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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - An Adaptive Multilooking Scheme for Multi-Temporal Insar Data
摘要： Multilooking is an effective speckle reduction tool for InSAR images. However, it has some limitations. Based on the De-specKS and NL-SAR algorithms, an adaptive multilooking scheme for multi-temporal InSAR data has been proposed in this paper. Simulated and real SAR datasets have been employed to evaluate the performance of this scheme. The results show that, by taking advantages of DespecKS and NL-SAR, the proposed scheme presents better detail preservation and speckle noise reduction performances comparing with these two advanced and classical multilooking algorithms.
关键词： Speckle noise reduction,multi-temporal InSAR data,NL-SAR,DespecKS,adaptive multi-looking
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE International Conference on Intelligence and Safety for Robotics (ISR) - Shenyang, China (2018.8.24-2018.8.27)] 2018 IEEE International Conference on Intelligence and Safety for Robotics (ISR) - Accelerating Noise-Free MRI Reconstruction for Image-Guided Medical Robot Interventions
摘要： Image-guided medical robot interventions require high quality medical image as well as high imaging speed. Parallel MRI reconstruction accelerates imaging speed with keeping quality of image content. An infinite impulse response (IIR) model has been proposed to improve the finite impulse response (FIR) model, which is applied in generalized auto-calibrating partially parallel acquisitions (GRAPPA) image reconstruction method. Recursive terms of IIR GRAPPA are able to improve conventional GRAPPA reconstruction quality. However it has the limitation that outliers and noise lead to poor estimation in the recursive coefficients. On the other hand, auto-regressive moving average (ARMA) is one of the most common models in time series analysis. Time series analysis is using the system time series data obtained by the curve fitting and parameter estimation to establish the mathematical model and theoretical methods. We propose a novel scheme using nonlinear ARMA (NLARMA) model to address the noise and outlier problems in IIR GRAPPA reconstruction. The proposed method extends the linear MA model which has been applied in conventional GRAPPA by incorporating both recursive and nonlinear terms. The results of experimental phantom and in vivo brain datasets illustrate the proposed method can decrease noise and aliasing artifacts comparing with conventional GRAPPA and IIR GRAPPA reconstruction.
关键词： GRAPPA,NLARMA,aliasing artifacts,IIR,ARMA,noise reduction,Parallel MRI
更新于2025-09-10 09:29:36
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Total Reflection Metasurface with Pure Modulated Signal
摘要： Metasurface has been proposed as one critical platform for orbital angular momentum (OAM) multiplexing. While metasurfaces have unique advantages to achieve light modulation with an ultrathin 2D layer, the relatively low transfer efficiency is a primary drawback. Such weakness leads to the mixing of unmodulated light into the output signal and greatly limits the functionality. A new design strategy is presented to fabricate self-filtering metasurface with pure signal light, which is computationally and experimentally verified on different applications, and it is also insensitive to the incident light polarization. Normal metasurface system requires bulky polarizer and filter, while our ultrathin design paves the way to multifunctional metasurface-based chip-scale circuits to replace the conventional bulky optical components. A proof-of-principle meta-cavity is designed to improve the transfer efficiency by 83%, while theoretical calculation shows 633% enhancement for an upgraded setup. This design can be widely applied to OAM optics, integrated photonics, optical sensing, data processing, and nanoimaging.
关键词： noise reduction,metasurfaces,nanophotonics,efficiency enhancement
更新于2025-09-04 15:30:14