Collaboration diagram for Gray images:

Classes
class	crn::Gray2BW
	Binarization action. More...

class	crn::Gray2BWThreshold
	Threshold binarization action. More...

class	crn::Gray2BWNiblack
	Niblack binarization action. More...

class	crn::Gray2BWSauvola
	Sauvola binarization action. More...

class	crn::Gray2BWkMeansHisto
	k-means histo binarization action More...

class	crn::Gray2BWLocalMin
	Local min binarization action. More...

class	crn::Gray2BWLocalMax
	Local max binarization action. More...

class	crn::Gray2BWFisher
	Fisher binarization action. More...

class	crn::Gray2BWEntropy
	Entropy binarization action. More...

class	crn::Gray2BWOtsu
	Otsu binarization action. More...

struct	crn::IsSerializable< Gray2BW >

struct	crn::IsSerializable< Gray2BWThreshold >

struct	crn::IsSerializable< Gray2BWNiblack >

struct	crn::IsSerializable< Gray2BWSauvola >

struct	crn::IsSerializable< Gray2BWkMeansHisto >

struct	crn::IsSerializable< Gray2BWLocalMin >

struct	crn::IsSerializable< Gray2BWLocalMax >

struct	crn::IsSerializable< Gray2BWFisher >

struct	crn::IsSerializable< Gray2BWEntropy >

struct	crn::IsSerializable< Gray2BWOtsu >

Typedefs
using	crn::ImageGray = Image< uint8_t >
	Grayscale image class. More...

using	crn::ImageIntGray = Image< int >
	Int grayscale image class. More...

using	crn::ImageDoubleGray = Image< double >
	double Grayscale image class More...

Functions
void	crn::Sqrt (ImageDoubleGray &img) noexcept
	Replaces the pixels with their square root. More...

template<typename T >
void	crn::Abs (Image< T > &img, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr) noexcept
	Replaces each pixel by its absolute value. More...

void	crn::AutoContrast (ImageGray &img)

template<typename T >
Histogram	crn::MakeHistogram (const Image< T > &img, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

Histogram	crn::MakeHistogram (const ImageGray &img)
	Creates an histogram from the pixels. More...

Histogram	crn::HorizontalProjection (const ImageGray &img)
	Computes the horizontal projection. More...

Histogram	crn::VerticalProjection (const ImageGray &img)
	Computes the vertical projection. More...

template<typename T >
size_t	crn::StrokesWidth (const Image< T > &img, size_t maxval=50, size_t defaultval=0, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

template<typename T >
size_t	crn::StrokesHeight (const Image< T > &img, size_t maxval=50, size_t defaultval=0, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

size_t	crn::EstimateLinesXHeight (const ImageGray &img, unsigned int xdiv=16)
	Computes the mean text line x-height. More...

size_t	crn::EstimateLeading (const ImageGray &img)
	Computes the median distance between two baselines. More...

Angle< Radian >	crn::EstimateSkew (const ImageGray &img)
	Estimates the mean skew of the document's lines. More...

template<typename T >
ImageRGB	crn::RandomColors (const Image< T > &img, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

template<typename T , typename CMP = std::less<T>>
ImageBW	crn::Threshold (const Image< T > &img, T thresh, CMP cmp=std::less< T >{})

template<typename T >
ImageBW	crn::Niblack (const Image< T > &img, size_t halfwin, double k=0.5, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

template<typename T >
ImageBW	crn::Sauvola (const Image< T > &img, size_t halfwin, double k=0.5, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

template<typename T >
ImageBW	crn::kMeansHisto (const Image< T > &img, size_t classes, size_t black_classes, size_t maxcnt=10000, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

template<typename T >
ImageBW	crn::LocalMin (const Image< T > &img, size_t area=1, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

template<typename T >
ImageBW	crn::LocalMax (const Image< T > &img, size_t area=1, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

template<typename T >
ImageBW	crn::Fisher (const Image< T > &img, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

template<typename T >
ImageBW	crn::Entropy (const Image< T > &img, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

template<typename T >
ImageBW	crn::Otsu (const Image< T > &img, typename std::enable_if< std::is_arithmetic< T >::value >::type *dummy=nullptr)

ImageBW	crn::MakeImageBW (const ImageGray &img)

Detailed Description

Typedef Documentation

using crn::ImageDoubleGray = typedef Image<double>

double Grayscale image class

This class is for grayscale images. Values in pixels' vector represent values for luminosity.

Author: Yann LEYDIER

Date: August 2007

Version: 0.4

Definition at line 87 of file CRNImageFormats.h.

using crn::ImageGray = typedef Image<uint8_t>

Grayscale image class.

This class is for grayscale images. Values in pixels' vector represent values for luminosity.

Author: Yann LEYDIER

Date: August 2007

Version: 0.4

Definition at line 59 of file CRNImageFormats.h.

using crn::ImageIntGray = typedef Image<int>

Int grayscale image class.

This class is for grayscale images. Values in pixels' vector represent values for luminosity.

Author: Yann LEYDIER

Date: August 2007

Version: 0.4

Definition at line 73 of file CRNImageFormats.h.

Function Documentation

template<typename T >

void crn::Abs	(	Image< T > &	img,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

noexcept

Replaces each pixel by its absolute value.

Definition at line 47 of file CRNImageGray.h.

void crn::AutoContrast ( ImageGray & img )

Stretches the histogram

Parameters

[in] img the image to modify

Definition at line 516 of file CRNImageGray.cpp.

template<typename T >

ImageBW crn::Entropy	(	const Image< T > &	img,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Creates a BW image using the entropy threshold

Parameters

[in] img the image to binarize

Returns: the newly created image or nullptr if the image was not allocated

Definition at line 553 of file CRNImageGray.h.

size_t crn::EstimateLeading ( const ImageGray & img )

Computes the median distance between two baselines.

Warning: very slow

Parameters

[in] img the source image

Returns: the median distance between two baselines

Definition at line 673 of file CRNImageGray.cpp.

size_t crn::EstimateLinesXHeight	(	const ImageGray &	img,
		unsigned int	xdiv = `16`
	)

Computes the mean text line x-height.

Computes the mean text line x-height

Parameters

[in] img the source image

Returns: the mean text line x-height

Definition at line 616 of file CRNImageGray.cpp.

Angle< Radian > crn::EstimateSkew ( const ImageGray & img )

Estimates the mean skew of the document's lines.

Estimates the mean skew of the document's lines

Parameters

[in] img the source image

Returns: the mean angle of the document's lines

Definition at line 727 of file CRNImageGray.cpp.

template<typename T >

ImageBW crn::Fisher	(	const Image< T > &	img,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Creates a BW image using the Fisher criterion

Parameters

[in] img the image to binarize

Returns: the newly created image or nullptr if the image was not allocated

Definition at line 521 of file CRNImageGray.h.

Histogram crn::HorizontalProjection ( const ImageGray & img )

Computes the horizontal projection.

Computes the horizontal projection

Returns: an histogram containing the projection

Definition at line 567 of file CRNImageGray.cpp.

template<typename T >

ImageBW crn::kMeansHisto	(	const Image< T > &	img,
		size_t	classes,
		size_t	black_classes,
		size_t	maxcnt = `10000`,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Creates a BW image through a classification of the histogram

Parameters

[in]	img	the image to binarize
[in]	classes	the total number of classes to compute
[in]	black_classes	the total number of classes that represent the black pixels
[in]	maxcnt	the maximal number of loops

Returns: the newly created image or nullptr if the image was not allocated

Definition at line 335 of file CRNImageGray.h.

template<typename T >

ImageBW crn::LocalMax	(	const Image< T > &	img,
		size_t	area = `1`,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Creates a BW image the local maxima

Parameters

[in]	img	the image to binarize
[in]	area	the half window size (window size = 1 + 2 * area).

Returns: the newly created image

Definition at line 463 of file CRNImageGray.h.

template<typename T >

ImageBW crn::LocalMin	(	const Image< T > &	img,
		size_t	area = `1`,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Creates a BW image the local minima

Parameters

[in]	img	the image to binarize
[in]	area	the half window size (window size = 1 + 2 * area).

Returns: the newly created image or nullptr if the image was not allocated

Definition at line 404 of file CRNImageGray.h.

template<typename T >

Histogram crn::MakeHistogram	(	const Image< T > &	img,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Creates an histogram from the pixels

Parameters

[in] img the image to binarize

Returns: the histogram

Definition at line 64 of file CRNImageGray.h.

Histogram crn::MakeHistogram ( const ImageGray & img )

Creates an histogram from the pixels.

Creates an histogram from the pixels

Parameters

[in] img the image to binarize

Returns: the histogram

Definition at line 601 of file CRNImageGray.cpp.

ImageBW crn::MakeImageBW ( const ImageGray & img )

Definition at line 935 of file CRNImageGray.cpp.

template<typename T >

ImageBW crn::Niblack	(	const Image< T > &	img,
		size_t	halfwin,
		double	k = `0.5`,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Creates a BW image using Niblack's algorithm the binarisation use a threshold on a square window of neighbouring pixels the threshold t is calculated by

mean m
standard deviation s
parameter k Pixels strictly inferior to the threshold become black, the others white.

t = m + k*s

Parameters

[in]	img	the image to binarize
[in]	halfwin	size of the square window of neighbouring pixels, from the border of the window to the central pixel
[in]	k	parameter k

Returns: the newly created image

Definition at line 229 of file CRNImageGray.h.

template<typename T >

ImageBW crn::Otsu	(	const Image< T > &	img,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Creates a BW image using the Otsu's algorithm

Parameters

[in] img the image to binarize

Returns: the newly created image or nullptr if the image was not allocated

Definition at line 585 of file CRNImageGray.h.

template<typename T >

ImageRGB crn::RandomColors	(	const Image< T > &	img,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Exports to an RGB image with random colors

Parameters

[in] img the source image

Returns: the newly created image

Definition at line 177 of file CRNImageGray.h.

template<typename T >

ImageBW crn::Sauvola	(	const Image< T > &	img,
		size_t	halfwin,
		double	k = `0.5`,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Creates a BW image using Sauvola's algorithm the binarisation use a threshold on a square window of neighbouring pixels the threshold t is calculated by

mean m
standard deviation s
dynamic range of std.dev. R
parameter k Pixels strictly inferior to the threshold become black, the others white.

t = m * (1 + k * (s / R - 1))

Parameters

[in]	img	the image to binarize
[in]	halfwin	size of the square window of neighbouring pixels, from the border of the window to the central pixel
[in]	k	parameter k

Returns: the newly created image

Definition at line 282 of file CRNImageGray.h.

void crn::Sqrt ( ImageDoubleGray & img )

noexcept

Replaces the pixels with their square root.

Replaces the pixels with their square root

Parameters

[in] img the image to modify

Definition at line 507 of file CRNImageGray.cpp.

template<typename T >

size_t crn::StrokesHeight	(	const Image< T > &	img,
		size_t	maxval = `50`,
		size_t	defaultval = `0`,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Computes the mean stroke height

Parameters

[in]	img	the image to binarize
[in]	maxval	if the mean stroke height is > maxval, then defaultval is returned
[in]	defaultval	the value returned if no mean stroke height can be computed

Returns: the mean stroke height

Definition at line 131 of file CRNImageGray.h.

template<typename T >

size_t crn::StrokesWidth	(	const Image< T > &	img,
		size_t	maxval = `50`,
		size_t	defaultval = `0`,
		typename std::enable_if< std::is_arithmetic< T >::value >::type *	dummy = `nullptr`
	)

Computes the mean stroke width

Parameters

[in]	img	the image to binarize
[in]	maxval	if the mean stroke width is > maxval, then defaultval is returned
[in]	defaultval	the value returned if no mean stroke width can be computed

Returns: the mean stroke width

Definition at line 90 of file CRNImageGray.h.

template<typename T , typename CMP = std::less<T>>

ImageBW crn::Threshold	(	const Image< T > &	img,
		T	thresh,
		CMP	cmp = `std::less<T>{}`
	)

Creates a BW image using a fixed threshold. Pixels strictly inferior to the threshold become black, the others white.

Parameters

[in]	img	the image to binarize
[in]	thresh	the threshold

Returns: the newly created image

Definition at line 204 of file CRNImageGray.h.

Histogram crn::VerticalProjection ( const ImageGray & img )

Computes the vertical projection.

Computes the vertical projection

Returns: an histogram containing the projection

Definition at line 583 of file CRNImageGray.cpp.

Classes

Typedefs

Functions

Detailed Description

Typedef Documentation

Function Documentation