How to deblur image using fourier transform in open-cv or emgu-cv? - image

Question

i saw this video about debluring images using fourier transform in matlab
video
and i want to convert the code in emgu cv
my code in emgucv :
string path = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
Image<Bgr, byte> img = new Image<Bgr, byte>(#"lal.png");
//blur the image
Image<Gray, byte> gray = img.Convert<Gray, byte>().SmoothBlur(31,31);
//convert image to float and get the fourier transform
Mat g_fl = gray.Convert<Gray, float>().Mat;
Matrix<float> dft_image = new Matrix<float>(g_fl.Size);
CvInvoke.Dft(g_fl, dft_image, Emgu.CV.CvEnum.DxtType.Forward, 0);
//here i make an image of kernel with size of the original
Image<Gray, float> ker = new Image<Gray, float>(img.Size);
ker.SetZero();
for (int x = 0; x < 31; x++)
{
for (int y = 0; y < 31; y++)
{
//31 * 31= 961
ker[y, x] = new Gray(1/961);
}
}
//get the fourier of the kernel
Matrix<float> dft_blur = new Matrix<float>(g_fl.Size);
CvInvoke.Dft(ker, dft_blur, Emgu.CV.CvEnum.DxtType.Forward, 0);
// fouier image / fourier blur
Matrix<float> res = new Matrix<float>(g_fl.Size);
for (int x=0;x<g_fl.Cols;x++)
{
for (int y = 0; y < g_fl.Rows; y++)
{
res[y, x] = dft_image[y, x] / dft_blur[y, x];
}
}
//get the inverse of fourier
Image<Gray, float> ready = new Image<Gray, float>(g_fl.Size);
CvInvoke.Dft(res, ready, Emgu.CV.CvEnum.DxtType.Inverse, 0);
CvInvoke.Imshow("deblur", ready.Convert<Gray,byte>());
CvInvoke.Imshow("original", gray);
CvInvoke.WaitKey(0);
but the result is black and not working , where is the mistake in my code
if you have a code in opencv python you can post it :)??
Thanks :)

Answer 1

My old implementation of wiener filter:
#include "stdafx.h"
#pragma once
#pragma comment(lib, "opencv_legacy220.lib")
#pragma comment(lib, "opencv_core220.lib")
#pragma comment(lib, "opencv_highgui220.lib")
#pragma comment(lib, "opencv_imgproc220.lib")
#include "c:\Users\Andrey\Documents\opencv\include\opencv\cv.h"
#include "c:\Users\Andrey\Documents\opencv\include\opencv\cxcore.h"
#include "c:\Users\Andrey\Documents\opencv\include\opencv\highgui.h"
#include <string>
#include <iostream>
#include <complex>
using namespace std;
using namespace cv;
//----------------------------------------------------------
// Compute real and implicit parts of FFT for given image
//----------------------------------------------------------
void ForwardFFT(Mat &Src, Mat *FImg)
{
int M = getOptimalDFTSize( Src.rows );
int N = getOptimalDFTSize( Src.cols );
Mat padded;
copyMakeBorder(Src, padded, 0, M - Src.rows, 0, N - Src.cols, BORDER_CONSTANT, Scalar::all(0));
// Create complex representation of our image
// planes[0] Real part, planes[1] Implicit part (zeros)
Mat planes[] = {Mat_<double>(padded), Mat::zeros(padded.size(), CV_64F)};
Mat complexImg;
merge(planes, 2, complexImg);
dft(complexImg, complexImg);
// As result, we also have Re and Im planes
split(complexImg, planes);
// Crop specter, if it have odd number of rows or cols
planes[0] = planes[0](Rect(0, 0, planes[0].cols & -2, planes[0].rows & -2));
planes[1] = planes[1](Rect(0, 0, planes[1].cols & -2, planes[1].rows & -2));
FImg[0]=planes[0].clone();
FImg[1]=planes[1].clone();
}
//----------------------------------------------------------
// Restore our image using specter
//----------------------------------------------------------
void InverseFFT(Mat *FImg,Mat &Dst)
{
Mat complexImg;
merge(FImg, 2, complexImg);
// Apply inverse FFT
idft(complexImg, complexImg);
split(complexImg, FImg);
Dst=FImg[0];
}
//----------------------------------------------------------
// Wiener filter
//----------------------------------------------------------
void wienerFilter(Mat &src,Mat &dst,Mat &_h,double k)
{
//---------------------------------------------------
// small number for numeric stability
//---------------------------------------------------
const double eps=1E-8;
//---------------------------------------------------
int ImgW=src.size().width;
int ImgH=src.size().height;
//--------------------------------------------------
Mat Yf[2];
ForwardFFT(src,Yf);
//--------------------------------------------------
Mat h;
h.create(ImgH,ImgW,CV_64F);
h=0;
_h.copyTo(h(Rect(0, 0, _h.size().width, _h.size().height)));
Mat Hf[2];
ForwardFFT(h,Hf);
//--------------------------------------------------
Mat Fu[2];
Fu[0].create(ImgH,ImgW,CV_64F);
Fu[1].create(ImgH,ImgW,CV_64F);
complex<double> a;
complex<double> b;
complex<double> c;
double Hf_Re;
double Hf_Im;
double Phf;
double hfz;
double hz;
double A;
for (int i=0;i<Hf[0].size().height;i++)
{
for (int j=0;j<Hf[0].size().width;j++)
{
Hf_Re=Hf[0].at<double>(i,j);
Hf_Im=Hf[1].at<double>(i,j);
Phf = Hf_Re*Hf_Re+Hf_Im*Hf_Im;
hfz=(Phf<eps)*eps;
hz =(h.at<double>(i,j)>0);
A=Phf/(Phf+hz+k);
a=complex<double>(Yf[0].at<double>(i,j),Yf[1].at<double>(i,j));
b=complex<double>(Hf_Re+hfz,Hf_Im+hfz);
c=a/b; // Deconvolution
// Other we do to remove division by 0
Fu[0].at<double>(i,j)=(c.real()*A);
Fu[1].at<double>(i,j)=(c.imag()*A);
}
}
//--------------------------------------------------
Fu[0]/=(ImgW*ImgH);
Fu[1]/=(ImgW*ImgH);
//--------------------------------------------------
InverseFFT(Fu,dst);
// remove out of rane values
for (int i=0;i<Hf[0].size().height;i++)
{
for (int j=0;j<Hf[0].size().width;j++)
{
if(dst.at<double>(i,j)>215){dst.at<double>(i,j)=215;}
if(dst.at<double>(i,j)<(-40)){dst.at<double>(i,j)=(-40);}
}
}
}
//----------------------------------------------------------
// Main
//----------------------------------------------------------
int _tmain(int argc, _TCHAR* argv[])
{
// Input image
Mat img;
// Load it from drive
img=imread("data/motion_fuzzy_lena.bmp",0);
//---------------------------------------------
imshow("Src image", img);
// Image size
int ImgW=img.size().width;
int ImgH=img.size().height;
// Deconvolution kernel (coefficient sum must be 1)
// Image was blurred using same kernel
Mat h;
h.create(1,10,CV_64F);
h=1/double(h.size().width*h.size().height);
// Apply filter
wienerFilter(img,img,h,0.05);
normalize(img,img, 0, 1, CV_MINMAX);
imshow("Result image", img);
cvWaitKey(0);
return 0;
}
The result: