com.openstego.desktop.util.dwt

Class DWTUtil

java.lang.Object

com.openstego.desktop.util.dwt.DWTUtil

public class DWTUtil
extends java.lang.Object

Class to handle Wavelet filters and other DWT utilities.

This class is conversion of C to Java for the file "wavelet.c" file provided by Peter Meerwald at:http://www.cosy.sbg.ac.at/~pmeerw/Watermarking/

Refer to his thesis on watermarking: Peter Meerwald, Digital Image Watermarking in the Wavelet Transfer Domain, Master's Thesis, Department of Scientific Computing, University of Salzburg, Austria, January 2001.

Method Summary

Modifier and Type	Method and Description
static void	convoluteLines(Image outputImg, Image inputImg, Filter filter, int method) Method to convolute lines
static void	convoluteRows(Image outputImg, Image inputImg, Filter filter, int method) Method to convolute rows
static void	decomposition(Image inputImg, Image coarseImg, Image horizontalImg, Image verticalImg, Image diagonalImg, Filter filterG, Filter filterH, int method) Method to decompose the image
static void	filterCutOff(Image inputImg, int inStart, int inLen, int inStep, Image outputImg, int outStart, int outLen, int outStep, Filter filter) Method to apply cut-off filter
static void	filterInvCutOff(Image inputImg, int inStart, int inLen, int inStep, Image outputImg, int outStart, int outLen, int outStep, Filter filter) Method to apply inverse cut-off filter
static void	filterInvMirror(Image inputImg, int inStart, int inLen, int inStep, Image outputImg, int outStart, int outLen, int outStep, Filter filter) Method to apply inverse mirror filter
static void	filterInvPeriodical(Image inputImg, int inStart, int inLen, int inStep, Image outputImg, int outStart, int outLen, int outStep, Filter filter) Method to apply inverse periodical filter
static void	filterMirror(Image inputImg, int inStart, int inLen, int inStep, Image outputImg, int outStart, int outLen, int outStep, Filter filter) Method to apply mirror filter
static void	filterPeriodical(Image inputImg, int inStart, int inLen, int inStep, Image outputImg, int outStart, int outLen, int outStep, Filter filter) Method to apply periodical filter
static int	findDeepestLevel(int width, int height) Method to get the deepest level possible for given image width and height
static double	getPixel(Image image, int x, int y) Get pixel value from the image
static void	invDecomposition(Image sumImg, Image coarseImg, Image horizontalImg, Image verticalImg, Image diagonalImg, FilterGH filterGH, int method) Method to perform inverse decomposition
static Image	inverseTransform(ImageTree tree, FilterGH[] filterGHList, int method) Method to perform inverse wavelet transform
static void	setPixel(Image image, int x, int y, double val) Set pixel value in the image
static ImageTree	waveletTransform(Image origImg, int level, FilterGH[] filterGHList, int method) Method to perform the wavelet transform
static ImageTree	waveletTransformWp(Image origImg, int currLevel, int level, FilterGH[] filterGHList, int method) Method to perform the wavelet transform (WP)

Methods inherited from class java.lang.Object

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

Method Detail

waveletTransform

public static ImageTree waveletTransform(Image origImg,
                                         int level,
                                         FilterGH[] filterGHList,
                                         int method)

Method to perform the wavelet transform

Parameters:

origImg - Original image

level - Decomposition level

filterGHList - List of filters

method - Wavelet filtering method

Returns:

Data after performing wavelet transform

waveletTransformWp

public static ImageTree waveletTransformWp(Image origImg,
                                           int currLevel,
                                           int level,
                                           FilterGH[] filterGHList,
                                           int method)

Method to perform the wavelet transform (WP)

Parameters:

origImg - Original image

currLevel - Current decomposition level

level - Decomposition level

filterGHList - List of filters

method - Wavelet filtering method

Returns:

Data after performing wavelet transform

decomposition

public static void decomposition(Image inputImg,
                                 Image coarseImg,
                                 Image horizontalImg,
                                 Image verticalImg,
                                 Image diagonalImg,
                                 Filter filterG,
                                 Filter filterH,
                                 int method)

Method to decompose the image

Parameters:

inputImg - Input image

coarseImg - Coarse image

horizontalImg - Horizontal image

verticalImg - Vertical image

diagonalImg - Diagonal image

filterG - G filter

filterH - H filter

method - Wavelet filtering method

convoluteLines

public static void convoluteLines(Image outputImg,
                                  Image inputImg,
                                  Filter filter,
                                  int method)

Method to convolute lines

Parameters:

outputImg - Output image

inputImg - Input image

filter - Filter to use

method - Wavelet filtering method

convoluteRows

public static void convoluteRows(Image outputImg,
                                 Image inputImg,
                                 Filter filter,
                                 int method)

Method to convolute rows

Parameters:

outputImg - Output image

inputImg - Input image

filter - Filter to use

method - Wavelet filtering method

filterCutOff

public static void filterCutOff(Image inputImg,
                                int inStart,
                                int inLen,
                                int inStep,
                                Image outputImg,
                                int outStart,
                                int outLen,
                                int outStep,
                                Filter filter)

Method to apply cut-off filter

Parameters:

inputImg - Input image

inStart - Start point for input image

inLen - Length of data for input image

inStep - Step for loop for input image

outputImg - Output image

outStart - Start point for output image

outLen - Length of data for output image

outStep - Step for loop for output image

filter - Filter

filterInvCutOff

public static void filterInvCutOff(Image inputImg,
                                   int inStart,
                                   int inLen,
                                   int inStep,
                                   Image outputImg,
                                   int outStart,
                                   int outLen,
                                   int outStep,
                                   Filter filter)

Method to apply inverse cut-off filter

Parameters:

inputImg - Input image

inStart - Start point for input image

inLen - Length of data for input image

inStep - Step for loop for input image

outputImg - Output image

outStart - Start point for output image

outLen - Length of data for output image

outStep - Step for loop for output image

filter - Filter

filterPeriodical

public static void filterPeriodical(Image inputImg,
                                    int inStart,
                                    int inLen,
                                    int inStep,
                                    Image outputImg,
                                    int outStart,
                                    int outLen,
                                    int outStep,
                                    Filter filter)

Method to apply periodical filter

Parameters:

inputImg - Input image

inStart - Start point for input image

inLen - Length of data for input image

inStep - Step for loop for input image

outputImg - Output image

outStart - Start point for output image

outLen - Length of data for output image

outStep - Step for loop for output image

filter - Filter

filterInvPeriodical

public static void filterInvPeriodical(Image inputImg,
                                       int inStart,
                                       int inLen,
                                       int inStep,
                                       Image outputImg,
                                       int outStart,
                                       int outLen,
                                       int outStep,
                                       Filter filter)

Method to apply inverse periodical filter

Parameters:

inputImg - Input image

inStart - Start point for input image

inLen - Length of data for input image

inStep - Step for loop for input image

outputImg - Output image

outStart - Start point for output image

outLen - Length of data for output image

outStep - Step for loop for output image

filter - Filter

filterMirror

public static void filterMirror(Image inputImg,
                                int inStart,
                                int inLen,
                                int inStep,
                                Image outputImg,
                                int outStart,
                                int outLen,
                                int outStep,
                                Filter filter)

Method to apply mirror filter

Parameters:

inputImg - Input image

inStart - Start point for input image

inLen - Length of data for input image

inStep - Step for loop for input image

outputImg - Output image

outStart - Start point for output image

outLen - Length of data for output image

outStep - Step for loop for output image

filter - Filter

filterInvMirror

public static void filterInvMirror(Image inputImg,
                                   int inStart,
                                   int inLen,
                                   int inStep,
                                   Image outputImg,
                                   int outStart,
                                   int outLen,
                                   int outStep,
                                   Filter filter)

Method to apply inverse mirror filter

Parameters:

inputImg - Input image

inStart - Start point for input image

inLen - Length of data for input image

inStep - Step for loop for input image

outputImg - Output image

outStart - Start point for output image

outLen - Length of data for output image

outStep - Step for loop for output image

filter - Filter

inverseTransform

public static Image inverseTransform(ImageTree tree,
                                     FilterGH[] filterGHList,
                                     int method)

Method to perform inverse wavelet transform

Parameters:

tree - Forward transformed DWT data

filterGHList - List of filters

method - Wavelet filter method

Returns:

Inverse transformed image data

invDecomposition

public static void invDecomposition(Image sumImg,
                                    Image coarseImg,
                                    Image horizontalImg,
                                    Image verticalImg,
                                    Image diagonalImg,
                                    FilterGH filterGH,
                                    int method)

Method to perform inverse decomposition

Parameters:

sumImg - Sum image

coarseImg - Coarse image

horizontalImg - Horizontal image

verticalImg - Vertical image

diagonalImg - Diagonal image

filterGH - Filter

method - Wavelet filter method

findDeepestLevel

public static int findDeepestLevel(int width,
                                   int height)

Method to get the deepest level possible for given image width and height

Parameters:

width - Image width

height - Image height

Returns:

Deepest possible level

setPixel

public static void setPixel(Image image,
                            int x,
                            int y,
                            double val)

Set pixel value in the image

Parameters:

image - Image

x - X position of pixel

y - Y position of pixel

val - Pixel value

getPixel

public static double getPixel(Image image,
                              int x,
                              int y)

Get pixel value from the image

Parameters:

image - Image

x - X position of pixel

y - Y position of pixel

Returns:

Pixel value