Package boofcv.alg.fiducial.calib.circle

Class DetectCircleHexagonalGrid<T extends ImageGray<T>>

java.lang.Object

boofcv.alg.fiducial.calib.circle.DetectCircleGrid<T>

boofcv.alg.fiducial.calib.circle.DetectCircleHexagonalGrid<T>

public class DetectCircleHexagonalGrid<T extends ImageGray<T>>
extends DetectCircleGrid<T>

Detects a hexagonal circle grid. Circles are spaced such that center of each circle is the same distance from each of its five neighbors. Rows and columns are counted in a zig-zag pattern, see example below. When there is symmetric ambiguity the canonical orientation is used.

Canonical orientation is defined as having the rows/columns matched, element (0,0) being occupied. If there are multiple solution a solution will be selected which is in counter-clockwise order (image coordinates) and if there is still ambiguity the ellipse closest to the image origin will be selected as (0,0).

For each circle there is one control point. The control point is first found by detecting all the ellipses, which is what a circle appears to be under perspective distortion. The center the ellipse might not match the physical center of the circle. The intersection of lines does not change under perspective distortion. The outer common tangent lines between neighboring ellipses are found. Then the intersection of two such lines is found. This intersection will be the physical center of the circle.

Example of a 24 by 28 grid; row, column.

See Also:

• KeyPointsCircleHexagonalGrid

Field Summary

Fields inherited from class boofcv.alg.fiducial.calib.circle.DetectCircleGrid

ellipseDetector, numCols, numRows

Constructor Summary

Constructors

Constructor	Description
DetectCircleHexagonalGrid(int numRows, int numCols, InputToBinary<T> inputToBinary, BinaryEllipseDetector<T> ellipseDetector, EllipsesIntoClusters clustering)	Creates and configures the detector

Method Summary

Modifier and Type	Method	Description
protected void	configureContourDetector(T gray)	Configures the contour detector based on the image size.
protected void	putGridIntoCanonical(EllipseClustersIntoGrid.Grid g)	Puts the grid into a canonical orientation
int	totalEllipses(int numRows, int numCols)	Computes the number of ellipses on the grid

Methods inherited from class boofcv.alg.fiducial.calib.circle.DetectCircleGrid

getBinary, getClustering, getClusters, getClustersPruned, getColumns, getEllipseDetector, getGrider, getGrids, getRows, isVerbose, process, setVerbose

Methods inherited from class java.lang.Object

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

Constructor Details

DetectCircleHexagonalGrid

public DetectCircleHexagonalGrid(int numRows,
 int numCols,
 InputToBinary<T> inputToBinary,
 BinaryEllipseDetector<T> ellipseDetector,
 EllipsesIntoClusters clustering)

Creates and configures the detector

Parameters:

numRows - number of rows in grid

numCols - number of columns in grid

inputToBinary - Converts the input image into a binary image

ellipseDetector - Detects ellipses inside the image

clustering - Finds clusters of ellipses

Method Details

configureContourDetector

protected void configureContourDetector(T gray)

Description copied from class: DetectCircleGrid

Configures the contour detector based on the image size. Setting a maximum contour and turning off recording of inner contours and improve speed and reduce the memory foot print significantly.

Specified by:

configureContourDetector in class DetectCircleGrid<T extends ImageGray<T>>

totalEllipses

public int totalEllipses(int numRows,
 int numCols)

Description copied from class: DetectCircleGrid

Computes the number of ellipses on the grid

Specified by:

totalEllipses in class DetectCircleGrid<T extends ImageGray<T>>

putGridIntoCanonical

protected void putGridIntoCanonical(EllipseClustersIntoGrid.Grid g)

Puts the grid into a canonical orientation

Specified by:

putGridIntoCanonical in class DetectCircleGrid<T extends ImageGray<T>>