필터 지우기
필터 지우기

How to convolve a wavelet with a signal to make a wedge model?

조회 수: 3 (최근 30일)
Maria Amr
Maria Amr 2021년 1월 16일
댓글: Maria Amr 2021년 1월 27일
I would appreciate if anyone can help me as I am new in MATLANB :(.
I have a signal and I want to convolve it with a wavelet and make a wedge mode. It is a seismic wedge model.Appreciated in advance!
My wavelet code is:
%.............................................
fr=30;% frequency
dt=.002;
T=0.1;
tt=-T:dt:T;
tsh=0.008;%time shifting
tr=round(length(tt)/2);
t=tt(tr:end);
zpr=(1-tt.^2*fr^2*pi^2).*exp(-tt.^2*pi^2*fr^2);%zero-phase ricker
figure(10)
plot(zpr)
%................................................
My signal is:
%...............................................
data=xlsread('1');
amp=data(:,2);%us/f
time=data(:,1);%ms
tim=time(1:1:end);
am=amp(1:1:end);
len=length(tim);
for i=1:len
if am(i)==-999.25
am(i)=am(i-1);
end
end
data1=zeros(len,2);
tti=round(tim);
for j=2:len
r(j)=(am(j)-am(j-1))/(am(j)+am(j-1));% reflection coefficients
end
plot(r)

채택된 답변

Afshin Aghayan
Afshin Aghayan 2021년 1월 27일
I wrote the following code a long time ago (2011) that can create seismic events based on their slope like wedge model. I hope it can be useful for you.
% This function diplays siemic events based on slope
clc
number=input('How maney events do you want to see? ');
x=input('Enter number of traces : ');
d=input('Enter trace interval in m : ');
t=input('Enter maximum recording time in ms : ');
f=input('Enter frequency of the Ricker wavelet (Hz) : ');
% Ricker wavelet equal ricker=(1-2(pi*f*t)^2)*exp(-(pi*f*t)^2))
n=(0:100);
wavelet=(1-2*(pi*f*(n-50)*0.001).^2).*exp(-(pi*f*(n-50)*0.001).^2);
% Creating the impedance matrix
ImpMatrix=zeros(t,x);
for num=1:number
slope=input(['Enter slope of the event#' num2str(num) ' in degree (e.g. 0 means horizontal line) : ']);
t0=input(['Enter start time of the event#' num2str(num) ' in ms : ']);
if t0==0; t0=1; end % In the case t0=0, we assume that the event is recorded at the first sample
for i=1:x
k=d*i;
t1=k*tand(slope)+t0;
if ceil(t1)<=t && ceil(t1)>0
ImpMatrix(ceil(t1),i)=1;
end
end
end
fieldCon=conv2(ImpMatrix,wavelet','same');
field=fieldCon(1:t,:);
%================================Display===================================
if exist('wigb') == 2 % check wigb function exists
figure, wigb(field);
ylabel('Time (ms)'), xlabel('Trace no.')
ylim([1 t])
end
figure,imagesc(field)
ylabel('Time (ms)'), xlabel('Trace no.')
% Afshin Aghayan
% 2011
  댓글 수: 1
Maria Amr
Maria Amr 2021년 1월 27일
Thank you so much Afshin Aghayan,
But would you please direct me how may I apply this code to my dataset? I mean I want to apply the code to a real reflection coefficient series with a constant sampling interval (e.g. 2 ms time tickness). how should I creat an arbitrary ImpMatrix " Creating the impedance matrix" ? Really appreciated!

댓글을 달려면 로그인하십시오.

추가 답변 (0개)

카테고리

Help CenterFile Exchange에서 Geology에 대해 자세히 알아보기

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by