资源简介
将雷达回波信号写为如下稀疏形式:
其中 为基矩阵, 为待求系数列向量。 为服从均值为0,方差为 的加性高斯噪声。目标向量 为已知元素集,包含N个变量,即 。
若每个元素独立向量 的概率密度为:
这也是系数向量 的最大似然估计,为一个二范数的求解问题(稀疏性得不到保证)。
代码片段和文件信息
function [weightsusedsigma2errbarscountalphaindexbasis] = BCS_fast_rvm(PHItsigma2etaadaptiveoptimalscale)
%------------------------------------------------------------------
% The BCS algorithm for the following paper:
% “Bayesian Compressive Sesning“ (Preprint 2007). The algorithm
% adopts from the fast RVM algorithm [Tipping & Faul 2003].
% Coded by: Shihao Ji ECE Duke University
% last change: Jan. 2 2007
% You are suggested to use mt_CS.m for improved robustness
%------------------------------------------------------------------
% Input for BCS:
% PHI: projection matrix
% t: CS measurements
% sigma2: initial noise variance
% If measurement noise exists and/or w is not truely sparse
% then sigma2 = std(t)^2/1e2 (suggested)
% If no measurement noise and w is truely sparse
% then sigma2 = std(t)^2/1e6 (suggested)
% This term is in fact not updated in the implementation to allow
% the fast algorithm. For this reason you are recommended to use
% mt_CS.m in which the noise variance is marginalized.
% eta: threshold for stopping the algorithm (suggested value: 1e-8)
% Input for Adaptive CS:
% adaptive: generate basis for adpative CS? (default: 0)
% optimal: use the rigorous implementation of adaptive CS? (default: 1)
% scale: diagonal loading parameter (default: 0.1)
% Output:
% weights: sparse weights
% used: the positions of sparse weights
% sigma2: re-estimated noise variance
% errbars: one standard deviation around the sparse weights
% basis: if adaptive==1 then basis = the next projection vector
%
if nargin < 5
adaptive = 0;
end
if nargin < 6
optimal = 1;
end
if nargin < 7
scale = 0.1;
end
% find initial alpha
[NM] = size(PHI);
PHIt = PHI‘*t;
PHI2 = sum(PHI.^2)‘;
ratio = (PHIt.^2)./PHI2;
[maxrindex] = max(ratio);
alpha = PHI2(index)/(maxr-sigma2);
% compute initial mu Sig S Q
phi = PHI(:index);
Hessian = alpha + phi‘*phi/sigma2;
Sig = 1/Hessian;
mu = Sig*PHIt(index)/sigma2;
left = PHI‘*phi/sigma2;
S = PHI2/sigma2-Sig*left.^2;
Q = PHIt/sigma2-Sig*PHIt(index)/sigma2*left;
%
for count = 1:10000
s = S; q = Q;
s(index) = alpha.*S(index)./(alpha-S(index));
q(index) = alpha.*Q(index)./(alpha-S(index));
theta = q.^2-s;
% choice the next alpha that maximizes marginal likelihood
ml = -inf*ones(1M);
ig0 = find(theta>0);
% index for re-estimate
[irefoowhich] = intersect(ig0index);
if ~isempty(ire)
Alpha = s(ire).^2./theta(ire);
delta = (alpha(which)-Alpha)./(Alpha.*alpha(which));
ml(ire) = Q(ire).^2.*delta./(S(ire).*delta+1)-log(1+S(
- 上一篇:鬼成像算法
- 下一篇:间接平差MATLAB程序
相关资源
- Pattern Recognition and Machine Learning(高清
- MATLAB 编程 第二版 Stephen J. Chapman 著
- 均值滤波和FFT频谱分析Matlab代码
- 《MATLAB扩展编程》代码
- HDB3码、AMI码的MATLAB实现
- 3点GPS定位MATLAB仿真
- MATLAB数字信号处理85个实用案例精讲入
- matlab从入门到精通pdf94795
- 欧拉放大论文及matlab代码
- 跳一跳辅助_matlab版本
- 全面详解LTE MATLAB建模、仿真与实现
- MIMO-OFDM无线通信技术及MATLAB实现_孙锴
- MATLAB Programming for Engineers 4th - Chapman
- matlab 各种谱分析对比
- 分数阶chen混沌matlab程序
- 基于粒子群算法的非合作博弈的matl
- MATLAB车流仿真 包括跟驰、延误
- matlab空间桁架计算程序
- 基于MATLAB的图像特征点匹配和筛选
- DMA-TVP-FAVAR
- GPS信号的码捕获matlab代码.7z
- 一维光子晶体MATLAB仿真代码吸收率折
- newmark法源程序
- 传统关联成像、计算鬼成像matlab
- pri传统分选算法
- 摆动滚子推杆盘形凸轮设计
- 医学图像重建作业matlab源码
- Matlab实现混沌系统的控制
- 检测疲劳驾驶
- Matlab锁相环仿真-Phase Locked Loop.rar
评论
共有 条评论