boofcv.alg.feature.shapes

Class SplitMergeLineFit

java.lang.Object

boofcv.alg.feature.shapes.SplitMergeLineFit

Direct Known Subclasses:

SplitMergeLineFitLoop, SplitMergeLineFitSegment

public abstract class SplitMergeLineFit
extends Object

Base class for algorithm which employ a split and merge strategy to fitting a set of line segments onto an ordered set of points. The lines are an approximation of the original shape described by the point list. This list can either be connected at the end (looped) or not, depending on the implementation. The points in the list are assumed to be ordered with each consecutive point connected to its neighbors. The output is a set of indexes which correspond to points in the original list that compose the line segments. A minimum of two indexes will be returned. The returned set of line segments is guaranteed to match the original set of points to within a use specified tolerance. That is, no point in the list will be more than 'tol' distance away from a line segment. The split and merge technique works by finding searching for the point which is the greatest distance from the two end points. If that point is more than 'tol' away the line is split. This is recursively repeated for each segment until no more are needed. After the initial segmentation the points are split and merged until no more changes happens or the maximum number of iterations has been reached. Lines are merged if the acute angle between them is less than a tolerance. Then the lines are checked to see if they need to be merged.

Author:

Peter Abeles

Field Summary

Fields

Modifier and Type	Field and Description
protected org.ddogleg.struct.GrowQueue_B	changed
protected List<georegression.struct.point.Point2D_I32>	contour
protected georegression.struct.line.LineParametric2D_F64	line
protected int	maxIterations
protected georegression.struct.point.Point2D_F64	point2D
protected org.ddogleg.struct.GrowQueue_I32	splits
protected double	toleranceMerge
protected double	toleranceSplitSq
protected org.ddogleg.struct.GrowQueue_I32	work

Constructor Summary

Constructors

Constructor and Description
SplitMergeLineFit(double toleranceSplit, double toleranceMerge, int maxIterations)

Method Summary

Methods

Modifier and Type	Method and Description
protected double	computeAcute(georegression.struct.point.Point2D_I32 a, georegression.struct.point.Point2D_I32 b, georegression.struct.point.Point2D_I32 c) Returns the acute angle in radians between the two lines
org.ddogleg.struct.GrowQueue_I32	getSplits() List of point indexes in the contour.
abstract void	process(List<georegression.struct.point.Point2D_I32> list) Approximates the input list with a set of line segments

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

maxIterations

protected int maxIterations

toleranceSplitSq

protected double toleranceSplitSq

toleranceMerge

protected double toleranceMerge

contour

protected List<georegression.struct.point.Point2D_I32> contour

line

protected georegression.struct.line.LineParametric2D_F64 line

point2D

protected georegression.struct.point.Point2D_F64 point2D

splits

protected org.ddogleg.struct.GrowQueue_I32 splits

work

protected org.ddogleg.struct.GrowQueue_I32 work

changed

protected org.ddogleg.struct.GrowQueue_B changed

Constructor Detail

SplitMergeLineFit

public SplitMergeLineFit(double toleranceSplit,
                 double toleranceMerge,
                 int maxIterations)

Parameters:

toleranceSplit - A line is split if a point is found that is more than this distance (pixels) away from the line.

toleranceMerge - Two lines are merged together if their angle is less than or equal to this number.

maxIterations - Maximum number of split and merge refinements. Set to zero to disable refinement

Method Detail

process

public abstract void process(List<georegression.struct.point.Point2D_I32> list)

Approximates the input list with a set of line segments

Parameters:

list - Ordered list of connected points.

computeAcute

protected double computeAcute(georegression.struct.point.Point2D_I32 a,
                  georegression.struct.point.Point2D_I32 b,
                  georegression.struct.point.Point2D_I32 c)

Returns the acute angle in radians between the two lines

getSplits

public org.ddogleg.struct.GrowQueue_I32 getSplits()

List of point indexes in the contour. Each point is the end of a line segment. A minimum of two points will be returned. NOTE: This list is modified the next time process is called.

Returns:

List of indexes