such as agriculture,industry,military,medical treatment,aerospace,etc.,from the daily use of mobile phones,tablets,digital cameras,microscopy systems,and photographic equipment As well as traffic monitoring,optical imaging systems are inseparable from theodolites,space telescopes,satellite imaging,and missile tracking.In order to better solve the two key issues of zoom and focus in the optical imaging system,this paper has conducted related research.The main work and results are as follows:1)Based on the research of the current zoom system and its imaging system principle,a new requirement for the imaging focusing system is clearly put forward:to achieve a clear image of the target without changing the target imaging size.The focusing system designed in this way can clearly capture and monitor the moving target in real time.2)In response to the needs of the adaptive focusing system,this paper studies the automatic zoom technology,compares the advantages and disadvantages of passive zoom and active zoom,and realizes the automatic zoom scheme of passive zoom mode.In the research of moving target recognition algorithm,a Vibe is proposed.A new algorithm for fusion of background difference and three-frame difference method,and the improved algorithm is evaluated.Finally,select the PETS2006 test set for experimentation.The experimental results show that the improved fusion algorithm can eliminate the "ghosting" phenomenon,and has high real-time performance,which can meet the requirements of automatic zooming.3)Research on autofocus technology,and propose an improved gradient direction threshold sharpness evaluation algorithm to quantify the image sharpness evaluation value.The improved sharpness evaluation algorithm uses local variance and global variance to improve the anti-noise performance of the algorithm,and at the same time uses the 8-direction Sobel operator to calculate the quantized value,which can eliminate the edge characteristics of the human eye.Using telephoto focal length and wide-angle focal length to conduct imaging experiments,and evaluate the improved definition algorithm,the results show that the algorithm has good real-time performance,high sensitivity and strong anti-noise ability.The specific performance is that the real-time performance is improved by 4.612% compared with the traditional algorithm,the sensitivity factor is increased by 4.21%,and the steepness is increased by 3.27%.4)Aiming at the problems of traditional focusing search algorithms that are easy to fall into local extremums,focusing mechanism motion errors,and low search efficiency of equal step length,a variable step length and adaptively variable search direction focusing search strategy is proposed.The focus direction change strategy determines the search direction,the step size adaptive adjustment strategy updates the search step size in real time,and the hill climbing algorithm idea is used to perform focus search.5)According to the automatic focusing scheme proposed in the full text,an automatic focusing system is designed on the Zynq development platform.Including hardware design,software program development,and "automatic focusing system control software" host computer design.The host computer is used to display images on the PC side in real time and control the focusing mechanism for zooming and focusing operations.After actual testing,it shows the designed automatic focusing The system can meet the requirements well,and can clearly display the targets shot in the telephoto focal length and wide-angle focal length respectively.