CODEWITHSUNDEEP
c#emgucv
user366312
user366312

Reputation: 16908

Fourier Transform in EmguCV 3.4.1

The following code doesn't compile in EmguCV 3.4.1.

        Image<Gray, float> image = new Image<Gray, float>(path);
        IntPtr complexImage = CvInvoke.cvCreateImage(image.Size, 
Emgu.CV.CvEnum.IplDepth.IplDepth32F, 2);

        CvInvoke.cvSetZero(complexImage);  // Initialize all elements to Zero
        CvInvoke.cvSetImageCOI(complexImage, 1);
        CvInvoke.cvCopy(image, complexImage, IntPtr.Zero);
        CvInvoke.cvSetImageCOI(complexImage, 0);

        Matrix<float> dft = new Matrix<float>(image.Rows, image.Cols, 2);
        CvInvoke.cvDFT(complexImage, dft, Emgu.CV.CvEnum.DxtType.Forward, 0);

        //The Real part of the Fourier Transform
        Matrix<float> outReal = new Matrix<float>(image.Size);
        //The imaginary part of the Fourier Transform
        Matrix<float> outIm = new Matrix<float>(image.Size);
        CvInvoke.cvSplit(dft, outReal, outIm, IntPtr.Zero, IntPtr.Zero);

        //Show The Data       
        CvInvoke.cvShowImage("Real", outReal);
        CvInvoke.cvShowImage("Imaginary ", outIm);

Some functions 

cvSetZero()
cvDFT()
cvShowImage()

are not available in this version of EmguCV.

How can I get around this issue?

Upvotes: 1

Views: 1665

Answers (2)

Quergo
Quergo

Reputation: 928

Since version 3.0 EmguCV goes more for Mat instead of Image. Also somemethods were moved from CvInvoke to Mat or Image or were renamed (example: CvInvoke.cvShowImage --> CvInvoke.Imshow).

I also had this problem with dft and tried to port the code from the openCV example to c#. This is what I work with (using EmguCV 3.4.1):

    var image = new Mat(path, ImreadModes.Grayscale);

    int a = CvInvoke.GetOptimalDFTSize(image.Rows);
    int b = CvInvoke.GetOptimalDFTSize(image.Cols);

    var extended = new Mat();
    CvInvoke.CopyMakeBorder(image, extended, 0, a - image.Rows, 0, b - image.Cols, BorderType.Constant, new MCvScalar(0));

    extended.ConvertTo(extended, DepthType.Cv32F);
    var vec = new VectorOfMat(extended, new Mat(extended.Size, DepthType.Cv32F, 1));
    var complex = new Mat();
    CvInvoke.Merge(vec, complex);

    CvInvoke.Dft(complex, complex, DxtType.Forward, 0);

    CvInvoke.Split(complex, vec);

    vec[0].ConvertTo(vec[0], DepthType.Cv8U);
    vec[1].ConvertTo(vec[1], DepthType.Cv8U);

    CvInvoke.Imshow("Real", vec[0]);
    CvInvoke.Imshow("Img", vec[1]);

Upvotes: 3

jspcal
jspcal

Reputation: 51904

Some methods have been renamed or moved. Use CvInvoke.Dft with Image.toUMat and UMat for the image manipulation. ImageViewer can be used for displaying images.

Image<Gray, float> image = new Image<Gray, float>(path);
UMat dftImage = new UMat(image.Size, Emgu.CV.CvEnum.DepthType.Cv32F, 2);
CvInvoke.Dft(image, dftImage, Emgu.CV.CvEnum.DxtType.Forward, image.Rows);

Upvotes: 2

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