Files
file	WlzContour.c
	Functions for extracting contours from objects.

Data Structures
struct	_WlzContour
	A collection of 2D polylines or 3D surface elements represented by a Woolz geometric model. Typedef: WlzContour. More...

Enumerations
enum	_WlzContourTriIsn2D { WLZ_CONTOUR_TIC2D_NONE, WLZ_CONTOUR_TIC2D_V1V0, WLZ_CONTOUR_TIC2D_V0V2, WLZ_CONTOUR_TIC2D_V2V1, WLZ_CONTOUR_TIC2D_V1S02, WLZ_CONTOUR_TIC2D_V0S21, WLZ_CONTOUR_TIC2D_V2S10, WLZ_CONTOUR_TIC2D_S10S02, WLZ_CONTOUR_TIC2D_S02S21, WLZ_CONTOUR_TIC2D_S21S10 }
	Classification of the intersection of a line segment with a triangle. Typedef: WlzContourTriIsn2D. More...

enum	_WlzContourBndSamMethod { WLZ_CONTOUR_BNDPTS_REGULAR, WLZ_CONTOUR_BNDPTS_RANDOM }
	Boudary point sampling methods. Typedef: WlzContourBndSamMethod. More...

enum	_WlzContourMethod { WLZ_CONTOUR_MTD_ISO, WLZ_CONTOUR_MTD_GRD, WLZ_CONTOUR_MTD_BND, WLZ_CONTOUR_MTD_RBFBND }
	Contour generation methods. Typedef: WlzContourMethod. More...

Functions
WlzContour *	WlzContourObjGrd (WlzObject srcObj, double ctrLo, double ctrHi, double ctrWth, int nrmFlg, WlzErrorNum dstErr)
	Creates a contour (list of connected edges or surface patches) from a Woolz object with values using a maximal gradient algorithm and retains the gradient vectors. The gradient vectors are only valid for valid vertex indicies and do not have unit length. More...

WlzContour *	WlzContourObj (WlzObject srcObj, WlzContourMethod ctrMtd, double ctrVal, double ctrWth, int nrmFlg, WlzErrorNum dstErr)
	Creates a contour (list of connected edges or surface patches) from a Woolz object's values. The source object should either a 2D or 3D domain object with values. This is the top level contour generation function which calls the appropriate function for the given contour type (dimension) and generation method. The given contour value is taken to be the iso-value for iso-value contours and the minimum gradient threshold value for maximal gradient contours. The contour width parameter is only used for maximal gradient contours where it is used to generate a recursive Deriche filter, see WlzRsvFilter(). More...

WlzContour *	WlzContourFromPoints (WlzObject dObj, WlzVertexType vtxType, int nSPts, WlzVertexP sPts, double sAlpha, int nIPts, WlzVertexP iPts, double iDist, double iAlpha, int nOPts, WlzVertexP oPts, double oDist, double oAlpha, double delta, double tau, double samFac, WlzErrorNum dstErr)
	Given three points sets: On, inside and outside some curve this function computes a contour for the curve. This is done by approximating (or interpolating) the distance function for the curve using multi order spline radial basis functions. The contour is then computed from the zero level set of the radial basis functions within the given distance object. The distance object sampling factor is used to subsample the distance object prior to cuting the zero value isosurface. The surface computed from a sampled distance object is then transformed using the inverse of the sampling transform. More...

WlzContour *	WlzContourGrdObj2D (WlzObject srcObj, WlzObject gGXObj, WlzObject gGYObj, double grdLo, double grdHi, double ftrPrm, int nrmFlg, WlzErrorNum dstErr)
	Creates an maximal gradient contour (list of edges) from a 2D Woolz object's values. More...

WlzContour *	WlzContourRBFBndObj3D (WlzObject gObj, int bErosion, int bDilation, int sDilation, int sFac, int oFac, double sAlpha, double oAlpha, double delta, double tau, double samFac, WlzErrorNum dstErr)
	Computes a 3D contour from the boundary of the given objects domain by extracting the zero level set of an approximate signed distance function computed using a multi-order spline radial basis function. The distance object sampling factor is used to subsample the distance object prior to cuting the zero value isosurface. The surface computed from a sampled distance object is then transformed using the inverse of the sampling transform. More...

Detailed Description

Enumeration Type Documentation

◆ _WlzContourTriIsn2D

enum _WlzContourTriIsn2D

Classification of the intersection of a line segment with a triangle. Typedef: WlzContourTriIsn2D.

Enumerator
WLZ_CONTOUR_TIC2D_NONE	No intersection
WLZ_CONTOUR_TIC2D_V1V0	Vertex 1 - vertex 0
WLZ_CONTOUR_TIC2D_V0V2	Vertex 0 - vertex 2
WLZ_CONTOUR_TIC2D_V2V1	Vertex 2 - vertex 1
WLZ_CONTOUR_TIC2D_V1S02	Vertex 1 - side 0-2
WLZ_CONTOUR_TIC2D_V0S21	Vertex 0 - side 2-1
WLZ_CONTOUR_TIC2D_V2S10	Vertex 2 - side 1-0
WLZ_CONTOUR_TIC2D_S10S02	Side 1-0 - side 0-2
WLZ_CONTOUR_TIC2D_S02S21	Side 0-2 - side 2-1
WLZ_CONTOUR_TIC2D_S21S10	Side 2-1 - side 1-0

◆ _WlzContourBndSamMethod

enum _WlzContourBndSamMethod

Boudary point sampling methods. Typedef: WlzContourBndSamMethod.

Enumerator
WLZ_CONTOUR_BNDPTS_REGULAR
WLZ_CONTOUR_BNDPTS_RANDOM

◆ _WlzContourMethod

enum _WlzContourMethod

Contour generation methods. Typedef: WlzContourMethod.

Enumerator
WLZ_CONTOUR_MTD_ISO	Iso-value.
WLZ_CONTOUR_MTD_GRD	Maximum gradient value.
WLZ_CONTOUR_MTD_BND	Object boundary.
WLZ_CONTOUR_MTD_RBFBND	Object boundary established using a radial basis function.

Function Documentation

◆ WlzContourObjGrd()

WlzContour* WlzContourObjGrd	(	WlzObject *	srcObj,
		double	ctrLo,
		double	ctrHi,
		double	ctrWth,
		int	nrmFlg,
		WlzErrorNum *	dstErr
	)

Creates a contour (list of connected edges or surface patches) from a Woolz object with values using a maximal gradient algorithm and retains the gradient vectors. The gradient vectors are only valid for valid vertex indicies and do not have unit length.

Returns: Contour, or NULL on error.

Parameters

srcObj	Given object from which to compute the contours. required.
ctrLo	Lower maximal gradient threshold value.
ctrHi	Higher maximal gradient threshold value.
ctrWth	Contour filter width.
nrmFlg	Add image gradients as normals to contour if non zero.
dstErr	Destination error pointer, may be NULL.

References _WlzValues::core, _WlzDomain::core, _WlzObject::domain, _WlzObject::type, _WlzObject::values, WLZ_2D_DOMAINOBJ, WLZ_3D_DOMAINOBJ, WLZ_ERR_DOMAIN_NULL, WLZ_ERR_NONE, WLZ_ERR_OBJECT_NULL, WLZ_ERR_VALUES_NULL, and WlzContourGrdObj2D().

Referenced by WlzRegICPObjsGrd().

◆ WlzContourObj()

WlzContour* WlzContourObj	(	WlzObject *	srcObj,
		WlzContourMethod	ctrMtd,
		double	ctrVal,
		double	ctrWth,
		int	nrmFlg,
		WlzErrorNum *	dstErr
	)

Creates a contour (list of connected edges or surface patches) from a Woolz object's values. The source object should either a 2D or 3D domain object with values. This is the top level contour generation function which calls the appropriate function for the given contour type (dimension) and generation method. The given contour value is taken to be the iso-value for iso-value contours and the minimum gradient threshold value for maximal gradient contours. The contour width parameter is only used for maximal gradient contours where it is used to generate a recursive Deriche filter, see WlzRsvFilter().

Returns: Contour, or NULL on error.

Parameters

srcObj	Given object from which to compute the contours.
ctrMtd	Contour generation method.
ctrVal	Contour value.
ctrWth	Contour filter width.
nrmFlg	Generate normals from image if possible.
dstErr	Destination error pointer, may be NULL.

References _WlzDomain::core, _WlzObject::domain, _WlzObject::type, WLZ_2D_DOMAINOBJ, WLZ_CONTOUR_MTD_ISO, WLZ_ERR_DOMAIN_NULL, WLZ_ERR_NONE, and WLZ_ERR_OBJECT_NULL.

◆ WlzContourFromPoints()

WlzContour* WlzContourFromPoints	(	WlzObject *	dObj,
		WlzVertexType	vtxType,
		int	nSPts,
		WlzVertexP	sPts,
		double	sAlpha,
		int	nIPts,
		WlzVertexP	iPts,
		double	iDist,
		double	iAlpha,
		int	nOPts,
		WlzVertexP	oPts,
		double	oDist,
		double	oAlpha,
		double	delta,
		double	tau,
		double	samFac,
		WlzErrorNum *	dstErr
	)

Given three points sets: On, inside and outside some curve this function computes a contour for the curve. This is done by approximating (or interpolating) the distance function for the curve using multi order spline radial basis functions. The contour is then computed from the zero level set of the radial basis functions within the given distance object. The distance object sampling factor is used to subsample the distance object prior to cuting the zero value isosurface. The surface computed from a sampled distance object is then transformed using the inverse of the sampling transform.

Returns: New contour or NULL on error.

Parameters

dObj	Object with double values, within which the distance function will be evaluated.
vtxType	Type of all vertices.
nSPts	Number of on surface points.
sPts	Positions of the on surface points.
sAlpha	Alpha value for the on surface points.
nIPts	Number of inside points.
iPts	Positions of the inside points.
iDist	Distance from surface for the inside points.
iAlpha	Alpha value for the inside points.
nOPts	Number of outside points.
oPts	Positions of the outside points.
oDist	Distance from surface for the outside points.
oAlpha	Alpha value for the outside points.
delta	Multiorder spline \(\delta\) smoothness parameter.
tau	Multiorder spline \(\tau\) smoothness parameter.
samFac	Distance object sampling factor.
dstErr	Destination error pointer, may be NULL.

References _WlzValues::core, _WlzDomain::core, _WlzObject::domain, _WlzVertexP::v, _WlzObject::values, WLZ_ERR_DOMAIN_NULL, WLZ_ERR_NONE, WLZ_ERR_OBJECT_NULL, WLZ_ERR_PARAM_DATA, WLZ_ERR_VALUES_NULL, WLZ_VERTEX_D3, WLZ_VERTEX_F3, and WLZ_VERTEX_I3.

◆ WlzContourGrdObj2D()

WlzContour* WlzContourGrdObj2D	(	WlzObject *	srcObj,
		WlzObject *	gGXObj,
		WlzObject *	gGYObj,
		double	grdLo,
		double	grdHi,
		double	ftrPrm,
		int	nrmFlg,
		WlzErrorNum *	dstErr
	)

Creates an maximal gradient contour (list of edges) from a 2D Woolz object's values.

Returns

Contour , or NULL on error.

          Creates an maximal gradient contour (list of edges)
          from a 2D Woolz object's values.
          Direction of gradient is encoded as:

                  +------+------+
                  |\   2 | 1   /|
                  |  \   |   /  |
                  | 3  \ | /  0 |
                  +------+------+
                  | 4  / | \  7 |
                  |  /   |   \  |
                  |/   5 | 6   \|
                  +------+------+

Parameters

srcObj	Given object from which to compute gradients for the contours.
gGXObj	If non NULL used for gradients across columns.
gGYObj	If non NULL used for gradient through lines.
grdLo	Lower threshold for modulus of gradient.
grdHi	Upper threshold for modulus of gradient.
ftrPrm	Filter width parameter.
nrmFlg	Add image gradients as normals to contour if non zero.
dstErr	Destination error pointer, may be NULL.

References ALC_ER_NONE, AlcBit2Calloc(), AlcDouble2Calloc(), AlcUnchar2Calloc(), _WlzRsvFilter::c, _WlzValues::core, _WlzDomain::core, _WlzGreyP::dbp, _WlzObject::domain, _WlzDomain::i, _WlzIntervalWSpace::intrmn, _WlzIntervalDomain::kol1, _WlzIntervalDomain::lastkl, _WlzIntervalWSpace::lftpos, _WlzIntervalDomain::line1, _WlzIntervalWSpace::linpos, _WlzContour::model, _WlzIntervalWSpace::nwlpos, _WlzGreyWSpace::pixeltype, _WlzIntervalWSpace::rgtpos, _WlzGreyWSpace::u_grintptr, _WlzGreyP::v, _WlzObject::values, _WlzIVertex2::vtX, _WlzIVertex2::vtY, WLZ_BIT_GET, WLZ_ERR_DOMAIN_NULL, WLZ_ERR_MEM_ALLOC, WLZ_ERR_NONE, WLZ_ERR_OBJECT_NULL, WLZ_ERR_VALUES_NULL, WLZ_GMMOD_2D, WLZ_GMMOD_2N, WLZ_GREY_DOUBLE, WLZ_RSVFILTER_ACTION_X, WLZ_RSVFILTER_ACTION_Y, WLZ_RSVFILTER_NAME_DERICHE_1, WlzAssignGMModel(), WlzBitLnSetItv(), WlzGMModelNew(), WlzInitGreyScan(), WlzMakeContour(), WlzNextGreyInterval(), WlzRsvFilterFreeFilter(), WlzRsvFilterMakeFilter(), WlzRsvFilterObj(), WlzValueCopyGreyToGrey(), WlzValueSetDouble(), and WlzValueSetUByte().

Referenced by WlzContourObjGrd().

◆ WlzContourRBFBndObj3D()

WlzContour* WlzContourRBFBndObj3D	(	WlzObject *	gObj,
		int	bErosion,
		int	bDilation,
		int	sDilation,
		int	sFac,
		int	oFac,
		double	sAlpha,
		double	oAlpha,
		double	delta,
		double	tau,
		double	samFac,
		WlzErrorNum *	dstErr
	)

Computes a 3D contour from the boundary of the given objects domain by extracting the zero level set of an approximate signed distance function computed using a multi-order spline radial basis function. The distance object sampling factor is used to subsample the distance object prior to cuting the zero value isosurface. The surface computed from a sampled distance object is then transformed using the inverse of the sampling transform.

Returns: Woolz contour or NULL on error.

Parameters

gObj	The given object.
bErosion	Object boundary erosion for interior points.
bDilation	Object boundary dilation for exterior points.
sDilation	Object boundary dilation for distance object used in surface extraction.
sFac	Sampling factor for surface points.
oFac	Sampling factor for interior and exterior points.
sAlpha	Degree of approximation for the surface boundary points. The multi-order spline \(\alpha\) parameter.
oAlpha	Degree of approximation for the interior and exterior points. The multi-order spline \(\alpha\) parameter.
delta	Multi-order spline \(\delta\) parameter.
tau	Multi-order spline \(tau\) parameter.
samFac	Distance object sampling factor.
dstErr	Destination error pointer, may be NULL.

References _WlzDomain::core, _WlzObject::domain, _WlzVertexP::i3, _WlzObject::type, _WlzVertexP::v, WLZ_3D_DOMAINOBJ, WLZ_CONTOUR_BNDPTS_RANDOM, WLZ_ERR_DOMAIN_NULL, WLZ_ERR_NONE, WLZ_ERR_OBJECT_NULL, WLZ_ERR_OBJECT_TYPE, WLZ_ERR_PARAM_DATA, WlzFreeObj(), WlzMakeSphereObject(), WlzStructDilation(), WlzStructErosion(), and WlzWriteObj().

Files

Data Structures

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ _WlzContourTriIsn2D

◆ _WlzContourBndSamMethod

◆ _WlzContourMethod

Function Documentation

◆ WlzContourObjGrd()

◆ WlzContourObj()

◆ WlzContourFromPoints()

◆ WlzContourGrdObj2D()

◆ WlzContourRBFBndObj3D()