I have been using Discrete Fourier Transform for preprocessing method. Now for classification, I need to take Discrete Fourier Transform,assign label to DFT and then train KNN for the training data.Then,for predicting data,i need to find k-nearest neighbours of test data and finally perform matching(euclidean).How to proceed with it using KNN now?
Below is my c++ code for DFT
using namespace std;
using namespace cv;
void takeDFT(Mat&source, Mat &destination)
{
Mat dftReady;
Mat originalComplex[2] = { source,Mat::zeros(source.size(),CV_32F) };
merge(originalComplex, 2, dftReady);
Mat dftOriginal;
dft(dftReady, dftOriginal, DFT_COMPLEX_OUTPUT);
destination = dftOriginal;
}
void recenterDFT(Mat &source)
{
// rearrange the quadrants of Fourier image
int centerX = source.cols / 2;
int centerY = source.rows / 2;
Mat q1(source, Rect(0, 0, centerX, centerY));
Mat q2(source, Rect(centerX, 0, centerX, centerY));
Mat q3(source, Rect(0, centerY, centerX, centerY));
Mat q4(source, Rect(centerX, centerY, centerX, centerY));
Mat swapMap;
q1.copyTo(swapMap);
q4.copyTo(q1);
swapMap.copyTo(q4);
q2.copyTo(swapMap);
q3.copyTo(q2);
swapMap.copyTo(q3);
}
void showDFT(Mat& source)
{
Mat splitArray[2] = { Mat::zeros(source.size(),CV_32F),Mat::zeros(source.size(),CV_32F)};
split(source, splitArray);
Mat dftMagnitude;
magnitude(splitArray[0],splitArray[1],dftMagnitude);
dftMagnitude += Scalar::all(1);
// switch to logarithmic scale
log(dftMagnitude,dftMagnitude);
normalize(dftMagnitude,dftMagnitude,0,1,CV_MINMAX);
recenterDFT(dftMagnitude);
imshow("DFT", dftMagnitude);
waitKey();
}
void invertDFT(Mat& source,Mat&destination)
{
Mat inverse;
dft(source,inverse,DFT_INVERSE | DFT_REAL_OUTPUT | DFT_SCALE);
destination = inverse;
}
int main()
{
Mat img = imread("canny.jpg", 0);
Mat dftInput1;
img.convertTo(dftInput1, CV_32FC1,1.0/255.0);
Mat dftOriginal;
takeDFT(dftInput1, dftOriginal);
showDFT(dftOriginal);
Mat invertedDFT;
invertDFT(dftOriginal, invertedDFT);
imshow("invertDFT Result", invertedDFT);
imwrite("DFTimg.jpg",invertedDFT);
waitKey();
}
My DFT code is working but not being able to proceed using KNN.
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