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41 #include "_cv.h"
42 
43 
44 /*F///////////////////////////////////////////////////////////////////////////////////////
45 //    Name:    cvMeanShift
46 //    Purpose: MeanShift algorithm
47 //    Context:
48 //    Parameters:
49 //      imgProb     - 2D object probability distribution
50 //      windowIn    - CvRect of CAMSHIFT Window intial size
51 //      numIters    - If CAMSHIFT iterates this many times, stop
52 //      windowOut   - Location, height and width of converged CAMSHIFT window
53 //      len         - If != NULL, return equivalent len
54 //      width       - If != NULL, return equivalent width
55 //      itersUsed   - Returns number of iterations CAMSHIFT took to converge
56 //    Returns:
57 //      The function itself returns the area found
58 //    Notes:
59 //F*/
60 CV_IMPL int
cvMeanShift(const void * imgProb,CvRect windowIn,CvTermCriteria criteria,CvConnectedComp * comp)61 cvMeanShift( const void* imgProb, CvRect windowIn,
62              CvTermCriteria criteria, CvConnectedComp* comp )
63 {
64     CvMoments moments;
65     int    i = 0, eps;
66     CvMat  stub, *mat = (CvMat*)imgProb;
67     CvMat  cur_win;
68     CvRect cur_rect = windowIn;
69 
70     CV_FUNCNAME( "cvMeanShift" );
71 
72     if( comp )
73         comp->rect = windowIn;
74 
75     moments.m00 = moments.m10 = moments.m01 = 0;
76 
77     __BEGIN__;
78 
79     CV_CALL( mat = cvGetMat( mat, &stub ));
80 
81     if( CV_MAT_CN( mat->type ) > 1 )
82         CV_ERROR( CV_BadNumChannels, cvUnsupportedFormat );
83 
84     if( windowIn.height <= 0 || windowIn.width <= 0 )
85         CV_ERROR( CV_StsBadArg, "Input window has non-positive sizes" );
86 
87     if( windowIn.x < 0 || windowIn.x + windowIn.width > mat->cols ||
88         windowIn.y < 0 || windowIn.y + windowIn.height > mat->rows )
89         CV_ERROR( CV_StsBadArg, "Initial window is not inside the image ROI" );
90 
91     CV_CALL( criteria = cvCheckTermCriteria( criteria, 1., 100 ));
92 
93     eps = cvRound( criteria.epsilon * criteria.epsilon );
94 
95     for( i = 0; i < criteria.max_iter; i++ )
96     {
97         int dx, dy, nx, ny;
98         double inv_m00;
99 
100         CV_CALL( cvGetSubRect( mat, &cur_win, cur_rect ));
101         CV_CALL( cvMoments( &cur_win, &moments ));
102 
103         /* Calculating center of mass */
104         if( fabs(moments.m00) < DBL_EPSILON )
105             break;
106 
107         inv_m00 = moments.inv_sqrt_m00*moments.inv_sqrt_m00;
108         dx = cvRound( moments.m10 * inv_m00 - windowIn.width*0.5 );
109         dy = cvRound( moments.m01 * inv_m00 - windowIn.height*0.5 );
110 
111         nx = cur_rect.x + dx;
112         ny = cur_rect.y + dy;
113 
114         if( nx < 0 )
115             nx = 0;
116         else if( nx + cur_rect.width > mat->cols )
117             nx = mat->cols - cur_rect.width;
118 
119         if( ny < 0 )
120             ny = 0;
121         else if( ny + cur_rect.height > mat->rows )
122             ny = mat->rows - cur_rect.height;
123 
124         dx = nx - cur_rect.x;
125         dy = ny - cur_rect.y;
126         cur_rect.x = nx;
127         cur_rect.y = ny;
128 
129         /* Check for coverage centers mass & window */
130         if( dx*dx + dy*dy < eps )
131             break;
132     }
133 
134     __END__;
135 
136     if( comp )
137     {
138         comp->rect = cur_rect;
139         comp->area = (float)moments.m00;
140     }
141 
142     return i;
143 }
144 
145 
146 /*F///////////////////////////////////////////////////////////////////////////////////////
147 //    Name:    cvCamShift
148 //    Purpose: CAMSHIFT algorithm
149 //    Context:
150 //    Parameters:
151 //      imgProb     - 2D object probability distribution
152 //      windowIn    - CvRect of CAMSHIFT Window intial size
153 //      criteria    - criteria of stop finding window
154 //      windowOut   - Location, height and width of converged CAMSHIFT window
155 //      orientation - If != NULL, return distribution orientation
156 //      len         - If != NULL, return equivalent len
157 //      width       - If != NULL, return equivalent width
158 //      area        - sum of all elements in result window
159 //      itersUsed   - Returns number of iterations CAMSHIFT took to converge
160 //    Returns:
161 //      The function itself returns the area found
162 //    Notes:
163 //F*/
164 CV_IMPL int
cvCamShift(const void * imgProb,CvRect windowIn,CvTermCriteria criteria,CvConnectedComp * _comp,CvBox2D * box)165 cvCamShift( const void* imgProb, CvRect windowIn,
166             CvTermCriteria criteria,
167             CvConnectedComp* _comp,
168             CvBox2D* box )
169 {
170     const int TOLERANCE = 10;
171     CvMoments moments;
172     double m00 = 0, m10, m01, mu20, mu11, mu02, inv_m00;
173     double a, b, c, xc, yc;
174     double rotate_a, rotate_c;
175     double theta = 0, square;
176     double cs, sn;
177     double length = 0, width = 0;
178     int itersUsed = 0;
179     CvConnectedComp comp;
180     CvMat  cur_win, stub, *mat = (CvMat*)imgProb;
181 
182     CV_FUNCNAME( "cvCamShift" );
183 
184     comp.rect = windowIn;
185 
186     __BEGIN__;
187 
188     CV_CALL( mat = cvGetMat( mat, &stub ));
189 
190     CV_CALL( itersUsed = cvMeanShift( mat, windowIn, criteria, &comp ));
191     windowIn = comp.rect;
192 
193     windowIn.x -= TOLERANCE;
194     if( windowIn.x < 0 )
195         windowIn.x = 0;
196 
197     windowIn.y -= TOLERANCE;
198     if( windowIn.y < 0 )
199         windowIn.y = 0;
200 
201     windowIn.width += 2 * TOLERANCE;
202     if( windowIn.x + windowIn.width > mat->width )
203         windowIn.width = mat->width - windowIn.x;
204 
205     windowIn.height += 2 * TOLERANCE;
206     if( windowIn.y + windowIn.height > mat->height )
207         windowIn.height = mat->height - windowIn.y;
208 
209     CV_CALL( cvGetSubRect( mat, &cur_win, windowIn ));
210 
211     /* Calculating moments in new center mass */
212     CV_CALL( cvMoments( &cur_win, &moments ));
213 
214     m00 = moments.m00;
215     m10 = moments.m10;
216     m01 = moments.m01;
217     mu11 = moments.mu11;
218     mu20 = moments.mu20;
219     mu02 = moments.mu02;
220 
221     if( fabs(m00) < DBL_EPSILON )
222         EXIT;
223 
224     inv_m00 = 1. / m00;
225     xc = cvRound( m10 * inv_m00 + windowIn.x );
226     yc = cvRound( m01 * inv_m00 + windowIn.y );
227     a = mu20 * inv_m00;
228     b = mu11 * inv_m00;
229     c = mu02 * inv_m00;
230 
231     /* Calculating width & height */
232     square = sqrt( 4 * b * b + (a - c) * (a - c) );
233 
234     /* Calculating orientation */
235     theta = atan2( 2 * b, a - c + square );
236 
237     /* Calculating width & length of figure */
238     cs = cos( theta );
239     sn = sin( theta );
240 
241     rotate_a = cs * cs * mu20 + 2 * cs * sn * mu11 + sn * sn * mu02;
242     rotate_c = sn * sn * mu20 - 2 * cs * sn * mu11 + cs * cs * mu02;
243     length = sqrt( rotate_a * inv_m00 ) * 4;
244     width = sqrt( rotate_c * inv_m00 ) * 4;
245 
246     /* In case, when tetta is 0 or 1.57... the Length & Width may be exchanged */
247     if( length < width )
248     {
249         double t;
250 
251         CV_SWAP( length, width, t );
252         CV_SWAP( cs, sn, t );
253         theta = CV_PI*0.5 - theta;
254     }
255 
256     /* Saving results */
257     if( _comp || box )
258     {
259         int t0, t1;
260         int _xc = cvRound( xc );
261         int _yc = cvRound( yc );
262 
263         t0 = cvRound( fabs( length * cs ));
264         t1 = cvRound( fabs( width * sn ));
265 
266         t0 = MAX( t0, t1 ) + 2;
267         comp.rect.width = MIN( t0, (mat->width - _xc) * 2 );
268 
269         t0 = cvRound( fabs( length * sn ));
270         t1 = cvRound( fabs( width * cs ));
271 
272         t0 = MAX( t0, t1 ) + 2;
273         comp.rect.height = MIN( t0, (mat->height - _yc) * 2 );
274 
275         comp.rect.x = MAX( 0, _xc - comp.rect.width / 2 );
276         comp.rect.y = MAX( 0, _yc - comp.rect.height / 2 );
277 
278         comp.rect.width = MIN( mat->width - comp.rect.x, comp.rect.width );
279         comp.rect.height = MIN( mat->height - comp.rect.y, comp.rect.height );
280         comp.area = (float) m00;
281     }
282 
283     __END__;
284 
285     if( _comp )
286         *_comp = comp;
287 
288     if( box )
289     {
290         box->size.height = (float)length;
291         box->size.width = (float)width;
292         box->angle = (float)(theta*180./CV_PI);
293         box->center = cvPoint2D32f( comp.rect.x + comp.rect.width*0.5f,
294                                     comp.rect.y + comp.rect.height*0.5f);
295     }
296 
297     return itersUsed;
298 }
299 
300 /* End of file. */
301