Contains basic algorithms to manipulate images. More...

#include <Algorithms.h>

Public Types
enum	MorphShape { SQUARE = 0, DISK }

enum	MorphBorder { BORDER_ZERO = 0, BORDER_FLIP }

Static Public Member Functions
static cv::Mat	dilateImage (const cv::Mat &bwImg, int seSize, MorphShape shape=Algorithms::SQUARE, int borderValue=0)
	Dilates the image bwImg with a given structuring element. More...

static cv::Mat	erodeImage (const cv::Mat &bwImg, int seSize, MorphShape shape=Algorithms::SQUARE, int borderValue=255)
	Erodes the image bwimg with a given structuring element. More...

static cv::Mat	createStructuringElement (int seSize, int shape)
	Creates the structuring element for morphological operations. More...

static cv::Mat	convolveSymmetric (const cv::Mat &hist, const cv::Mat &kernel)
	Convolves a histogram symmetrically. Symmetric convolution means that the convolution is flipped around at the histograms borders. This is specifically useful for orientation histograms (since 0° corresponds to 360° More...

static cv::Mat	get1DGauss (double sigma)
	Computes a 1D Gaussian filter kernel. The kernel's size is adjusted to the standard deviation. More...

static cv::Mat	threshOtsu (const cv::Mat &srcImg, int thType=CV_THRESH_BINARY_INV)
	Threshold an image using Otsu as threshold. More...

static cv::Mat	convolveIntegralImage (const cv::Mat &src, const int kernelSizeX, const int kernelSizeY=0, MorphBorder norm=BORDER_ZERO)
	Convolves an integral image by means of box filters. This functions applies box filtering. It is specifically useful for the computation of image sums, mean filtering and standard deviation with big kernel sizes. More...

static void	setBorderConst (cv::Mat &src, float val=0.0f)
	Sets the border to a constant value (1 pixel width). More...

static void	invertImg (cv::Mat &srcImg, cv::Mat mask=cv::Mat())
	Inverts the img. More...

static void	mulMask (cv::Mat &src, cv::Mat mask=cv::Mat())
	Applies a mask to the image. More...

static cv::Mat	preFilterArea (const cv::Mat &img, int minArea, int maxArea=-1)
	Prefilters an binary image according to the blob size. Should be done to remove small blobs and to reduce the runtime of cvFindContours. More...

static cv::Mat	computeHist (const cv::Mat img, const cv::Mat mask=cv::Mat())
	Computes the histogram of an image. More...

static double	getThreshOtsu (const cv::Mat &hist, const double otsuThresh=0)
	Gets the Otsu threshold based on a certain histogram. More...

static double	normAngleRad (double angle, double startIvl=0.0, double endIvl=2.0 *CV_PI)
	Computes the normalized angle within startIvl and endIvl. More...

static double	angleDist (double angle1, double angle2, double maxAngle=2.0 *CV_PI)
	Computes the distance between two angles. Hence, min(angleDiff, CV_PI*2-(angleDiff)) More...

static cv::Mat	estimateMask (const cv::Mat &src, bool preFilter=true)
	Estimates the mask. More...

static cv::Mat	rotateImage (const cv::Mat &src, double angleRad, int interpolation=cv::INTER_CUBIC, cv::Scalar borderValue=cv::Scalar(0))
	Rotates an image according to the angle obtained. The new image bounds are minimized with respect to the angle obtained. positive angle values mean counterclockwise rotation More...

static double	logGammaLanczos (double x)
	Computes the natural logarithm of the absolute value of the gamma function of x using the Lanczos approximation. See http ://www.rskey.org/gamma.htm More...

static double	logGammaWindschitl (double x)
	Computes the natural logarithm of the absolute value of the gamma function of x using Windschitl method. More...

static double	logGamma (double x)
	Computes the natural logarithm of the absolute value of the gamma function of x.When x>15 use log_gamma_windschitl(), otherwise use log_gamma_lanczos(). More...

static int	doubleEqual (double a, double b)
	The resulting rounding error after floating point computations depend on the specific operations done.The same number computed by different algorithms could present different rounding errors.For a useful comparison, an estimation of the relative rounding error should be considered and compared to a factor times EPS.The factor should be related to the cumulated rounding error in the chain of computation.Here, as a simplification, a fixed factor is used. More...

static double	absAngleDiff (double a, double b)

static double	signedAngleDiff (double a, double b)

static QPointF	calcRotationSize (double angleRad, const QPointF &srcSize)
	Calculates the image size of the rotated image. More...

static double	min (const QVector< double > &vec)
	Returns the minimum of the vector or DBL_MAX if vec is empty. More...

static double	max (const QVector< double > &vec)
	Returns the maximum value of vec or -DBL_MAX if vec is empty. More...

template<typename numFmt >
static double	statMoment (const QList< numFmt > &valuesIn, double momentValue, int interpolated=1)
	Computes robust statistical moments (quantiles). More...

template<typename sFmt , typename mFmt >
static void	mulMaskIntern (cv::Mat src, const cv::Mat mask)

template<typename sFmt >
static void	setBorderConstIntern (cv::Mat src, sFmt val)

Detailed Description

Contains basic algorithms to manipulate images.

Member Enumeration Documentation

enum rdf::Algorithms::MorphBorder

Enumerator
BORDER_ZERO
BORDER_FLIP

enum rdf::Algorithms::MorphShape

Enumerator
SQUARE
DISK

Member Function Documentation

double rdf::Algorithms::absAngleDiff	(	double	a,
		double	b
	)

static

double rdf::Algorithms::angleDist	(	double	angle1,
		double	angle2,
		double	maxAngle = `2.0*CV_PI`
	)

static

Computes the distance between two angles. Hence, min(angleDiff, CV_PI*2-(angleDiff))

Parameters

angle1	The angle1.
angle2	The angle2.

Returns: The angular distance.

QPointF rdf::Algorithms::calcRotationSize	(	double	angleRad,
		const QPointF &	srcSize
	)

static

Calculates the image size of the rotated image.

Parameters

angleRad	The angle in radians.
srcSize	Size of the source image.

Returns: The Size of the rotated image.

cv::Mat rdf::Algorithms::computeHist	(	const cv::Mat	img,
		const cv::Mat	mask = `cv::Mat()`
	)

static

Computes the histogram of an image.

Parameters

img	The source img CV_32FC1.
mask	The mask CV_8UC1 or CV_32FC1.

Returns: The histogram of the img as cv::mat CV_32FC1.

cv::Mat rdf::Algorithms::convolveIntegralImage	(	const cv::Mat &	src,
		const int	kernelSizeX,
		const int	kernelSizeY = `0`,
		MorphBorder	norm = `BORDER_ZERO`
	)

static

Convolves an integral image by means of box filters. This functions applies box filtering. It is specifically useful for the computation of image sums, mean filtering and standard deviation with big kernel sizes.

Parameters

src	The integral image CV_64FC1.
kernelSizeX	The box filter's size.
kernelSizeY	The box filter's size.
norm	If BORDER_ZERO an image sum is computed, if BORDER_FLIP a mean filtering is applied.

Returns: The convolved image CV_32FC1.

cv::Mat rdf::Algorithms::convolveSymmetric	(	const cv::Mat &	hist,
		const cv::Mat &	kernel
	)

static

Convolves a histogram symmetrically. Symmetric convolution means that the convolution is flipped around at the histograms borders. This is specifically useful for orientation histograms (since 0° corresponds to 360°

Parameters

hist	The histogram CV_32FC1.
kernel	The convolution kernel CV_32FC1.

Returns: The convolved Histogram CV_32FC1.

cv::Mat rdf::Algorithms::createStructuringElement	(	int	seSize,
		int	shape
	)

static

Creates the structuring element for morphological operations.

Parameters

seSize	Size of the structuring element.
shape	The shape (either Square or Disk).

Returns: A cvMat containing the structuring element (CV_8UC1).

cv::Mat rdf::Algorithms::dilateImage	(	const cv::Mat &	bwImg,
		int	seSize,
		MorphShape	shape = `Algorithms::SQUARE`,
		int	borderValue = `0`
	)

static

Dilates the image bwImg with a given structuring element.

Parameters

bwImg	The bwImg: a grayscale image CV_8U (or CV_32F [0 1] but slower).
seSize	The structuring element's size.
shape	The shape (either Square or Disk).
borderValue	The border value.

Returns: An dilated image (CV_8U or CV_32F).

int rdf::Algorithms::doubleEqual	(	double	a,
		double	b
	)

static

The resulting rounding error after floating point computations depend on the specific operations done.The same number computed by different algorithms could present different rounding errors.For a useful comparison, an estimation of the relative rounding error should be considered and compared to a factor times EPS.The factor should be related to the cumulated rounding error in the chain of computation.Here, as a simplification, a fixed factor is used.

Parameters

a	Input a
b	Input b

Returns: equal if relative error <= factor x eps

cv::Mat rdf::Algorithms::erodeImage	(	const cv::Mat &	bwImg,
		int	seSize,
		MorphShape	shape = `Algorithms::SQUARE`,
		int	borderValue = `255`
	)

static

Erodes the image bwimg with a given structuring element.

Parameters

bwImg	The bwimg: a grayscale image CV_8U (or CV_32F [0 1] but slower).
seSize	The structuring element's size.
shape	The shape (either Square or Disk).
borderValue	The border value.

Returns: An eroded image (CV_8U or CV_32F).

cv::Mat rdf::Algorithms::estimateMask	(	const cv::Mat &	src,
		bool	preFilter = `true`
	)

static

Estimates the mask.

Parameters

src	The source image.

Returns: The estimated mask.

cv::Mat rdf::Algorithms::get1DGauss ( double sigma )

static

Computes a 1D Gaussian filter kernel. The kernel's size is adjusted to the standard deviation.

Parameters

sigma The standard deviation of the Gaussian.

Returns: The Gaussian kernel CV_32FC1

double rdf::Algorithms::getThreshOtsu	(	const cv::Mat &	hist,
		const double	otsuThresh = `0`
	)

static

Gets the Otsu threshold based on a certain histogram.

Parameters

hist	The histogram CV_32FC1.
otsuThresh	The otsu threshold - deprecated.

Returns: The computed threshold.

void rdf::Algorithms::invertImg	(	cv::Mat &	srcImg,
		cv::Mat	mask = `cv::Mat()`
	)

static

Inverts the img.

Parameters

srcImg	The source img CV_32FC1 [0 1] or CV_8UC1.
mask	The mask.

double rdf::Algorithms::logGamma ( double x )

static

Computes the natural logarithm of the absolute value of the gamma function of x.When x>15 use log_gamma_windschitl(), otherwise use log_gamma_lanczos().

Parameters

x	The Input x.

Returns: Natural Logarithm

double rdf::Algorithms::logGammaLanczos ( double x )

static

Computes the natural logarithm of the absolute value of the gamma function of x using the Lanczos approximation. See http ://www.rskey.org/gamma.htm

Parameters

x	Input value

Returns: Natural Algorithm

double rdf::Algorithms::logGammaWindschitl ( double x )

static

Computes the natural logarithm of the absolute value of the gamma function of x using Windschitl method.

Parameters

x	Input Value x

Returns: Natural Log using Windschitl

double rdf::Algorithms::max ( const QVector< double > & vec )

static

Returns the maximum value of vec or -DBL_MAX if vec is empty.

Parameters

vec	A vector with double values.

Returns: the maximum

double rdf::Algorithms::min ( const QVector< double > & vec )

static

Returns the minimum of the vector or DBL_MAX if vec is empty.

Parameters

vec	A vector with double values.

Returns: the minimum

void rdf::Algorithms::mulMask	(	cv::Mat &	src,
		cv::Mat	mask = `cv::Mat()`
	)

static

Applies a mask to the image.

Parameters

src	The source img CV_8U or CV_32F.
mask	The optional mask CV_8U or CV_32F.

template<typename sFmt , typename mFmt >

static void rdf::Algorithms::mulMaskIntern	(	cv::Mat	src,
		const cv::Mat	mask
	)

inlinestatic

double rdf::Algorithms::normAngleRad	(	double	angle,
		double	startIvl = `0.0`,
		double	endIvl = `2.0*CV_PI`
	)

static

Computes the normalized angle within startIvl and endIvl.

Parameters

angle	The angle in rad.
startIvl	The intervals lower bound.
endIvl	The intervals upper bound.

Returns: The angle within [startIvl endIvl].

cv::Mat rdf::Algorithms::preFilterArea	(	const cv::Mat &	img,
		int	minArea,
		int	maxArea = `-1`
	)

static

Prefilters an binary image according to the blob size. Should be done to remove small blobs and to reduce the runtime of cvFindContours.

Parameters

img	The source img CV_8UC1.
minArea	The blob size threshold in pixel.
maxArea	The maximum area.

Returns: A CV_8UC1 binary image with all blobs smaller than minArea removed.

cv::Mat rdf::Algorithms::rotateImage	(	const cv::Mat &	src,
		double	angleRad,
		int	interpolation = `cv::INTER_CUBIC`,
		cv::Scalar	borderValue = `cv::Scalar(0)`
	)

static

Rotates an image according to the angle obtained. The new image bounds are minimized with respect to the angle obtained. positive angle values mean counterclockwise rotation

Parameters

src	The source image.
angleRad	The angle in RAD.
interpolation	The interpolation.
borderValue	The border value.

Returns: The rotated image.

void rdf::Algorithms::setBorderConst	(	cv::Mat &	src,
		float	val = `0.0f`
	)

static

Sets the border to a constant value (1 pixel width).

Parameters

src	The source image CV_32F or CV_8U.
val	The border value.

template<typename sFmt >

static void rdf::Algorithms::setBorderConstIntern	(	cv::Mat	src,
		sFmt	val
	)

inlinestatic

double rdf::Algorithms::signedAngleDiff	(	double	a,
		double	b
	)

static

template<typename numFmt >

static double rdf::Algorithms::statMoment	(	const QList< numFmt > &	valuesIn,
		double	momentValue,
		int	interpolated = `1`
	)

inlinestatic

Computes robust statistical moments (quantiles).

Parameters

valuesIn	The statistical set (samples).
momentValue	The statistical moment value (0.5 = median, 0.25 and 0.75 = quartiles).
interpolated	A flag if the value should be interpolated if the length of the list is even.

Returns: The statistical moment.

cv::Mat rdf::Algorithms::threshOtsu	(	const cv::Mat &	srcImg,
		int	thType = `CV_THRESH_BINARY_INV`
	)

static

Threshold an image using Otsu as threshold.

Parameters

srcImg The source img CV_8UC1 or CV_8UC3.

Returns: A binary image CV_8UC1

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

src/Core/Algorithms.h
src/Core/Algorithms.cpp

Public Types

Static Public Member Functions

Detailed Description

Member Enumeration Documentation

Member Function Documentation