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links edgels together to form digital curves. More...
#include <vtkLinkEdgels.h>
Inherits vtkPolyDataAlgorithm.
Public Types | |
typedef vtkPolyDataAlgorithm | Superclass |
Public Member Functions | |
virtual int | IsA (const char *type) |
vtkLinkEdgels * | NewInstance () const |
void | PrintSelf (ostream &os, vtkIndent indent) |
virtual void | SetLinkThreshold (double) |
virtual double | GetLinkThreshold () |
virtual void | SetPhiThreshold (double) |
virtual double | GetPhiThreshold () |
virtual void | SetGradientThreshold (double) |
virtual double | GetGradientThreshold () |
Static Public Member Functions | |
static int | IsTypeOf (const char *type) |
static vtkLinkEdgels * | SafeDownCast (vtkObjectBase *o) |
static vtkLinkEdgels * | New () |
Protected Member Functions | |
virtual vtkObjectBase * | NewInstanceInternal () const |
vtkLinkEdgels () | |
~vtkLinkEdgels () | |
virtual int | RequestData (vtkInformation *, vtkInformationVector **, vtkInformationVector *) |
virtual int | FillInputPortInformation (int port, vtkInformation *info) |
void | LinkEdgels (int xdim, int ydim, double *image, vtkDataArray *inVectors, vtkCellArray *newLines, vtkPoints *newPts, vtkDoubleArray *outScalars, vtkDoubleArray *outVectors, int z) |
Protected Attributes | |
double | GradientThreshold |
double | PhiThreshold |
double | LinkThreshold |
links edgels together to form digital curves.
vtkLinkEdgels links edgels into digital curves which are then stored as polylines. The algorithm works one pixel at a time only looking at its immediate neighbors. There is a GradientThreshold that can be set that eliminates any pixels with a smaller gradient value. This can be used as the lower threshold of a two value edgel thresholding.
For the remaining edgels, links are first tried for the four connected neighbors. A successful neighbor will satisfy three tests. First both edgels must be above the gradient threshold. Second, the difference between the orientation between the two edgels (Alpha) and each edgels orientation (Phi) must be less than LinkThreshold. Third, the difference between the two edgels Phi values must be less than PhiThreshold. The most successful link is selected. The measure is simply the sum of the three angle differences (actually stored as the sum of the cosines). If none of the four connect neighbors succeeds, then the eight connect neighbors are examined using the same method.
This filter requires gradient information so you will need to use a vtkImageGradient at some point prior to this filter. Typically a vtkNonMaximumSuppression filter is also used. vtkThresholdEdgels can be used to complete the two value edgel thresholding as used in a Canny edge detector. The vtkSubpixelPositionEdgels filter can also be used after this filter to adjust the edgel locations.
Definition at line 61 of file vtkLinkEdgels.h.
typedef vtkPolyDataAlgorithm vtkLinkEdgels::Superclass |
Definition at line 64 of file vtkLinkEdgels.h.
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Definition at line 92 of file vtkLinkEdgels.h.
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vtkLinkEdgels* vtkLinkEdgels::NewInstance | ( | ) | const |
void vtkLinkEdgels::PrintSelf | ( | ostream & | os, |
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Construct instance of vtkLinkEdgels with GradientThreshold set to 0.1, PhiThreshold set to 90 degrees and LinkThreshold set to 90 degrees.
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Set/Get the threshold for Phi vs. Alpha link thresholding.
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Set/Get the threshold for Phi vs. Alpha link thresholding.
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Set/get the threshold for Phi vs. Phi link thresholding.
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Set/get the threshold for Phi vs. Phi link thresholding.
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Set/Get the threshold for image gradient thresholding.
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Set/Get the threshold for image gradient thresholding.
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Definition at line 101 of file vtkLinkEdgels.h.
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Definition at line 102 of file vtkLinkEdgels.h.
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Definition at line 103 of file vtkLinkEdgels.h.