| The oil spill pollution on seawater is the main source of marine environmental pollution.In recent years,the bi-directional reflectance distribution functions(BRDF)is limited to the visible bandwidth and the oil-seawater contrast lacks of experiment's data in mainland.Therefore,it is a significant field for the research of the BRDF of oil spill on seawater and the oil-seawater contrast.Meanwhile,the BRDF measurement system used to measure bi-directional reflection characteristics is restricted by its structure,the smaller rotation radius and the lower positioning accuracy,therefore some adjustments need to be done for its structure and transmission methods.In addition,the limitation of optical remote sensing in terms of inaccurately identifying the oil spill pollution area from seawater and the confused boundary contrastcaused requirements for the bandwidth selection,technical parameters and the optical design.Based on the study of the spectral reflection characteristics of oil spill pollution on seawater,a bi-directional reflectance distribution function measurement system with small shielding radius,large rotation radius and accurate positioning was designed in this thesis.Meanwhile,the wide field of view airborne ultraviolet remote sensing,its key parameters,design and main technology were also presented.The main work of the thesis as following:1)The research of the optical properties of oil spill pollution on seawater consist of three parts: Firstly,the reflection characteristics between oil spill and seawater background,the bi-directional reflectance distribution function(BRDF),the oil-seawater contrast and the albedo were acquired;Secondly,the normalized solar glint of seawater and oil spill were studied and analyzed and explained the "critical point" of oil spill image at home and abroad.Thirdly,a method has been put forward to peel the sun glint received by remote sensing,thus improving signal-to-noise ratio of this optical remote sensing.2)According to the measurement demand for BRDF,the measurement system with less light obscuration,high positioning accuracy and large turning radius was designed.After determination the basic structure of the BRDF measurement system,the kinematic characteristics of the modified arc-gear synchronous belt were analyzed and the tooth bending stress and tooth surface contact stress were also described briefly.Finally,by the method of changing the location of laser spot center location,the geometric positioning accuracy was 0.21° and showing that the setting accuracy of this system meets the design requirements.3)Based on the application of visible light,thermal infrared and near ultraviolet in the field of oil spill pollution,the specifications of airborne ultraviolet were listed: the wavelength between 320 to 400 nm,relative aperture1/3.5,and field of view ±20°,instantaneous field of view 0.7143 mrad and pixel size 25?m.By the initial structure and the optimization using ZEMAX software,the imaging quality met the application requirements.Moreover,the SNR was estimated and the performance of fabrication was analyzed.Finally,the ultraviolet imaging system was integrated and the optical performance was tested.4)The BRDF of seawater and oil spill on seawater was measured by the above BRDF measurement system in the open air experiments.Through these outdoor experiments,the BRDF,the spilled oil-water contrast curve and the albedo were obtained,and it showed it had advantage for ultraviolet waveband in the application of identifying and monitoring the oil spill area on seawater.In addition,the airborne ultraviolet imaging system and this system without the ultraviolet filter were applied in the experiment of sweeping oil spill.It proved that the ultraviolet waveband can be applied to obtain the whole image of spilled oil areas,especially for the crued oil spill on sea surface. |
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