Accelerated generation of holograms with ultra-low memory symmetrically high-compressed look-up table

Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents a hologram generation method,i.e.,a symmetrically high-compressed look-up table method,which can reduce memory usage by50%.In offline computing,half of the basic horizontal and vertical modulation factors are stored,halving the memory requirements without affecting inline speed.Currently,its potential extends to various holographic applications,including the production of optical diffraction elements.

WinoNet:Reconfigurable look-up table-based Winograd accelerator for arbitrary precision convolutional neural network inference

To solve the hardware deployment problem caused by the vast demanding computational complexity of convolutional layers and limited hardware resources for the hardware network inference,a look-up table(LUT)-based convolution architecture built on a field-programmable gate array using integer multipliers and addition trees is used.With the help of the Winograd algorithm,the optimization of convolution and multiplication is realized to reduce the computational complexity.The LUT-based operator is further optimized to construct a processing unit(PE).Simultaneously optimized storage streams improve memory access efficiency and solve bandwidth constraints.The data toggle rate is reduced to optimize power consumption.The experimental results show that the use of the Winograd algorithm to build basic processing units can significantly reduce the number of multipliers and achieve hardware deployment acceleration,while the time-division multiplexing of processing units improves resource utilization.Under this experimental condition,compared with the traditional convolution method,the architecture optimizes computing resources by 2.25 times and improves the peak throughput by 19.3 times.The LUT-based Winograd accelerator can effectively solve the deployment problem caused by limited hardware resources.

A general purpose exact Rayleigh scattering look-up table for ocean color remote sensing

The current exact Rayleigh scattering calculation of ocean color remote sensing uses the look-up table （LUT）, which is usually created for a special remote sensor and cannot be applied to other sensors. For practical application, a general purpose Rayleigh scattering LUT which can be applied to all ocean color remote sensors is generated. An adding-doubling method to solve the vector radiative transfer equation in the plane-parallel atmosphere is deduced in detail. Compared with the exact Rayleigh scattering radiance derived from the MODIS exact Rayleigh scattering LUT, it is proved that the relative error of Rayleigh scattering calculation with the adding-doubling method is less than 0.25%, which meets the required accuracy of the atmospheric correction of ocean color remote sensing. Therefore, the adding-doubling method can be used to generate the exact Rayleigh scattering LUT for the ocean color remote sensors. Finally, the general purpose exact Rayleigh scattering LUT is generated using the adding-doubling method. On the basis of the general purpose LUT, the calculated Rayleigh scattering radiance is tested by comparing with the LUTs ofMODIS, SeaWiFS and the other ocean color sensors, showing that the relative errors are all less than 0.5%, and this general purpose LUT can be applied to all ocean color remote sensors.

Fine Doppler shift acquisition algorithm for BeiDou software receiver by a look-up table

The BeiDou software receiver uses the fast Fourier transform(FFT)to perform the acquisition.The Doppler shift estimation accuracy should be less than 500 Hz to ensure satellite signals to enter a locked state in the tracking loop.Since the frequency step is usually 500 Hz or larger,the Doppler shift estimation accuracy cannot guarantee that satellite signals are brought into a stable tracking state.The straightforward solutions consist in increasing the sampling time and using zero-padding to improve the frequency resolution of the FFT.However,these solutions intensify the complexity and amount of computation.The contradiction between the acquisition accuracy and the computational load leads us to research for a more simple and effective algorithm,which achieves fine acquisition by a look-up table.After coarse acquisition using the parallel frequency acquisition(PFA)algorithm,the proposed algorithm optimizes the Doppler shift estimation through the look-up table method based on the FFT results to improve the acquisition accuracy of the Doppler shift with a minimal additional computing load.When the Doppler shift is within the queryable range of the table,the proposed algorithm can improve the Doppler shift estimation accuracy to 50 Hz for the BeiDou B1I signal.

Performance of global look-up table strategy in digital image correlation with cubic B-spline interpolation and bicubic interpolation

Global look-up table strategy proposed recently has been proven to be an efficient method to accelerate the interpolation, which is the most time-consuming part in the iterative sub-pixel digital image correlation （DIC） algorithms. In this paper, a global look-up table strategy with cubic B-spline interpolation is developed for the DIC method based on the inverse compositional Gauss-Newton （IC-GN） algorithm. The performance of this strategy, including accuracy, precision, and computation efficiency, is evaluated through a theoretical and experimental study, using the one with widely employed bicubic interpolation as a benchmark. The global look-up table strategy with cubic B-spline interpolation improves significantly the accuracy of the IC-GN algorithm-based DIC method compared with the one using the bicubic interpolation, at a trivial price of computation efficiency.

Research of NO_(2) vertical profiles with look-up table method based on MAX-DOAS

Obtaining the vertical distribution profile of trace gas is of great significance for studying the diffusion procedure of air pollution.In this article,a look-up table method based on multi-axis differential optical absorption spectroscopy(MAX-DOAS)technology is established for retrieving the tropospheric NO_(2) vertical distribution profiles.This method retrieves the aerosol extinction profiles with minimum cost function.Then,the aerosol extinction profiles and the atmospheric radiation transfer model(RTM)are employed to establish the look-up table for retrieving the NO_(2) vertical column densities(VCDs)and profiles.The measured NO_(2) differential slant column densities(DSCDs)are compared with the NO_(2) DSCDs simulated by the atmospheric RTM,and the NO_(2) VCDs,the weight factor of NO_(2) in the boundary layer,and the boundary layer height are obtained by the minimization process.The look-up table is established to retrieve NO_(2) VCDs based on MAX-DOAS measurements in Huaibei area,and the results are compared with the data from Copernicus Atmospheric Monitoring Service(CAMS)model.It is found that there are nearly consistent and the correlation coefficient R2 is more than 0.86.The results show that this technology provides a more convenient and accurate retrieval method for the stereoscopic monitoring of atmospheric environment.

Atmospheric CO_2 retrieval with a look-up-table based method by combining near and thermal infrared spectra

In order to precisely retrieve the atmospheric CO2 , a retrieval method based on both near infrared （NIR） and thermal infrared （TIR） is established firstly. Then a look-up-table （LUT） based fast line-by-line radiative transfer model （RTM） was integrated into the retrieval procedure to accelerate radiative transfer calculations. The LUT stores gas absorption cross-sections as a function of temperature, pressure and wavenumber. It could greatly reduce calculating time in radiative transfer compared to direct line-by-line method. Then retrieval was simulated using NIR, TIR and both bands. The retrieved CO2 profiles suggest joint approach could reconstruct CO2 profile better than those using NIR or TIR alone. Joint retrieval using both bands simultaneously could provide better constrain to CO2 vertical distribution in the whole troposphere.

利用LUT替换的FPGA保护数字水印技术

提出一种新的基于查找表替换的IP核数字水印技术,利用基于存储式逻辑阵列块(Memory Logic ArrayBlock,MLAB)的RAM结构替换原设计文件中的查找表,在其中添加水印数据.使用此方法使嵌入的水印可以避免被优化工具删除,提高了数字水印的安全性.实验表明,此方法嵌入数字水印的效率高,资源开销较低,优于其它基于查找表的数字水印方法.

FPGA芯片的链结构LUT自测试方法研究

基于内建自测试(BIST)思想的FPGA测试方法利用被测芯片中的资源来构建测试所需的TPG或ORA,以减少测试对输入输出引脚和外部ATE的需求。传统的FPGA芯片BIST方法仅考虑自测试结构内被配置为CUT的资源,从而需要进行多次组测试来完成整个芯片的测试。在现有LUT自测试链结构的基础上,通过合理选择TPG的电路结构及测试配置,能够在相同测试开销下增加TPG部分的故障覆盖率,提高测试效率。

Differential Spatial Modulation Mapping Algorithms

Differential spatial modulation(DSM)is a multiple-input multiple-output(MIMO)transmission scheme.It has attracted extensive research interest due to its ability to transmit additional data without increasing any radio frequency chain.In this paper,DSM is investigated using two mapping algorithms:Look-Up Table Order(LUTO)and Permutation Method(PM).Then,the bit error rate(BER)performance and complexity of the two mapping algorithms in various antennas and modulation methods are verified by simulation experiments.The results show that PM has a lower BER than the LUTO mapping algorithm,and the latter has lower complexity than the former.

Area and Speed Efficient Implementation of Symmetric FIR Digital Filter through Reduced Parallel LUT Decomposed DA Approach

This brief proposes an area and speed efficient implementation of symmetric finite impulse response (FIR) digital filter using reduced parallel look-up table (LUT) distributed arithmetic (DA) based approach. The complexity lying in the realization of FIR filter is dominated by the multiplier structure. This complexity grows further with filter order, which results in increased area, power, and reduced speed of operation. The speed of operation is improved over multiply-accumulate approach using multiplier less conventional DA based design and decomposed DA based design. Both the structure requires B clock cycles to get the filter output for the input width of B, which limits the speed of DA structure. This limitation is addressed using parallel LUTs, called high speed DA FIR, at the expense of additional hardware cost. With large number of taps, the number of LUTs and its size also becomes large. In the proposed method, by exploiting coefficient symmetry property, the number of LUTs in the decomposed DA form is reduced by a factor of about 2. This proposed approach is applied in high speed DA based FIR design, to obtain area and speed efficient structure. The proposed design offers around 40% less area and 53.98% less slice-delay product (SDP) than the high throughput DA based structure when it’s implemented over Xilinx Virtex-5 FPGA device-XC5VSX95T-1FF1136 for 16-tap symmetric FIR filter. The proposed design on the same FPGA device, supports up to 607 MHz input sampling frequency, and offers 60.5% more speed and 67.71% less SDP than the systolic DA based design.

基于LUT的多目机场视频实时拼接算法设计与实现

针对机场中多路实时视频信号的情况,开展了8路视频实时全景拼接的算法研究工作,基本完成了8路视频实时全景拼接算法的设计与实现。首先,借助现有全景图片合成软件,完成了图像配准,即找出每路视频图像到全景图的像素坐标映射关系;完成图像配准之后,根据像素坐标映射关系建立查找表,利用查找表,同时使用OpenMP多核并行加速,完成视频每一帧的实时拼接。相邻两路视频之间的重叠区域使用线性融合的方法进行融合。实验结果表明,该研究方法可完成8路960×540分辨率视频的实时全景拼接,得到无明显畸变全景画面。

基于分布式算法的线性相位滤波器设计及优化

设计了一种实现等波纹带通滤波的线性相位FIR滤波器,分布式算法被用于具体实现过程,并在此基础上进行优化。根据Ⅰ类线性相位滤波器的系数特点,对滤波器进行降阶。通过拆分查找表,减少查找表的规模,从而减小芯片面积。采用并行计算改进分布式算法体系结构,提高运算速度。最后,用Modelsim对不同频率正弦信号进行滤波仿真。

The establishment of crystal position look-up table for positron emission tomography with block detectors

A method has been developed to establish the crystal position look-up table for positron emission tomography with block detectors. It is based on the principle that the counts in crystal position histogram obey the Gaussian mixture model (GMM). This method has taken full consideration of the characteristics of the GMM and the detector itself. The experimental results have proved that it is simple, reliable, and universal.

CRC Look-up Table Optimization for Single-Bit Error Correction

Many communication systems use the cyclic redundancy code （CRC） technique for protecting key data fields from transmission errors by enabling both single-bit error correction and multi-bit error detection. The look-up table design is very important for the error-correction implementation. This paper presents a CRC look-up table optimization method for single-bit error correction. The optimization method minimizes the address length of the pre-designed look-up table while satisfying certain restrictions. The circuit implementation is also presented to show the feasibility of the method in the application specific integrated circuit design. An application of the optimization method in the generic framing procedure protocol is implemented using field programmable gatearrays. The result shows that the memory address length has been minimized, while keeping a very simple circuit implementation.

Device and circuit analysis of a sub 20 nm double gate MOSFET with gate stack using a look-up-table-based approach

In this paper, we explore the possibility of mapping devices designed in TCAD environment to its modeled version developed in cadence virtuoso environment using a look-up table （LUT） approach. Circuit simu- lation of newly designed devices in TCAD environment is a very slow and tedious process involving complex scripting. Hence, the LUT based modeling approach has been proposed as a faster and easier alternative in ca- dence environment. The LUTs are prepared by extracting data from the device characteristics obtained from device simulation in TCAD. A comparative study is shown between the TCAD simulation and the LUT-based alternative to showcase the accuracy of modeled devices. Finally the look-up table approach is used to evaluate the perform- ance of circuits implemented using 14 nm nMOSFET.

Accurate and fast table look-up models for leakage current analysis in 65nm CMOS technology

Novel physical models for leakage current analysis in 65 nm technology are proposed. Taking into consideration the process variations and emerging effects in nano-scaled technology, the presented models are capable of accurately estimating the subthreshold leakage current and junction tunneling leakage current in 65 nm technology. Based on the physical models, new table look-up models are developed and first applied to leakage current analysis in pursuit of higher simulation speed. Simulation results show that the novel physical models are in excellent agreement with the data measured from the foundry in the 65 nm process, and the proposed table look-up models can provide great computational efficiency by using suitable interpolation techniques. Compared with the traditional physical-based models, the table look-up models can achieve 2.5X speedup on average on a variety of industry circuits.

高分2号图像业务化大气校正查找表的设计与实现

为实现高分2号图像(GF2)业务化大气校正,利用矢量6S模型(6SV)将辐射传输散射与吸收进行分离计算,其中散射部分采用涵盖各种大气模式、气溶胶类型、成像几何等条件下的大气校正查找表(look-up tables,LUTs)表示,大气吸收部分采用6SV拟合计算的6种大气模式下大气透过率的经验公式表示,这种处理有效简化了查找表大小.在内存4 GB、主频3.10 GHz条件下,通过比较基于本查找表方法和基于FLAASH大气校正软件对北京地区一景GF2数据处理.结果表明:以6SV模型直接大气校正法结果作为真值,两者的绝对误差分别为0.8%和2.6%,处理时间分别为77 s和240 s,该大气校正查找表在处理精度和效率更加适合业务化大气校正.

查找表联合记忆效应补偿技术的宽带自适应预失真算法

为了能够对记忆型功率放大器线性化处理,并能一定程度克服其记忆效应,该文介绍一种自适应数字预失真器。该数字预失真器采用查找表与记忆效应补偿技术相结合的方法,并且利用内插值方法有效减小了查找表幅度量化过程产生的误差。相比记忆多项式预失真器,这种预失真器的计算复杂度较小,却能够得到与其相近的线性化效果。基于功率放大器记忆多项式模型,利用OFDM(Orthogonal Frequency Division Multiplexing)宽带信号验证该文提出的预失真器对记忆型非线性功率放大器的良好线性化效果。

结合SVM分类器与HOG特征提取的行人检测

针对基于方向梯度直方图(HOG)的行人检测方案存在运算量大、实时性差的问题,设计一个内嵌支持向量机(SVM)分类器的HOG特征提取归一化模块,并将其应用于行人检测。提出两级流水线架构,第1级采用16×16像素块扫描,并结合查找表的方式生成HOG,以减少乘法器资源消耗量,第2级将15路并行SVM内嵌到HOG归一化模块中,通过提前启动SVM降低15路SVM乘累加器的位宽。利用面向硬件实现的自动消除检测重复性算法,进一步提高检测准确性。实验结果表明,该方案能够以100 MHz时钟频率运行在Spartan6 FPGA芯片上,每秒可处理47帧SVGA(800×600)分辨率的图像,具有较高的行人检测实时性和准确率。