FFTW (+OpenCV) - drawing 2d spectrum

Hello everyone,
I'm currently trying to create a program (although "create" is a wrong word as my code is based on what I find in the web) which will load an image, compute the FFT and will show the spectrum as an image.

Until now I have:

Code:

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#include <stdio.h>
#include "cv.h"
#include "highgui.h"
#include "fftw3.h"

void iplimage_dft(IplImage*);

int main(int argc, char** argv)
{
        IplImage* img;

        img = cvLoadImage(argc == 2 ? argv[1] : "mustang.jpg", 0);
        iplimage_dft(img);

        return 0;
}

void iplimage_dft(IplImage* img)
{
        IplImage*                img1, * img2;
        fftw_complex* in, * dft;
        fftw_plan                        plan_f;
        int                                        i, j, k, w, h, N;

        /* Copy input image */
        img1 = cvCloneImage(img);


        w = img1->width;
        h = img1->height;
        N = w * h;

        /* Create output image */
        img2 = cvCreateImage(cvSize(w, h), 8, 1);

        /* Allocate input data for FFTW */
        in  = (fftw_complex*) fftw_malloc(sizeof(fftw_complex) * N);
        dft  = (fftw_complex*) fftw_malloc(sizeof(fftw_complex) * N);

        /* Create plan */
        plan_f = fftw_plan_dft_2d(w, h, in, dft, FFTW_FORWARD, FFTW_ESTIMATE);
       
        /* Populate input data in row-major order */
        for (i = 0, k = 0; i < h; i++)
        {
                for (j = 0; j < w; j++, k++)
                {
                        in[k][0] = ((uchar*)(img1->imageData + i * img1->widthStep))[j];
                        in[k][1] = 0.;
                }
        }

        /* forward DFT */
        fftw_execute(plan_f);


        /* creating spectrum */
        for (i = 0, k = 0; i < h; i++)
        {
                for (j = 0; j < w; j++, k++)
                        ((uchar*)(img2->imageData + i * img2->widthStep))[j] = sqrt(pow(dft[k][0],2) + pow(dft[k][1],2));
        }               

        cvShowImage("iplimage_dft(): original", img1);
        cvShowImage("iplimage_dft(): result", img2);
        cvWaitKey(0);

        /* Free memory */
        fftw_destroy_plan(plan_f);
        fftw_free(in);
        fftw_free(dft);
        cvReleaseImage(&img1);
        cvReleaseImage(&img2);
}

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And there is a problem with the "creating spectrum" lines. Instead of a spectrum I have some "noise". What am I doing wrong? I would be very grateful for some help.
Thanks in advance,
Narren