This class implements the Marching Squares algorithm to find isolines on 2D image slices. More...

#include <CSOMarchingSquares.h>

Classes
struct	FillCSOParameters

Public Member Functions
	CSOMarchingSquares ()
	Constructor.

	~CSOMarchingSquares ()
	Destructor.

void	reset ()
	Resets the state of the object.

void	setInterpolation (bool use)
	Specifies whether the algorithm should interpolate the contour bi-linearly.

void	setImage (float *image, int imgSizeX, int imgSizeY)
	Sets the 2D image to track/find contours on.

void	setFunction (CSOFunction *implicitFunction, const Matrix4 &voxelToWorldMatrix, int startX, int startY, int imgSizeX, int imgSizeY, int voxelZPosition)
	Sets a 3D interpolation function, an image size and voxel size, and a fixed z-offset.

void	findIsoLine (int startPosX, int startPosY, float isoValue, bool takeShortestPath, CSOMarchingSquaresCell::vecPoint2D &positions)
	Looks for an isoline on the `image`.

void	findAllIsoLines (float isoValue, bool takeShortestPath, std::vector< CSOMarchingSquaresCell::vecPoint2D > &vecPositions)
	Finds all contours on the `image` with isovalue `isovalue`. Returns them in a vector of 2D position vectors.

bool	fillCSO (FillCSOParameters &parameters)
	Fills the given CSO with seed points according to the given list of points.

Protected Member Functions
void	_findStartPosition (int &startX, int &startY)
	Searches for a starting position such that startX/startY make up the top-left voxel position of a cell that is intersected by the isoline.

bool	_findNearestIsoCell (int voxelPosX, int voxelPosY, CSOMarchingSquaresCell &cell)
	Searches for the first cell that is an iso-cell starting from [`voxelPosX`, `voxelPosY`]. Returns true if a cell was found, i.e., `cell` is valid.

bool	_findNearestIsoCell (int voxelPos[2], CSOMarchingSquaresCell &cell)
	Searches for the first cell that is an iso-cell starting from [`voxelPos`[0], `voxelPos`[1]]. Returns true if a cell was found, i.e., `cell` is valid.

void	_trackIsoCell (CSOMarchingSquaresCell startCell, const int initialFromDir, CSOMarchingSquaresCell::vecPoint2D &positions, std::vector< std::array< unsigned char, 2 > > *cellsVisitedDirections=nullptr)
	Tracks the isoline starting from the `startCell`.

void	_createCell (int topLeftVoxel[2], CSOMarchingSquaresCell &cell)
	Creates a new cell at position `topLeftVoxel`[2].

void	_createCell (int topLeftVoxel[2], std::set< unsigned int > &cellsVisited, std::queue< CSOMarchingSquaresCell > &cellFront)
	Creates a new cell at position `topLeftVoxel`[2], and keeps track whether this cell has already been created.

void	_createCell (int topLeftVoxel[2], CSOMarchingSquaresCell &cell, float values[4], char cellConfig)
	Creates a new cell at position `topLeftVoxel`[2].

int	_walkToCell (const CSOMarchingSquaresCell &fromCell, int fromDir, CSOMarchingSquaresCell &toCell)
	Creates a cell `toCell` from the cell `fromCell` coming from `fromDir`.

int	_getPossibleEnterDirection (const CSOMarchingSquaresCell &cell) const

unsigned int	_getKey (const CSOMarchingSquaresCell &cell) const
	Returns the key for a cell. For example, this can be used for hashtables.

unsigned int	_getKey (int x, int y) const
	Returns the key for a position for hashtables.

float	_getValueAt (int x, int y)
	Returns the value of the image or function at the given position.

bool	_isInImage (int x, int y) const
	Returns whether the x,y coordinates are within the image.

Protected Attributes
float *	_image
	Pointer to input image.

int	_imageSizeX
	The x extent of the input image.

int	_imageSizeY
	The y extent of the input image.

int	_startX
	Starting voxel x (function).

int	_startY
	Starting voxel y (function).

float	_isoValue
	The isovalue to find the isoline for.

CSOFunction *	_function
	An implicit function.

int	_voxelZPosition
	The z-position of the voxels.

Matrix4	_voxelToWorldMatrix
	The voxel-to-world matrix.

bool	_bInterpolatePoints
	Should the contour be interpolated bi-linearly?

boost::unordered_map< int, double >	_existingValues
	A map holding all computed image/function values.

Detailed Description

This class implements the Marching Squares algorithm to find isolines on 2D image slices.

One can either find an isoline starting from a start point or find all contours on that slice.

Definition at line 38 of file CSOMarchingSquares.h.

Constructor & Destructor Documentation

◆ CSOMarchingSquares()

ml::CSOMarchingSquares::CSOMarchingSquares ( )

Constructor.

◆ ~CSOMarchingSquares()

ml::CSOMarchingSquares::~CSOMarchingSquares ( )

Destructor.

Member Function Documentation

◆ _createCell() [1/3]

void ml::CSOMarchingSquares::_createCell	(	int	topLeftVoxel[2],
		CSOMarchingSquaresCell &	cell
	)

protected

Creates a new cell at position topLeftVoxel[2].

◆ _createCell() [2/3]

void ml::CSOMarchingSquares::_createCell	(	int	topLeftVoxel[2],
		CSOMarchingSquaresCell &	cell,
		float	values[4],
		char	cellConfig
	)

protected

Creates a new cell at position topLeftVoxel[2].

◆ _createCell() [3/3]

void ml::CSOMarchingSquares::_createCell	(	int	topLeftVoxel[2],
		std::set< unsigned int > &	cellsVisited,
		std::queue< CSOMarchingSquaresCell > &	cellFront
	)

protected

Creates a new cell at position topLeftVoxel[2], and keeps track whether this cell has already been created.

◆ _findNearestIsoCell() [1/2]

bool ml::CSOMarchingSquares::_findNearestIsoCell	(	int	voxelPos[2],
		CSOMarchingSquaresCell &	cell
	)

protected

Searches for the first cell that is an iso-cell starting from [voxelPos[0], voxelPos[1]]. Returns true if a cell was found, i.e., cell is valid.

◆ _findNearestIsoCell() [2/2]

bool ml::CSOMarchingSquares::_findNearestIsoCell	(	int	voxelPosX,
		int	voxelPosY,
		CSOMarchingSquaresCell &	cell
	)

protected

Searches for the first cell that is an iso-cell starting from [voxelPosX, voxelPosY]. Returns true if a cell was found, i.e., cell is valid.

◆ _findStartPosition()

void ml::CSOMarchingSquares::_findStartPosition	(	int &	startX,
		int &	startY
	)

protected

Searches for a starting position such that startX/startY make up the top-left voxel position of a cell that is intersected by the isoline.

◆ _getKey() [1/2]

unsigned int ml::CSOMarchingSquares::_getKey ( const CSOMarchingSquaresCell & cell ) const

inlineprotected

Returns the key for a cell. For example, this can be used for hashtables.

Definition at line 194 of file CSOMarchingSquares.h.

References ml::CSOMarchingSquaresCell::_topLeftVoxel.

◆ _getKey() [2/2]

unsigned int ml::CSOMarchingSquares::_getKey	(	int	x,
		int	y
	)		const

inlineprotected

Returns the key for a position for hashtables.

Definition at line 201 of file CSOMarchingSquares.h.

◆ _getPossibleEnterDirection()

int ml::CSOMarchingSquares::_getPossibleEnterDirection ( const CSOMarchingSquaresCell & cell ) const

inlineprotected

Returns: A start direction from which one can enter the created cell.

Definition at line 208 of file CSOMarchingSquares.h.

References ml::CSOMarchingSquaresCell::getToDirection().

◆ _getValueAt()

float ml::CSOMarchingSquares::_getValueAt	(	int	x,
		int	y
	)

protected

Returns the value of the image or function at the given position.

◆ _isInImage()

bool ml::CSOMarchingSquares::_isInImage	(	int	x,
		int	y
	)		const

protected

Returns whether the x,y coordinates are within the image.

◆ _trackIsoCell()

void ml::CSOMarchingSquares::_trackIsoCell	(	CSOMarchingSquaresCell	startCell,
		const int	initialFromDir,
		CSOMarchingSquaresCell::vecPoint2D &	positions,
		std::vector< std::array< unsigned char, 2 > > *	cellsVisitedDirections = `nullptr`
	)

protected

Tracks the isoline starting from the startCell.

If this is not an iso-cell (i.e., the isoline intersects this cell), it just returns. One can optionally pass a map where to save all visited cells.

◆ _walkToCell()

int ml::CSOMarchingSquares::_walkToCell	(	const CSOMarchingSquaresCell &	fromCell,
		int	fromDir,
		CSOMarchingSquaresCell &	toCell
	)

protected

Creates a cell toCell from the cell fromCell coming from fromDir.

This method first looks for the direction leaving the fromCell coming from the direction fromDir.

Returns: The direction from which one enters the toCell

◆ fillCSO()

bool ml::CSOMarchingSquares::fillCSO ( FillCSOParameters & parameters )

Fills the given CSO with seed points according to the given list of points.

◆ findAllIsoLines()

void ml::CSOMarchingSquares::findAllIsoLines	(	float	isoValue,
		bool	takeShortestPath,
		std::vector< CSOMarchingSquaresCell::vecPoint2D > &	vecPositions
	)

Finds all contours on the image with isovalue isovalue. Returns them in a vector of 2D position vectors.

◆ findIsoLine()

void ml::CSOMarchingSquares::findIsoLine	(	int	startPosX,
		int	startPosY,
		float	isoValue,
		bool	takeShortestPath,
		CSOMarchingSquaresCell::vecPoint2D &	positions
	)

Looks for an isoline on the image.

It starts searching for a starting cell using the startPos parameters and then tracks this cell. All contour points are pushed back to the positions vector.

◆ reset()

void ml::CSOMarchingSquares::reset ( )

Resets the state of the object.

◆ setFunction()

void ml::CSOMarchingSquares::setFunction	(	CSOFunction *	implicitFunction,
		const Matrix4 &	voxelToWorldMatrix,
		int	startX,
		int	startY,
		int	imgSizeX,
		int	imgSizeY,
		int	voxelZPosition
	)

inline

Sets a 3D interpolation function, an image size and voxel size, and a fixed z-offset.

NOTE that this approach supports only an axial scanning of the function only at the moment; if this class should scan in sagittal or coronal direction as well, some extra flag needs to be provided.

Definition at line 165 of file CSOMarchingSquares.h.

◆ setImage()

void ml::CSOMarchingSquares::setImage	(	float *	image,
		int	imgSizeX,
		int	imgSizeY
	)

inline

Sets the 2D image to track/find contours on.

Definition at line 151 of file CSOMarchingSquares.h.

◆ setInterpolation()

void ml::CSOMarchingSquares::setInterpolation ( bool use )

inline

Specifies whether the algorithm should interpolate the contour bi-linearly.

Definition at line 187 of file CSOMarchingSquares.h.

Member Data Documentation

◆ _bInterpolatePoints

bool ml::CSOMarchingSquares::_bInterpolatePoints

protected

Should the contour be interpolated bi-linearly?

Definition at line 143 of file CSOMarchingSquares.h.

◆ _existingValues

boost::unordered_map<int, double> ml::CSOMarchingSquares::_existingValues

protected

A map holding all computed image/function values.

Definition at line 146 of file CSOMarchingSquares.h.

◆ _function

CSOFunction* ml::CSOMarchingSquares::_function

protected

An implicit function.

Definition at line 136 of file CSOMarchingSquares.h.

◆ _image

float* ml::CSOMarchingSquares::_image

protected

Pointer to input image.

Definition at line 122 of file CSOMarchingSquares.h.

◆ _imageSizeX

int ml::CSOMarchingSquares::_imageSizeX

protected

The x extent of the input image.

Definition at line 124 of file CSOMarchingSquares.h.

◆ _imageSizeY

int ml::CSOMarchingSquares::_imageSizeY

protected

The y extent of the input image.

Definition at line 126 of file CSOMarchingSquares.h.

◆ _isoValue

float ml::CSOMarchingSquares::_isoValue

protected

The isovalue to find the isoline for.

Definition at line 134 of file CSOMarchingSquares.h.

◆ _startX

int ml::CSOMarchingSquares::_startX

protected

Starting voxel x (function).

Definition at line 129 of file CSOMarchingSquares.h.

◆ _startY

int ml::CSOMarchingSquares::_startY

protected

Starting voxel y (function).

Definition at line 131 of file CSOMarchingSquares.h.

◆ _voxelToWorldMatrix

Matrix4 ml::CSOMarchingSquares::_voxelToWorldMatrix

protected

The voxel-to-world matrix.

Definition at line 140 of file CSOMarchingSquares.h.

◆ _voxelZPosition

int ml::CSOMarchingSquares::_voxelZPosition

protected

The z-position of the voxels.

Definition at line 138 of file CSOMarchingSquares.h.

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

MeVisLab/Standard/Sources/ML/MLCSO/CSOTools/CSOMarchingSquares.h

Classes

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ CSOMarchingSquares()

◆ ~CSOMarchingSquares()

Member Function Documentation

◆ _createCell() [1/3]

◆ _createCell() [2/3]

◆ _createCell() [3/3]

◆ _findNearestIsoCell() [1/2]

◆ _findNearestIsoCell() [2/2]

◆ _findStartPosition()

◆ _getKey() [1/2]

◆ _getKey() [2/2]

◆ _getPossibleEnterDirection()

◆ _getValueAt()

◆ _isInImage()

◆ _trackIsoCell()

◆ _walkToCell()

◆ fillCSO()

◆ findAllIsoLines()

◆ findIsoLine()

◆ reset()

◆ setFunction()

◆ setImage()

◆ setInterpolation()

Member Data Documentation

◆ _bInterpolatePoints

◆ _existingValues

◆ _function

◆ _image

◆ _imageSizeX

◆ _imageSizeY

◆ _isoValue

◆ _startX

◆ _startY

◆ _voxelToWorldMatrix

◆ _voxelZPosition