Opencv + FFTW3 图象高斯高低通滤波
1：LPF
公式：
out
(
i
,
j
)
=
exp
(-((
i
-
M
/
2
)^
2
+(
j
-
N
/
2
)^
2
)/
2
/
sigma
^
2
);
代码：
void LPF_Fliter(vector&data, int cols, int rows, double gamma)
{
float gamma22 = 2 * gamma*gamma;
float temp = 0.0;
int halfRows = cvRound(rows / 2);
int halfCols = cvRound(cols / 2);
char debug[12] = { 0 };
for (int j = 1; j <= rows; j++)
{
for (int i = 1; i <= cols; i++)
{
temp = (pow(j - halfRows, 2) + pow(i - halfCols, 2));
data.push_back(exp(-temp / gamma22));
}
}
}
2：HPF:
公式：
out
(
i
,
j
)
=
1
-
exp
(-((
i
-
M
/
2
)^
2
+(
j
-
N
/
2
)^
2
)/
2
/
sigma
^
2
);
代码：
void HPF_Fliter(vector&data, int cols, int rows, double gamma)
{
#if 1
float gamma22 = 2 * gamma*gamma;
float temp = 0.0;
int halfRows = cvRound(rows / 2);
int halfCols = cvRound(cols / 2);
char debug[12] = { 0 };
for (int j = 1; j <= rows; j++)
{
for (int i = 1; i <= cols; i++)
{
temp = (pow(j - halfRows, 2) + pow(i - halfCols, 2));
data.push_back(1.0 - exp(-temp / gamma22));
}
}
#else
fstream readFile("C:\\Users\\Tony\\Desktop\\debug.txt", ios::in);
string temp;
int lineCount = 0;
while (getline(readFile, temp))
{
vectordest;
split(temp, "\t", dest);
lineCount++;
if (dest.size() > 1)
{
for (int i = 0; i < dest.size(); i++)
{
//printf_s("%s\tn", dest.at(i));
data.push_back(atof(dest.at(i).c_str()));
}
}
//printf_s("\n");
}
#endif
}
//生成频谱图：
//生成频谱模板
void test()
{
int i;
fftw_complex*din, *out;
fftw_plan p,backp;
Mat image = imread("C:\\Users\\Tony\\Desktop\\Image\\lenaCopy.bmp", CV_LOAD_IMAGE_GRAYSCALE);
din = (fftw_complex *)fftw_malloc(sizeof(fftw_complex)*image.cols*image.rows);
out = (fftw_complex *)fftw_malloc(sizeof(fftw_complex)*image.cols*image.rows);
Mat floatImage(image.size(), CV_32FC1);
image.convertTo(floatImage, CV_32FC1);
for (size_t j = 0; j < image.rows; j++)
{
for (size_t i = 0; i < image.cols; i++)
{
din[i + j*image.cols][0] = *floatImage.ptr(j, i);
din[i + j*image.cols][1] = 0;
}
}
//forward fft
p = fftw_plan_dft_2d(image.rows, image.cols, din, out, FFTW_FORWARD, FFTW_ESTIMATE);
fftw_execute(p);
Mat Resource(image.size(), CV_32FC1);
Mat Imsource(image.size(), CV_32FC1);
for (size_t j = 0; j < image.rows; j++)
{
for (size_t i = 0; i < image.cols; i++)
{
*Resource.ptr(j, i) = out[i + j*image.cols][0];//实部
*Imsource.ptr(j, i) = out[i + j*image.cols][1];//虚部
}
}
Mat Redest(image.size(), CV_32FC1);
Mat Imdest(image.size(), CV_32FC1);
fftshift(Resource, Redest);
fftshift(Imsource, Imdest);
Mat absImage(image.size(), CV_32FC1);
for (size_t j = 0; j < image.rows; j++)
{
for (size_t i = 0; i < image.cols; i++)
{
*absImage.ptr(j, i) = sqrt(pow(*Redest.ptr(j, i), 2) + pow(*Imdest.ptr(j, i), 2));
}
}
absImage += Scalar::all(1);
Mat logImage(image.size(), CV_32FC1);
log(absImage, logImage);
//SaveData(logImage);
double min = 0.0, max = 0.0;
minMaxLoc(logImage, &min, &max);
double scale = 255/(max-min);
double shift = -min*scale;
Mat myImage(image.size(), CV_8UC1);
convertScaleAbs(logImage, myImage, scale, shift);
imwrite("C:\\Users\\Tony\\Desktop\\lenaCopy.bmp", myImage);
} 高低通滤波：
void testOne()
{
int i;
fftw_complex*din, *out;
fftw_plan p, backp;
Mat image = imread("C:\\Users\\Tony\\Desktop\\blur.bmp", CV_LOAD_IMAGE_GRAYSCALE);
din = (fftw_complex *)fftw_malloc(sizeof(fftw_complex)*image.cols*image.rows);
out = (fftw_complex *)fftw_malloc(sizeof(fftw_complex)*image.cols*image.rows);
Mat floatImage(image.size(), CV_32FC1);
image.convertTo(floatImage, CV_32FC1);
for (size_t j = 0; j < image.rows; j++)
{
for (size_t i = 0; i < image.cols; i++)
{
din[i + j*image.cols][0] = *floatImage.ptr(j, i);
din[i + j*image.cols][1] = 0.0;
}
}
//forward fft
p = fftw_plan_dft_2d(image.rows, image.cols, din, out, FFTW_FORWARD, FFTW_ESTIMATE);
fftw_execute(p);
//图像频谱中心化
Mat Resource(image.size(), CV_32FC1);
Mat Imsource(image.size(), CV_32FC1);//虚部
Mat Redest(image.size(), CV_32FC1);
Mat Imdest(image.size(), CV_32FC1);//虚部
for (size_t j = 0; j < image.rows; j++)
{
for (size_t i = 0; i < image.cols; i++)
{
*Resource.ptr(j, i) = out[i + j*image.cols][0];//实部
*Imsource.ptr(j, i) = out[i + j*image.cols][1];//虚部
}
}
fftshift(Resource, Redest);
fftshift(Imsource, Imdest);//虚部
//图像频谱乘以不通的数据,构建滤波
vectordata;
HPF_Fliter(data, image.cols, image.rows, 10);
//LPF_Fliter(data, image.cols, image.rows, 100);
Mat filterRe(image.size(), CV_32FC1);
Mat filterIm(image.size(), CV_32FC1);//虚部
for (size_t j = 0; j < image.rows; j++)
{
for (size_t i = 0; i < image.cols; i++)
{
*filterRe.ptr(j, i) = *Redest.ptr(j, i) * data.at(j*image.cols + i);//实部
*filterIm.ptr(j, i) = *Imdest.ptr(j, i) * data.at(j*image.cols + i);//虚部
}
}
//图像频谱逆中心化
Mat NotCenterRedest(image.size(), CV_32FC1);
Mat NotCenterImdest(image.size(), CV_32FC1);//虚部
ifftShift(filterRe, NotCenterRedest);
ifftShift(filterIm, NotCenterImdest);//虚部
//重新构造复数，傅里叶反变换
fftw_complex *spectrum = (fftw_complex *)fftw_malloc(sizeof(fftw_complex)*image.cols*image.rows);
for (size_t j = 0; j < image.rows; j++)
{
for (size_t i = 0; i < image.cols; i++)
{
spectrum[j*image.cols + i][0] = *NotCenterRedest.ptr(j, i);//实部
spectrum[j*image.cols + i][1] = *NotCenterImdest.ptr(j, i);//虚部
}
}
//傅里叶反变换
fftw_complex *result = (fftw_complex *)fftw_malloc(sizeof(fftw_complex)*image.cols*image.rows);
backp = fftw_plan_dft_2d(image.rows, image.cols, spectrum, result, FFTW_BACKWARD, FFTW_ESTIMATE);
fftw_execute(backp);
int size = image.cols*image.rows;
Mat IvsResource(image.size(), CV_32FC1, Scalar::all(0));
//Mat IvsImsource(image.size(), CV_32FC1, Scalar::all(0));//虚部
//Mat ifftImage(image.size(), CV_32FC1, Scalar::all(0));
Mat myImage(image.size(), CV_8UC1);
for (size_t j = 0; j < image.rows; j++)
{
for (size_t i = 0; i < image.cols; i++)
{
*IvsResource.ptr(j, i) = result[i + j*image.cols][0] / size;//实部
//*IvsImsource.ptr(j, i) = result[i + j*image.cols][1] / size;//虚部
//*ifftImage.ptr(j, i) = sqrt(pow(result[i + j*image.cols][0], 2) + pow(result[i + j*image.cols][1], 2));
*myImage.ptr(j, i) = cvRound(abs(*IvsResource.ptr(j, i)));//实部
}
}
//SaveData(IvsResource);
imwrite("C:\\Users\\Tony\\Desktop\\Copy.bmp", myImage);
Mat gammaImage(image.size(), CV_8UC1);
GammaCorrection(myImage, gammaImage, 0.3);
//释放资源
fftw_destroy_plan(p);
fftw_destroy_plan(backp);
fftw_free(din);
fftw_free(out);
fftw_free(result);
}