#include <ImageComparison.hh>

Collaboration diagram for ImageComparison:

Public Member Functions
	ImageComparison (const Image &img1, const Image &img2)
	~ImageComparison (void)
int	rows (void) const
int	cols (void) const
int	size (void) const
Image *	difference (coeff magnify=1, bool reverse=false)
double	cmpsnr (void)
double	cmpmse (void)
lq	distlq (double percent, FilterSet &flt, imgtype type)
double	distlqd (double percent, FilterSet &flt, imgtype type)
Static Public Member Functions
static Image *	truncateForLq (const Image &image, double percent, FilterSet &flt, const decomp t=STANDARD)
static double	calcLqDetailScore (const Image &truncated1, const Image &truncated2, int colorChannel=0)
static double	calcLqAverageScore (const Image &truncated1, const Image &truncated2, int colorChannel=0)
static Image *	truncateForLq (const Image &image, int nKeptCoeffs, FilterSet &flt, const decomp t=STANDARD)
static ImageInformation *	imageInfoForLq (const Image &image, int nKeptCoeffs, FilterSet &flt, const decomp t=STANDARD)
static const float *	getWeights (const imgtype imgType, int channel)
Protected Member Functions
int	level (int pos)
double	weight (int y, int x, imgtype type)
double	lq_sum (imgtype type, bool reverse, bool oldLqd=false)
Protected Attributes
int	m_ysize
int	m_xsize
int	m_xysize
Image *	m_images [2]
logvals *	m_lqcache
double	m_lqDWeights [2][N_WEIGHTS]
int	m_lqcachesize
Static Protected Attributes
static const float	m_scWeights [][N_WEIGHTS]
static const float	m_drWeights [][N_WEIGHTS]

Detailed Description

A class for differences between two images

Definition at line 43 of file ImageComparison.hh.

Constructor & Destructor Documentation

ImageComparison::ImageComparison	(	const Image &	img1,
		const Image &	img2
	)

Constructor. Creates copies of the two images. If the two images have different dimensions they will be resized to the largest common dimensions.

Parameters:

img1	the first image
img2	the second image

ImageComparison::~ImageComparison ( void )

Destructor. Releases allocated memory.

Member Function Documentation

static double ImageComparison::calcLqAverageScore	(	const Image &	truncated1,
		const Image &	truncated2,
		int	colorChannel = `0`
	)		`[static]`

Calculate an $L^q$ average score for a greyscale image / single color channel.

Parameters:

truncated1	the first image already truncated (see truncateForLq)
truncated2	the second image already truncated (see truncateForLq)
colorChannel	the number of the color channel to which the two images correspond, this is important as it has an effect on the weights chosen when calculating the score

Returns:: the average score

static double ImageComparison::calcLqDetailScore	(	const Image &	truncated1,
		const Image &	truncated2,
		int	colorChannel = `0`
	)		`[static]`

Calculate an $L^q$ detail score for a greyscale image / single color channel.

Parameters:

truncated1	the first image already truncated (see truncateForLq)
truncated2	the second image already truncated (see truncateForLq)
colorChannel	the number of the color channel to which the two images correspond, this is important as it has an effect on the weights chosen when calculating the score

Returns:: the detail score

double ImageComparison::cmpmse ( void )

Compare with another image producing the mean square error. Stolen from Geoff Davis' Wavelet Coder kit.

Returns:: The MSE

double ImageComparison::cmpsnr ( void )

Compare with another image producing the PSNR. Stolen from Geoff Davis' Wavelet Coder kit.

Returns:: The PSNR

int ImageComparison::cols ( void ) const [inline]

Return the number of columns.

Returns:: the number of columns

Definition at line 64 of file ImageComparison.hh.

References m_xsize.

Image* ImageComparison::difference	(	coeff	magnify = `1`,
		bool	reverse = `false`
	)

Produce an image holding the difference between the first and the second image

Parameters:

magnify	multiply the result by a factor to increase / decrease visibility
reverse	reverse the subtraction (take img1 - img2)

Returns:: a new image containing the difference

lq ImageComparison::distlq	(	double	percent,
		FilterSet &	flt,
		imgtype	type
	)

Calculate the distance to another image according to the $L^q$ norm. Idea and basic algorithm from Jacobs, Finkelstein, Salesin: "Fast multiresolution image querying", Proc. of SIGGRAPH, 95. Note that this method is deprecated as it does not strictly conform to the original algorithm. I propose using the static methods truncateForLq and calcLqAverageAcore, calcLqDetailScore instead.

Exceptions:

invalid_argument image is not square

Parameters:

percent	the relative number of Wavelet coefficients to compare
flt	the filter to use
type	the type of the images to be assumed (drawn or scanned)

Returns:: The $L^q$ norm

double ImageComparison::distlqd	(	double	percent,
		FilterSet &	flt,
		imgtype	type
	)

Calculate the distance to another image according to the old $L^qd$ norm. Idea and basic algorithm from Jacobs, Finkelstein, Salesin: "Fast multiresolution image querying", Proc. of SIGGRAPH, 95.

Exceptions:

invalid_argument image is not square

Parameters:

percent	the relative number of Wavelet coefficients to compare
flt	the filter to use
type	the type of the images to be assumed (drawn or scanned)

Returns:: The $L^qd$ norm

static const float* ImageComparison::getWeights	(	const imgtype	imgType,
		int	channel
	)		`[static]`

Return a reference to the weight table for a given type.

Parameters:

imgType	the type (scanned or drawn)
channel	the channel (Y, U, V)

Returns:: the weight table

static ImageInformation* ImageComparison::imageInfoForLq	(	const Image &	image,
		int	nKeptCoeffs,
		FilterSet &	flt,
		const decomp	t = `STANDARD`
	)		`[static]`

Calculates a feature vector for the $L^q$ and $L^qd$ metrics.

Parameters:

image	the image
nKeptCoeffs	the absolute number of Wavelet coefficients to keep
flt	the filter to use
t	the decomposition type to use (default: Standard)

Returns:: an image information of overall average the n most significant coeffs sorted by absolute

int ImageComparison::level ( int pos ) [protected]

Helper method for distlq(). Calculates the weighing level for a position

Parameters:

pos	the position (row or col)

Returns:: the level

double ImageComparison::lq_sum	(	imgtype	type,
		bool	reverse,
		bool	oldLqd = `false`
	)		`[protected]`

Helper method for distlq(). Calculate the sum of differences of the two decomposed images.

Parameters:

type	the type (drawn or scanned) to be assumed
reverse	if true, subract the first from the second image
oldLqd	if true, calculate the old Lqd way: add up the score for differing locations instead of subtracting the scores for identical values

int ImageComparison::rows ( void ) const [inline]

Return the number of rows.

Returns:: the number of rows

Definition at line 60 of file ImageComparison.hh.

References m_ysize.

int ImageComparison::size ( void ) const [inline]

Return the overall size.

Returns:: the overall size

Definition at line 68 of file ImageComparison.hh.

References m_xysize.

static Image* ImageComparison::truncateForLq	(	const Image &	image,
		double	percent,
		FilterSet &	flt,
		const decomp	t = `STANDARD`
	)		`[static]`

Calculates a feature vector for the $L^q$ and $L^qd$ metrics.

Parameters:

image	the image
percent	the relative number of Wavelet coefficients to keep
flt	the filter to use
t	the decomposition type to use (default: Standard)

Returns:: an image of overall average and truncated coeffs

static Image* ImageComparison::truncateForLq	(	const Image &	image,
		int	nKeptCoeffs,
		FilterSet &	flt,
		const decomp	t = `STANDARD`
	)		`[static]`

Calculates a feature vector for the $L^q$ and $L^qd$ metrics.

Parameters:

image	the image
nKeptCoeffs	the absolute number of Wavelet coefficients to keep
flt	the filter to use
t	the decomposition type to use (default: Standard)

Returns:: an image of overall average and truncated coeffs

double ImageComparison::weight	(	int	y,
		int	x,
		imgtype	type
	)		`[protected]`

Helper method for distlq(). Calculate the weight for a position (y, x).

Parameters:

y	the row
x	the col
type	the images' type to be assumed (drawn or scanned)

Returns:: the position's weight

Member Data Documentation

const float ImageComparison::m_drWeights[][N_WEIGHTS] [static, protected]

The default weight tables for drawn images.

Definition at line 233 of file ImageComparison.hh.

Image* ImageComparison::m_images[2] [protected]

An array holding the two images to be compared.

Definition at line 220 of file ImageComparison.hh.

logvals* ImageComparison::m_lqcache [protected]

A cache needed by distlq() to avoid repeated calculation of floor (log (i) / log (2)).

Definition at line 224 of file ImageComparison.hh.

int ImageComparison::m_lqcachesize [protected]

The size of the m_lqcache. Always as big as MAX (rows, cols).

Definition at line 236 of file ImageComparison.hh.

double ImageComparison::m_lqDWeights[2][N_WEIGHTS] [protected]

The six weights for scanned images, needed by distlq(), Y channel, according to Jacobs et.al.

Definition at line 228 of file ImageComparison.hh.

const float ImageComparison::m_scWeights[][N_WEIGHTS] [static, protected]

The default weight tables for scanned images.

Definition at line 231 of file ImageComparison.hh.

int ImageComparison::m_xsize [protected]

Number of cols.

Definition at line 215 of file ImageComparison.hh.

Referenced by cols().

int ImageComparison::m_xysize [protected]

Overall size.

Definition at line 217 of file ImageComparison.hh.

Referenced by size().

int ImageComparison::m_ysize [protected]

Number of rows.

Definition at line 213 of file ImageComparison.hh.

Referenced by rows().

The documentation for this class was generated from the following file:

ImageComparison.hh

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation