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41 #include "_cv.h"
42 
43 #define CONV( A, B, C)  ( (float)( A +  (B<<1)  + C ) )
44 
45 typedef struct
46 {
47     float xx;
48     float xy;
49     float yy;
50     float xt;
51     float yt;
52     float alpha;                /* alpha = 1 / ( 1/lambda + xx + yy ) */
53 }
54 icvDerProductEx;
55 
56 /*F///////////////////////////////////////////////////////////////////////////////////////
57 //    Name: icvCalcOpticalFlowHS_8u32fR (Horn & Schunck method )
58 //    Purpose: calculate Optical flow for 2 images using Horn & Schunck algorithm
59 //    Context:
60 //    Parameters:
61 //            imgA          -  pointer to first frame ROI
62 //            imgB          -  pointer to second frame ROI
63 //            imgStep       -  width of single row of source images in bytes
64 //            imgSize       -  size of the source image ROI
65 //            usePrevious   - use previous (input) velocity field.
66 //            velocityX     - pointer to horizontal and
67 //            velocityY     - vertical components of optical flow ROI
68 //            velStep       - width of single row of velocity frames in bytes
69 //            lambda        - Lagrangian multiplier
70 //            criteria      - criteria of termination processmaximum number of iterations
71 //
72 //    Returns: CV_OK         - all ok
73 //             CV_OUTOFMEM_ERR  - insufficient memory for function work
74 //             CV_NULLPTR_ERR - if one of input pointers is NULL
75 //             CV_BADSIZE_ERR   - wrong input sizes interrelation
76 //
77 //    Notes:  1.Optical flow to be computed for every pixel in ROI
78 //            2.For calculating spatial derivatives we use 3x3 Sobel operator.
79 //            3.We use the following border mode.
80 //              The last row or column is replicated for the border
81 //              ( IPL_BORDER_REPLICATE in IPL ).
82 //
83 //
84 //F*/
85 static CvStatus CV_STDCALL
icvCalcOpticalFlowHS_8u32fR(uchar * imgA,uchar * imgB,int imgStep,CvSize imgSize,int usePrevious,float * velocityX,float * velocityY,int velStep,float lambda,CvTermCriteria criteria)86 icvCalcOpticalFlowHS_8u32fR( uchar*  imgA,
87                              uchar*  imgB,
88                              int     imgStep,
89                              CvSize imgSize,
90                              int     usePrevious,
91                              float*  velocityX,
92                              float*  velocityY,
93                              int     velStep,
94                              float   lambda,
95                              CvTermCriteria criteria )
96 {
97     /* Loops indexes */
98     int i, j, k, address;
99 
100     /* Buffers for Sobel calculations */
101     float *MemX[2];
102     float *MemY[2];
103 
104     float ConvX, ConvY;
105     float GradX, GradY, GradT;
106 
107     int imageWidth = imgSize.width;
108     int imageHeight = imgSize.height;
109 
110     int ConvLine;
111     int LastLine;
112 
113     int BufferSize;
114 
115     float Ilambda = 1 / lambda;
116     int iter = 0;
117     int Stop;
118 
119     /* buffers derivatives product */
120     icvDerProductEx *II;
121 
122     float *VelBufX[2];
123     float *VelBufY[2];
124 
125     /* variables for storing number of first pixel of image line */
126     int Line1;
127     int Line2;
128     int Line3;
129 
130     int pixNumber;
131 
132     /* auxiliary */
133     int NoMem = 0;
134 
135     /* Checking bad arguments */
136     if( imgA == NULL )
137         return CV_NULLPTR_ERR;
138     if( imgB == NULL )
139         return CV_NULLPTR_ERR;
140 
141     if( imgSize.width <= 0 )
142         return CV_BADSIZE_ERR;
143     if( imgSize.height <= 0 )
144         return CV_BADSIZE_ERR;
145     if( imgSize.width > imgStep )
146         return CV_BADSIZE_ERR;
147 
148     if( (velStep & 3) != 0 )
149         return CV_BADSIZE_ERR;
150 
151     velStep /= 4;
152 
153     /****************************************************************************************/
154     /* Allocating memory for all buffers                                                    */
155     /****************************************************************************************/
156     for( k = 0; k < 2; k++ )
157     {
158         MemX[k] = (float *) cvAlloc( (imgSize.height) * sizeof( float ));
159 
160         if( MemX[k] == NULL )
161             NoMem = 1;
162         MemY[k] = (float *) cvAlloc( (imgSize.width) * sizeof( float ));
163 
164         if( MemY[k] == NULL )
165             NoMem = 1;
166 
167         VelBufX[k] = (float *) cvAlloc( imageWidth * sizeof( float ));
168 
169         if( VelBufX[k] == NULL )
170             NoMem = 1;
171         VelBufY[k] = (float *) cvAlloc( imageWidth * sizeof( float ));
172 
173         if( VelBufY[k] == NULL )
174             NoMem = 1;
175     }
176 
177     BufferSize = imageHeight * imageWidth;
178 
179     II = (icvDerProductEx *) cvAlloc( BufferSize * sizeof( icvDerProductEx ));
180     if( (II == NULL) )
181         NoMem = 1;
182 
183     if( NoMem )
184     {
185         for( k = 0; k < 2; k++ )
186         {
187             if( MemX[k] )
188                 cvFree( &MemX[k] );
189 
190             if( MemY[k] )
191                 cvFree( &MemY[k] );
192 
193             if( VelBufX[k] )
194                 cvFree( &VelBufX[k] );
195 
196             if( VelBufY[k] )
197                 cvFree( &VelBufY[k] );
198         }
199         if( II )
200             cvFree( &II );
201         return CV_OUTOFMEM_ERR;
202     }
203 /****************************************************************************************\
204 *         Calculate first line of memX and memY                                          *
205 \****************************************************************************************/
206     MemY[0][0] = MemY[1][0] = CONV( imgA[0], imgA[0], imgA[1] );
207     MemX[0][0] = MemX[1][0] = CONV( imgA[0], imgA[0], imgA[imgStep] );
208 
209     for( j = 1; j < imageWidth - 1; j++ )
210     {
211         MemY[0][j] = MemY[1][j] = CONV( imgA[j - 1], imgA[j], imgA[j + 1] );
212     }
213 
214     pixNumber = imgStep;
215     for( i = 1; i < imageHeight - 1; i++ )
216     {
217         MemX[0][i] = MemX[1][i] = CONV( imgA[pixNumber - imgStep],
218                                         imgA[pixNumber], imgA[pixNumber + imgStep] );
219         pixNumber += imgStep;
220     }
221 
222     MemY[0][imageWidth - 1] =
223         MemY[1][imageWidth - 1] = CONV( imgA[imageWidth - 2],
224                                         imgA[imageWidth - 1], imgA[imageWidth - 1] );
225 
226     MemX[0][imageHeight - 1] =
227         MemX[1][imageHeight - 1] = CONV( imgA[pixNumber - imgStep],
228                                          imgA[pixNumber], imgA[pixNumber] );
229 
230 
231 /****************************************************************************************\
232 *     begin scan image, calc derivatives                                                 *
233 \****************************************************************************************/
234 
235     ConvLine = 0;
236     Line2 = -imgStep;
237     address = 0;
238     LastLine = imgStep * (imageHeight - 1);
239     while( ConvLine < imageHeight )
240     {
241         /*Here we calculate derivatives for line of image */
242         int memYline = (ConvLine + 1) & 1;
243 
244         Line2 += imgStep;
245         Line1 = Line2 - ((Line2 == 0) ? 0 : imgStep);
246         Line3 = Line2 + ((Line2 == LastLine) ? 0 : imgStep);
247 
248         /* Process first pixel */
249         ConvX = CONV( imgA[Line1 + 1], imgA[Line2 + 1], imgA[Line3 + 1] );
250         ConvY = CONV( imgA[Line3], imgA[Line3], imgA[Line3 + 1] );
251 
252         GradY = (ConvY - MemY[memYline][0]) * 0.125f;
253         GradX = (ConvX - MemX[1][ConvLine]) * 0.125f;
254 
255         MemY[memYline][0] = ConvY;
256         MemX[1][ConvLine] = ConvX;
257 
258         GradT = (float) (imgB[Line2] - imgA[Line2]);
259 
260         II[address].xx = GradX * GradX;
261         II[address].xy = GradX * GradY;
262         II[address].yy = GradY * GradY;
263         II[address].xt = GradX * GradT;
264         II[address].yt = GradY * GradT;
265 
266         II[address].alpha = 1 / (Ilambda + II[address].xx + II[address].yy);
267         address++;
268 
269         /* Process middle of line */
270         for( j = 1; j < imageWidth - 1; j++ )
271         {
272             ConvX = CONV( imgA[Line1 + j + 1], imgA[Line2 + j + 1], imgA[Line3 + j + 1] );
273             ConvY = CONV( imgA[Line3 + j - 1], imgA[Line3 + j], imgA[Line3 + j + 1] );
274 
275             GradY = (ConvY - MemY[memYline][j]) * 0.125f;
276             GradX = (ConvX - MemX[(j - 1) & 1][ConvLine]) * 0.125f;
277 
278             MemY[memYline][j] = ConvY;
279             MemX[(j - 1) & 1][ConvLine] = ConvX;
280 
281             GradT = (float) (imgB[Line2 + j] - imgA[Line2 + j]);
282 
283             II[address].xx = GradX * GradX;
284             II[address].xy = GradX * GradY;
285             II[address].yy = GradY * GradY;
286             II[address].xt = GradX * GradT;
287             II[address].yt = GradY * GradT;
288 
289             II[address].alpha = 1 / (Ilambda + II[address].xx + II[address].yy);
290             address++;
291         }
292         /* Process last pixel of line */
293         ConvX = CONV( imgA[Line1 + imageWidth - 1], imgA[Line2 + imageWidth - 1],
294                       imgA[Line3 + imageWidth - 1] );
295 
296         ConvY = CONV( imgA[Line3 + imageWidth - 2], imgA[Line3 + imageWidth - 1],
297                       imgA[Line3 + imageWidth - 1] );
298 
299 
300         GradY = (ConvY - MemY[memYline][imageWidth - 1]) * 0.125f;
301         GradX = (ConvX - MemX[(imageWidth - 2) & 1][ConvLine]) * 0.125f;
302 
303         MemY[memYline][imageWidth - 1] = ConvY;
304 
305         GradT = (float) (imgB[Line2 + imageWidth - 1] - imgA[Line2 + imageWidth - 1]);
306 
307         II[address].xx = GradX * GradX;
308         II[address].xy = GradX * GradY;
309         II[address].yy = GradY * GradY;
310         II[address].xt = GradX * GradT;
311         II[address].yt = GradY * GradT;
312 
313         II[address].alpha = 1 / (Ilambda + II[address].xx + II[address].yy);
314         address++;
315 
316         ConvLine++;
317     }
318 /****************************************************************************************\
319 *      Prepare initial approximation                                                     *
320 \****************************************************************************************/
321     if( !usePrevious )
322     {
323         float *vx = velocityX;
324         float *vy = velocityY;
325 
326         for( i = 0; i < imageHeight; i++ )
327         {
328             memset( vx, 0, imageWidth * sizeof( float ));
329             memset( vy, 0, imageWidth * sizeof( float ));
330 
331             vx += velStep;
332             vy += velStep;
333         }
334     }
335 /****************************************************************************************\
336 *      Perform iterations                                                                *
337 \****************************************************************************************/
338     iter = 0;
339     Stop = 0;
340     LastLine = velStep * (imageHeight - 1);
341     while( !Stop )
342     {
343         float Eps = 0;
344         address = 0;
345 
346         iter++;
347 /****************************************************************************************\
348 *     begin scan velocity and update it                                                  *
349 \****************************************************************************************/
350         Line2 = -velStep;
351         for( i = 0; i < imageHeight; i++ )
352         {
353             /* Here average velocity */
354 
355             float averageX;
356             float averageY;
357             float tmp;
358 
359             Line2 += velStep;
360             Line1 = Line2 - ((Line2 == 0) ? 0 : velStep);
361             Line3 = Line2 + ((Line2 == LastLine) ? 0 : velStep);
362             /* Process first pixel */
363             averageX = (velocityX[Line2] +
364                         velocityX[Line2 + 1] + velocityX[Line1] + velocityX[Line3]) / 4;
365 
366             averageY = (velocityY[Line2] +
367                         velocityY[Line2 + 1] + velocityY[Line1] + velocityY[Line3]) / 4;
368 
369             VelBufX[i & 1][0] = averageX -
370                 (II[address].xx * averageX +
371                  II[address].xy * averageY + II[address].xt) * II[address].alpha;
372 
373             VelBufY[i & 1][0] = averageY -
374                 (II[address].xy * averageX +
375                  II[address].yy * averageY + II[address].yt) * II[address].alpha;
376 
377             /* update Epsilon */
378             if( criteria.type & CV_TERMCRIT_EPS )
379             {
380                 tmp = (float)fabs(velocityX[Line2] - VelBufX[i & 1][0]);
381                 Eps = MAX( tmp, Eps );
382                 tmp = (float)fabs(velocityY[Line2] - VelBufY[i & 1][0]);
383                 Eps = MAX( tmp, Eps );
384             }
385             address++;
386             /* Process middle of line */
387             for( j = 1; j < imageWidth - 1; j++ )
388             {
389                 averageX = (velocityX[Line2 + j - 1] +
390                             velocityX[Line2 + j + 1] +
391                             velocityX[Line1 + j] + velocityX[Line3 + j]) / 4;
392                 averageY = (velocityY[Line2 + j - 1] +
393                             velocityY[Line2 + j + 1] +
394                             velocityY[Line1 + j] + velocityY[Line3 + j]) / 4;
395 
396                 VelBufX[i & 1][j] = averageX -
397                     (II[address].xx * averageX +
398                      II[address].xy * averageY + II[address].xt) * II[address].alpha;
399 
400                 VelBufY[i & 1][j] = averageY -
401                     (II[address].xy * averageX +
402                      II[address].yy * averageY + II[address].yt) * II[address].alpha;
403                 /* update Epsilon */
404                 if( criteria.type & CV_TERMCRIT_EPS )
405                 {
406                     tmp = (float)fabs(velocityX[Line2 + j] - VelBufX[i & 1][j]);
407                     Eps = MAX( tmp, Eps );
408                     tmp = (float)fabs(velocityY[Line2 + j] - VelBufY[i & 1][j]);
409                     Eps = MAX( tmp, Eps );
410                 }
411                 address++;
412             }
413             /* Process last pixel of line */
414             averageX = (velocityX[Line2 + imageWidth - 2] +
415                         velocityX[Line2 + imageWidth - 1] +
416                         velocityX[Line1 + imageWidth - 1] +
417                         velocityX[Line3 + imageWidth - 1]) / 4;
418 
419             averageY = (velocityY[Line2 + imageWidth - 2] +
420                         velocityY[Line2 + imageWidth - 1] +
421                         velocityY[Line1 + imageWidth - 1] +
422                         velocityY[Line3 + imageWidth - 1]) / 4;
423 
424 
425             VelBufX[i & 1][imageWidth - 1] = averageX -
426                 (II[address].xx * averageX +
427                  II[address].xy * averageY + II[address].xt) * II[address].alpha;
428 
429             VelBufY[i & 1][imageWidth - 1] = averageY -
430                 (II[address].xy * averageX +
431                  II[address].yy * averageY + II[address].yt) * II[address].alpha;
432 
433             /* update Epsilon */
434             if( criteria.type & CV_TERMCRIT_EPS )
435             {
436                 tmp = (float)fabs(velocityX[Line2 + imageWidth - 1] -
437                                   VelBufX[i & 1][imageWidth - 1]);
438                 Eps = MAX( tmp, Eps );
439                 tmp = (float)fabs(velocityY[Line2 + imageWidth - 1] -
440                                   VelBufY[i & 1][imageWidth - 1]);
441                 Eps = MAX( tmp, Eps );
442             }
443             address++;
444 
445             /* store new velocity from old buffer to velocity frame */
446             if( i > 0 )
447             {
448                 memcpy( &velocityX[Line1], VelBufX[(i - 1) & 1], imageWidth * sizeof( float ));
449                 memcpy( &velocityY[Line1], VelBufY[(i - 1) & 1], imageWidth * sizeof( float ));
450             }
451         }                       /*for */
452         /* store new velocity from old buffer to velocity frame */
453         memcpy( &velocityX[imageWidth * (imageHeight - 1)],
454                 VelBufX[(imageHeight - 1) & 1], imageWidth * sizeof( float ));
455 
456         memcpy( &velocityY[imageWidth * (imageHeight - 1)],
457                 VelBufY[(imageHeight - 1) & 1], imageWidth * sizeof( float ));
458 
459         if( (criteria.type & CV_TERMCRIT_ITER) && (iter == criteria.max_iter) )
460             Stop = 1;
461         if( (criteria.type & CV_TERMCRIT_EPS) && (Eps < criteria.epsilon) )
462             Stop = 1;
463     }
464     /* Free memory */
465     for( k = 0; k < 2; k++ )
466     {
467         cvFree( &MemX[k] );
468         cvFree( &MemY[k] );
469         cvFree( &VelBufX[k] );
470         cvFree( &VelBufY[k] );
471     }
472     cvFree( &II );
473 
474     return CV_OK;
475 } /*icvCalcOpticalFlowHS_8u32fR*/
476 
477 
478 /*F///////////////////////////////////////////////////////////////////////////////////////
479 //    Name:    cvCalcOpticalFlowHS
480 //    Purpose: Optical flow implementation
481 //    Context:
482 //    Parameters:
483 //             srcA, srcB - source image
484 //             velx, vely - destination image
485 //    Returns:
486 //
487 //    Notes:
488 //F*/
489 CV_IMPL void
cvCalcOpticalFlowHS(const void * srcarrA,const void * srcarrB,int usePrevious,void * velarrx,void * velarry,double lambda,CvTermCriteria criteria)490 cvCalcOpticalFlowHS( const void* srcarrA, const void* srcarrB, int usePrevious,
491                      void* velarrx, void* velarry,
492                      double lambda, CvTermCriteria criteria )
493 {
494     CV_FUNCNAME( "cvCalcOpticalFlowHS" );
495 
496     __BEGIN__;
497 
498     CvMat stubA, *srcA = (CvMat*)srcarrA;
499     CvMat stubB, *srcB = (CvMat*)srcarrB;
500     CvMat stubx, *velx = (CvMat*)velarrx;
501     CvMat stuby, *vely = (CvMat*)velarry;
502 
503     CV_CALL( srcA = cvGetMat( srcA, &stubA ));
504     CV_CALL( srcB = cvGetMat( srcB, &stubB ));
505 
506     CV_CALL( velx = cvGetMat( velx, &stubx ));
507     CV_CALL( vely = cvGetMat( vely, &stuby ));
508 
509     if( !CV_ARE_TYPES_EQ( srcA, srcB ))
510         CV_ERROR( CV_StsUnmatchedFormats, "Source images have different formats" );
511 
512     if( !CV_ARE_TYPES_EQ( velx, vely ))
513         CV_ERROR( CV_StsUnmatchedFormats, "Destination images have different formats" );
514 
515     if( !CV_ARE_SIZES_EQ( srcA, srcB ) ||
516         !CV_ARE_SIZES_EQ( velx, vely ) ||
517         !CV_ARE_SIZES_EQ( srcA, velx ))
518         CV_ERROR( CV_StsUnmatchedSizes, "" );
519 
520     if( CV_MAT_TYPE( srcA->type ) != CV_8UC1 ||
521         CV_MAT_TYPE( velx->type ) != CV_32FC1 )
522         CV_ERROR( CV_StsUnsupportedFormat, "Source images must have 8uC1 type and "
523                                            "destination images must have 32fC1 type" );
524 
525     if( srcA->step != srcB->step || velx->step != vely->step )
526         CV_ERROR( CV_BadStep, "source and destination images have different step" );
527 
528     IPPI_CALL( icvCalcOpticalFlowHS_8u32fR( (uchar*)srcA->data.ptr, (uchar*)srcB->data.ptr,
529                                             srcA->step, cvGetMatSize( srcA ), usePrevious,
530                                             velx->data.fl, vely->data.fl,
531                                             velx->step, (float)lambda, criteria ));
532     __END__;
533 }
534 
535 /* End of file. */
536