Module imagingbook.spectral

Package imagingbook.spectral.dft

Class Dft1dDirect

java.lang.Object

imagingbook.spectral.dft.Dft1dDirect

All Implemented Interfaces:

Dft1d

Direct Known Subclasses:

Dft1dDirect.Double, Dft1dDirect.Float

public abstract class Dft1dDirect
extends Object

Direct (slow) implementation of the 1-dimensional DFT using tabulated sine and cosine values. Note that this class has no public constructor - instantiate sub-class Dft1dDirect.Float or Dft1dDirect.Double instead, as shown below. See Sec. 18.4.1 of [1] for additional details.

Usage example (for float data):

 float[] re = {1, 2, 3, 4, 5, 3, 0};
 float[] im = {0, 0, 0, 0, 0, 0, 0};
 Dft1d.Float dft = new Dft1dDirect.Float(re.length);
 dct.forward(re, im);  // re/im now is the DFT spectrum
 dct.inverse(re, im);  // re/im now is the original signal 
 ...
 

[1] W. Burger, M.J. Burge, Digital Image Processing – An Algorithmic Introduction, 3rd ed, Springer (2022).

Version:

2022/10/23

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Dft1dDirect.Double	One-dimensional DFT implementation using double data.
static class	Dft1dDirect.Float	One-dimensional DFT implementation using float data.

Method Summary

Modifier and Type	Method	Description
ScalingMode	getScalingMode()	Returns the scaling mode of this DFT (see ScalingMode).
int	getSize()	Returns the size of this DFT (length of data vectors).

Methods inherited from class java.lang.Object

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

Method Details

getSize

public int getSize()

Description copied from interface: Dft1d

Returns the size of this DFT (length of data vectors).

Specified by:

getSize in interface Dft1d

Returns:

the size of this DFT

getScalingMode

public ScalingMode getScalingMode()

Description copied from interface: Dft1d

Returns the scaling mode of this DFT (see ScalingMode).

Specified by:

getScalingMode in interface Dft1d

Returns:

the scaling mode of this DFT.