平面偏振光在某些晶体内沿其轴方向传播时,虽然没有发生双折射,却发现透射光的振动面对于原入射光的振动面旋转了一个角度,晶体的这种性质称为旋光性。后来从实验中发现,某些液体也具有旋光性,如果迎着光的传播方向看,旋光性物质使振动...平面偏振光在某些晶体内沿其轴方向传播时,虽然没有发生双折射,却发现透射光的振动面对于原入射光的振动面旋转了一个角度,晶体的这种性质称为旋光性。后来从实验中发现,某些液体也具有旋光性,如果迎着光的传播方向看,旋光性物质使振动面沿顺时针方向旋转,称为右旋物质;使振动面沿逆时针方向旋转,称为左旋物质。实验表明,振动面旋转的角度Φ与其所通过的旋光性物质的厚度 L 成正比;若为液体,则又正比于溶液的浓度 C,此外,旋转角还与入射光波长及溶液温度等有关。对溶液来说,振动面的旋转角:展开更多
An optimization of polarimetric contrast enhancement method is proposed to detect ships with lowship-to-clutter power ratio.The received power is calculated with Kennaugh matrix and an iterative algo-rithm is adopted ...An optimization of polarimetric contrast enhancement method is proposed to detect ships with lowship-to-clutter power ratio.The received power is calculated with Kennaugh matrix and an iterative algo-rithm is adopted to get the optimal polarimetric states.The optimization method depresses the power of o-cean clutter and increases the power of ship signal.With the double effects,the contrast of ship to oceanis dramatically increased.Thus small ship or weak signals of low ship-to-ocean power ratio can easily bedetected.Ship signals can be distinguished from speckle noise using the different variation trend after op-timization,and thus the threshold problem can be avoided.Moreover,the analyses of different ship'sKennaugh matrices give two implications.One is that the results are affected little by choosing differentKennaugh matrices of ships with strong intensity from Synthetic Aperture Radar(SAR)images.The otheris that ship's Kennaugh matrix chosen from real SAR images is more favorable than that of ideal scatter-ing.Finally,the optimization results are confirmed by polarimetric scattering angle and co-polarizationphase difference.展开更多
文摘平面偏振光在某些晶体内沿其轴方向传播时,虽然没有发生双折射,却发现透射光的振动面对于原入射光的振动面旋转了一个角度,晶体的这种性质称为旋光性。后来从实验中发现,某些液体也具有旋光性,如果迎着光的传播方向看,旋光性物质使振动面沿顺时针方向旋转,称为右旋物质;使振动面沿逆时针方向旋转,称为左旋物质。实验表明,振动面旋转的角度Φ与其所通过的旋光性物质的厚度 L 成正比;若为液体,则又正比于溶液的浓度 C,此外,旋转角还与入射光波长及溶液温度等有关。对溶液来说,振动面的旋转角:
基金This work was supported by grant No.9187006-02 of the Chinese National Science Foundation(Major Item)grant No.1870605 of the Chinese National Science Foundationand Key Item of Chinese Academy of Science No.87-64-10.
基金the High Technology Research and Development Programme of China(No.2002AA633120)Sharing and Opening Projects of ENVISAT ASAR Data
文摘An optimization of polarimetric contrast enhancement method is proposed to detect ships with lowship-to-clutter power ratio.The received power is calculated with Kennaugh matrix and an iterative algo-rithm is adopted to get the optimal polarimetric states.The optimization method depresses the power of o-cean clutter and increases the power of ship signal.With the double effects,the contrast of ship to oceanis dramatically increased.Thus small ship or weak signals of low ship-to-ocean power ratio can easily bedetected.Ship signals can be distinguished from speckle noise using the different variation trend after op-timization,and thus the threshold problem can be avoided.Moreover,the analyses of different ship'sKennaugh matrices give two implications.One is that the results are affected little by choosing differentKennaugh matrices of ships with strong intensity from Synthetic Aperture Radar(SAR)images.The otheris that ship's Kennaugh matrix chosen from real SAR images is more favorable than that of ideal scatter-ing.Finally,the optimization results are confirmed by polarimetric scattering angle and co-polarizationphase difference.
