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/*
 * Copyright (c) 2022, 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.abst.fiducial.calib;

import boofcv.abst.geo.calibration.DetectSingleFiducialCalibration;
import boofcv.alg.distort.LensDistortionNarrowFOV;
import boofcv.alg.feature.detect.chess.DetectChessboardCornersXPyramid;
import boofcv.alg.fiducial.calib.chess.ChessboardCornerClusterFinder;
import boofcv.alg.fiducial.calib.chess.ChessboardCornerClusterToGrid;
import boofcv.alg.fiducial.calib.chess.ChessboardCornerClusterToGrid.GridInfo;
import boofcv.alg.fiducial.calib.chess.DetectChessboardXCornerPatterns;
import boofcv.alg.geo.calibration.CalibrationObservation;
import boofcv.struct.distort.Point2Transform2_F64;
import boofcv.struct.image.GrayF32;
import georegression.struct.point.Point2D_F64;
import lombok.Getter;
import org.ddogleg.struct.DogArray;
import org.jetbrains.annotations.Nullable;

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

/**
 * Detector for chessboard calibration targets which searches for X-Corners.
 * Returns the first chessboard which is detected and matches the expected size is returned.
 *
 * @author Peter Abeles
 */
@SuppressWarnings({"NullAway.Init"})
public class CalibrationDetectorChessboardX implements DetectSingleFiducialCalibration {

	@Getter int cornerRows, cornerCols;

	@Getter DetectChessboardXCornerPatterns detectorX;

	// transform from input pixels to undistorted pixels
	@Nullable Point2Transform2_F64 pixel2undist;

	List layoutPoints;
	CalibrationObservation detected;

	public CalibrationDetectorChessboardX( ConfigChessboardX config, ConfigGridDimen shape ) {
		detectorX = new DetectChessboardXCornerPatterns<>(config, GrayF32.class);

		cornerRows = shape.numRows - 1;
		cornerCols = shape.numCols - 1;

		layoutPoints = gridChess(shape.numRows, shape.numCols, shape.shapeSize);

		detectorX.getClusterToGrid().setCheckShape(( r, c ) -> r == cornerRows && c == cornerCols);
	}

	@Override
	public boolean process( GrayF32 input ) {
		detectorX.findPatterns(input);
		DogArray found = detectorX.getFoundChessboard();

		if (found.size >= 1) {
			detected = new CalibrationObservation();
			GridInfo info = found.get(0);

			for (int i = 0; i < info.nodes.size(); i++) {
				detected.add(i, info.nodes.get(i).corner);
			}

			// remove lens distortion
			if (pixel2undist != null) {
				for (int i = 0; i < info.nodes.size(); i++) {
					Point2D_F64 p = detected.points.get(i).p;
					pixel2undist.compute(p.x, p.y, p);
				}
			}

			return true;
		} else {
			detected = new CalibrationObservation();
			return false;
		}
	}

	@Override public CalibrationObservation getDetectedPoints() {
		return detected;
	}

	@Override public List getLayout() {
		return layoutPoints;
	}

	@Override
	public void setLensDistortion( @Nullable LensDistortionNarrowFOV distortion, int width, int height ) {
		if (distortion == null)
			pixel2undist = null;
		else {
			pixel2undist = distortion.undistort_F64(true, true);
		}
	}

	public DetectChessboardCornersXPyramid getDetector() {
		return detectorX.getDetector();
	}

	public ChessboardCornerClusterFinder getClusterFinder() {
		return detectorX.getClusterFinder();
	}

	public ChessboardCornerClusterToGrid getClusterToGrid() {
		return detectorX.getClusterToGrid();
	}

	/**
	 * This target is composed of a checkered chess board like squares. Each corner of an interior square
	 * touches an adjacent square, but the sides are separated. Only interior square corners provide
	 * calibration points.
	 *
	 * @param numRows Number of grid rows in the calibration target
	 * @param numCols Number of grid columns in the calibration target
	 * @param squareWidth How wide each square is. Units are target dependent.
	 * @return Target description
	 */
	public static List gridChess( int numRows, int numCols, double squareWidth ) {
		List all = new ArrayList<>();

		// convert it into the number of calibration points
		numCols = numCols - 1;
		numRows = numRows - 1;

		// center the grid around the origin. length of a size divided by two
		double startX = -((numCols - 1)*squareWidth)/2.0;
		double startY = -((numRows - 1)*squareWidth)/2.0;

		for (int i = numRows - 1; i >= 0; i--) {
			double y = startY + i*squareWidth;
			for (int j = 0; j < numCols; j++) {
				double x = startX + j*squareWidth;
				all.add(new Point2D_F64(x, y));
			}
		}

		return all;
	}
}