www.pudn.com > 666bandelets_toolbox.zip > perform_haar_transform.h

 
/*------------------------------------------------------------------------------*/ 
/**  
 *  \file   perform_haar_transform.h 
 *  \brief  Definition of class \c perform_haar_transform 
 *  \author Gabriel Peyré 
 *  \date   5-21-2005 
 */  
/*------------------------------------------------------------------------------*/ 
 
#ifndef _PERFORM_HAAR_TRANSFORM_H_ 
#define _PERFORM_HAAR_TRANSFORM_H_ 
 
#include  
 
void perform_haar_transform_1d( const double* x, double* y, int n, int Jmin, int dir=1 ) 
{
    const double a = 1.0/sqrt(2.0);
    // copy to perform inplace computation
    memcpy( y,x,n*sizeof(double) );

    if( dir==1 )
    { 
        int k = 1, t;
        double tmp; 
        /* forward transform */
        while( k<=n-1 )
        { 
            t = 0; 
            while( t+k<=n-1 ) 
            { 
                // perform a transform for y[t] and y[t+k] 
                tmp = a*(y[t]-y[t+k]); 
                y[t] = a*(y[t]+y[t+k]); 
                y[t+k] = tmp; 
                t += 2*k; 
            } 
            k *= 2; 
        }
    }
    else
    { 
        int l = log2(n-1); 
        int k = 1 << l;		// 2^l
        int t;
        double tmp; 
        /* backward transform */
        while( k>0 )
        { 
            t = 0; 
            while( t+k<=n-1 ) 
            { 
                // perform a transform for y[t] and y[t+k] 
                tmp = a*(y[t]-y[t+k]); 
                y[t] = a*(y[t]+y[t+k]); 
                y[t+k] = tmp; 
                t += 2*k; 
            } 
            if( k==1 ) 
                return; 
            k = k>>1; 
        } 
    } 
} 
 
#define X(i,j) x[i+(j)*n] 
#define Y(i,j) y[i+(j)*n] 
void perform_haar_transform_2d( const double* x, double* y, int n, int Jmin, int dir=1 ) 
{
    const double a = 1.0/sqrt(2.0);
    double tmp; 
    int k = 1, tx, ty;
    // copy to perform inplace computation
    memcpy( y,x,n*n*sizeof(double) );

    if( dir==1 )
    { 
        /* forward transform */
        while( k<=n-1 )
        { 
            // transform on X 
            for( ty=0; ty0 )
        { 
            // transform on Y 
            for( tx=0; tx>1; 
        } 
    } 
} 
 
 
#endif // _PERFORM_HAAR_TRANSFORM_H_ 
 
 
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//  Copyright (c) Gabriel Peyré 
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