AddRadialPtoN_F64.java

/*
 * Copyright (c) 2011-2016, 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.distort.radtan;

import boofcv.struct.distort.Point2Transform2_F64;
import georegression.geometry.GeometryMath_F64;
import georegression.struct.point.Point2D_F64;
import org.ejml.data.DenseMatrix64F;
import org.ejml.ops.CommonOps;

/**
 * Given an undistorted pixel coordinate, compute the distorted normalized image coordinate.
 *
 * @author Peter Abeles
 */
public class AddRadialPtoN_F64 implements Point2Transform2_F64 {

	// distortion parameters
	protected RadialTangential_F64 params;

	private DenseMatrix64F K_inv = new DenseMatrix64F(3, 3);
	private Point2D_F64 temp0 = new Point2D_F64();

	public AddRadialPtoN_F64() {
	}

	/**
	 * Specify camera calibration parameters
	 *
	 * @param fx   Focal length x-axis in pixels
	 * @param fy   Focal length y-axis in pixels
	 * @param skew skew in pixels
	 * @param cx   camera center x-axis in pixels
	 * @param cy   center center y-axis in pixels
	 */
	public AddRadialPtoN_F64 setK( /**/double fx, /**/double fy, /**/double skew, /**/double cx, /**/double cy) {

		K_inv.zero();
		K_inv.set(0, 0, fx);
		K_inv.set(1, 1, fy);
		K_inv.set(0, 1, skew);
		K_inv.set(0, 2, cx);
		K_inv.set(1, 2, cy);
		K_inv.set(2, 2, 1);

		CommonOps.invert(K_inv);

		return this;
	}

	/**
	 * Specify intrinsic camera parameters
	 *
	 * @param radial Radial distortion parameters
	 */
	public AddRadialPtoN_F64 setDistortion( /**/double[] radial, /**/double t1, /**/double t2) {
		params = new RadialTangential_F64(radial, t1, t2);
		return this;
	}

	/**
	 * Adds radial distortion
	 *
	 * @param x   Undistorted x-coordinate pixel
	 * @param y   Undistorted y-coordinate pixel
	 * @param out Distorted pixel coordinate.
	 */
	@Override
	public void compute(double x, double y, Point2D_F64 out) {
		double sum = 0;

		double radial[] = params.radial;
		double t1 = params.t1, t2 = params.t2;

		temp0.x = x;
		temp0.y = y;

		// out is undistorted normalized image coordinate
		GeometryMath_F64.mult(K_inv, temp0, out);

		double r2 = out.x * out.x + out.y * out.y;
		double ri2 = r2;

		for (int i = 0; i < radial.length; i++) {
			sum += radial[i] * ri2;
			ri2 *= r2;
		}

		double tx = 2 * t1 * out.x * out.y + t2 * (r2 + 2 * out.x * out.x);
		double ty = t1 * (r2 + 2 * out.y * out.y) + 2 * t2 * out.x * out.y;

		// now compute the distorted normalized image coordinate
		out.x = out.x*(1 + sum) + tx;
		out.y = out.y*(1 + sum) + ty;
	}
}