This is a collection of Matlab and Python scripts to simulate seismic wave propagation in 1-D and 2-D.The wave propagation is based on the first-order acoustic wave equation in stress-velocity formulation (e.g. Virieux (1986)), which is solved by Finite-Differences on a staggered-grid.
In this repository 1-D and 2-D versions of Finite-Difference wave simulation codes are available in Matlab and Python.The source code can be found in the directory Matlab/
, Python/
and JupyterNotebook
, respectively.
Higher spatial-orders are achieved by a classical Taylor expansion.
For higher temporal-orders there are two methods available:
Lax–Wendroff method (only in 1-D). Theory: Dablain (1986)
Adams-Bashforth method. Theory: Bohlen & Wittkamp (2016)
To explore the influence of different orders of accuracy you can run the script FD_1D_compare
or FD_2D_compare
.
Moreover, in 1-D there scripts to calculate and plot the numerical dispersion as well as the numerical dissipation (Adams-Bashforth method) are provided. Up to now, this scripts are Matlab only. The underlying theory is given in Bohlen & Wittkamp (2016).
Bohlen, T., & Wittkamp, F. (2016). Three-dimensional viscoelastic time-domain finite-difference seismic modeling using the staggered Adams–Bashforth time integrator. Geophysical Journal International, 204(3), 1781-1788.
Dablain, M. A. (1986). The application of high-order differencing to the scalar wave equation. Geophysics, 51(1), 54-66.
Virieux, J. (1986). P-SV wave propagation in heterogeneous media: Velocity-stress finite-difference method. Geophysics, 51(4), 889-901.
This collection is available under the GNU General Public License v3.0. See the LICENCE
file for more information.
AEC回声抑制算法,这个比较难,目前可以使用directsound进行处理,不过只能在xp下使用,别的系统不支持! 目前gips对本算法有出色的实现,skype就是使用的该引擎! 要想自己实现,恐怕很困难! AEC 模块是 Microsoft DirectSound 底层结构的一部分。该组件包括下列特性和限制: AEC只在不超过 25×15×9 英尺的小房间才会有效; AEC只对单声道有效,
转自:http://blog.csdn.net/u011202336/article/details/9238699 背景:回声与啸叫的产生 http://blog.csdn.net/u011202336/article/details/9238397 参考资料: http://www.speex.org/docs/manual 从代码分析,下边是Speex test demo [cpp
前段时间,搞了一阵声学回声消除,非常郁闷,因为没有成功,但可以说学到一点东西吧,至少理论上懂了一点。 为什么需要声学回声消除呢?在一般的VOIP软件或视频会议系统中,假设我们只有A和B两个人在通话,首先,A的声音传给B,B然后用喇叭放出来,而这时B的MIC呢则会采集到喇叭放出来的声音,然后传回给A,如果这个传输的过程中时延足够大,A就会听到一个和自己刚才说过的话一样的声音,这就是回声,声学回声消除