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 （...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.展开更多
Aiming at harmonic detection, fast Fourier transform can only detect integer harmonics precisely, short time Fourier transform can detect non-integer harmonics with low resolution, and some former wavelet based method...Aiming at harmonic detection, fast Fourier transform can only detect integer harmonics precisely, short time Fourier transform can detect non-integer harmonics with low resolution, and some former wavelet based methods have no aliasing-reduction scheme which result in low measurement precision and poor robustness. A frequency-domain interpolation algorithm to detect harmonics is proposed by choosing Shannon wavelet. Shannon wavelet is an orthogonal wavelet possessing best ideal frequency domain localization ability, it can restrict wavelet abasing but bring about Gibbs oscillation phenomenon simultaneously. An interpolation algorithm is developed to overcome this problem. Simulation reveals that the proposed method can effectively cancel aliasing, spectral leakage and Gibbs phenomenon, so it provides an effective means for power system harmonic analysis.展开更多
针对平面麦克风阵列的声源三维坐标估计问题,文中在TDOA(Time Difference of Arrival)声源定位算法中引入粒子群优化算法进行位置估计。利用PHAT(Phase Transform)加权函数的广义互相关法计算得到时延差的真实值,结合麦克风的坐标位置,...针对平面麦克风阵列的声源三维坐标估计问题,文中在TDOA(Time Difference of Arrival)声源定位算法中引入粒子群优化算法进行位置估计。利用PHAT(Phase Transform)加权函数的广义互相关法计算得到时延差的真实值,结合麦克风的坐标位置,通过几何关系计算出假设声源到达麦克风之间的时延差的估计值。设计时延真实值和估计值差值的平方和为粒子适应度函数,利用粒子群优化算法搜索空间中符合适应度函数的声源点,实现声源位置估计。仿真结果表明,在计算速度与球形插值法相近的情况下,文中所提算法比球形插值法具有更好的鲁棒性和抗噪性。展开更多
基金financially supported by the National Natural Science Foundation of China(11202081,11272124,and 11472109)the State Key Lab of Subtropical Building Science,South China University of Technology(2014ZC17)
文摘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.
文摘Aiming at harmonic detection, fast Fourier transform can only detect integer harmonics precisely, short time Fourier transform can detect non-integer harmonics with low resolution, and some former wavelet based methods have no aliasing-reduction scheme which result in low measurement precision and poor robustness. A frequency-domain interpolation algorithm to detect harmonics is proposed by choosing Shannon wavelet. Shannon wavelet is an orthogonal wavelet possessing best ideal frequency domain localization ability, it can restrict wavelet abasing but bring about Gibbs oscillation phenomenon simultaneously. An interpolation algorithm is developed to overcome this problem. Simulation reveals that the proposed method can effectively cancel aliasing, spectral leakage and Gibbs phenomenon, so it provides an effective means for power system harmonic analysis.
文摘针对平面麦克风阵列的声源三维坐标估计问题,文中在TDOA(Time Difference of Arrival)声源定位算法中引入粒子群优化算法进行位置估计。利用PHAT(Phase Transform)加权函数的广义互相关法计算得到时延差的真实值,结合麦克风的坐标位置,通过几何关系计算出假设声源到达麦克风之间的时延差的估计值。设计时延真实值和估计值差值的平方和为粒子适应度函数,利用粒子群优化算法搜索空间中符合适应度函数的声源点,实现声源位置估计。仿真结果表明,在计算速度与球形插值法相近的情况下,文中所提算法比球形插值法具有更好的鲁棒性和抗噪性。
