Discussion :

[FST_PFE]

Salut,
je suis entrain de faire l'augmentation de d'image d'empreinte digitale en utilisant
le Transformée de Fourier TF dont le principe est le suivant:
on divise l'image en blocs de 32*32 pixels et à chaque bloc, on applique le TF on obtient F(u,V), ensuite on le multuplie par son amplitude puissance k=1.4, enfin on applique au resultat le Inverse de TF on obtient donc l'image augmenté.

je suis besoin d'aide pour le coder.j'ai déja commencé mais je me suis bloqué au niveau de multiplication de spectre par l'amplitude^k.

Merci d'avance

[ammar_diabolo]

Est ce que tu peut écrire ton code pour t'aider

[FST_PFE]

Salut,voila le code:

#include <cxcore.h>
#include <cv.h>
#include <highgui.h>

IplImage *copySubImage(IplImage *img,int xorigine,int yorigine,int width,int height)
{
CvRect roi;
IplImage *resultat;
roi.x= xorigine;
roi.y=yorigine;
roi.width=width;
roi.height=height;
cvSetImageROI(img,roi);
resultat=cvCreateImage(cvSize(roi.width,roi.height),img->depth,img->Channels );
cvCopy(im,resultat);
cvResetImageROI(img);
return resultat;
}

// Rearrange the quadrants of Fourier image so that the origin is at
// the image center
// src & dst arrays of equal size & type
void cvShiftDFT(CvArr * src_arr, CvArr * dst_arr )
{
CvMat * tmp;
CvMat q1stub, q2stub;
CvMat q3stub, q4stub;
CvMat d1stub, d2stub;
CvMat d3stub, d4stub;
CvMat * q1, * q2, * q3, * q4;
CvMat * d1, * d2, * d3, * d4;

CvSize size = cvGetSize(src_arr);
CvSize dst_size = cvGetSize(dst_arr);
int cx, cy;

if(dst_size.width != size.width ||
dst_size.height != size.height){
cvError( CV_StsUnmatchedSizes, "cvShiftDFT", "Source and Destination arrays must have equal sizes", __FILE__, __LINE__ );
}

if(src_arr==dst_arr){
tmp = cvCreateMat(size.height/2, size.width/2, cvGetElemType(src_arr));
}

cx = size.width/2;
cy = size.height/2; // image center

q1 = cvGetSubRect( src_arr, &q1stub, cvRect(0,0,cx, cy) );
q2 = cvGetSubRect( src_arr, &q2stub, cvRect(cx,0,cx,cy) );
q3 = cvGetSubRect( src_arr, &q3stub, cvRect(cx,cy,cx,cy) );
q4 = cvGetSubRect( src_arr, &q4stub, cvRect(0,cy,cx,cy) );
d1 = cvGetSubRect( src_arr, &d1stub, cvRect(0,0,cx,cy) );
d2 = cvGetSubRect( src_arr, &d2stub, cvRect(cx,0,cx,cy) );
d3 = cvGetSubRect( src_arr, &d3stub, cvRect(cx,cy,cx,cy) );
d4 = cvGetSubRect( src_arr, &d4stub, cvRect(0,cy,cx,cy) );

if(src_arr!=dst_arr){
if( !CV_ARE_TYPES_EQ( q1, d1 )){
cvError( CV_StsUnmatchedFormats, "cvShiftDFT", "Source and Destination arrays must have the same format", __FILE__, __LINE__ );
}
cvCopy(q3, d1, 0);
cvCopy(q4, d2, 0);
cvCopy(q1, d3, 0);
cvCopy(q2, d4, 0);
}
else{
cvCopy(q3, tmp, 0);
cvCopy(q1, q3, 0);
cvCopy(tmp, q1, 0);
cvCopy(q4, tmp, 0);
cvCopy(q2, q4, 0);
cvCopy(tmp, q2, 0);
}
}

int main(int argc, char ** argv)
{

IplImage * im;
IplImage * img;

IplImage * realInput;
IplImage * imaginaryInput;
IplImage * complexInput;
int dft_M, dft_N;
CvMat* dft_A, tmp;
IplImage * image_Re;
IplImage * image_Im;

double m, M;

img = cvLoadImage( "fingerprint.jpg", CV_LOAD_IMAGE_GRAYSCALE );
if( !img )
return -1;
im = cvCreateImage( cvGetSize(im), IPL_DEPTH_64F, 1);
im=copySubImage(img,0,0,32,32);
realInput = cvCreateImage( cvGetSize(im), IPL_DEPTH_64F, 1);
imaginaryInput = cvCreateImage( cvGetSize(im), IPL_DEPTH_64F, 1);
complexInput = cvCreateImage( cvGetSize(im), IPL_DEPTH_64F, 2);

cvScale(im, realInput, 1.0, 0.0);
cvZero(imaginaryInput);
cvMerge(realInput, imaginaryInput, NULL, NULL, complexInput);

dft_M = cvGetOptimalDFTSize( im->height - 1 );
dft_N = cvGetOptimalDFTSize( im->width - 1 );

dft_A = cvCreateMat( dft_M, dft_N, CV_64FC2 );
image_Re = cvCreateImage( cvSize(dft_N, dft_M), IPL_DEPTH_64F, 1);
image_Im = cvCreateImage( cvSize(dft_N, dft_M), IPL_DEPTH_64F, 1);

// copy A to dft_A and pad dft_A with zeros
cvGetSubRect( dft_A, &tmp, cvRect(0,0, im->width, im->height));
cvCopy( complexInput, &tmp, NULL );
if( dft_A->cols > im->width )
{
cvGetSubRect( dft_A, &tmp, cvRect(im->width,0, dft_A->cols - im->width, im->height));
cvZero( &tmp );
}

// no need to pad bottom part of dft_A with zeros because of
// use nonzero_rows parameter in cvDFT() call below

cvDFT( dft_A, dft_A, CV_DXT_FORWARD, complexInput->height );

cvNamedWindow("win", 0);
cvNamedWindow("magnitude", 0);
cvShowImage("win", im);

// Split Fourier in real and imaginary parts
cvSplit( dft_A, image_Re, image_Im, 0, 0 );

// Compute the magnitude of the spectrum Mag = sqrt(Re^2 + Im^2)
cvPow( image_Re, image_Re, 2.0);
cvPow( image_Im, image_Im, 2.0);
cvAdd( image_Re, image_Im, image_Re, NULL);
cvPow( image_Re, image_Re, 0.5 );
IplImag *Mg=cvCloneImage(image_Re);
// Compute log(1 + Mag)
cvAddS( image_Re, cvScalarAll(1.0), image_Re, NULL ); // 1 + Mag
cvLog( image_Re, image_Re ); // log(1 + Mag)


// Rearrange the quadrants of Fourier image so that the origin is at
// the image center
cvShiftDFT( image_Re, image_Re );

cvMinMaxLoc(image_Re, &m, &M, NULL, NULL, NULL);
cvScale(image_Re, image_Re, 1.0/(M-m), 1.0*(-m)/(M-m));
cvShowImage("magnitude", image_Re);
//multiplication par l'amplitude^k avec k=1.4
cvPow(Mg,Mg,1.4);
for(int x=0;x<image_Re->height;x++)
for(int y=0;y<image_Re->width;y++)
cvSetReal2D(image_Re,x,y,cvGetReal2D(image_Re,x,y)* cvGetReal2D(Mg,x,y));

cvDFT(image_Re,image_Re,CV_DXT_INVERSE);
cvNamedWindow("inverse DFT", 0);
cvShowImage("inverse DFT", image_Re);


cvWaitKey(-1);
return 0;
}

j'ai besoin de me vérifier si l'image Mg est l'amplitude de TF ou non et est ce que mon manipulation d'image surtout pour le TF inverse est correct ou non.
NB: ce code traite uniquement un bloc.

Merci d'avance de m'aider.

[FST_PFE]

Salut,
c'est urgent svp si quelqu'un peux m'aider.