00001
00002 /***************************************************************************
00003  *  circle.cpp - Implementation of a circle shape finder
00004  *
00005  *  Generated: Thu May 16 2005
00006  *  Copyright  2005  Tim Niemueller [www.niemueller.de]
00007  *                   Hu Yuxiao      <Yuxiao.Hu@rwth-aachen.de>
00008  *
00009  ****************************************************************************/
00010
00011 /*  This program is free software; you can redistribute it and/or modify
00012  *  it under the terms of the GNU General Public License as published by
00013  *  the Free Software Foundation; either version 2 of the License, or
00014  *  (at your option) any later version. A runtime exception applies to
00015  *  this software (see LICENSE.GPL_WRE file mentioned below for details).
00016  *
00017  *  This program is distributed in the hope that it will be useful,
00018  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00019  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00020  *  GNU Library General Public License for more details.
00021  *
00022  *  Read the full text in the LICENSE.GPL_WRE file in the doc directory.
00023  */
00024
00025 #include <cmath>
00026 #include <models/shape/circle.h>
00027
00028 using namespace std;
00029 using namespace fawkes;
00030 
00031 /** @class Circle <models/shape/circle.h>
00032  * Circle shape.
00033  */
00034 
00035 /** Constructor. */
00036 Circle::Circle()
00037 {
00038       center.x=center.y=0.0f;
00039       radius = -1.0f;
00040       count = 0;
00041 }
00042 
00043 /** Constructor.
00044  * @param c center
00045  * @param r radius
00046  * @param n number of pixels
00047  */
00048 Circle::Circle(const center_in_roi_t& c, float r, int n)
00049 {
00050       center = c;
00051       radius = r;
00052       count = n;
00053 }
00054 
00055 /** Print info.
00056  * @param stream stream to print to
00057  */
00058 void
00059 Circle::printToStream(std::ostream &stream)
00060 {
00061         stream  << "center=(" << center.x << "," << center.y << ")"
00062                 << "   radius=" << radius << "    count= " << count;
00063 }
00064 
00065 /** Fit circle.
00066  * Fit a circle through the given points.
00067  * @param points points to fit circle through.
00068  */
00069 void
00070 Circle::fitCircle (vector< point_t > &points)
00071 {
00072         // due to fixed width, do not use arrays to save addressing time...
00073         double A00=0.0, A01=0.0, A02=0.0;
00074         double A10=0.0, A11=0.0, A12=0.0;
00075         double A20=0.0, A21=0.0, A22=0.0;
00076         double b0 =0.0, b1 =0.0, b2 =0.0;
00077
00078         // generating A'A and A'b
00079         int count = points.size();
00080         for (int i = 0; i < count; i++)
00081         {
00082                 point_t &t = points[i];
00083                 double x0 = 2.0f * t.x;
00084                 double y0 = 2.0f * t.y;
00085                 double b = (double)(t.x * t.x + t.y * t.y);
00086                 A00 += x0 * x0;
00087                 A01 += x0 * y0;
00088                 A02 += x0;
00089                 A10 += y0 * x0;
00090                 A11 += y0 * y0;
00091                 A12 += y0;
00092                 A20 += x0;
00093                 A21 += y0;
00094                 A22 += 1.0;
00095                 b0  += x0 * b;
00096                 b1  += y0 * b;
00097                 b2  += b;
00098         }
00099
00100         // solve the resulting 3 by 3 equations
00101         double delta =          + A00 * A11 * A22 + A01 * A12 * A20 + A02 * A10 * A21
00102                                 - A00 * A12 * A21 - A01 * A10 * A22 - A02 * A11 * A20;
00103         center.x = (float)( (   + b0 * A11 * A22 + A01 * A12 * b2 + A02 * b1 * A21
00104                                 - b0 * A12 * A21 - A01 * b1 * A22 - A02 * A11 * b2 ) / delta);
00105         center.y = (float)( (   + A00 * b1 * A22 + b0 * A12 * A20 + A02 * A10 * b2
00106                                 - A00 * A12 * b2 - b0 * A10 * A22 - A02 * b1 * A20 ) / delta);
00107         radius = (float)sqrt( ( + A00 * A11 * b2 + A01 * b1 * A20 + b0 * A10 * A21
00108                                 - A00 * b1 * A21 - A01 * A10 * b2 - b0 * A11 * A20 ) / delta
00109                                 + center.x * center.x + center.y * center.y);
00110         count = points.size();
00111 }
00112
00113
00114 void
00115 Circle::setMargin( unsigned int margin )
00116 {
00117   this->margin = margin;
00118 }
00119
00120
00121 bool
00122 Circle::isClose( unsigned int in_roi_x, unsigned int in_roi_y )
00123 {
00124   float dx = in_roi_x - center.x;
00125   float dy = in_roi_y - center.y;
00126
00127   float dist = sqrt( dx * dx + dy * dy );
00128
00129   return ( (dist <= (radius + margin)) &&
00130            (dist >= (radius - margin)) );
00131
00132 }