TestAddRadialPtoN_F32.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 georegression.geometry.GeometryMath_F32;
import georegression.struct.point.Point2D_F32;
import org.ejml.data.DenseMatrix64F;
import org.ejml.ops.CommonOps;
import org.junit.Test;

import static org.junit.Assert.assertEquals;

/**
 * @author Peter Abeles
 */
public class TestAddRadialPtoN_F32 {
	/**
	 * Manually compute the distorted coordinate for a point and see if it matches
	 */
	@Test
	public void againstManual() {
		againstManual(0,0);
		againstManual(-0.5f,0.03f);
	}

	public void againstManual( float t1, float t2 ) {
		float fx = 600;
		float fy = 500;
		float skew = 2;
		float xc = 300;
		float yc = 350;

		/**/double radial[]= new /**/double[]{0.01f,-0.03f};

		Point2D_F32 orig = new Point2D_F32(19.5f,400.1f); // undistorted pixel coordinates

		Point2D_F32 normPt = new Point2D_F32();

		DenseMatrix64F K = new DenseMatrix64F(3,3,true,fx,skew,xc,0,fy,yc,0,0,1);
		DenseMatrix64F K_inv = new DenseMatrix64F(3,3);
		CommonOps.invert(K, K_inv);

		// compute normalized image coordinate
		GeometryMath_F32.mult(K_inv, orig, normPt);

		float nx = normPt.x; // undistorted normalized image coordinates
		float ny = normPt.y;

		float r2 = nx*nx + ny*ny;
		float ri2 = 1;
		float sum = 0;
		for( int i = 0; i < radial.length; i++ ) {
			ri2 *= r2;
			sum += radial[i]*ri2;
		}

		// distorted normalized image coordinates
		float dnx = nx + nx*sum + 2*t1*nx*ny + t2*(r2 + 2*nx*nx);
		float dny = ny + ny*sum + t1*(r2 + 2*ny*ny) + 2*t2*nx*ny;

		AddRadialPtoN_F32 alg = new AddRadialPtoN_F32().setK(fx, fy, skew, xc, yc).
				setDistortion(radial, t1, t2);

		Point2D_F32 found = new Point2D_F32();

		alg.compute(orig.x,orig.y,found);

		assertEquals(dnx,found.x,1e-4);
		assertEquals(dny,found.y,1e-4);
	}
}