1D DWT/IDWT Demo using dwt function

Notes

1. dwt and dwt_sym functions are interchangeable in the following code as they take the same arguments.

2. Please make sure that right header file is included. Following sample program links to wavelet2d.h which is the header for shared libraries. wavelet2s.h must be included for static libraries.

Sample Code

```

//============================================================================ // Name : wavedemo1.cpp // Author : Rafat Hussain // Version : // Copyright : // Description : 1D DWT Demo //============================================================================

include

include

include "wavelet2d.h"

include

include

include

using namespace std;

int main() { cout << "******J- LEVEL DISCRETE WAVELET TRANSFORM IMPLEMENTATION*******" << endl; // prints cout << "This program accepts signal from the user in a file format " << endl; cout << "and performs Discrete Wavelet Transform with specified " << endl; cout << "wavelet. " << endl; cout << " " << endl; cout << " The Following Wavelets are in the Database: " << endl; cout << " haar, db1, db2, db3, db4, db5, db6, db7, db8, db9, db10, " << endl; cout << " db11, db12, db13, db14, db15. " << endl; cout << " bior1.1, bio1.3, bior1.5, bior2.2, bior2.4,bior2.6,bior2.8, " << endl; cout << " bior3.1, bior3.3, bior3.5, bior3.7, bior3.9, bior4.4," << endl; cout << " bior5.5, bior6.8." << endl; cout << " coif1, coif2, coif3, coif4, coif5." << endl; cout << "Please Enter the Wavelet Name at the Prompt( No quotes) :" << endl;

    string nm; // nm will store the name of Wavelet Family
    cin >> nm;
    cout << "Enter the name of signal file at the Prompt eg., signal.txt :" << endl;
    char inp[50];
    cin >> inp;
    vector<double> sig;
    ifstream sig_inp(inp);
    if ( !sig_inp.good()){
        cout << "The File doesn't exist"<< endl;
    }
    while (sig_inp) {
        double temp;
        sig_inp >> temp;
        sig.push_back(temp);
    }
    sig.pop_back();
    vector<double> original;
    original = sig;
    cout << "Please Enter the Number of DWT Stages J             :" << endl;

    int J;
    cin >> J ;

    vector<double> dwt_output, flag;

    // perform J-Level DWT
    vector<int> length;

    dwt_sym(sig, J, nm, dwt_output,flag,length);
        ofstream dwtout("dwtout.txt");
        for (unsigned int i = 0; i < dwt_output.size(); i++){
         dwtout << dwt_output[i] << endl;

    }


    //Perform J-Level IDWT
    vector<double> output;
    idwt_sym(dwt_output, flag,nm,output,length);

    ofstream sig1("recon.txt");
    ofstream diff("diff.txt");

    cout <<" Recon signal size" << output.size() << endl;
    for (unsigned int i = 0; i < output.size(); i++){
        sig1 << output[i] << endl;
        diff << output[i] - original[i] << endl;

    }
    //gnudwtplot(J);
    return 0;

}

```

This sample program asks user for wavelet name, signal file and number of DWT stages. It then computes DWT of the input signal and then the IDWT from the wavelet coefficients so obtained.

As can be seen, outputs are in .txt format but they can be modified and plotted with any software of your choice.

Length 256 Piecewise Regular signal from WaveLab

2 Level DWT Decomposition Coefficients obtained using db2 wavelet

Reconstructed Signal After IDWT computations