An indirect imager working at terahertz band is presented and implemented,which is suitable for high-resolution planar object detection.The proposed imager employs a simple quasi-optics design to transmit and to recei...An indirect imager working at terahertz band is presented and implemented,which is suitable for high-resolution planar object detection.The proposed imager employs a simple quasi-optics design to transmit and to receive terahertz waves,and adopts incoherent detection technology to extract the intensity of echoed signal,which results in a relatively low complexity and cost.Moreover,the Fienup Fourier phase-retrieval algorithm is successfully modified and is applied to retrieve the phase of the echoed signal and reconstruct the target image.Imaging experiments on typical planar objects are performed with the imager working at 0.2 THz,and the experimental results demonstrate the good performance of the proposed imager and validate the effectiveness of the reconstruction algorithm.展开更多
We derive the TE-mode two-dimensional multi-resolution time-domain(MRTD)iterative equations based on compactly supported wavelet basis functions as Haar,Daubechies and Coifman,and we develop a basis function selectabl...We derive the TE-mode two-dimensional multi-resolution time-domain(MRTD)iterative equations based on compactly supported wavelet basis functions as Haar,Daubechies and Coifman,and we develop a basis function selectable electromagnetic scattering forward model according to the derived equations.Meanwhile,we propose a new absorbing boundary named the FDTD/PML connection absorbing boundary condition to simplify the field calculation at the boundary area.Compared with the perfectly matched layer(PML),the proposed boundary can reduce the computing cost largely,especially for high order MRTD calculation.The simulation results show that the absorbing effect of the proposed boundary is good,and the model has higher computing accuracy and cost less time to achieve convergence compared to the finite-difference time-domain(FDTD)algorithm.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11174280,60990323,and 60990320the Knowledge Innovation Program of the Chinese Academy of Sciences under Grant No YYYJ-1123.
文摘An indirect imager working at terahertz band is presented and implemented,which is suitable for high-resolution planar object detection.The proposed imager employs a simple quasi-optics design to transmit and to receive terahertz waves,and adopts incoherent detection technology to extract the intensity of echoed signal,which results in a relatively low complexity and cost.Moreover,the Fienup Fourier phase-retrieval algorithm is successfully modified and is applied to retrieve the phase of the echoed signal and reconstruct the target image.Imaging experiments on typical planar objects are performed with the imager working at 0.2 THz,and the experimental results demonstrate the good performance of the proposed imager and validate the effectiveness of the reconstruction algorithm.
基金Supported by the National Natural Science Foundation of China under Grant 61172017.
文摘We derive the TE-mode two-dimensional multi-resolution time-domain(MRTD)iterative equations based on compactly supported wavelet basis functions as Haar,Daubechies and Coifman,and we develop a basis function selectable electromagnetic scattering forward model according to the derived equations.Meanwhile,we propose a new absorbing boundary named the FDTD/PML connection absorbing boundary condition to simplify the field calculation at the boundary area.Compared with the perfectly matched layer(PML),the proposed boundary can reduce the computing cost largely,especially for high order MRTD calculation.The simulation results show that the absorbing effect of the proposed boundary is good,and the model has higher computing accuracy and cost less time to achieve convergence compared to the finite-difference time-domain(FDTD)algorithm.
