jigl.image.utils
Class FFT

java.lang.Object
  |
  +--jigl.image.utils.FFT

public class FFT

extends Object

Computes the Fast Fourier Transform of an image. Please note, the input images must be square and a power of two. To get the correct shape of Fourier transform, you should shif the result image both right by half width and up by half height.

If you apply a forward FFT and finally apply an inverse FFT, be sure to adjust the range of the final image because it may become very big or small.

Field Summary

private static int	IMAG Static constant definition, which is 2
private static int	REAL Static constant definition, which is 1

Constructor Summary

FFT()
Default constructor.

Method Summary

private static ComplexImage	convertToComplex(double[] data, int[] nn) Utlity method
private static ComplexImage	doFFT(Image im, boolean forward) Utility function
static ComplexImage	forward(Image im) Perform the forward Fast Fourier Transform on im
private static ComplexImage	fourn(double[] data, int[] nn, int ndim, boolean forward) Utility methods
static ComplexImage	reverse(Image im) Perform the forward Fast Fourier Transform on im

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

REAL

private static final int REAL

Static constant definition, which is 1

See Also:

Constant Field Values

IMAG

private static final int IMAG

Static constant definition, which is 2

See Also:

Constant Field Values

Constructor Detail

FFT

public FFT()

Default constructor.

Method Detail

forward

public static ComplexImage forward(Image im)

Perform the forward Fast Fourier Transform on im

reverse

public static ComplexImage reverse(Image im)

Perform the forward Fast Fourier Transform on im

doFFT

private static ComplexImage doFFT(Image im,
                                  boolean forward)

Utility function

fourn

private static ComplexImage fourn(double[] data,
                                  int[] nn,
                                  int ndim,
                                  boolean forward)

Utility methods

convertToComplex

private static ComplexImage convertToComplex(double[] data,
                                             int[] nn)

Utlity method