Package boofcv.alg.transform.fft

Class DiscreteFourierTransformOps

java.lang.Object
boofcv.alg.transform.fft.DiscreteFourierTransformOps
public class DiscreteFourierTransformOps extends Object
Various functions related to DiscreteFourierTransform.

  • Constructor Details

    • DiscreteFourierTransformOps

      public DiscreteFourierTransformOps()

  • Method Details

    • createTransformF32

      public static DiscreteFourierTransform<GrayF32,InterleavedF32> createTransformF32()
      Creates a DiscreteFourierTransform for images of type GrayF32.
      Returns:
      DiscreteFourierTransform
      See Also:

    • createTransformF64

      public static DiscreteFourierTransform<GrayF64,InterleavedF64> createTransformF64()
      Creates a DiscreteFourierTransform for images of type GrayF64.
      Returns:
      DiscreteFourierTransform
      See Also:

    • isPowerOf2

      public static boolean isPowerOf2(int x)
      true if the number provided is a power of two
      Parameters:
      x - number
      Returns:
      true if it is a power of two

    • nextPow2

      public static int nextPow2(int x)
      Returns the closest power-of-two number greater than or equal to x.
      Returns:
      the closest power-of-two number greater than or equal to x

    • checkImageArguments

      public static void checkImageArguments(ImageBase image, ImageInterleaved transform)
      Checks to see if the image and its transform are appropriate sizes . The transform should have twice the width and twice the height as the image.
      Parameters:
      image - Storage for an image
      transform - Storage for a Fourier Transform

    • shiftZeroFrequency

      public static void shiftZeroFrequency(InterleavedF32 transform, boolean forward)
      Moves the zero-frequency component into the image center (width/2,height/2). This function can be called to undo the transform.
      Parameters:
      transform - the DFT which is to be shifted.
      forward - If true then it does the shift in the forward direction. If false then it undoes the transforms.

    • shiftZeroFrequency

      public static void shiftZeroFrequency(InterleavedF64 transform, boolean forward)
      Moves the zero-frequency component into the image center (width/2,height/2). This function can be called to undo the transform.
      Parameters:
      transform - the DFT which is to be shifted.
      forward - If true then it does the shift in the forward direction. If false then it undoes the transforms.

    • magnitude

      public static void magnitude(InterleavedF32 transform, GrayF32 magnitude)
      Computes the magnitude of the complex image:
      magnitude = sqrt( real2 + imaginary2 )
      Parameters:
      transform - (Input) Complex interleaved image
      magnitude - (Output) Magnitude of image

    • magnitude

      public static void magnitude(InterleavedF64 transform, GrayF64 magnitude)
      Computes the magnitude of the complex image:
      magnitude = sqrt( real2 + imaginary2 )
      Parameters:
      transform - (Input) Complex interleaved image
      magnitude - (Output) Magnitude of image

    • phase

      public static void phase(InterleavedF32 transform, GrayF32 phase)
      Computes the phase of the complex image:
      phase = atan2( imaginary , real )
      Parameters:
      transform - (Input) Complex interleaved image
      phase - (output) Phase of image

    • phase

      public static void phase(InterleavedF64 transform, GrayF64 phase)
      Computes the phase of the complex image:
      phase = atan2( imaginary , real )
      Parameters:
      transform - (Input) Complex interleaved image
      phase - (output) Phase of image

    • realToComplex

      public static void realToComplex(GrayF32 real, InterleavedF32 complex)
      Converts a regular image into a complex interleaved image with the imaginary component set to zero.
      Parameters:
      real - (Input) Regular image.
      complex - (Output) Equivalent complex image.

    • realToComplex

      public static void realToComplex(GrayF64 real, InterleavedF64 complex)
      Converts a regular image into a complex interleaved image with the imaginary component set to zero.
      Parameters:
      real - (Input) Regular image.
      complex - (Output) Equivalent complex image.

    • multiplyRealComplex

      public static void multiplyRealComplex(GrayF32 realA, InterleavedF32 complexB, InterleavedF32 complexC)
      Performs element-wise complex multiplication between a real image and a complex image.
      Parameters:
      realA - (Input) Regular image
      complexB - (Input) Complex image
      complexC - (Output) Complex image

    • multiplyRealComplex

      public static void multiplyRealComplex(GrayF64 realA, InterleavedF64 complexB, InterleavedF64 complexC)
      Performs element-wise complex multiplication between a real image and a complex image.
      Parameters:
      realA - (Input) Regular image
      complexB - (Input) Complex image
      complexC - (Output) Complex image

    • multiplyComplex

      public static void multiplyComplex(InterleavedF32 complexA, InterleavedF32 complexB, InterleavedF32 complexC)
      Performs element-wise complex multiplication between two complex images.
      Parameters:
      complexA - (Input) Complex image
      complexB - (Input) Complex image
      complexC - (Output) Complex image

    • multiplyComplex

      public static void multiplyComplex(InterleavedF64 complexA, InterleavedF64 complexB, InterleavedF64 complexC)
      Performs element-wise complex multiplication between two complex images.
      Parameters:
      complexA - (Input) Complex image
      complexB - (Input) Complex image
      complexC - (Output) Complex image