This is the corrected code. It had a few mistakes:
- It was reading a wrong wisdom.fftw file (from some old test...). Now, It always creates a new fftw_plan and a new file.
- I misunderstood how it works the fftw library with in-place and out-of-place parameters. I had to change mallocs for the correct padding for "in-place" (I added +2 in malloc functions).
- In order to restore the image, I had to divide by its size ((width+2) * height) how it is explained in this link.
`
/* load image */
string bmpFileNameImage = "files/polyp.bmp";
BMPImage bmpImage(bmpFileNameImage);
int width = bmpImage.width();
int height = bmpImage.height();
vector<double> pixelColors;
vector<uint8_t> image = bmpImage.copyBits();
//get one channel from the image
Uint8ToDouble(image,pixelColors,bmpImage.width(),bmpImage.height(),1);
//We don't reuse old wisdom.fftw... It can be corrupt
/*
FILE * file = fopen("wisdom.fftw", "r");
if (file) {
fftw_import_wisdom_from_file(file);
fclose(file);
} */
double *wisdomInput = (double *) fftw_malloc(sizeof(double)*height*(width+2));
const fftw_plan forward =fftw_plan_dft_r2c_2d(width,height,wisdomInput,reinterpret_cast<fftw_complex *>(wisdomInput),FFTW_PATIENT);
const fftw_plan inverse = fftw_plan_dft_c2r_2d(width,height,reinterpret_cast<fftw_complex *>(wisdomInput),wisdomInput, FFTW_PATIENT);
double *bitsColors =(double *)fftw_malloc((width) * height * sizeof(double));
for (int y = 0; y < height; y++) {
for (int x = 0; x < width+2; x++) {
if (x < width) {
int currentIndex = ((y * width) + (x));
bitsColors[currentIndex] = (static_cast<double>(result[y * (width+2) + x])) / (height*width);
}
}
}
fftw_free (wisdomInput);
fftw_free (out);
fftw_free (result);
fftw_free (bitsColors);
fftw_destroy_plan(forward);
fftw_destroy_plan(inverse);
fftw_cleanup();
}
`