imagingbook.pub.hough

Class HoughTransformLines.HoughLine

java.lang.Object

imagingbook.pub.hough.HoughTransformLines.HoughLine

All Implemented Interfaces:

Comparable<HoughTransformLines.HoughLine>

Enclosing class:

HoughTransformLines

public class HoughTransformLines.HoughLine
extends Object
implements Comparable<HoughTransformLines.HoughLine>

This class represents a straight line in Hessian normal form, i.e., x * cos(angle) + y * sin(angle) = radius. It is implemented as a non-static inner class of HoughTransformLines since its instances refer to the particular enclosing Hough transform object.

Constructor Summary

Constructors

Constructor and Description
HoughLine(double angle, double radius, int count) Public constructor (only available with an enclosing HoughTransformLines instance!)

Method Summary

Modifier and Type	Method and Description
int	compareTo(HoughTransformLines.HoughLine hl2) Required by the Comparable interface, used for sorting lines by their point count.
void	draw(ij.process.ImageProcessor ip, double thickness) This is a brute-force drawing method which simply marks all image pixels that are sufficiently close to the HoughLine hl.
double	getAngle()
int	getCount()
double	getDistance(double x, double y) Returns the perpendicular distance between this line and the point (x, y).
double	getDistance(Point2D p) Returns the perpendicular distance between this line and the point p.
double	getRadius()
Point2D	getReferencePoint()
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

HoughLine

public HoughLine(double angle,
                 double radius,
                 int count)

Public constructor (only available with an enclosing HoughTransformLines instance!)

Parameters:

angle - angle

radius - radius

count - count

Method Detail

getAngle

public double getAngle()

Returns:

The angle of this line.

getRadius

public double getRadius()

Returns:

The radius of this line with respect to the reference point (xc, yc) of the enclosing HoughTransformLines instance.

getCount

public int getCount()

Returns:

The accumulator count associated with this line.

getReferencePoint

public Point2D getReferencePoint()

getDistance

public double getDistance(double x,
                          double y)

Returns the perpendicular distance between this line and the point (x, y). The result may be positive or negative, depending on which side of the line (x, y) is located.

Parameters:

x - x-coordinate of point position.

y - y-coordinate of point position.

Returns:

The perpendicular distance between this line and the point (x, y).

getDistance

public double getDistance(Point2D p)

Returns the perpendicular distance between this line and the point p. The result may be positive or negative, depending on which side of the line p is located.

Parameters:

p - point position.

Returns:

The perpendicular distance between this line and the point p.

draw

public void draw(ij.process.ImageProcessor ip,
                 double thickness)

This is a brute-force drawing method which simply marks all image pixels that are sufficiently close to the HoughLine hl. The drawing color for ip must be previously set.

Parameters:

ip - The ImageProcessor to draw to.

thickness - The thickness of the lines to be drawn.

compareTo

public int compareTo(HoughTransformLines.HoughLine hl2)

Required by the Comparable interface, used for sorting lines by their point count.

Specified by:

compareTo in interface Comparable<HoughTransformLines.HoughLine>

Parameters:

hl2 - another HoughTransformLines.HoughLine instance.

toString

public String toString()

Overrides:

toString in class Object