Platform Jitter Effect On Image Quality Of Spaceborne TDICCD Camera

With the expansion of information needs, using aerospace technology to obtainremote sensing images of high quality and extract useful information from themhave broad application prospects in many fields. TDICCD works in multistage delayintegration way in order to increase light energy and improve SNR. It can obtainhigh quality images without decreasing system resolution and working speed whichhas became the main technology for increasing the performance of remote sensor.However, during the satellite’s on-orbit working process, the reaction flywheel、solarpanels、moment gyroscope and other components can produced vibration which willmake the space borne remote sensor jitter. Jitter will cause image point fuzzy duringthe exposure time and lead image quality decrease. With the development ofspacecraft attitude control technology, platform isolation method and optical systemdesign, ground resolution of remote sensor continuously improves. Jitter has becomean important factor affecting the quality of high resolution remote sensing image. Tostudy the influence law of jitter to image quality of high resolution remote sensing,and propose constraints to the design of the system’s stability and vibration isolationthrough quantitative analysis is of great significance. Paper’s main works are asfollows.First of all, the vibration of satellite platform was discussed. Mechanism ofimage blur and geometric deformation due to vibration was analyzed based on Line Spread Function. Though analyzing the effect of image motion on the imagingprocess of TDICCD camera, proposed the numerical calculation formulas ofModulation Transfer Function caused by linear vibration、sinusoidal vibration andrandom vibration. The relationship between vibration and image degradation wasdiscussed as an example with sinusoidal vibration.Secondly, relationship between the ground object and image was established bythe method of homogeneous coordinate transformation. Simulation model ofdynamic imaging of TDICCD according to the imaging principle of samplingsystem was put forward. Numerical integration and pixel interpolation combiningwith principle of charge superposition were used in the model. Based on thesimulation model, the influence of jitter parameters on the image quality werediscussed detailedly. Mean Square Error and Structural Similarity IndexMeasurement were adopted to evaluate the quality of simulated images. UsingMTF=0.95as the constraint condition to obtain the amplitude-frequency curve ofsinusoidal vibration.Thirdly, micro-vibration experiment of XX space camera was introduced. Themethod of dealing with experiment data was put forward to analyze the influence ofplatform jitter on image quality. Then the influence on image quality under differentworking conditions was evaluated using MTF.At last, physical simulation platform of jitter imaging was established based onmodal vibration exciter and high-speed CCD camera. Jitter imaging conditionsinvolved in simulation experiments are simulated and the validity of the simulation’sconclusions was proved.