boofcv.alg.fiducial.calib.squares.SquaresIntoClusters Maven / Gradle / Ivy

/*
 * Copyright (c) 2021, 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.squares;

import org.ddogleg.struct.DogArray;

import java.util.ArrayList;
import java.util.List;

/**
 * Base class for clustering unorganized squares into different types of clusters.
 *
 * @author Peter Abeles
 */
public class SquaresIntoClusters {

	protected DogArray nodes = new DogArray<>(SquareNode::new);

	// storage for found clusters
	protected DogArray> clusters = new DogArray(ArrayList::new);

	// storage for open list when clustering points
	protected List open = new ArrayList<>();

	protected SquareGraph graph = new SquareGraph();

	/**
	 * Reset and recycle data structures from the previous run
	 */
	protected void recycleData() {
		for (int i = 0; i < nodes.size(); i++) {
			SquareNode n = nodes.get(i);
			for (int j = 0; j < n.edges.length; j++) {
				if (n.edges[j] != null) {
					graph.detachEdge(n.edges[j]);
				}
			}
		}
		for (int i = 0; i < nodes.size(); i++) {
			SquareNode n = nodes.get(i);
			for (int j = 0; j < n.edges.length; j++) {
				if (n.edges[j] != null)
					throw new RuntimeException("BUG!");
			}
		}

		nodes.reset();

		for (int i = 0; i < clusters.size; i++) {
			clusters.get(i).clear();
		}
		clusters.reset();
	}

	/**
	 * Put sets of nodes into the same list if they are some how connected
	 */
	protected void findClusters() {

		for (int i = 0; i < nodes.size(); i++) {
			SquareNode n = nodes.get(i);

			if (n.graph < 0) {
				n.graph = clusters.size();
				List graph = clusters.grow();
				graph.add(n);
				addToCluster(n, graph);
			}
		}
	}

	/**
	 * Finds all neighbors and adds them to the graph. Repeated until there are no more nodes to add to the graph
	 */
	void addToCluster( SquareNode seed, List graph ) {
		open.clear();
		open.add(seed);
		while (!open.isEmpty()) {
			SquareNode n = open.remove(open.size() - 1);

			for (int i = 0; i < n.square.size(); i++) {
				SquareEdge edge = n.edges[i];
				if (edge == null)
					continue;

				SquareNode other;
				if (edge.a == n)
					other = edge.b;
				else if (edge.b == n)
					other = edge.a;
				else
					throw new RuntimeException("BUG!");

				if (other.graph == SquareNode.RESET_GRAPH) {
					other.graph = n.graph;
					graph.add(other);
					open.add(other);
				} else if (other.graph != n.graph) {
					throw new RuntimeException("BUG! " + other.graph + " " + n.graph);
				}
			}
		}
	}
}