1/*M///////////////////////////////////////////////////////////////////////////////////////
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11//                For Open Source Computer Vision Library
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40//M*/
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*/
60CV_IMPL int
61cvMeanShift( 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*/
164CV_IMPL int
165cvCamShift( 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