FreeMat

- Main Page
- Related Pages

vtkSubPixelPositionEdgels

Section: Visualization Toolkit Graphics Classes

# Usage

vtkSubPixelPositionEdgels is a filter that takes a series of linked edgels (digital curves) and gradient maps as input. It then adjusts the edgel locations based on the gradient data. Specifically, the algorithm first determines the neighboring gradient magnitudes of an edgel using simple interpolation of its neighbors. It then fits the following three data points: negative gradient direction gradient magnitude, edgel gradient magnitude and positive gradient direction gradient magnitude to a quadratic function. It then solves this quadratic to find the maximum gradient location along the gradient orientation. It then modifies the edgels location along the gradient orientation to the calculated maximum location. This algorithm does not adjust an edgel in the direction orthogonal to its gradient vector.

To create an instance of class vtkSubPixelPositionEdgels, simply invoke its constructor as follows

      obj = vtkSubPixelPositionEdgels

# Methods

The class vtkSubPixelPositionEdgels has several methods that can be used. They are listed below. Note that the documentation is translated automatically from the VTK sources, and may not be completely intelligible. When in doubt, consult the VTK website. In the methods listed below, `obj` is an instance of the vtkSubPixelPositionEdgels class.

- `string = obj.GetClassName ()`
- `int = obj.IsA (string name)`
- `vtkSubPixelPositionEdgels = obj.NewInstance ()`
- `vtkSubPixelPositionEdgels = obj.SafeDownCast (vtkObject o)`
- `obj.SetGradMaps (vtkStructuredPoints gm)` - Set/Get the gradient data for doing the position adjustments.
- `vtkStructuredPoints = obj.GetGradMaps ()` - Set/Get the gradient data for doing the position adjustments.
- `obj.SetTargetFlag (int )` - These methods can make the positioning look for a target scalar value instead of looking for a maximum.
- `int = obj.GetTargetFlag ()` - These methods can make the positioning look for a target scalar value instead of looking for a maximum.
- `obj.TargetFlagOn ()` - These methods can make the positioning look for a target scalar value instead of looking for a maximum.
- `obj.TargetFlagOff ()` - These methods can make the positioning look for a target scalar value instead of looking for a maximum.
- `obj.SetTargetValue (double )` - These methods can make the positioning look for a target scalar value instead of looking for a maximum.
- `double = obj.GetTargetValue ()` - These methods can make the positioning look for a target scalar value instead of looking for a maximum.