Research On Key Technologies Of Digital Imaging Cassette Of The Sensitive Film Gun Camera

Aerial gun camera is a kind of small cine-camera installed on the fighter plane(aerofoil, headpiece or seating accommodation). It is the unique equipment whichrecords the firing effect of the fighter. At present, though the film camera has beenwidely used on the domestic fighter, it's unable to satisfy the requirement of flighttraining. There are some disadvantages of film camera, such asenvironment-dependent interpretation, low interpretation precision, bad reliability,low efficiency and high cost of films. Consequently, it restricts the improvement oftraining quality.Considering the special service environment and function of gun camera, anembedded digital imaging cassette compatible to the existing gun camera is studiedand designed. The digital imaging cassette can replace the film cassette and achievethe function of recording information. Using digital imaging cassette to record firingeffect instead of film cassette will effectively improve interpretation efficiency,precision, training quality and make automatic interpretation possible.The system can capture images at 10 frames per second. The image all have onemega pixels. 4 pieces of FLASH store data time-shared without buffer andcompression. The total capability of FLASH is 512 mega bytes. Digital imagingcassette is supplied by its own battery and isolated from electrical system of thefighter to avoid the affect of strong current and electromagnetic field of the fighter.The main research work of this paper includes:1. Circuit of digital imaging cassette has been designed basing on CMOSimage sensor, several bulk-storage FLASH and CPLD.2. Theoretical study on optical units of digital imaging cassette is carried out,and a method to enlarge the gun camera's field of view by adding a concavelens before the gun camera is presented. Such a scheme can cover theshortage of the image sensor' photo-sensitive portion.3. USB data switch is designed to transfer image data from digital cassette toPC.4. The debug of the whole system is accomplished. Problems that occur duringthe debug and matters that need attention are summarized. Furthermore,some methods to improve the performance of the system are discussed.5. Based on the experiments, we come up with two methods of digital imagingof gun camera: The first one is to change the gun camera and make it as aspecial digital imaging system. If so, the gun camera will not support thefilm cassette. The second method is to enable the digital imaging cassette tofit the gun camera. Then the gun camera can work with film cassette anddigital imaging cassette. But since currently gun camera is designedspecially for film cassette, while working under such a condition the digitalimaging cassette will depress its performance such as resolution reduction,and trigger instability.