- n stands for what?
- 2.559375 where this number comes from?
- deriv=(val(n,:))/2.559375; i dont undrstand 'val' it gives error when i run it and says fix val with eval and again gives me error
How to calculate the energy of details and approxmiations coefficients of discret wavelet transform ?
조회 수: 5 (최근 30일)
이전 댓글 표시
Hi everyone, i calculate the energy of details and approxmiations coefficients of discret wavelet transform .i used DWT(Daub4) Here is the code
for n=1:23
deriv=(val(n,:))/2.559375;
t=(0:length(deriv)-1)/Fs;
result{n} = filtfilt(d1,deriv);
[c,l]=wavedec(result{n},4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea,Ed]=wenergy(c,l)
energie{n} = {Ea, Ed};
end
And when i was looking for the formula of the energy i found this :
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/166203/image.png)
and as i understand the energy is the percentage of energy corresponding to the approximation and the details
So when i was trying to write a C code using this formula and the values of cd1,cd2,cd3,cd4 i don't get the same values that i have with matlab So i want to know where i wrong ?
i mean to calcuate the energy i should use [cd1,cd2,cd3,cd4]??
Please i need a clarification,Thanks
댓글 수: 1
Ewunate Assaye Kassaw
2020년 6월 18일
hello sir
it gives me a hint thanks for that
i have questions
can you help me please?
답변 (2개)
Jiaxin Tu
2019년 2월 28일
That's because wenergy gives the percentage of power out of 100.
If you divide your calculations with the formula by the sum of energy *100 you will get the same answer
댓글 수: 0
Ewunate Assaye Kassaw
2020년 6월 18일
hello sir
it gives me a hint thanks for that
i have questions
- n stands for what?
- 2.559375 where this number comes from?
- deriv=(val(n,:))/2.559375; i dont undrstand 'val' it gives error when i run it and says fix val with eval and again gives me error
can you help me please?
댓글 수: 0
참고 항목
카테고리
Help Center 및 File Exchange에서 Discrete Multiresolution Analysis에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!