Techniques And Applications Research On Airborne Multispectral Digital Camera System

The major objective this thesis is the key technique research of the airborne multispectral digital camera system and its application on the remote sensing of oriental migratory locust. The main research works are list bellow: 1. An airborne multispectral digital camera system has been successfully developed based on area CCD sensors and other peripheral facilities. In fact, the whole system includes three different multispectral camera systems, Easier cameras with optical filter system, MS4100 high-resolution 3-CCD digital multispectral cameral and Kodak professional DCS760 camera. Those systems have their independent hardware and control software, and they can be used either in combine mode or separate mode. IEEE-1394 Bus and Camera Link technique are used to capture the image data. IEEE-13 94 Bus and CameraLink are the latest advance in communications interface technology for transmitting digital data. The computer, controlled by a executable program under windows operating system, provides all control functions including exposure time control, exposure interval control, retrieving images from grabber, saving images to disk array, displaying captured images for real time monitor and recording GPS information. The GPS receiver provide 1PPS pulse signal to trigger circuit, and provide the GPS locations to the control computer as well. The control programs are developed using VC++6.0, and compatible with WINDOWS NT/2000 operating system.2. For the first time in China, the airborne multispectral digital camera system was used to research the remote sensing of the oriental migratory locust. After analysing the biological and environmental characteristics of the locust, the detect method was proposed that we can monitor the spectral changes of the vegetable caused by the locusts. In august 2002, a flight experiment had been done to monitor the locust area in Nandagang farmland in Hebei province. A large amount of excellent image were acquired in this experiment. And the result denoted that the airborne remote sensing method was feasible. On the other hand, the result indicated that the newly designed digital camera systems were successful.3. For frame transfer CCD sensor, in the phase of the frame data transfering, thelight source still hit the sensors surface while part of the image was moving toward the light shielded region. So the image was polluted, and we call this frame transfer smear. In this thesis, a restoration algrithm has been proposed to recover the frame transfer smear. And effect of this algrithm had been testify by many ground and flight images.4. On the radiometric correct process of multispectral image, an in-flight statistic template correcting method was introduced. And this method was testified using 1431 multispectral images acquired in the test flight.5. After analysing the difficulties and disadvantages of the optical band register, image register method was adopted instead of the optical register. This is implemented by using the precise hardware synchronic trigger control circuit and the after flight image process. As a result, the camera heads do not need to be aligned at the precision of pixel level. The only requirement is that the field of view of all cameras is roughly the same. One more advantage of image register is that the replacement of different lens and optical filters would not be limited in this system. This will greatly enhance the system performance and adjustability.