Files
file	WlzCbThreshold.c
	Threshold an object using a callback function to determine if the pixel value satifies the threshold criteria.

file	WlzCompThresh.c
	Functions for computing a threshold value from a histogram object.

file	WlzConComThreshold.c
	Functions to perform connected component thresholding.

file	WlzHyThreshold.c
	A hysteresis threshold filter.

file	WlzRGBAThreshold.c
	Threshold functions for RGBA objects.

file	WlzThreshold.c
	Thresholds 2D or 3D domain objects with values.

Macros
#define	WLZ_THRESH_ADD_ITV_1(N, NL1, NLL, NK1, NKL, G, IWS, TV, P, OP, K, OV)
	Computes the number of intervals for WlzThreshold() from integral grey values or floating point if not comparing equality. The following parameters are required: More...

#define	WLZ_THRESH_ADD_ITV_FE_1(N, NL1, NLL, NK1, NKL, G, IWS, TV, P, E, K, OV)
	Computes the number of intervals for WlzThreshold() from floating point grey values using an equality operator. The following parameters are required: More...

#define	WLZ_THRESH_ADD_ITV_RGB_1(N, NL1, NLL, NK1, NKL, G, IWS, TV, OP, K, OV)
	Computes the number of intervals for WlzThreshold() from RGBA grey values using a modulus operator to compute a scalar grey value from the RGBA value. The following parameters are required: More...

#define	WLZ_THRESH_ADD_ITV_2(N, NK1, G, ITV, IWS, TV, P, OP, K, OV)
	Constructs the intervals for WlzThreshold() from integral grey values or floating point if not comparing equality. The following parameters are required: More...

#define	WLZ_THRESH_ADD_ITV_FE_2(N, NK1, G, ITV, IWS, TV, P, E, K, OV)
	Constructs the intervals for WlzThreshold() from floating point grey values using an equality operator. The following parameters are required: More...

#define	WLZ_THRESH_ADD_ITV_RGB_2(N, NK1, G, ITV, IWS, TV, P, OP, K, OV)
	Constructs the intervals for WlzThreshold() from RGBA grey values using a modulus operator to compute a scalar grey value from the RGBA value. The following parameters are required: More...

Enumerations
enum	_WlzCompThreshType { WLZ_COMPTHRESH_FOOT, WLZ_COMPTHRESH_DEPTH, WLZ_COMPTHRESH_GRADIENT, WLZ_COMPTHRESH_FRACMIN, WLZ_COMPTHRESH_SMOOTHSPLIT, WLZ_COMPTHRESH_OTSU }
	Automatic threshold computation methods. The histogram may need to be smoothed for these algorithms to work. Typedef: WlzCompThreshType. More...

enum	_WlzThresholdType { WLZ_THRESH_LOW = 0, WLZ_THRESH_HIGH, WLZ_THRESH_EQUAL }
	Threshold value selection. Typedef: WlzThresholdType. More...

enum	_WlzRGBAThresholdType { WLZ_RGBA_THRESH_NONE, WLZ_RGBA_THRESH_SINGLE, WLZ_RGBA_THRESH_MULTI, WLZ_RGBA_THRESH_PLANE, WLZ_RGBA_THRESH_SLICE, WLZ_RGBA_THRESH_BOX, WLZ_RGBA_THRESH_SPHERE }
	Colour threshold type selection. Typedef: WlzRGBAThresholdType. More...

Functions
WlzErrorNum	WlzCompThresholdVT (WlzObject hObj, WlzCompThreshType method, double param0, double param1, double extraFrac, WlzPixelV dstTV, WlzThresholdType *dstTType)
	Computes a threshold value and type using the given histogram and method. More...

WlzErrorNum	WlzCompThreshold (double dstThrVal, WlzObject histObj, WlzCompThreshType method, double extraFrac)
	Computes a threshold value from the given histogram object using the given method. More...

WlzObject *	WlzConComThreshold2D (WlzObject gObj, int nSeeds, WlzIVertex2 seeds, WlzThresholdType tHiLo, int xtr, double rad, WlzThresholdType rHiLo, WlzErrorNum *dstErr)
	Performs connected component thresholding of the given object using the given 2D seed points. See also WlzConComThreshold3D(), WlzConComThreshold() and WlzThreshold(). More...

WlzObject *	WlzConComThreshold3D (WlzObject gObj, int nSeeds, WlzIVertex3 seeds, WlzThresholdType tHiLo, int xtr, double rad, WlzThresholdType rHiLo, WlzErrorNum *dstErr)
	Performs connected component thresholding of the given object using the given 3D seed points. See also WlzConComThreshold2D(), WlzConComThreshold() and WlzThreshold(). More...

WlzObject *	WlzConComThreshold (WlzObject gObj, int nSeeds, WlzVertexType seedType, WlzVertexP seeds, WlzThresholdType tHiLo, int xtr, double rad, WlzThresholdType rHiLo, WlzErrorNum dstErr)
	Performs connected component thresholding of the given object using the given coordinates of seed points within the given object. See also WlzConComThreshold2D(), WlzConComThreshold3D() and WlzThreshold(). More...

WlzObject *	WlzHyThreshold (WlzObject srcObj, WlzPixelV pThrV, WlzPixelV sThrV, WlzThresholdType hilo, WlzConnectType con, WlzErrorNum dstErr)
	Hysteresis thresholds the given Woolz object. Values are in the domain of the hysteresis threshold'd object if they are above/below the primary threshold or above/below the secondary threshold and connected to values above/below the primary threshold. More...

WlzObject *	WlzRGBAMultiThreshold (WlzObject obj, WlzPixelV lowVal, WlzPixelV highVal, WlzUInt combineMode, WlzErrorNum dstErr)
	Apply independent thresholds to each colour channel independently and combine according to the settings encoded in combineMode. Each channel can have one of two modes: WLZ_BO_AND and WLZ_BO_OR. These are encoded into a single mode variable using the RGBA macro, e.g.: WLZ_RGBA_RGBA_SET(combineMode, redMode, greenMode, blueMode, 255);. More...

WlzObject *	WlzThreshold (WlzObject obj, WlzPixelV threshV, WlzThresholdType highlow, WlzErrorNum dstErr)
	Thresholds a woolz grey-level object, 2D or 3D. More...

Detailed Description

Macro Definition Documentation

◆ WLZ_THRESH_ADD_ITV_1

#define WLZ_THRESH_ADD_ITV_1	(	N,
		NL1,
		NLL,
		NK1,
		NKL,
		G,
		IWS,
		TV,
		P,
		OP,
		K,
		OV
	)

Computes the number of intervals for WlzThreshold() from integral grey values or floating point if not comparing equality. The following parameters are required:

N Number of intervals to be computed: nints.
NL1 Minimum line coordinate: nl1.
NLL Maximum line coordinate: nll.
NK1 Minimum column coordinate nk1.
NKL Maximum column coordinate nkl.
G The grey pointer: g.
IWS The interval workspace: iwsp.
TV The threshold value: thresh_i.
P The grey pointer union member: eg ubp.
OP The comparison operator: < for WLZ_THRESH_LOW, >= for WLZ_THRESH_HIGH and == for WLZ_THRESH_EQUAL.
K Column index: colno.
OV Over interval: over.

◆ WLZ_THRESH_ADD_ITV_FE_1

#define WLZ_THRESH_ADD_ITV_FE_1	(	N,
		NL1,
		NLL,
		NK1,
		NKL,
		G,
		IWS,
		TV,
		P,
		E,
		K,
		OV
	)

Computes the number of intervals for WlzThreshold() from floating point grey values using an equality operator. The following parameters are required:

N Number of intervals to be computed: nints.
NL1 Minimum line coordinate: nl1.
NLL Maximum line coordinate: nll.
NK1 Minimum column coordinate nk1.
NKL Maximum column coordinate nkl.
G The grey pointer: g.
IWS The interval workspace: iwsp.
TV The threshold value: thresh_i.
P The grey pointer union member: eg ubp.
E The epsilon value for floating point comparison, should be > 0.0.
K Column index: colno.
OV Over interval: over.

◆ WLZ_THRESH_ADD_ITV_RGB_1

#define WLZ_THRESH_ADD_ITV_RGB_1	(	N,
		NL1,
		NLL,
		NK1,
		NKL,
		G,
		IWS,
		TV,
		OP,
		K,
		OV
	)

Computes the number of intervals for WlzThreshold() from RGBA grey values using a modulus operator to compute a scalar grey value from the RGBA value. The following parameters are required:

N Number of intervals to be computed: nints.
NL1 Minimum line coordinate: nl1.
NLL Maximum line coordinate: nll.
NK1 Minimum column coordinate nk1.
NKL Maximum column coordinate nkl.
G The grey pointer: g.
IWS The interval workspace: iwsp.
TV The threshold value: thresh_i.
OP The comparison operator: < for WLZ_THRESH_LOW, >= for WLZ_THRESH_HIGH and == for WLZ_THRESH_EQUAL.
K Column index: colno.
OV Over interval: over.

◆ WLZ_THRESH_ADD_ITV_2

#define WLZ_THRESH_ADD_ITV_2	(	N,
		NK1,
		G,
		ITV,
		IWS,
		TV,
		P,
		OP,
		K,
		OV
	)

Value:

{ \
  for((K)=((IWS).lftpos);(K)<=((IWS).rgtpos);++(K)) \
  { \
    if((*(G).P)OP(TV)) \
    { \
      if(!(OV)) \
      { \
        (OV)=1; \
        ((ITV)->ileft)=(K)-(NK1); \
      } \
    } \
    else \
    { \
      if(OV) \
      { \
        (OV)=0; \
        ((ITV)->iright)=(K)-(NK1)-1; \
        ++(N); \
        ++(ITV); \
      } \
    } \
    ++((G).P); \
  } \
}

Constructs the intervals for WlzThreshold() from integral grey values or floating point if not comparing equality. The following parameters are required:

N Number of intervals to be computed: nints.
NK1 Minimum column coordinate nk1.
G The grey pointer: g.
ITV The interval pointer.
IWS The interval workspace: iwsp.
TV The threshold value: thresh_i.
P The grey pointer union member: eg ubp.
OP The comparison operator: < for WLZ_THRESH_LOW, >= for WLZ_THRESH_HIGH and == for WLZ_THRESH_EQUAL.
K Column index: colno.
OV Over interval: over.

◆ WLZ_THRESH_ADD_ITV_FE_2

#define WLZ_THRESH_ADD_ITV_FE_2	(	N,
		NK1,
		G,
		ITV,
		IWS,
		TV,
		P,
		E,
		K,
		OV
	)

Value:

{ \
  for((K)=((IWS).lftpos);(K)<=((IWS).rgtpos);++(K)) \
  { \
    if((*((G).P)<((TV)-(E)))||(*((G).P)>((TV)+(E)))) \
    { \
      if(OV) \
      { \
        (OV)=0; \
        ((ITV)->iright)=(K)-(NK1)-1; \
        ++(N); \
        ++(ITV); \
      } \
    } \
    else \
    { \
      if(!(OV)) \
      { \
        (OV)=1; \
        ((ITV)->ileft)=(K)-(NK1); \
      } \
    } \
    ++((G).P); \
  } \
}

Constructs the intervals for WlzThreshold() from floating point grey values using an equality operator. The following parameters are required:

N Number of intervals to be computed: nints.
NK1 Minimum column coordinate nk1.
G The grey pointer: g.
ITV The interval pointer.
IWS The interval workspace: iwsp.
TV The threshold value: thresh_i.
P The grey pointer union member: eg ubp.
E The epsilon value for floating point comparison, should be > 0.0.
K Column index: colno.
OV Over interval: over.

◆ WLZ_THRESH_ADD_ITV_RGB_2

#define WLZ_THRESH_ADD_ITV_RGB_2	(	N,
		NK1,
		G,
		ITV,
		IWS,
		TV,
		P,
		OP,
		K,
		OV
	)

Value:

{ \
  for((K)=((IWS).lftpos);(K)<=((IWS).rgtpos);++(K)) \
  { \
    if((WLZ_RGBA_MODULUS_2(*(G).P))OP(TV)) \
    { \
      if(!(OV)) \
      { \
        (OV)=1; \
        ((ITV)->ileft)=(K)-(NK1); \
      } \
    } \
    else \
    { \
      if(OV) \
      { \
        (OV)=0; \
        ((ITV)->iright)=(K)-(NK1)-1; \
        ++(N); \
        ++(ITV); \
      } \
    } \
    ++((G).P); \
  } \
}

Constructs the intervals for WlzThreshold() from RGBA grey values using a modulus operator to compute a scalar grey value from the RGBA value. The following parameters are required:

N Number of intervals to be computed: nints.
NK1 Minimum column coordinate nk1.
G The grey pointer: g.
ITV The interval pointer.
IWS The interval workspace: iwsp.
TV The threshold value: thresh_i.
P The grey pointer union member: eg ubp.
OP The comparison operator: < for WLZ_THRESH_LOW, >= for WLZ_THRESH_HIGH and == for WLZ_THRESH_EQUAL.
K Column index: colno.
OV Over interval: over.

Enumeration Type Documentation

◆ _WlzCompThreshType

enum _WlzCompThreshType

Automatic threshold computation methods.
The histogram may need to be smoothed for these algorithms to work. Typedef: WlzCompThreshType.

Enumerator
WLZ_COMPTHRESH_FOOT	Can not determine threshold type. The threshold value is intercept of a line fitted to the upper slope of the histogram main peak with the abscissa.
WLZ_COMPTHRESH_DEPTH	Can not determine threshold type. The threshold value is that point to the right of the histogram peak that is maximally distant from the chord joining the peak and the histogram right hand end point. The histogram may need to be smoothed for this algorithm to work.
WLZ_COMPTHRESH_GRADIENT	Can not determine threshold type. The threshold value is the first point to the right of the histogram main peak at which the gradient falls to zero (cf finding a minimum). To find the slope of the histogram at some point a straight line is fitted through the point \(\pm\) a fixed number of points to either side.
WLZ_COMPTHRESH_FRACMIN	The threshold type is determined from the position of the histogram's maximum and the threshold value is the minimum following the specified fraction of the values.
WLZ_COMPTHRESH_SMOOTHSPLIT	The threshold value is found by heavily smoothing the histogram and looking for the minimum. Successively lesser smoothing values are then applied and at each iteration the minimum closest to the previous is found.
WLZ_COMPTHRESH_OTSU	The threshold value is found by using Otsu's method. This is a clustering-based algorithm which computes an optimum threshold value that separates the two classes of an (assumed) bi-modal histogram.

◆ _WlzThresholdType

enum _WlzThresholdType

Threshold value selection. Typedef: WlzThresholdType.

Enumerator
WLZ_THRESH_LOW	Threshold < given value
WLZ_THRESH_HIGH	Threshold >= given value
WLZ_THRESH_EQUAL	Threshold == given value

◆ _WlzRGBAThresholdType

enum _WlzRGBAThresholdType

Colour threshold type selection. Typedef: WlzRGBAThresholdType.

Enumerator
WLZ_RGBA_THRESH_NONE
WLZ_RGBA_THRESH_SINGLE
WLZ_RGBA_THRESH_MULTI
WLZ_RGBA_THRESH_PLANE
WLZ_RGBA_THRESH_SLICE
WLZ_RGBA_THRESH_BOX
WLZ_RGBA_THRESH_SPHERE

Function Documentation

◆ WlzCompThresholdVT()

WlzErrorNum WlzCompThresholdVT	(	WlzObject *	hObj,
		WlzCompThreshType	method,
		double	param0,
		double	param1,
		double	extraFrac,
		WlzPixelV *	dstTV,
		WlzThresholdType *	dstTType
	)

Computes a threshold value and type using the given histogram and method.

Returns: Woolz error code.

Parameters

hObj
method	Threshold value method.
param0	First passed parameter: WLZ_COMPTHRESH_FRACMIN = minimum fraction of values which are background. WLZ_COMPTHRESH_SMOOTHSPLIT = minimum smoothing value for WlzHistogramSmooth(). Otherwise not used.
param1	First passed parameter: WLZ_COMPTHRESH_SMOOTHSPLIT = maximum smoothing value for WlzHistogramSmooth().
extraFrac	Extra fraction to be added or subtracted from the threshold value.
dstTV	Destination pointer for threshold value, may be NULL.
dstTType	Destination pointer for threshold type, may be NULL.

References _WlzHistogramDomain::binSize, _WlzGreyV::dbv, _WlzObject::domain, _WlzDomain::hist, _WlzHistogramDomain::maxBins, _WlzHistogramDomain::nBins, _WlzHistogramDomain::origin, _WlzPixelV::type, _WlzObject::type, _WlzHistogramDomain::type, _WlzPixelV::v, WLZ_COMPTHRESH_DEPTH, WLZ_COMPTHRESH_FOOT, WLZ_COMPTHRESH_GRADIENT, WLZ_ERR_DOMAIN_DATA, WLZ_ERR_DOMAIN_NULL, WLZ_ERR_DOMAIN_TYPE, WLZ_ERR_NONE, WLZ_ERR_OBJECT_NULL, WLZ_ERR_OBJECT_TYPE, WLZ_ERR_UNIMPLEMENTED, WLZ_GREY_DOUBLE, WLZ_HISTOGRAM, WLZ_HISTOGRAMDOMAIN_FLOAT, WLZ_HISTOGRAMDOMAIN_INT, WLZ_THRESH_HIGH, and WlzHistogramBinMax().

Referenced by WlzSplitObj().

◆ WlzCompThreshold()

WlzErrorNum WlzCompThreshold	(	double *	dstThrVal,
		WlzObject *	histObj,
		WlzCompThreshType	method,
		double	extraFrac
	)

Computes a threshold value from the given histogram object using the given method.

Returns: Woolz error code.

Parameters

dstThrVal	Destination pointer for the threshold value.
histObj	Given histogram object.
method	Given method.
extraFrac	Extra fraction added onto the threshold value, ie: thrVal += thrVal * extraFrac.

References _WlzHistogramDomain::binSize, _WlzObject::domain, _WlzDomain::hist, _WlzHistogramDomain::maxBins, _WlzHistogramDomain::nBins, _WlzObject::type, _WlzHistogramDomain::type, WLZ_COMPTHRESH_FOOT, WLZ_DBG, WLZ_DBG_LVL_1, WLZ_ERR_DOMAIN_DATA, WLZ_ERR_DOMAIN_NULL, WLZ_ERR_DOMAIN_TYPE, WLZ_ERR_NONE, WLZ_ERR_OBJECT_NULL, WLZ_ERR_OBJECT_TYPE, WLZ_ERR_PARAM_NULL, WLZ_HISTOGRAM, WLZ_HISTOGRAMDOMAIN_FLOAT, and WLZ_HISTOGRAMDOMAIN_INT.

◆ WlzConComThreshold2D()

WlzObject* WlzConComThreshold2D	(	WlzObject *	gObj,
		int	nSeeds,
		WlzIVertex2 *	seeds,
		WlzThresholdType	tHiLo,
		int	xtr,
		double	rad,
		WlzThresholdType	rHiLo,
		WlzErrorNum *	dstErr
	)

Performs connected component thresholding of the given object using the given 2D seed points. See also WlzConComThreshold3D(), WlzConComThreshold() and WlzThreshold().

Returns: New (thresholded) Woolz object or NULL on error.

Parameters

gObj	Given object to threshold, this must be either an empty object or a 2D domain object with values.
nSeeds	Number of seed positions supplied.
seeds	The given seed positions.
tHiLo	Threshold mode parameter.
xtr	Percent extra to add to threshold value.
rad	Radius of region around seed in which to establish threshold value.
rHiLo	How to choose threshold from the region around each seed.
dstErr	Destination error pointer, may be NULL.

References _WlzVertexP::i2, _WlzObject::type, WLZ_2D_DOMAINOBJ, WLZ_EMPTY_OBJ, WLZ_ERR_NONE, WLZ_ERR_OBJECT_NULL, WLZ_ERR_OBJECT_TYPE, WLZ_VERTEX_I2, and WlzConComThreshold().

◆ WlzConComThreshold3D()

WlzObject* WlzConComThreshold3D	(	WlzObject *	gObj,
		int	nSeeds,
		WlzIVertex3 *	seeds,
		WlzThresholdType	tHiLo,
		int	xtr,
		double	rad,
		WlzThresholdType	rHiLo,
		WlzErrorNum *	dstErr
	)

Performs connected component thresholding of the given object using the given 3D seed points. See also WlzConComThreshold2D(), WlzConComThreshold() and WlzThreshold().

Returns: New (thresholded) Woolz object or NULL on error.

Parameters

gObj	Given object to threshold, this must be an empty object or either a 2 or 3D domain object with values.
nSeeds	Number of seed positions supplied.
seeds	The given seed positions.
tHiLo	Threshold mode parameter.
xtr	Percent extra to add to threshold value.
rad	Radius of region around seed in which to establish threshold value.
rHiLo	How to choose threshold from the region around each seed.
dstErr	Destination error pointer, may be NULL.

References _WlzVertexP::i3, _WlzObject::type, WLZ_2D_DOMAINOBJ, WLZ_3D_DOMAINOBJ, WLZ_EMPTY_OBJ, WLZ_ERR_NONE, WLZ_ERR_OBJECT_NULL, WLZ_ERR_OBJECT_TYPE, WLZ_VERTEX_I3, and WlzConComThreshold().

◆ WlzConComThreshold()

WlzObject* WlzConComThreshold	(	WlzObject *	gObj,
		int	nSeeds,
		WlzVertexType	seedType,
		WlzVertexP	seeds,
		WlzThresholdType	tHiLo,
		int	xtr,
		double	rad,
		WlzThresholdType	rHiLo,
		WlzErrorNum *	dstErr
	)

Performs connected component thresholding of the given object using the given coordinates of seed points within the given object. See also WlzConComThreshold2D(), WlzConComThreshold3D() and WlzThreshold().

Returns: New (thresholded) Woolz object or NULL on error.

Parameters

gObj	Given object to threshold, this may be an empty object or either a 2 or 3D domain object with values.
nSeeds	Number of seed positions supplied.
seedType
seeds	The given seed positions. If the given object is a 3D domain object the the seeds must be of type WlzIVertex3 otherwise they may be WlzIVertex2 or WlzIVertex3.
tHiLo	Threshold mode parameter with WLZ_THRESH_HIGH >= threshold value, WLZ_THRESH_EQUAL == threshold value and WLZ_THRESH_LOW <= threshold value. Watch out this is slightly different from WlzThreshold().
xtr	Percent extra to add to threshold value where \[ v_{thresh} = v_{seed} \frac{100 \pm xtr}{100} \] with the sign being: \(-\) for WLZ_THRESH_HIGH and \(+\) for WLZ_THRESH_LOW. If the value of tHiLo is WLZ_THRESH_EQUAL then this parameter is ignored.
rad	Radius of region around seed in which to establish threshold value, 0.0 implies a single voxel.
rHiLo	How to choose threshold from the region around each seed: WLZ_THRESH_HIGH - highest, WLZ_THRESH_EQUAL - mean and WLZ_THRESH_LOW - lowest. Unused if region radius is 0.0.
dstErr	Destination error pointer, may be NULL.

References _WlzValues::core, _WlzDomain::core, _WlzObject::domain, _WlzVertexP::i2, _WlzVertexP::i3, _WlzPixelV::type, _WlzObject::type, _WlzObject::values, _WlzIVertex2::vtX, _WlzIVertex3::vtX, _WlzIVertex2::vtY, _WlzIVertex3::vtY, _WlzIVertex3::vtZ, WLZ_0_CONNECTED, WLZ_26_CONNECTED, WLZ_2D_DOMAINOBJ, WLZ_3D_DOMAINOBJ, WLZ_8_CONNECTED, WLZ_EMPTY_OBJ, WLZ_ERR_DOMAIN_NULL, WLZ_ERR_NONE, WLZ_ERR_OBJECT_NULL, WLZ_ERR_OBJECT_TYPE, WLZ_ERR_PARAM_DATA, WLZ_ERR_PARAM_TYPE, WLZ_ERR_VALUES_NULL, WLZ_GREY_FLOAT, WLZ_VERTEX_I2, WLZ_VERTEX_I3, WlzAssignObject(), WlzGreyValueMakeWSp(), WlzMakeEmpty(), and WlzMakeSphereObject().

Referenced by WlzConComThreshold2D(), and WlzConComThreshold3D().

◆ WlzHyThreshold()

WlzObject* WlzHyThreshold	(	WlzObject *	srcObj,
		WlzPixelV	pThrV,
		WlzPixelV	sThrV,
		WlzThresholdType	hilo,
		WlzConnectType	con,
		WlzErrorNum *	dstErr
	)

Hysteresis thresholds the given Woolz object. Values are in the domain of the hysteresis threshold'd object if they are above/below the primary threshold or above/below the secondary threshold and connected to values above/below the primary threshold.

Returns: Thresholded object or NULL on error.

Parameters

srcObj	Object to be thresholded.
pThrV	Primary hysteresis threshold value.
sThrV	Threshold for above or below values.
hilo	Threshold for above or below values.
con	Connectivity to examine for hysteresis.
dstErr	Destination error pointer, may be null.

References _WlzValues::core, _WlzDomain::core, _WlzGreyV::dbv, _WlzObject::domain, _WlzGreyV::flv, _WlzGreyV::inv, _WlzObject::plist, _WlzGreyV::rgbv, _WlzGreyV::shv, _WlzPixelV::type, _WlzGreyV::ubv, _WlzPixelV::v, _WlzObject::values, WLZ_0_CONNECTED, WLZ_EMPTY_OBJ, WLZ_ERR_DOMAIN_NULL, WLZ_ERR_GREY_TYPE, WLZ_ERR_NONE, WLZ_ERR_OBJECT_NULL, WLZ_ERR_VALUES_NULL, WLZ_GREY_DOUBLE, WLZ_GREY_FLOAT, WLZ_GREY_INT, WLZ_GREY_RGBA, WLZ_GREY_SHORT, WLZ_GREY_UBYTE, WlzDilation(), WlzFreeObj(), WlzIntersect2(), WlzMakeMain(), WlzThreshold(), WlzUnion2(), and WlzValueConvertPixel().

Referenced by WlzCannyDeriche().

◆ WlzRGBAMultiThreshold()

WlzObject* WlzRGBAMultiThreshold	(	WlzObject *	obj,
		WlzPixelV	lowVal,
		WlzPixelV	highVal,
		WlzUInt	combineMode,
		WlzErrorNum *	dstErr
	)

Apply independent thresholds to each colour channel independently and combine according to the settings encoded in combineMode. Each channel can have one of two modes: WLZ_BO_AND and WLZ_BO_OR. These are encoded into a single mode variable using the RGBA macro, e.g.: WLZ_RGBA_RGBA_SET(combineMode, redMode, greenMode, blueMode, 255);.

The macro WLZ_RGBA_RED_GET(combineMode) will return redMode and similarly for green and blue.

Returns: Thresholded object

Parameters

obj	Object to be thresholded
lowVal	RGB low values
highVal	RGB high values
combineMode	Combination rules as an RGBA encoded unsigned integer
dstErr	Error return

Source:: WlzRGBAThreshold.c

References _WlzValues::core, _WlzObject::domain, _WlzGreyV::inv, _WlzCompoundArray::n, _WlzCompoundArray::o, _WlzValues::obj, _WlzGreyV::rgbv, _WlzPixelV::type, _WlzObject::type, _WlzPixelV::v, _WlzObject::values, WLZ_2D_DOMAINOBJ, WLZ_3D_DOMAINOBJ, WLZ_BO_AND, WLZ_COMPOUND_ARR_1, WLZ_COMPOUND_ARR_2, WLZ_EMPTY_OBJ, WLZ_ERR_NONE, WLZ_ERR_OBJECT_DATA, WLZ_ERR_OBJECT_NULL, WLZ_ERR_OBJECT_TYPE, WLZ_ERR_PARAM_TYPE, WLZ_ERR_VALUES_NULL, WLZ_GREY_INT, WLZ_GREY_RGBA, WLZ_RGBA_BLUE_GET, WLZ_RGBA_GREEN_GET, WLZ_RGBA_RED_GET, WLZ_RGBA_SPACE_RGB, WLZ_THRESH_HIGH, WLZ_THRESH_LOW, WLZ_TRANS_OBJ, WlzAssignObject(), WlzFreeObj(), WlzIntersect2(), WlzIsEmpty(), WlzMakeEmpty(), WlzMakeMain(), WlzRGBAToCompound(), WlzThreshold(), and WlzUnion2().

Referenced by WlzRGBABoxThreshold().

◆ WlzThreshold()

WlzObject* WlzThreshold	(	WlzObject *	obj,
		WlzPixelV	threshV,
		WlzThresholdType	highlow,
		WlzErrorNum *	dstErr
	)

Thresholds a woolz grey-level object, 2D or 3D.

Returns: New Woolz object or NULL on error.

Parameters

obj	Object to be thresholded.
threshV	Threshold pixel value.
highlow	Mode parameter with possible values: WLZ_THRESH_LOW - thresholded object is of values < given value. WLZ_THRESH_HIGH - thresholded object is of values >= given value. WLZ_THRESH_EQUAL - thresholded object is of values == given value.
dstErr	Destination pointer for error number, may be NULL.

References _WlzObject::type, WLZ_2D_DOMAINOBJ, WLZ_ERR_NONE, and WLZ_ERR_OBJECT_NULL.

Referenced by WlzBSplineToDomain(), WlzDomainFill3D(), WlzDomainNearby(), WlzGetProjectionFromObject(), WlzGreyExtremumObj(), WlzHyThreshold(), WlzIndexObjToCompound(), WlzOffsetDist(), WlzPointsFromDomObj(), WlzRGBAMultiThreshold(), WlzScalarFeatures2D(), WlzSplitMontageObj(), and WlzSplitObj().

Files

Macros

Enumerations

Functions

Detailed Description

Macro Definition Documentation

◆ WLZ_THRESH_ADD_ITV_1

◆ WLZ_THRESH_ADD_ITV_FE_1

◆ WLZ_THRESH_ADD_ITV_RGB_1

◆ WLZ_THRESH_ADD_ITV_2

◆ WLZ_THRESH_ADD_ITV_FE_2

◆ WLZ_THRESH_ADD_ITV_RGB_2

Enumeration Type Documentation

◆ _WlzCompThreshType

◆ _WlzThresholdType

◆ _WlzRGBAThresholdType

Function Documentation

◆ WlzCompThresholdVT()

◆ WlzCompThreshold()

◆ WlzConComThreshold2D()

◆ WlzConComThreshold3D()

◆ WlzConComThreshold()

◆ WlzHyThreshold()

◆ WlzRGBAMultiThreshold()

◆ WlzThreshold()