boofcv.alg.fiducial.calib.grid.DetectSquareGridFiducial Maven / Gradle / Ivy
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/*
* Copyright (c) 2011-2018, Peter Abeles. All Rights Reserved.
*
* This file is part of BoofCV (http://boofcv.org).
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package boofcv.alg.fiducial.calib.grid;
import boofcv.abst.filter.binary.BinaryContourFinder;
import boofcv.abst.filter.binary.InputToBinary;
import boofcv.alg.fiducial.calib.squares.*;
import boofcv.alg.shapes.polygon.DetectPolygonBinaryGrayRefine;
import boofcv.struct.image.GrayU8;
import boofcv.struct.image.ImageGray;
import georegression.struct.point.Point2D_F64;
import georegression.struct.shapes.Polygon2D_F64;
import java.util.ArrayList;
import java.util.List;
/**
* Detect a square grid calibration target and returns the corner points of each square. This calibration grid is
* specified by a set of squares which are organized in a grid pattern. All squares are the same size. The entire
* grid must be visible. Space between the squares is specified as a ratio of the square size. The grid will be
* oriented so that returned points are in counter clockwise (CCW) ordering, which appears to be CW in the image.
*
* There is also always at least two solutions to the ordering. For sake of consistency it will select
* the orientation where index 0 is the closest to the origin.
*
*
*
* 
*
* Example of a 4 by 3 grid (row then column).
*
*
* @author Peter Abeles
*/
public class DetectSquareGridFiducial> {
// dimension of square grid. This only refers to black squares and not the white space
int numCols;
int numRows;
// converts input image into a binary image
InputToBinary inputToBinary;
// detector for squares
DetectPolygonBinaryGrayRefine detectorSquare;
// Converts detected squares into a graph and into grids
SquaresIntoRegularClusters s2c;
SquareRegularClustersIntoGrids c2g;
// output results. Grid of calibration points in row-major order
List calibrationPoints = new ArrayList<>();
int calibRows;
int calibCols;
SquareGridTools tools = new SquareGridTools();
// storage for binary image
GrayU8 binary = new GrayU8(1,1);
List> clusters;
List found = new ArrayList<>();
/**
* COnfigures the detector
*
* @param numRows Number of black squares in the grid rows
* @param numCols Number of black squares in the grid columns
* @param spaceToSquareRatio Ratio of spacing between the squares and the squares width
* @param inputToBinary Converts input image into a binary image
* @param detectorSquare Detects the squares in the image. Must be configured to detect squares
*/
public DetectSquareGridFiducial(int numRows, int numCols, double spaceToSquareRatio,
InputToBinary inputToBinary ,
DetectPolygonBinaryGrayRefine detectorSquare) {
this.numRows = numRows;
this.numCols = numCols;
this.inputToBinary = inputToBinary;
this.detectorSquare = detectorSquare;
// some unit tests will pass in a null value
if( detectorSquare != null ) {
detectorSquare.getDetector().setOutputClockwise(true);
detectorSquare.getDetector().setConvex(true);
detectorSquare.getDetector().setNumberOfSides(4, 4);
}
s2c = new SquaresIntoRegularClusters(spaceToSquareRatio,Integer.MAX_VALUE, 1.35);
c2g = new SquareRegularClustersIntoGrids(numCols*numRows);
calibRows = numRows*2;
calibCols = numCols*2;
}
/**
* Process the image and detect the calibration target
*
* @param image Input image
* @return true if a calibration target was found and false if not
*/
public boolean process( T image ) {
configureContourDetector(image);
binary.reshape(image.width,image.height);
inputToBinary.process(image,binary);
detectorSquare.process(image, binary);
detectorSquare.refineAll();
detectorSquare.getPolygons(found,null);
clusters = s2c.process(found);
c2g.process(clusters);
List grids = c2g.getGrids();
SquareGrid match = null;
double matchSize = 0;
for( SquareGrid g : grids ) {
if (g.columns != numCols || g.rows != numRows) {
if( g.columns == numRows && g.rows == numCols ) {
tools.transpose(g);
} else {
continue;
}
}
double size = tools.computeSize(g);
if( size > matchSize ) {
matchSize = size;
match = g;
}
}
if( match != null ) {
if( tools.checkFlip(match) ) {
tools.flipRows(match);
}
tools.putIntoCanonical(match);
if( !tools.orderSquareCorners(match) )
return false;
extractCalibrationPoints(match);
return true;
}
return false;
}
/**
* 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.
*/
private void configureContourDetector(T gray) {
// determine the maximum possible size of a square when viewed head on
// this doesn't take in account the spacing between squares and will be an over estimate
int maxContourSize = Math.max(gray.width,gray.height)/Math.max(numCols,numRows);
BinaryContourFinder contourFinder = detectorSquare.getDetector().getContourFinder();
contourFinder.setMaxContour(maxContourSize*4*2);
contourFinder.setSaveInnerContour(false);
}
List row0 = new ArrayList<>();
List row1 = new ArrayList<>();
/**
* Extracts the calibration points from the corners of a fully ordered grid
*/
void extractCalibrationPoints(SquareGrid grid) {
calibrationPoints.clear();
for (int row = 0; row < grid.rows; row++) {
row0.clear();
row1.clear();
for (int col = 0; col < grid.columns; col++) {
Polygon2D_F64 square = grid.get(row,col).square;
row0.add(square.get(0));
row0.add(square.get(1));
row1.add(square.get(3));
row1.add(square.get(2));
}
calibrationPoints.addAll(row0);
calibrationPoints.addAll(row1);
}
// calibCols = grid.columns*2;
// calibRows = grid.rows*2;
}
public List getCalibrationPoints() {
return calibrationPoints;
}
public int getCalibrationRows() {
return calibRows;
}
public int getCalibrationCols() {
return calibCols;
}
public DetectPolygonBinaryGrayRefine getDetectorSquare() {
return detectorSquare;
}
public List> getClusters() {
return clusters;
}
public SquaresIntoRegularClusters getSquaresIntoClusters() {
return s2c;
}
public SquareRegularClustersIntoGrids getGrids() {
return c2g;
}
public GrayU8 getBinary() {
return binary;
}
public int getColumns() {
return numCols;
}
public int getRows() {
return numRows;
}
}