Studying the depth-diameter relationship of impact craters around the Oceanus Procellarum area together with values for simple crater,complex crater and basin confirms two inflections in the depth/diameter （d/D） cur...Studying the depth-diameter relationship of impact craters around the Oceanus Procellarum area together with values for simple crater,complex crater and basin confirms two inflections in the depth/diameter （d/D） curve.We classify impact craters to three types,which are simple crater,complex crater and basin.Using the most ＇pristine＇ or deepest craters in the data,three kinds of depth-diameter relationships are determined：the linear fit for simple crater is d=0.126D＋0.490 2;the best empirical power fit for complex crater is d=0.327 3D0.625 2;the best empirical power fit for basin is d=0.300 4D0.463 3,where d is the depth of the crater and D is the diameter of the crater,both in kilometers.The depth-diameter relationship for basin is characterized by a lower slope than that for complex craters,demonstrating that this morphologic transition corresponds to a further decrease in the depth of an impact structure relative to its diameter with increasing size.These relationships can then be used to estimate the theoretical depth of any impact radius,and therefore can be used to estimate the pristine shape of the crater around the Oceanus Procellarum area.The study of Oceanus Procellarum will help humankind to learn more about the origin and evolution of the moon.展开更多
A background removal method based on two-dimensional notch filtering in the frequency domain for polarization interference imaging spectrometers（PIISs） is implemented. According to the relationship between the spati...A background removal method based on two-dimensional notch filtering in the frequency domain for polarization interference imaging spectrometers（PIISs） is implemented. According to the relationship between the spatial domain and the frequency domain, the notch filter is designed with several parameters of PIISs, and the interferogram without a background is obtained. Both the simulated and the experimental results demonstrate that the background removal method is feasible and robust with a high processing speed. In addition, this method can reduce the noise level of the reconstructed spectrum, and it is insusceptible to a complicated background, compared with the polynomial fitting and empirical mode decomposition（EMD） methods.展开更多
基金supported by the 863 Key Project (No. 2004AA735020)the Chang’e Data Special Funding
文摘Studying the depth-diameter relationship of impact craters around the Oceanus Procellarum area together with values for simple crater,complex crater and basin confirms two inflections in the depth/diameter （d/D） curve.We classify impact craters to three types,which are simple crater,complex crater and basin.Using the most ＇pristine＇ or deepest craters in the data,three kinds of depth-diameter relationships are determined：the linear fit for simple crater is d=0.126D＋0.490 2;the best empirical power fit for complex crater is d=0.327 3D0.625 2;the best empirical power fit for basin is d=0.300 4D0.463 3,where d is the depth of the crater and D is the diameter of the crater,both in kilometers.The depth-diameter relationship for basin is characterized by a lower slope than that for complex craters,demonstrating that this morphologic transition corresponds to a further decrease in the depth of an impact structure relative to its diameter with increasing size.These relationships can then be used to estimate the theoretical depth of any impact radius,and therefore can be used to estimate the pristine shape of the crater around the Oceanus Procellarum area.The study of Oceanus Procellarum will help humankind to learn more about the origin and evolution of the moon.
基金supported by the Major Program of the National Natural Science Foundation of China(No.41530422)the National Science and Technology Major Project of the Ministry of Science and Technology of China(No.32-Y30B08-9001-13/15)+1 种基金the National Natural Science Foundation of China(Nos.61275184,61540018,61405153,and 60278019)the National High Technology Research and Development Program of China(No.2012AA121101)
文摘A background removal method based on two-dimensional notch filtering in the frequency domain for polarization interference imaging spectrometers（PIISs） is implemented. According to the relationship between the spatial domain and the frequency domain, the notch filter is designed with several parameters of PIISs, and the interferogram without a background is obtained. Both the simulated and the experimental results demonstrate that the background removal method is feasible and robust with a high processing speed. In addition, this method can reduce the noise level of the reconstructed spectrum, and it is insusceptible to a complicated background, compared with the polynomial fitting and empirical mode decomposition（EMD） methods.
