org.openimaj.image.processing.resize

Class ResizeProcessor

java.lang.Object

org.openimaj.image.processing.resize.ResizeProcessor

All Implemented Interfaces:

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

@Reference(type=Incollection,
           author="Schumacher, Dale",
           title="Graphics Gems III",
           year="1992",
           pages={"8","","16"},
           chapter="General Filtered Image Rescaling",
           url="http://dl.acm.org/citation.cfm?id=130745.130747",
           editor="Kirk, David",
           publisher="Academic Press Professional, Inc.",
           customData={"isbn","0-12-409671-9","numpages","9","acmid","130747","address","San Diego, CA, USA"})
public class ResizeProcessor
extends Object
implements SinglebandImageProcessor<Float,FImage>

Image processor and utility methods that can resize images.

Based on filter_rcg.c by Dale Schumacher and Ray Gardener from Graphics Gems III, with improvements from TwelveMonkeys and ImageMagick, which in-particular fix normalisation problems.

Author:

David Dupplaw (dpd@ecs.soton.ac.uk), Sina Samangooei (ss@ecs.soton.ac.uk), Jonathon Hare (jsh2@ecs.soton.ac.uk)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ResizeProcessor.Mode The resize mode to use.

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

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

Field Summary

Fields

Modifier and Type	Field and Description
static ResizeFilterFunction	DEFAULT_FILTER The default TriangleFilter (bilinear-interpolation filter) used by instances of ResizeProcessor, unless otherwise specified.

Constructor Summary

Constructors

Constructor and Description
ResizeProcessor(float amount) Constructor a resize processor that will rescale the image by a given scale factor using the default filter function.
ResizeProcessor(float newX, float newY) Construct a resize processor that will rescale the image to the given width and height with the default filter function.
ResizeProcessor(float newX, float newY, ResizeFilterFunction ff) Construct a resize processor that will rescale the image to the given width and height with the given filter function.
ResizeProcessor(float amount, ResizeFilterFunction ff) Constructor a resize processor that will rescale the image by a given scale factor using the given filter function.
ResizeProcessor(int maxSize) Construct a resize processor that will rescale images that are taller or wider than the given size such that their biggest side is equal to the given size.
ResizeProcessor(int maxSizeArea, boolean area) Construct a resize processor that will rescale images that are either bigger than a maximum area or are taller or wider than the given size such that their biggest side is equal to the given size.
ResizeProcessor(int newX, int newY, boolean aspectRatio) Construct a resize processor that will rescale the image to the given width and height (optionally maintaining aspect ratio) with the default filter function.
ResizeProcessor(int newX, int newY, boolean aspectRatio, ResizeFilterFunction filterf) Construct a resize processor that will rescale the image to the given width and height (optionally maintaining aspect ratio) with the given filter function.
ResizeProcessor(ResizeProcessor.Mode mode) Constructor that takes the resize mode.

Method Summary

Modifier and Type	Method and Description
static FImage	doubleSize(FImage image) Double the size of the image.
static <I extends Image<?,I> & SinglebandImageProcessor.Processable<Float,FImage,I>> I	doubleSize(I image) Double the size of the image.
static FImage	halfSize(FImage image) Halve the size of the image.
static <I extends Image<?,I> & SinglebandImageProcessor.Processable<Float,FImage,I>> I	halfSize(I image) Halve the size of the image.
protected static void	internalDoubleSize(FImage image)
protected static void	internalHalfSize(FImage image)
void	processImage(FImage image) Process an image.
static FImage	resample(FImage in, int newX, int newY) Returns a new image that is a resampled version of the given image.
static FImage	resample(FImage in, int newX, int newY, boolean aspect) Resamples the given image returning it as a reference.
static FImage	resample(FImage in, int newX, int newY, boolean aspect, ResizeFilterFunction filterf) Resamples the given image returning it as a reference.
static FImage	resizeMax(FImage image, int maxDim) Resize an image such that its biggest size is at most as big as the given size.
static FImage	resizeMax(FImage image, int maxDim, ResizeFilterFunction filterf) Resize an image such that its biggest size is at most as big as the given size.
static FImage	resizeMaxArea(FImage image, int maxArea) Resize an image such that its area size is at most as big as the given area.
static FImage	resizeMaxArea(FImage image, int maxArea, ResizeFilterFunction filterf) Resize an image such that its area size is at most as big as the given area.
void	setFilterFunction(ResizeFilterFunction filterFunction) Set the filter function used by the filter
static FImage	zoom(FImage in, FImage dst, ResizeFilterFunction filterf) Resizes bitmaps while resampling them.
static FImage	zoom(FImage in, Rectangle inRect, FImage dst, Rectangle dstRect) Draws one portion of an image into another, resampling as necessary using the default filter function.
static FImage	zoom(FImage in, Rectangle inRect, FImage dst, Rectangle dstRect, ResizeFilterFunction filterf) Draws one portion of an image into another, resampling as necessary.
static FImage	zoomInplace(FImage in, int newX, int newY) Resizes an image.
static FImage	zoomInplace(FImage in, int newX, int newY, ResizeFilterFunction filterf) Resizes an image.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_FILTER

public static final ResizeFilterFunction DEFAULT_FILTER

The default TriangleFilter (bilinear-interpolation filter) used by instances of ResizeProcessor, unless otherwise specified.

Constructor Detail

ResizeProcessor

public ResizeProcessor(ResizeProcessor.Mode mode)

Constructor that takes the resize mode. Use this function if you only want to double or halve the image size.

Parameters:

mode - The resize mode.

ResizeProcessor

public ResizeProcessor(float amount,
                       ResizeFilterFunction ff)

Constructor a resize processor that will rescale the image by a given scale factor using the given filter function.

Parameters:

amount - The amount to scale the image by

ff - The resize filter function to use.

ResizeProcessor

public ResizeProcessor(float newX,
                       float newY,
                       ResizeFilterFunction ff)

Construct a resize processor that will rescale the image to the given width and height with the given filter function. By default, this method will retain the image's aspect ratio.

Parameters:

newX - The new width of the image.

newY - The new height of the image.

ff - The filter function to use.

ResizeProcessor

public ResizeProcessor(float amount)

Constructor a resize processor that will rescale the image by a given scale factor using the default filter function.

Parameters:

amount - The amount to scale the image by

ResizeProcessor

public ResizeProcessor(float newX,
                       float newY)

Construct a resize processor that will rescale the image to the given width and height with the default filter function. By default, this method will retain the image's aspect ratio which means that the resulting image may have dimensions less than those specified here.

Parameters:

newX - The new width of the image.

newY - The new height of the image.

ResizeProcessor

public ResizeProcessor(int maxSize)

Construct a resize processor that will rescale images that are taller or wider than the given size such that their biggest side is equal to the given size. Images that have both sides smaller than the given size will be unchanged.

Parameters:

maxSize - The maximum allowable height or width

ResizeProcessor

public ResizeProcessor(int maxSizeArea,
                       boolean area)

Construct a resize processor that will rescale images that are either bigger than a maximum area or are taller or wider than the given size such that their biggest side is equal to the given size. Images that have a smaller area or both sides smaller than the given size will be unchanged.

Parameters:

maxSizeArea - The maximum allowable area, or height or width

area - If true, then the limit is the area; false means limit is longest side.

ResizeProcessor

public ResizeProcessor(int newX,
                       int newY,
                       boolean aspectRatio)

Construct a resize processor that will rescale the image to the given width and height (optionally maintaining aspect ratio) with the default filter function. If aspectRatio is false the image will be stretched to fit within the new width and height. If aspectRatio is set to true, the resulting images may have dimensions less than those specified here.

Parameters:

newX - The new width of the image.

newY - The new height of the image.

aspectRatio - Whether to maintain the aspect ratio or not

ResizeProcessor

public ResizeProcessor(int newX,
                       int newY,
                       boolean aspectRatio,
                       ResizeFilterFunction filterf)

Construct a resize processor that will rescale the image to the given width and height (optionally maintaining aspect ratio) with the given filter function. If aspectRatio is false the image will be stretched to fit within the new width and height. If aspectRatio is set to true, the resulting images may have dimensions less than those specified here.

Parameters:

newX - The new width of the image.

newY - The new height of the image.

aspectRatio - Whether to maintain the aspect ratio or not

filterf - The filter function

Method Detail

processImage

public void processImage(FImage image)

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.

See Also:

ImageProcessor.processImage(org.openimaj.image.Image)

setFilterFunction

public void setFilterFunction(ResizeFilterFunction filterFunction)

Set the filter function used by the filter

Parameters:

filterFunction - the filter function

resizeMax

public static FImage resizeMax(FImage image,
                               int maxDim,
                               ResizeFilterFunction filterf)

Resize an image such that its biggest size is at most as big as the given size. Images whose sides are smaller than the given size are untouched.

Parameters:

image - the image to resize

maxDim - the maximum allowable length for the longest side.

filterf - The filter function

Returns:

the input image, appropriately resized.

resizeMaxArea

public static FImage resizeMaxArea(FImage image,
                                   int maxArea,
                                   ResizeFilterFunction filterf)

Resize an image such that its area size is at most as big as the given area. Images whose ares are smaller than the given area are untouched.

Parameters:

image - the image to resize

maxArea - the maximum allowable area.

filterf - The filter function

Returns:

the input image, appropriately resized.

resizeMax

public static FImage resizeMax(FImage image,
                               int maxDim)

Resize an image such that its biggest size is at most as big as the given size. Images whose sides are smaller than the given size are untouched.

Parameters:

image - the image to resize

maxDim - the maximum allowable length for the longest side.

Returns:

the input image, resized appropriately

resizeMaxArea

public static FImage resizeMaxArea(FImage image,
                                   int maxArea)

Resize an image such that its area size is at most as big as the given area. Images whose ares are smaller than the given area are untouched.

Parameters:

image - the image to resize

maxArea - the maximum allowable area.

Returns:

the input image, resized appropriately

doubleSize

public static <I extends Image<?,I> & SinglebandImageProcessor.Processable<Float,FImage,I>> I doubleSize(I image)

Double the size of the image.

Type Parameters:

I - the image type

Parameters:

image - The image to double in size

Returns:

a copy of the original image with twice the size

doubleSize

public static FImage doubleSize(FImage image)

Double the size of the image.

Parameters:

image - The image to double in size

Returns:

a copy of the original image with twice the size

internalDoubleSize

protected static void internalDoubleSize(FImage image)

halfSize

public static <I extends Image<?,I> & SinglebandImageProcessor.Processable<Float,FImage,I>> I halfSize(I image)

Halve the size of the image.

Type Parameters:

I -

Parameters:

image - The image halve in size

Returns:

a copy of the input image with half the size

halfSize

public static FImage halfSize(FImage image)

Halve the size of the image. Note that this method just samples every other pixel and will produce aliasing unless the image has been pre-filtered.

Parameters:

image - The image halve in size

Returns:

a copy the the image with half the size

internalHalfSize

protected static void internalHalfSize(FImage image)

resample

public static FImage resample(FImage in,
                              int newX,
                              int newY)

Returns a new image that is a resampled version of the given image.

Parameters:

in - The source image

newX - The new width of the image

newY - The new height of the image

Returns:

A new FImage

resample

public static FImage resample(FImage in,
                              int newX,
                              int newY,
                              boolean aspect)

Resamples the given image returning it as a reference. If aspect is true, the aspect ratio of the image will be retained, which means newX or newY could be smaller than given here. The dimensions of the new image will not be larger than newX or newY. Side-affects the given image.

Parameters:

in - The source image

newX - The new width of the image

newY - The new height of the image

aspect - Whether to maintain the aspect ratio

Returns:

the input image, resized appropriately

resample

public static FImage resample(FImage in,
                              int newX,
                              int newY,
                              boolean aspect,
                              ResizeFilterFunction filterf)

Resamples the given image returning it as a reference. If aspect is true, the aspect ratio of the image will be retained, which means newX or newY could be smaller than given here. The dimensions of the new image will not be larger than newX or newY. Side-affects the given image.

Parameters:

in - The source image

newX - The new width of the image

newY - The new height of the image

aspect - Whether to maintain the aspect ratio

filterf - The filter function

Returns:

the input image, resized appropriately

zoomInplace

public static FImage zoomInplace(FImage in,
                                 int newX,
                                 int newY)

Resizes an image.

Parameters:

in - The source image

newX - The desired width of the image

newY - The desired height of the image

Returns:

the input image, resized appropriately

zoomInplace

public static FImage zoomInplace(FImage in,
                                 int newX,
                                 int newY,
                                 ResizeFilterFunction filterf)

Resizes an image.

Parameters:

newX - New width of the image

newY - New height of the image

in - The source image

filterf - The filter function

Returns:

the input image, resized appropriately

zoom

public static FImage zoom(FImage in,
                          FImage dst,
                          ResizeFilterFunction filterf)

Resizes bitmaps while resampling them.

Parameters:

dst - Destination Image

in - Source Image

filterf - Filter to use

Returns:

the destination image

zoom

public static FImage zoom(FImage in,
                          Rectangle inRect,
                          FImage dst,
                          Rectangle dstRect)

Draws one portion of an image into another, resampling as necessary using the default filter function.

Parameters:

dst - Destination Image

in - Source Image

inRect - the location of pixels in the source image

dstRect - the destination of pixels in the destination image

Returns:

the destination image

zoom

public static FImage zoom(FImage in,
                          Rectangle inRect,
                          FImage dst,
                          Rectangle dstRect,
                          ResizeFilterFunction filterf)

Draws one portion of an image into another, resampling as necessary.

Parameters:

dst - Destination Image

in - Source Image

inRect - the location of pixels in the source image

dstRect - the destination of pixels in the destination image

filterf - Filter to use

Returns:

the destination image