boofcv.alg.feature.detect.quadblob

Class FindQuadCorners

java.lang.Object

boofcv.alg.feature.detect.quadblob.FindQuadCorners

public class FindQuadCorners
extends java.lang.Object

Find a list of corner pixels in a blob using its contour. Four corners are assumed. A list of candidate corners is done looking for local minimums in acute angle across the contour. From these candidates the candidate with the smallest acute angle is selected and used as the initial seed. Next the candidate which is the farthest distance is selected. This process is repeated two more times, each time maximizing the distance to all the previously selected corners.

Constructor Summary

Constructors

Constructor and Description
FindQuadCorners()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	computeResponse(java.util.List<georegression.struct.point.Point2D_I32> contour, int radius, double[] response) Computes the acute angle for each pixel in the contour.
protected static georegression.struct.point.Point2D_I32	findAverage(java.util.List<georegression.struct.point.Point2D_I32> contour, georegression.struct.point.Point2D_I32 ret) Find the average of all the points in the list.
java.util.List<georegression.struct.point.Point2D_I32>	process(java.util.List<georegression.struct.point.Point2D_I32> contour) Finds corners from list of contour points and orders contour points into clockwise order.
protected static void	sortByAngleCCW(georegression.struct.point.Point2D_I32 center, java.util.List<georegression.struct.point.Point2D_I32> contour) Sorts the points in counter clockwise direction around the provided point

Methods inherited from class java.lang.Object

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

Constructor Detail

FindQuadCorners

public FindQuadCorners()

Method Detail

process

public java.util.List<georegression.struct.point.Point2D_I32> process(java.util.List<georegression.struct.point.Point2D_I32> contour)

Finds corners from list of contour points and orders contour points into clockwise order.

Parameters:

contour - An unordered list of contour points. Is modified to be on clockwise order.

Returns:

List of 4 best corner points in clockwise order.

findAverage

protected static georegression.struct.point.Point2D_I32 findAverage(java.util.List<georegression.struct.point.Point2D_I32> contour,
                                                 georegression.struct.point.Point2D_I32 ret)

Find the average of all the points in the list.

sortByAngleCCW

protected static void sortByAngleCCW(georegression.struct.point.Point2D_I32 center,
                  java.util.List<georegression.struct.point.Point2D_I32> contour)

Sorts the points in counter clockwise direction around the provided point

Parameters:

center - Point that the angle is computed relative to

contour - List of all the points which are to be sorted by angle

computeResponse

protected void computeResponse(java.util.List<georegression.struct.point.Point2D_I32> contour,
                   int radius,
                   double[] response)

Computes the acute angle for each pixel in the contour. The acute angle is computed by selecting two points which are 'radius' indexes away and finding the relative angle between those two vectors.