org.generation5.vision
Class LineHoughTransformOp

java.lang.Object
  org.generation5.vision.HoughTransformOp
      org.generation5.vision.LineHoughTransformOp

public class LineHoughTransformOp

extends HoughTransformOp

This class implements a Line Hough transform. It is heavily based on code written by Timothy Sharman for the excellent HIPR2 resource site (http://homepages.inf.ed.ac.uk/rbf/HIPR2/hipr_top.htm).

Field Summary

protected long[][]	houghAccumulator The accumulator.
protected java.awt.Color	lineColor The line colour used for the superimposed image (default WHITE).
protected int	localPeakNeighbourhood The local peak neighbourhood.
protected long	maxAccValue The maximum accumulator value.
protected double	thetaStep The theta step.

Constructor Summary

LineHoughTransformOp()
Creates a new instance of LineHoughTransformOp

Method Summary

java.awt.image.BufferedImage	getAccumulatorImage() Returns the accumulator as an image.
java.awt.Color	getLineColor() Get the line colour used.
int	getLocalPeakNeighbourhood() Get the local peak neighbourhood.
protected long	getMaximum() Get the maximum value in the accumulator.
java.awt.image.BufferedImage	getSuperimposed(java.awt.image.BufferedImage img, double threshold) Returns the superimposed image.
static void	main(java.lang.String[] args) Simple test function.
void	run(java.awt.image.BufferedImage img) Runs the line Hough Transform.
void	setLineColor(java.awt.Color lc) Set the line colour used for the superimposed image.
void	setLocalPeakNeighbourhood(int lpn) Set the local peak neighbourhood.

Methods inherited from class java.lang.Object

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

Field Detail

houghAccumulator

protected long[][] houghAccumulator

The accumulator.

maxAccValue

protected long maxAccValue

The maximum accumulator value.

localPeakNeighbourhood

protected int localPeakNeighbourhood

The local peak neighbourhood.

thetaStep

protected double thetaStep

The theta step.

lineColor

protected java.awt.Color lineColor

The line colour used for the superimposed image (default WHITE).

Constructor Detail

LineHoughTransformOp

public LineHoughTransformOp()

Creates a new instance of LineHoughTransformOp

Method Detail

setLineColor

public void setLineColor(java.awt.Color lc)

Set the line colour used for the superimposed image.

Parameters:

lc - the new line colour.

getLineColor

public java.awt.Color getLineColor()

Get the line colour used.

Returns:

the current line colour used.

setLocalPeakNeighbourhood

public void setLocalPeakNeighbourhood(int lpn)

Set the local peak neighbourhood.

Parameters:

lpn - the new local peak neighbourhood.

getLocalPeakNeighbourhood

public int getLocalPeakNeighbourhood()

Get the local peak neighbourhood.

Returns:

the current local peak neighbourhood.

getMaximum

protected long getMaximum()

Get the maximum value in the accumulator.

Returns:

the maximum value.

getAccumulatorImage

public java.awt.image.BufferedImage getAccumulatorImage()

Returns the accumulator as an image. Values are scaled linearly according to the maximum value.

Specified by:

getAccumulatorImage in class HoughTransformOp

Returns:

the accumulator image.

run

public void run(java.awt.image.BufferedImage img)

Runs the line Hough Transform. Note that the input image must be an edge-only, greyscale image (ie, must have been passed through an edge detector and thresholding filter).

Specified by:

run in class HoughTransformOp

Parameters:

img - input image.

getSuperimposed

public java.awt.image.BufferedImage getSuperimposed(java.awt.image.BufferedImage img,
                                                    double threshold)

Returns the superimposed image. This can be a full-colour version of the image the Hough transform has been run on.

Specified by:

getSuperimposed in class HoughTransformOp

Parameters:

img - the input image.

threshold - the accumulator threshold.

Returns:

the superimposed image.

main

public static void main(java.lang.String[] args)

Simple test function.

Parameters:

args - the command line arguments