diva.sketch.features

Class FEUtilities

java.lang.Object

diva.sketch.features.FEUtilities

public class FEUtilities
extends Object

Common calculation methods used in path filtering and feature extraction processes.

Version:

$Revision: 1.17 $

Author:

Heloise Hse (hwawen@eecs.berkeley.edu)

Constructor Summary

Constructors

Constructor and Description
FEUtilities()

Method Summary

Modifier and Type	Method and Description
static double	calcAngle(Line2D line1, Line2D line2) Calculate the angle (in radians) in between the given vectors.
static double	calcLengthRatio(Line2D line1, Line2D line2) Calculate the ratio of line1's length and line2's length.
static double	computeAngle(double xhead, double yhead, double xtail, double ytail) Given a 2D vector, find the angle (in radians) formed between this vector and the horizontal vector pointing in the positive x direction.
static double	distance(double x1, double y1, double x2, double y2) Return the Euclidean distance between two points, (x1, y1) and (x2, y2).
static double	distanceSquared(double x1, double y1, double x2, double y2) Return the square of the distance between two points, (x1, y1) and (x2, y2).
static double	dotProduct(double x1, double y1, double x2, double y2, double x3, double y3) Return the dot product of the vector (x1, y1)(x2, y2) and the vector (x2, y2)(x3, y3).
static double	dotProduct(double p1xh, double p1yh, double p1xt, double p1yt, double p2xh, double p2yh, double p2xt, double p2yt) Return the dot product of the vector (p1xh, p1yh)(p1xt, p1yt) and the vector (p2xh,p2yh)(p2xt, p2yt) h = head, t = tail, tail-------->head
static double	findArea(Point2D p1, Point2D p2, Point2D p3) Given three points each represents the vertex of a triangle, return the area of this triangle.
static double	findSlope(double p1x, double p1y, double p2x, double p2y) Find the slope of the line formed by two points (p1x, p1y) and (p2x, p2y).
static double	pathLength(double[] xvals, double[] yvals, int num) Return the total pathlength by summing over the distance of consecutive points in the array.
static double	pathLength(double[] xvals, double[] yvals, int startIndex, int endIndex) calculate the path length starting from the startIndex to the endIndex (inclusive) of the points in the array.

Methods inherited from class java.lang.Object

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

Constructor Detail

FEUtilities

public FEUtilities()

Method Detail

calcAngle

public static double calcAngle(Line2D line1,
                               Line2D line2)

Calculate the angle (in radians) in between the given vectors.

calcLengthRatio

public static double calcLengthRatio(Line2D line1,
                                     Line2D line2)

Calculate the ratio of line1's length and line2's length. (line1/line2);

computeAngle

public static double computeAngle(double xhead,
                                  double yhead,
                                  double xtail,
                                  double ytail)

Given a 2D vector, find the angle (in radians) formed between this vector and the horizontal vector pointing in the positive x direction. Return Double.NaN if the 2 points given are the same points.

distance

public static double distance(double x1,
                              double y1,
                              double x2,
                              double y2)

Return the Euclidean distance between two points, (x1, y1) and (x2, y2).

distanceSquared

public static double distanceSquared(double x1,
                                     double y1,
                                     double x2,
                                     double y2)

Return the square of the distance between two points, (x1, y1) and (x2, y2).

dotProduct

public static double dotProduct(double x1,
                                double y1,
                                double x2,
                                double y2,
                                double x3,
                                double y3)

Return the dot product of the vector (x1, y1)(x2, y2) and the vector (x2, y2)(x3, y3).

dotProduct

public static double dotProduct(double p1xh,
                                double p1yh,
                                double p1xt,
                                double p1yt,
                                double p2xh,
                                double p2yh,
                                double p2xt,
                                double p2yt)

Return the dot product of the vector (p1xh, p1yh)(p1xt, p1yt) and the vector (p2xh,p2yh)(p2xt, p2yt) h = head, t = tail, tail-------->head

findArea

public static double findArea(Point2D p1,
                              Point2D p2,
                              Point2D p3)

Given three points each represents the vertex of a triangle, return the area of this triangle.

findSlope

public static double findSlope(double p1x,
                               double p1y,
                               double p2x,
                               double p2y)

Find the slope of the line formed by two points (p1x, p1y) and (p2x, p2y).

pathLength

public static double pathLength(double[] xvals,
                                double[] yvals,
                                int num)

Return the total pathlength by summing over the distance of consecutive points in the array.

pathLength

public static double pathLength(double[] xvals,
                                double[] yvals,
                                int startIndex,
                                int endIndex)

calculate the path length starting from the startIndex to the endIndex (inclusive) of the points in the array.