Gaussian beam migration （GBM） is an effec- tive and robust depth seismic imaging method, which overcomes the disadvantage of Kirchhoff migration in imaging multiple arrivals and has no steep-dip limitation of one-wa...Gaussian beam migration （GBM） is an effec- tive and robust depth seismic imaging method, which overcomes the disadvantage of Kirchhoff migration in imaging multiple arrivals and has no steep-dip limitation of one-way wave equation migration. However, its imaging quality depends on the initial beam parameters, which can make the beam width increase and wave-front spread with the propagation of the central ray, resulting in poor migration accuracy at depth, especially for exploration areas with complex geological structures. To address this problem, we present an adaptive focused beam method for shot-domain prestack depth migration. Using the infor- mation of the input smooth velocity field, we first derive an adaptive focused parameter, which makes a seismic beam focused along the whole central ray to enhance the wave- field construction accuracy in both the shallow and deep regions. Then we introduce this parameter into the GBM, which not only improves imaging quality of deep reflectors but also makes the shallow small-scale geological struc- tures well-defined. As well, using the amplitude-preserved extrapolation operator and deconvolution imaging condi- tion, the concept of amplitude-preserved imaging has been included in our method. Typical numerical examples and the field data processing results demonstrate the validity and adaptability of our method.展开更多
The fluorescence from the out-of-focus region excited by the sidelobes of a Bessel beam is the major concern for light-sheet fluorescence microscopy （LSFM） with Bessel beam plane illumination. Here, we propose a met...The fluorescence from the out-of-focus region excited by the sidelobes of a Bessel beam is the major concern for light-sheet fluorescence microscopy （LSFM） with Bessel beam plane illumination. Here, we propose a method of applying the subtractive imaging to overcome the limitation of the conventional LSFM with Bessel beam plane illumination. In the proposed method, the sample is imaged twice by line scanning using the extended solid Bessel beam and the ring-like Bessel beam. By subtracting between the two images with similar out-of-focus blur, the improved image quality with the suppression of the Bessel beam sidelobes and enhanced sectioning ability with improved contrast are demonstrated.展开更多
A fluorescence detection scheme is applied to image an atomic beam. Using two laser diodes as the sources of detection light and pumping light respectively, the fluorescence image of the atomic beam is then observed b...A fluorescence detection scheme is applied to image an atomic beam. Using two laser diodes as the sources of detection light and pumping light respectively, the fluorescence image of the atomic beam is then observed by a commercial CCD-camera, which is corresponding to the atomic state and velocity distribution. The detection scheme has a great utilization in the experiments of cold atoms and atomic optics.展开更多
The work proposes a three-laser-beam streak tube imaging lidar system. Besides the main measuring laser beam,the second beam is used to decrease the error of time synchronization. The third beam has n＋0.5 pixels＇ di...The work proposes a three-laser-beam streak tube imaging lidar system. Besides the main measuring laser beam,the second beam is used to decrease the error of time synchronization. The third beam has n＋0.5 pixels＇ difference compared to the main measuring beam on a CCD, and it is used to correct the error caused by CCD discrete sampling. A three-dimensional（3D） imaging experiment using this scheme is carried out with time bin size of 0.066 ns（i.e., corresponding to a distance of 9.9 mm）. An image of a 3D model is obtained with the depth resolution of 〈2 mm, which corresponds to ~0.2 pixel.展开更多
文摘Gaussian beam migration （GBM） is an effec- tive and robust depth seismic imaging method, which overcomes the disadvantage of Kirchhoff migration in imaging multiple arrivals and has no steep-dip limitation of one-way wave equation migration. However, its imaging quality depends on the initial beam parameters, which can make the beam width increase and wave-front spread with the propagation of the central ray, resulting in poor migration accuracy at depth, especially for exploration areas with complex geological structures. To address this problem, we present an adaptive focused beam method for shot-domain prestack depth migration. Using the infor- mation of the input smooth velocity field, we first derive an adaptive focused parameter, which makes a seismic beam focused along the whole central ray to enhance the wave- field construction accuracy in both the shallow and deep regions. Then we introduce this parameter into the GBM, which not only improves imaging quality of deep reflectors but also makes the shallow small-scale geological struc- tures well-defined. As well, using the amplitude-preserved extrapolation operator and deconvolution imaging condi- tion, the concept of amplitude-preserved imaging has been included in our method. Typical numerical examples and the field data processing results demonstrate the validity and adaptability of our method.
基金supported by the National Natural Science Foundation of China(Nos.61665006,61661028,61565012,and 61378062)the Natural Science Foundation of Jiangxi Province(Nos.20161BAB212041,20162BCB23012,and 20171ACB21018)
文摘The fluorescence from the out-of-focus region excited by the sidelobes of a Bessel beam is the major concern for light-sheet fluorescence microscopy （LSFM） with Bessel beam plane illumination. Here, we propose a method of applying the subtractive imaging to overcome the limitation of the conventional LSFM with Bessel beam plane illumination. In the proposed method, the sample is imaged twice by line scanning using the extended solid Bessel beam and the ring-like Bessel beam. By subtracting between the two images with similar out-of-focus blur, the improved image quality with the suppression of the Bessel beam sidelobes and enhanced sectioning ability with improved contrast are demonstrated.
文摘A fluorescence detection scheme is applied to image an atomic beam. Using two laser diodes as the sources of detection light and pumping light respectively, the fluorescence image of the atomic beam is then observed by a commercial CCD-camera, which is corresponding to the atomic state and velocity distribution. The detection scheme has a great utilization in the experiments of cold atoms and atomic optics.
基金supported by the National Key Scientific Instrument and Equipment Development Projects of China(No.2012YQ040164)
文摘The work proposes a three-laser-beam streak tube imaging lidar system. Besides the main measuring laser beam,the second beam is used to decrease the error of time synchronization. The third beam has n＋0.5 pixels＇ difference compared to the main measuring beam on a CCD, and it is used to correct the error caused by CCD discrete sampling. A three-dimensional（3D） imaging experiment using this scheme is carried out with time bin size of 0.066 ns（i.e., corresponding to a distance of 9.9 mm）. An image of a 3D model is obtained with the depth resolution of 〈2 mm, which corresponds to ~0.2 pixel.
