Sensitivity encoding(SENSE)is a parallel magnetic resonance imaging(MRI)reconstruction model by utilizing the sensitivity information of receiver coils to achieve image reconstruction.The existing SENSE-based reconstr...Sensitivity encoding(SENSE)is a parallel magnetic resonance imaging(MRI)reconstruction model by utilizing the sensitivity information of receiver coils to achieve image reconstruction.The existing SENSE-based reconstruction algorithms usually used nonadaptive sparsifying transforms,resulting in a limited reconstruction accuracy.Therefore,we proposed a new model for accurate parallel MRI reconstruction by combining the L0 norm regularization term based on the efficient sum of outer products dictionary learning(SOUPDIL)with the SENSE model,called SOUPDIL-SENSE.The SOUPDIL-SENSE model is mainly solved by utilizing the variable splitting and alternating direction method of multipliers techniques.The experimental results on four human datasets show that the proposed algorithm effectively promotes the image sparsity,eliminates the noise and artifacts of the reconstructed images,and improves the reconstruction accuracy.展开更多
High-speed 3D imaging via light detection and ranging(LiDAR)is critical for autonomous driving,which demands a high point acquisition rate(PAR)with extended non-ambiguity ranges.Random-modulation continuous-wave(RMCW)...High-speed 3D imaging via light detection and ranging(LiDAR)is critical for autonomous driving,which demands a high point acquisition rate(PAR)with extended non-ambiguity ranges.Random-modulation continuous-wave(RMCW)schemes leverage chaotic orthogonality to enable robust parallelization for LiDAR.However,existing RMCW parallel architectures face key limitations:parallel detection requires one detector per channel(increasing complexity),and slow-axis mechanical scanning restricts practically achievable 3D PAR to merely tens of kHz,despite nominal MHz-level PAR via spectral scanning.Here,we propose a time-stretching enhanced parallel chaotic LiDAR(TEPCL)architecture to address these issues.With an integrated microcomb configured as the pulsed chaotic source,all-optical encoding based on time-stretching assigns multi-channel chaotic pulses to distinct temporal slots,enabling single-pixel recording of all-channel signals and eliminating multi-detector needs.By introducing acousto-optic scanning to achieve inter-axis rate matching with fast-axis spectral scanning,we realize MHz-rate all-solid-state biaxial scanning.As a result,we achieve a genuine 1 MHz overall system PAR for 3D imaging via single-pixel parallel detection,with five parallel channels,a ranging accuracy of∼6 mm,and a frame rate of 432.9 fps with 2310 points per frame.Benefiting from the intrinsic orthogonality of the comb lines,the system realizes absolute unambiguous ranging and robust anti-interference capability,which can independently demodulate each channel even when their echoes are completely overlapped temporally.This compact,allsolid-state,low-complexity TEPCL system holds promise for multi-user intelligent driving and paves the way for highly integrated on-chip LiDAR.展开更多
Aiming at parallel distributed constant false alarm rate (CFAR) detection employing K/N fusion rule,an optimization algorithm based on the genetic algorithm with interval encoding is proposed. N-1 local probabilitie...Aiming at parallel distributed constant false alarm rate (CFAR) detection employing K/N fusion rule,an optimization algorithm based on the genetic algorithm with interval encoding is proposed. N-1 local probabilities of false alarm are selected as optimization variables. And the encoding intervals for local false alarm probabilities are sequentially designed by the person-by-person optimization technique according to the constraints. By turning constrained optimization to unconstrained optimization,the problem of increasing iteration times due to the punishment technique frequently adopted in the genetic algorithm is thus overcome. Then this optimization scheme is applied to spacebased synthetic aperture radar (SAR) multi-angle collaborative detection,in which the nominal factor for each local detector is determined. The scheme is verified with simulations of cases including two,three and four independent SAR systems. Besides,detection performances with varying K and N are compared and analyzed.展开更多
A low density parity check(LDPC)encoder with the codes of(8176,7154)and encoding rate of 7/8 under CCSDS standard for near space communication is designed.Based on LDPC encoding theory,the FPGA-based coding algorithm ...A low density parity check(LDPC)encoder with the codes of(8176,7154)and encoding rate of 7/8 under CCSDS standard for near space communication is designed.Based on LDPC encoding theory,the FPGA-based coding algorithm is designed.Based on the characteristics of LDPC generating matrix,the cyclic shift register is introduced as the core of the encoding circuit,and the shift-register-Adder-Accumulator(SRAA)structure is adopted to realize the fast calculation of matrix multiplication,so as to construct the encoding module with partial parallel encoding circuit as the core.In addition,the serial port input and output module,RAM storage module and control module are also designed,which together constitute the encoder system.The design scheme is implemented by FPGA hardware and verified by simulation and experiment.The results show that the test results of the designed LDPC encoder are consistent with the theoretical results.Therefore,the coding system is practical,and the design method is simple and efficient.展开更多
Given the substantially increasing complexity of embedded systems, the use of relatively detailed clock cycle-accurate simulators for the design-space exploration is impractical in the early design stages. Raising the...Given the substantially increasing complexity of embedded systems, the use of relatively detailed clock cycle-accurate simulators for the design-space exploration is impractical in the early design stages. Raising the abstraction level is nowadays widely seen as a solution to bridge the gap between the increasing system complexity and the low design productivity. For this, several system-level design tools and methodologies have been introduced to efficiently explore the design space of heterogeneous signal processing systems. In this paper, we demonstrate the effectiveness and the flexibility of the Sesame/Artemis system-level modeling and simulation methodology for efficient peformance evaluation and rapid architectural exploration of the increasing complexity heterogeneous embedded media systems. For this purpose, we have selected a system level design of a very high complexity media application;a H.264/AVC (Advanced Video Codec) video encoder. The encoding performances will be evaluated using system-level simulations targeting multiple heterogeneous multiprocessors platforms.展开更多
Implementing video applications on emerging multi-core processors is a promising technique for personal, real-time multi-media applications. However, when porting the legacy parallel video encoders developed for clust...Implementing video applications on emerging multi-core processors is a promising technique for personal, real-time multi-media applications. However, when porting the legacy parallel video encoders developed for clusters to shared-memory multi-cores, the existing parallel algorithms result in workload imbalances on different cores and communication inefficiencies. This paper describes a strip-wise parallel scheme to balance workloads and a hybrid communication mechanism to reduce communication overhead. The implementation of the H.264 parallel encoder on an eight CPU Intel Xeon system achieves 5x to 6x speed-up over a single thread encoder and achieves a 29% performance improvement over the commonly used master-slave schemes on clusters. The paper also gives further analysis on scalability, parallel efficiency, workload balance, and communication overhead as the number of cores varies.展开更多
基于JESD204B接口协议设计和实现了一种新型8B10B编码器。利用极性信息简化编码码表;利用3B4B与5B6B并行编码提升电路工作频率;利用人为加入一位均衡信息,减少逻辑处理层数。仿真结果表明,电路单元面积1 756 mm2、功耗1.13 m W及最大工...基于JESD204B接口协议设计和实现了一种新型8B10B编码器。利用极性信息简化编码码表;利用3B4B与5B6B并行编码提升电路工作频率;利用人为加入一位均衡信息,减少逻辑处理层数。仿真结果表明,电路单元面积1 756 mm2、功耗1.13 m W及最大工作频率342 m Hz,相较于传统方法具有一定的改进且完全符合JESD204B协议规范。可应用于基于JESD204B接口协议的高速串行接口的设计中。展开更多
基金the National Natural Science Foundation of China(No.61861023)the Yunnan Fundamental Research Project(No.202301AT070452)。
摘要Sensitivity encoding(SENSE)is a parallel magnetic resonance imaging(MRI)reconstruction model by utilizing the sensitivity information of receiver coils to achieve image reconstruction.The existing SENSE-based reconstruction algorithms usually used nonadaptive sparsifying transforms,resulting in a limited reconstruction accuracy.Therefore,we proposed a new model for accurate parallel MRI reconstruction by combining the L0 norm regularization term based on the efficient sum of outer products dictionary learning(SOUPDIL)with the SENSE model,called SOUPDIL-SENSE.The SOUPDIL-SENSE model is mainly solved by utilizing the variable splitting and alternating direction method of multipliers techniques.The experimental results on four human datasets show that the proposed algorithm effectively promotes the image sparsity,eliminates the noise and artifacts of the reconstructed images,and improves the reconstruction accuracy.
基金National Key Research and Development Program of China(2021YFA1401003)National Natural Science Foundation of China(U25A20518,U24A6010,52488301)。
摘要High-speed 3D imaging via light detection and ranging(LiDAR)is critical for autonomous driving,which demands a high point acquisition rate(PAR)with extended non-ambiguity ranges.Random-modulation continuous-wave(RMCW)schemes leverage chaotic orthogonality to enable robust parallelization for LiDAR.However,existing RMCW parallel architectures face key limitations:parallel detection requires one detector per channel(increasing complexity),and slow-axis mechanical scanning restricts practically achievable 3D PAR to merely tens of kHz,despite nominal MHz-level PAR via spectral scanning.Here,we propose a time-stretching enhanced parallel chaotic LiDAR(TEPCL)architecture to address these issues.With an integrated microcomb configured as the pulsed chaotic source,all-optical encoding based on time-stretching assigns multi-channel chaotic pulses to distinct temporal slots,enabling single-pixel recording of all-channel signals and eliminating multi-detector needs.By introducing acousto-optic scanning to achieve inter-axis rate matching with fast-axis spectral scanning,we realize MHz-rate all-solid-state biaxial scanning.As a result,we achieve a genuine 1 MHz overall system PAR for 3D imaging via single-pixel parallel detection,with five parallel channels,a ranging accuracy of∼6 mm,and a frame rate of 432.9 fps with 2310 points per frame.Benefiting from the intrinsic orthogonality of the comb lines,the system realizes absolute unambiguous ranging and robust anti-interference capability,which can independently demodulate each channel even when their echoes are completely overlapped temporally.This compact,allsolid-state,low-complexity TEPCL system holds promise for multi-user intelligent driving and paves the way for highly integrated on-chip LiDAR.
基金New Century Program for Excellent Talents of Minis-try of Education of China (NECT-06-0166)The Eleventh Five-year Scientific and Technological Development Plan of National Defense Pre-study Foundation (A2120060006)
摘要Aiming at parallel distributed constant false alarm rate (CFAR) detection employing K/N fusion rule,an optimization algorithm based on the genetic algorithm with interval encoding is proposed. N-1 local probabilities of false alarm are selected as optimization variables. And the encoding intervals for local false alarm probabilities are sequentially designed by the person-by-person optimization technique according to the constraints. By turning constrained optimization to unconstrained optimization,the problem of increasing iteration times due to the punishment technique frequently adopted in the genetic algorithm is thus overcome. Then this optimization scheme is applied to spacebased synthetic aperture radar (SAR) multi-angle collaborative detection,in which the nominal factor for each local detector is determined. The scheme is verified with simulations of cases including two,three and four independent SAR systems. Besides,detection performances with varying K and N are compared and analyzed.
摘要A low density parity check(LDPC)encoder with the codes of(8176,7154)and encoding rate of 7/8 under CCSDS standard for near space communication is designed.Based on LDPC encoding theory,the FPGA-based coding algorithm is designed.Based on the characteristics of LDPC generating matrix,the cyclic shift register is introduced as the core of the encoding circuit,and the shift-register-Adder-Accumulator(SRAA)structure is adopted to realize the fast calculation of matrix multiplication,so as to construct the encoding module with partial parallel encoding circuit as the core.In addition,the serial port input and output module,RAM storage module and control module are also designed,which together constitute the encoder system.The design scheme is implemented by FPGA hardware and verified by simulation and experiment.The results show that the test results of the designed LDPC encoder are consistent with the theoretical results.Therefore,the coding system is practical,and the design method is simple and efficient.
摘要Given the substantially increasing complexity of embedded systems, the use of relatively detailed clock cycle-accurate simulators for the design-space exploration is impractical in the early design stages. Raising the abstraction level is nowadays widely seen as a solution to bridge the gap between the increasing system complexity and the low design productivity. For this, several system-level design tools and methodologies have been introduced to efficiently explore the design space of heterogeneous signal processing systems. In this paper, we demonstrate the effectiveness and the flexibility of the Sesame/Artemis system-level modeling and simulation methodology for efficient peformance evaluation and rapid architectural exploration of the increasing complexity heterogeneous embedded media systems. For this purpose, we have selected a system level design of a very high complexity media application;a H.264/AVC (Advanced Video Codec) video encoder. The encoding performances will be evaluated using system-level simulations targeting multiple heterogeneous multiprocessors platforms.
基金Supported by the National Natural Science Foundation of China(No. 60236020)
摘要Implementing video applications on emerging multi-core processors is a promising technique for personal, real-time multi-media applications. However, when porting the legacy parallel video encoders developed for clusters to shared-memory multi-cores, the existing parallel algorithms result in workload imbalances on different cores and communication inefficiencies. This paper describes a strip-wise parallel scheme to balance workloads and a hybrid communication mechanism to reduce communication overhead. The implementation of the H.264 parallel encoder on an eight CPU Intel Xeon system achieves 5x to 6x speed-up over a single thread encoder and achieves a 29% performance improvement over the commonly used master-slave schemes on clusters. The paper also gives further analysis on scalability, parallel efficiency, workload balance, and communication overhead as the number of cores varies.
摘要基于JESD204B接口协议设计和实现了一种新型8B10B编码器。利用极性信息简化编码码表;利用3B4B与5B6B并行编码提升电路工作频率;利用人为加入一位均衡信息,减少逻辑处理层数。仿真结果表明,电路单元面积1 756 mm2、功耗1.13 m W及最大工作频率342 m Hz,相较于传统方法具有一定的改进且完全符合JESD204B协议规范。可应用于基于JESD204B接口协议的高速串行接口的设计中。