org.openimaj.image.processing.convolution

Class FourierConvolve

java.lang.Object

org.openimaj.image.processing.convolution.FourierConvolve

All Implemented Interfaces:

ImageProcessor<FImage>, Processor<FImage>, SinglebandImageProcessor<Float,FImage>

public class FourierConvolve
extends Object
implements SinglebandImageProcessor<Float,FImage>

FImage convolution performed in the fourier domain.

Author:

Jonathon Hare (jsh2@ecs.soton.ac.uk)

Nested Class Summary

Nested classes/interfaces inherited from interface org.openimaj.image.processor.SinglebandImageProcessor

SinglebandImageProcessor.Processable<T,S extends Image<T,S>,I extends Image<?,I>>

Constructor Summary

Constructors

Constructor and Description
FourierConvolve(FImage kernel) Construct the convolution operator with the given kernel
FourierConvolve(float[][] kernel) Construct the convolution operator with the given kernel

Method Summary

Modifier and Type	Method and Description
static FImage	convolve(FImage image, float[][] kernel, boolean inplace) Convolve an image with a kernel using an FFT.
static FImage	convolvePrepared(FImage image, FImage filter, boolean centered) Convolve an image with a pre-prepared frequency domain filter.
void	processImage(FImage image) Process an image.

Methods inherited from class java.lang.Object

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

Constructor Detail

FourierConvolve

public FourierConvolve(float[][] kernel)

Construct the convolution operator with the given kernel

Parameters:

kernel - the kernel

FourierConvolve

public FourierConvolve(FImage kernel)

Construct the convolution operator with the given kernel

Parameters:

kernel - the kernel

Method Detail

processImage

public void processImage(FImage image)

Description copied from interface: ImageProcessor

Process an image. Implementing classes must alter the image passed in-place or assign the output to the input using Image.internalAssign(Image).

Specified by:

processImage in interface ImageProcessor<FImage>

Parameters:

image - The image to process in place.

convolve

public static FImage convolve(FImage image,
                              float[][] kernel,
                              boolean inplace)

Convolve an image with a kernel using an FFT.

Parameters:

image - The image to convolve

kernel - The kernel

inplace - if true, then output overwrites the input, otherwise a new image is created.

Returns:

convolved image

convolvePrepared

public static FImage convolvePrepared(FImage image,
                                      FImage filter,
                                      boolean centered)

Convolve an image with a pre-prepared frequency domain filter. The filter must have the same height as the image and twice the width (to account for the imaginary components). Real and imaginary components should be interlaced across the rows.

Parameters:

image - The image to convolve

filter - the prepared frequency domain filter

centered - true if the prepared filter has the highest frequency in the centre.

Returns:

convolved image