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rafat / wavelib

C Implementation of 1D and 2D Wavelet Transforms (DWT,SWT and MODWT) along with 1D Wavelet packet Transform and 1D Continuous Wavelet Transform.
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Hi, #16

Open sunyyhyzx opened 5 years ago

sunyyhyzx commented 5 years ago

Hi,

“getDWTRecCoeff” reconstructs the signal on a specific branch by setting all other branch values to zero.

getDWTRecCoeff(double coeff, int length, const char ctype, const char ext, int level, int J, double lpr, double hpr, int lf, int siglength, double *reccoeff)

Here the two important inputs are ctype (values "appx" and "det") and level which determine the branch to be reconstructed. One application of getDWTRecCoeff is to obtain Multiresolution Analysis at a specific branch that is synced with the output.

For example, one level periodic decomposition of a length 256 signal will yield two length 128 approximation and detail signals. These signals aren't very useful for direct eyeball analysis as their lengths aren't the same as that of the input. You can build length 256 signal at both branches using getDWTRecCoeff.

I will soon add more documentation about this and 2D functionality that I have implemented recently.

Rafat

On 5/21/19, sunyyhyzx notifications@github.com wrote:

Hi Rafat,

I do not konw the “getDWTRecCoeff” function very much. I can not find any help for this function. can you give me an explanatory note to Function“getDWTRecCoeff”?

And can you give an simple eample for using this function?

Any help much appreciated.

Thanks,

--Yanyun Sun From China

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https://github.com/rafat/wavelib/issues/14

Originally posted by @rafat in https://github.com/rafat/wavelib/issues/14#issuecomment-494589821

sunyyhyzx commented 5 years ago

Hi， Thank you for your warmly reply. I am a student, and now using your open code to learn the wavelet decomposition. I use function "modwt2(wt, inp)" to deconpose a grid named X and obtain the "wavecoeffs", Then I can use the function "getWT2Coeffs(wt, wavecoeffs, J, "A", &ir, &ic)" to obtain the approximation coeffs which has the same size with the input grid X. But I do not want obtain the coeffs , I want the reconstructed Wavelet Approximation Approximation throug the approximation coeffs, which function should I use? Any help much appreciated. Thank you very much! :)