Stray Light Analysis And Measurement And Baffle System Design Of Microsatellite Spaceborne Remote Sensing Camera

Microsatellite spaceborne remote sensing visible light camera images terrestrial area objects. Both radiation within and out of the field of view can always bring stray light on its image plane. The stray light is unwanted and can seriously degrade image quality of the camera as its amplitude increases. In order to enhance imaging performance of the microsatellite space camera, its stray light is analyzed and its baffle system designed is improved through modeling and simulation. The veiling glare index of the camera lenses is tested with our established measurement setup.In the first chapter, the development of investigation on stray light in optical system is introduced. The necessity of study on the stray light in microsatellite remote sensing camera is described.In the second chapter, the generation mechanism and the suppress measure of stray light are presented. Based on radiation transfer theory, the principle for suppressing stray light by means of baffle, vane, extinction material, optical coating, etc is introduced.In the third chapter, after the opto-mechanism of our remote sensing camera is modeled its stray light is analyzed and then its corresponding baffle system is designed. At first, according to the optical and mechanical parameters of the camera, its opto-mechanic model is established with Lighttools software. Then considered the experience of stray light suppression and the constrained and available space within microsatellite, its main and primary baffles are designed. At last, in addition to the ghost images formed by the even reflections of its optical surfaces, its veiling glare index is analyzed and calculated through modeling the index measurement setup.In the fourth chapter, in order to further enhance its capability to suppress stray light, the above baffle designed with experience is improved. The modification includes that a conical structure is incorporated at the center of main baffle and that inner vanes are designed on the tube wall between the primary and the secondary mirrors. The simulation computation shows that the stray light performance of the improved design is nearly better one order than the former.In the fifth chapter, the veiling glare index of our camera lens is tested. Based on the principle of black-patch measurement, experiment instrument is set up with an integral sphere system. The veiling glare index of the former lens is measured It is shown that the measurement is basically consistent with above simulation result.The sixth chapter summarizes the work in the thesis, and looks ahead further tasks.