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1 /*!
2  * \copy
3  *     Copyright (c)  2013, Cisco Systems
4  *     All rights reserved.
5  *
6  *     Redistribution and use in source and binary forms, with or without
7  *     modification, are permitted provided that the following conditions
8  *     are met:
9  *
10  *        * Redistributions of source code must retain the above copyright
11  *          notice, this list of conditions and the following disclaimer.
12  *
13  *        * Redistributions in binary form must reproduce the above copyright
14  *          notice, this list of conditions and the following disclaimer in
15  *          the documentation and/or other materials provided with the
16  *          distribution.
17  *
18  *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19  *     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20  *     LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21  *     FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
22  *     COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23  *     INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
24  *     BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25  *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
26  *     CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  *     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
28  *     ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  *     POSSIBILITY OF SUCH DAMAGE.
30  *
31  */
32 
33 #include "BackgroundDetection.h"
34 
35 WELSVP_NAMESPACE_BEGIN
36 
37 #define LOG2_BGD_OU_SIZE    (4)
38 #define LOG2_BGD_OU_SIZE_UV (LOG2_BGD_OU_SIZE-1)
39 #define BGD_OU_SIZE         (1<<LOG2_BGD_OU_SIZE)
40 #define BGD_OU_SIZE_UV      (BGD_OU_SIZE>>1)
41 #define BGD_THD_SAD         (2*BGD_OU_SIZE*BGD_OU_SIZE)
42 #define BGD_THD_ASD_UV      (4*BGD_OU_SIZE_UV)
43 #define LOG2_MB_SIZE        (4)
44 #define OU_SIZE_IN_MB       (BGD_OU_SIZE >> 4)
45 #define Q_FACTOR            (8)
46 #define BGD_DELTA_QP_THD    (3)
47 
48 #define OU_LEFT         (0x01)
49 #define OU_RIGHT        (0x02)
50 #define OU_TOP          (0x04)
51 #define OU_BOTTOM       (0x08)
52 
CBackgroundDetection(int32_t iCpuFlag)53 CBackgroundDetection::CBackgroundDetection (int32_t iCpuFlag) {
54   m_eMethod = METHOD_BACKGROUND_DETECTION;
55   WelsMemset (&m_BgdParam, 0, sizeof (m_BgdParam));
56   m_iLargestFrameSize = 0;
57 }
58 
~CBackgroundDetection()59 CBackgroundDetection::~CBackgroundDetection() {
60   WelsFree (m_BgdParam.pOU_array);
61 }
62 
Process(int32_t iType,SPixMap * pSrcPixMap,SPixMap * pRefPixMap)63 EResult CBackgroundDetection::Process (int32_t iType, SPixMap* pSrcPixMap, SPixMap* pRefPixMap) {
64   EResult eReturn = RET_INVALIDPARAM;
65 
66   if (pSrcPixMap == NULL || pRefPixMap == NULL)
67     return eReturn;
68 
69   m_BgdParam.pCur[0] = (uint8_t*)pSrcPixMap->pPixel[0];
70   m_BgdParam.pCur[1] = (uint8_t*)pSrcPixMap->pPixel[1];
71   m_BgdParam.pCur[2] = (uint8_t*)pSrcPixMap->pPixel[2];
72   m_BgdParam.pRef[0] = (uint8_t*)pRefPixMap->pPixel[0];
73   m_BgdParam.pRef[1] = (uint8_t*)pRefPixMap->pPixel[1];
74   m_BgdParam.pRef[2] = (uint8_t*)pRefPixMap->pPixel[2];
75   m_BgdParam.iBgdWidth = pSrcPixMap->sRect.iRectWidth;
76   m_BgdParam.iBgdHeight = pSrcPixMap->sRect.iRectHeight;
77   m_BgdParam.iStride[0] = pSrcPixMap->iStride[0];
78   m_BgdParam.iStride[1] = pSrcPixMap->iStride[1];
79   m_BgdParam.iStride[2] = pSrcPixMap->iStride[2];
80 
81   int32_t iCurFrameSize = m_BgdParam.iBgdWidth * m_BgdParam.iBgdHeight;
82   if (m_BgdParam.pOU_array == NULL || iCurFrameSize > m_iLargestFrameSize) {
83     WelsFree (m_BgdParam.pOU_array);
84     m_BgdParam.pOU_array = AllocateOUArrayMemory (m_BgdParam.iBgdWidth, m_BgdParam.iBgdHeight);
85     m_iLargestFrameSize = iCurFrameSize;
86   }
87 
88   if (m_BgdParam.pOU_array == NULL)
89     return eReturn;
90 
91   BackgroundDetection (&m_BgdParam);
92 
93   return RET_SUCCESS;
94 }
95 
Set(int32_t iType,void * pParam)96 EResult CBackgroundDetection::Set (int32_t iType, void* pParam) {
97   if (pParam == NULL) {
98     return RET_INVALIDPARAM;
99   }
100 
101   SBGDInterface* pInterface = (SBGDInterface*)pParam;
102 
103   m_BgdParam.pBackgroundMbFlag = (int8_t*)pInterface->pBackgroundMbFlag;
104   m_BgdParam.pCalcRes = pInterface->pCalcRes;
105 
106   return RET_SUCCESS;
107 }
108 
AllocateOUArrayMemory(int32_t iWidth,int32_t iHeight)109 inline SBackgroundOU* CBackgroundDetection::AllocateOUArrayMemory (int32_t iWidth, int32_t iHeight) {
110   int32_t       iMaxOUWidth     = (BGD_OU_SIZE - 1 + iWidth) >> LOG2_BGD_OU_SIZE;
111   int32_t       iMaxOUHeight    = (BGD_OU_SIZE - 1 + iHeight) >> LOG2_BGD_OU_SIZE;
112   return (SBackgroundOU*)WelsMalloc (iMaxOUWidth * iMaxOUHeight * sizeof (SBackgroundOU));
113 }
114 
GetOUParameters(SVAACalcResult * sVaaCalcInfo,int32_t iMbIndex,int32_t iMbWidth,SBackgroundOU * pBgdOU)115 void CBackgroundDetection::GetOUParameters (SVAACalcResult* sVaaCalcInfo, int32_t iMbIndex, int32_t iMbWidth,
116     SBackgroundOU* pBgdOU) {
117   int32_t       iSubSD[4];
118   uint8_t       iSubMAD[4];
119   int32_t       iSubSAD[4];
120 
121   uint8_t (*pMad8x8)[4];
122   int32_t (*pSad8x8)[4];
123   int32_t (*pSd8x8)[4];
124 
125   pSad8x8 = sVaaCalcInfo->pSad8x8;
126   pMad8x8 = sVaaCalcInfo->pMad8x8;
127   pSd8x8  = sVaaCalcInfo->pSumOfDiff8x8;
128 
129   iSubSAD[0] = pSad8x8[iMbIndex][0];
130   iSubSAD[1] = pSad8x8[iMbIndex][1];
131   iSubSAD[2] = pSad8x8[iMbIndex][2];
132   iSubSAD[3] = pSad8x8[iMbIndex][3];
133 
134   iSubSD[0] = pSd8x8[iMbIndex][0];
135   iSubSD[1] = pSd8x8[iMbIndex][1];
136   iSubSD[2] = pSd8x8[iMbIndex][2];
137   iSubSD[3] = pSd8x8[iMbIndex][3];
138 
139   iSubMAD[0] = pMad8x8[iMbIndex][0];
140   iSubMAD[1] = pMad8x8[iMbIndex][1];
141   iSubMAD[2] = pMad8x8[iMbIndex][2];
142   iSubMAD[3] = pMad8x8[iMbIndex][3];
143 
144   pBgdOU->iSD   = iSubSD[0] + iSubSD[1] + iSubSD[2] + iSubSD[3];
145   pBgdOU->iSAD  = iSubSAD[0] + iSubSAD[1] + iSubSAD[2] + iSubSAD[3];
146   pBgdOU->iSD   = WELS_ABS (pBgdOU->iSD);
147 
148   // get the max absolute difference (MAD) of OU and min value of the MAD of sub-blocks of OU
149   pBgdOU->iMAD = WELS_MAX (WELS_MAX (iSubMAD[0], iSubMAD[1]), WELS_MAX (iSubMAD[2], iSubMAD[3]));
150   pBgdOU->iMinSubMad = WELS_MIN (WELS_MIN (iSubMAD[0], iSubMAD[1]), WELS_MIN (iSubMAD[2], iSubMAD[3]));
151 
152   // get difference between the max and min SD of the SDs of sub-blocks of OU
153   pBgdOU->iMaxDiffSubSd = WELS_MAX (WELS_MAX (iSubSD[0], iSubSD[1]), WELS_MAX (iSubSD[2], iSubSD[3])) -
154                           WELS_MIN (WELS_MIN (iSubSD[0], iSubSD[1]), WELS_MIN (iSubSD[2], iSubSD[3]));
155 }
156 
ForegroundBackgroundDivision(vBGDParam * pBgdParam)157 void CBackgroundDetection::ForegroundBackgroundDivision (vBGDParam* pBgdParam) {
158   int32_t iPicWidthInOU         = pBgdParam->iBgdWidth  >> LOG2_BGD_OU_SIZE;
159   int32_t iPicHeightInOU        = pBgdParam->iBgdHeight >> LOG2_BGD_OU_SIZE;
160   int32_t iPicWidthInMb         = (15 + pBgdParam->iBgdWidth) >> 4;
161 
162   SBackgroundOU* pBackgroundOU = pBgdParam->pOU_array;
163 
164   for (int32_t j = 0; j < iPicHeightInOU; j ++) {
165     for (int32_t i = 0; i < iPicWidthInOU; i++) {
166       GetOUParameters (pBgdParam->pCalcRes, (j * iPicWidthInMb + i) << (LOG2_BGD_OU_SIZE - LOG2_MB_SIZE), iPicWidthInMb,
167                        pBackgroundOU);
168 
169       pBackgroundOU->iBackgroundFlag = 0;
170       if (pBackgroundOU->iMAD > 63) {
171         pBackgroundOU++;
172         continue;
173       }
174       if ((pBackgroundOU->iMaxDiffSubSd <= pBackgroundOU->iSAD >> 3
175            || pBackgroundOU->iMaxDiffSubSd <= (BGD_OU_SIZE * Q_FACTOR))
176           && pBackgroundOU->iSAD < (BGD_THD_SAD << 1)) { //BGD_OU_SIZE*BGD_OU_SIZE>>2
177         if (pBackgroundOU->iSAD <= BGD_OU_SIZE * Q_FACTOR) {
178           pBackgroundOU->iBackgroundFlag = 1;
179         } else {
180           pBackgroundOU->iBackgroundFlag = pBackgroundOU->iSAD < BGD_THD_SAD ?
181                                            (pBackgroundOU->iSD < (pBackgroundOU->iSAD * 3) >> 2) :
182                                            (pBackgroundOU->iSD << 1 < pBackgroundOU->iSAD);
183         }
184       }
185       pBackgroundOU++;
186     }
187   }
188 }
CalculateAsdChromaEdge(uint8_t * pOriRef,uint8_t * pOriCur,int32_t iStride)189 inline int32_t CBackgroundDetection::CalculateAsdChromaEdge (uint8_t* pOriRef, uint8_t* pOriCur, int32_t iStride) {
190   int32_t ASD = 0;
191   int32_t idx;
192   for (idx = 0; idx < BGD_OU_SIZE_UV; idx++) {
193     ASD += *pOriCur - *pOriRef;
194     pOriRef += iStride;
195     pOriCur += iStride;
196   }
197   return WELS_ABS (ASD);
198 }
199 
ForegroundDilation23Luma(SBackgroundOU * pBackgroundOU,SBackgroundOU * pOUNeighbours[])200 inline bool CBackgroundDetection::ForegroundDilation23Luma (SBackgroundOU* pBackgroundOU,
201     SBackgroundOU* pOUNeighbours[]) {
202   SBackgroundOU* pOU_L = pOUNeighbours[0];
203   SBackgroundOU* pOU_R = pOUNeighbours[1];
204   SBackgroundOU* pOU_U = pOUNeighbours[2];
205   SBackgroundOU* pOU_D = pOUNeighbours[3];
206 
207   if (pBackgroundOU->iMAD > pBackgroundOU->iMinSubMad << 1) {
208     int32_t iMaxNbrForegroundMad;
209     int32_t iMaxNbrBackgroundMad;
210     int32_t aBackgroundMad[4];
211     int32_t aForegroundMad[4];
212 
213     aForegroundMad[0] = (pOU_L->iBackgroundFlag - 1) & pOU_L->iMAD;
214     aForegroundMad[1] = (pOU_R->iBackgroundFlag - 1) & pOU_R->iMAD;
215     aForegroundMad[2] = (pOU_U->iBackgroundFlag - 1) & pOU_U->iMAD;
216     aForegroundMad[3] = (pOU_D->iBackgroundFlag - 1) & pOU_D->iMAD;
217     iMaxNbrForegroundMad = WELS_MAX (WELS_MAX (aForegroundMad[0], aForegroundMad[1]), WELS_MAX (aForegroundMad[2],
218                                      aForegroundMad[3]));
219 
220     aBackgroundMad[0] = ((!pOU_L->iBackgroundFlag) - 1) & pOU_L->iMAD;
221     aBackgroundMad[1] = ((!pOU_R->iBackgroundFlag) - 1) & pOU_R->iMAD;
222     aBackgroundMad[2] = ((!pOU_U->iBackgroundFlag) - 1) & pOU_U->iMAD;
223     aBackgroundMad[3] = ((!pOU_D->iBackgroundFlag) - 1) & pOU_D->iMAD;
224     iMaxNbrBackgroundMad = WELS_MAX (WELS_MAX (aBackgroundMad[0], aBackgroundMad[1]), WELS_MAX (aBackgroundMad[2],
225                                      aBackgroundMad[3]));
226 
227     return ((iMaxNbrForegroundMad > pBackgroundOU->iMinSubMad << 2) || (pBackgroundOU->iMAD > iMaxNbrBackgroundMad << 1
228             && pBackgroundOU->iMAD <= (iMaxNbrForegroundMad * 3) >> 1));
229   }
230   return 0;
231 }
232 
ForegroundDilation23Chroma(int8_t iNeighbourForegroundFlags,int32_t iStartSamplePos,int32_t iPicStrideUV,vBGDParam * pBgdParam)233 inline bool CBackgroundDetection::ForegroundDilation23Chroma (int8_t iNeighbourForegroundFlags,
234     int32_t iStartSamplePos, int32_t iPicStrideUV, vBGDParam* pBgdParam) {
235   static const int8_t kaOUPos[4]        = {OU_LEFT, OU_RIGHT, OU_TOP, OU_BOTTOM};
236   int32_t       aEdgeOffset[4]          = {0, BGD_OU_SIZE_UV - 1, 0, iPicStrideUV* (BGD_OU_SIZE_UV - 1)};
237   int32_t       iStride[4]              = {iPicStrideUV, iPicStrideUV, 1, 1};
238 
239   // V component first, high probability because V stands for red color and human skin colors have more weight on this component
240   for (int32_t i = 0; i < 4; i++) {
241     if (iNeighbourForegroundFlags & kaOUPos[i]) {
242       uint8_t* pRefC = pBgdParam->pRef[2] + iStartSamplePos + aEdgeOffset[i];
243       uint8_t* pCurC = pBgdParam->pCur[2] + iStartSamplePos + aEdgeOffset[i];
244       if (CalculateAsdChromaEdge (pRefC, pCurC, iStride[i]) > BGD_THD_ASD_UV) {
245         return 1;
246       }
247     }
248   }
249   // U component, which stands for blue color, low probability
250   for (int32_t i = 0; i < 4; i++) {
251     if (iNeighbourForegroundFlags & kaOUPos[i]) {
252       uint8_t* pRefC = pBgdParam->pRef[1] + iStartSamplePos + aEdgeOffset[i];
253       uint8_t* pCurC = pBgdParam->pCur[1] + iStartSamplePos + aEdgeOffset[i];
254       if (CalculateAsdChromaEdge (pRefC, pCurC, iStride[i]) > BGD_THD_ASD_UV) {
255         return 1;
256       }
257     }
258   }
259 
260   return 0;
261 }
262 
ForegroundDilation(SBackgroundOU * pBackgroundOU,SBackgroundOU * pOUNeighbours[],vBGDParam * pBgdParam,int32_t iChromaSampleStartPos)263 inline void CBackgroundDetection::ForegroundDilation (SBackgroundOU* pBackgroundOU, SBackgroundOU* pOUNeighbours[],
264     vBGDParam* pBgdParam, int32_t iChromaSampleStartPos) {
265   int32_t iPicStrideUV = pBgdParam->iStride[1];
266   int32_t iSumNeighBackgroundFlags = pOUNeighbours[0]->iBackgroundFlag + pOUNeighbours[1]->iBackgroundFlag +
267                                       pOUNeighbours[2]->iBackgroundFlag + pOUNeighbours[3]->iBackgroundFlag;
268 
269   if (pBackgroundOU->iSAD > BGD_OU_SIZE * Q_FACTOR) {
270     switch (iSumNeighBackgroundFlags) {
271     case 0:
272     case 1:
273       pBackgroundOU->iBackgroundFlag = 0;
274       break;
275     case 2:
276     case 3:
277       pBackgroundOU->iBackgroundFlag = !ForegroundDilation23Luma (pBackgroundOU, pOUNeighbours);
278 
279       // chroma component check
280       if (pBackgroundOU->iBackgroundFlag == 1) {
281         int8_t iNeighbourForegroundFlags = (!pOUNeighbours[0]->iBackgroundFlag) | ((!pOUNeighbours[1]->iBackgroundFlag) << 1)
282                                             | ((!pOUNeighbours[2]->iBackgroundFlag) << 2) | ((!pOUNeighbours[3]->iBackgroundFlag) << 3);
283         pBackgroundOU->iBackgroundFlag = !ForegroundDilation23Chroma (iNeighbourForegroundFlags, iChromaSampleStartPos,
284                                          iPicStrideUV, pBgdParam);
285       }
286       break;
287     default:
288       break;
289     }
290   }
291 }
BackgroundErosion(SBackgroundOU * pBackgroundOU,SBackgroundOU * pOUNeighbours[])292 inline void CBackgroundDetection::BackgroundErosion (SBackgroundOU* pBackgroundOU, SBackgroundOU* pOUNeighbours[]) {
293   if (pBackgroundOU->iMaxDiffSubSd <= (BGD_OU_SIZE * Q_FACTOR)) { //BGD_OU_SIZE*BGD_OU_SIZE>>2
294     int32_t iSumNeighBackgroundFlags = pOUNeighbours[0]->iBackgroundFlag + pOUNeighbours[1]->iBackgroundFlag +
295                                        pOUNeighbours[2]->iBackgroundFlag + pOUNeighbours[3]->iBackgroundFlag;
296     int32_t sumNbrBGsad = (pOUNeighbours[0]->iSAD & (-pOUNeighbours[0]->iBackgroundFlag)) + (pOUNeighbours[2]->iSAD &
297                           (-pOUNeighbours[2]->iBackgroundFlag))
298                           + (pOUNeighbours[1]->iSAD & (-pOUNeighbours[1]->iBackgroundFlag)) + (pOUNeighbours[3]->iSAD &
299                               (-pOUNeighbours[3]->iBackgroundFlag));
300     if (pBackgroundOU->iSAD * iSumNeighBackgroundFlags <= (3 * sumNbrBGsad) >> 1) {
301       if (iSumNeighBackgroundFlags == 4) {
302         pBackgroundOU->iBackgroundFlag = 1;
303       } else {
304         if ((pOUNeighbours[0]->iBackgroundFlag & pOUNeighbours[1]->iBackgroundFlag)
305             || (pOUNeighbours[2]->iBackgroundFlag & pOUNeighbours[3]->iBackgroundFlag)) {
306           pBackgroundOU->iBackgroundFlag = !ForegroundDilation23Luma (pBackgroundOU, pOUNeighbours);
307         }
308       }
309     }
310   }
311 }
312 
SetBackgroundMbFlag(int8_t * pBackgroundMbFlag,int32_t iPicWidthInMb,int32_t iBackgroundMbFlag)313 inline void CBackgroundDetection::SetBackgroundMbFlag (int8_t* pBackgroundMbFlag, int32_t iPicWidthInMb,
314     int32_t iBackgroundMbFlag) {
315   *pBackgroundMbFlag = iBackgroundMbFlag;
316 }
317 
UpperOUForegroundCheck(SBackgroundOU * pCurOU,int8_t * pBackgroundMbFlag,int32_t iPicWidthInOU,int32_t iPicWidthInMb)318 inline void CBackgroundDetection::UpperOUForegroundCheck (SBackgroundOU* pCurOU, int8_t* pBackgroundMbFlag,
319     int32_t iPicWidthInOU, int32_t iPicWidthInMb) {
320   if (pCurOU->iSAD > BGD_OU_SIZE * Q_FACTOR) {
321     SBackgroundOU* pOU_L = pCurOU - 1;
322     SBackgroundOU* pOU_R = pCurOU + 1;
323     SBackgroundOU* pOU_U = pCurOU - iPicWidthInOU;
324     SBackgroundOU* pOU_D = pCurOU + iPicWidthInOU;
325     if (pOU_L->iBackgroundFlag + pOU_R->iBackgroundFlag + pOU_U->iBackgroundFlag + pOU_D->iBackgroundFlag <= 1) {
326       SetBackgroundMbFlag (pBackgroundMbFlag, iPicWidthInMb, 0);
327       pCurOU->iBackgroundFlag = 0;
328     }
329   }
330 }
331 
ForegroundDilationAndBackgroundErosion(vBGDParam * pBgdParam)332 void CBackgroundDetection::ForegroundDilationAndBackgroundErosion (vBGDParam* pBgdParam) {
333   int32_t iPicStrideUV          = pBgdParam->iStride[1];
334   int32_t iPicWidthInOU         = pBgdParam->iBgdWidth  >> LOG2_BGD_OU_SIZE;
335   int32_t iPicHeightInOU        = pBgdParam->iBgdHeight >> LOG2_BGD_OU_SIZE;
336   int32_t iOUStrideUV           = iPicStrideUV << (LOG2_BGD_OU_SIZE - 1);
337   int32_t iPicWidthInMb         = (15 + pBgdParam->iBgdWidth) >> 4;
338 
339   SBackgroundOU* pBackgroundOU = pBgdParam->pOU_array;
340   int8_t*        pVaaBackgroundMbFlag = (int8_t*)pBgdParam->pBackgroundMbFlag;
341   SBackgroundOU* pOUNeighbours[4];//0: left; 1: right; 2: top; 3: bottom
342 
343   pOUNeighbours[2]      = pBackgroundOU;//top OU
344   for (int32_t j = 0; j < iPicHeightInOU; j ++) {
345     int8_t* pRowSkipFlag = pVaaBackgroundMbFlag;
346     pOUNeighbours[0]    = pBackgroundOU;//left OU
347     pOUNeighbours[3]    = pBackgroundOU + (iPicWidthInOU & ((j == iPicHeightInOU - 1) - 1)); //bottom OU
348     for (int32_t i = 0; i < iPicWidthInOU; i++) {
349       pOUNeighbours[1] = pBackgroundOU + (i < iPicWidthInOU - 1); //right OU
350 
351       if (pBackgroundOU->iBackgroundFlag)
352         ForegroundDilation (pBackgroundOU, pOUNeighbours, pBgdParam, j * iOUStrideUV + (i << LOG2_BGD_OU_SIZE_UV));
353       else
354         BackgroundErosion (pBackgroundOU, pOUNeighbours);
355 
356       // check the up OU
357       if (j > 1 && i > 0 && i < iPicWidthInOU - 1 && pOUNeighbours[2]->iBackgroundFlag == 1) {
358         UpperOUForegroundCheck (pOUNeighbours[2], pRowSkipFlag - OU_SIZE_IN_MB * iPicWidthInMb, iPicWidthInOU, iPicWidthInMb);
359       }
360 
361       SetBackgroundMbFlag (pRowSkipFlag, iPicWidthInMb, pBackgroundOU->iBackgroundFlag);
362 
363       // preparation for the next OU
364       pRowSkipFlag += OU_SIZE_IN_MB;
365       pOUNeighbours[0] = pBackgroundOU;
366       pOUNeighbours[2]++;
367       pOUNeighbours[3]++;
368       pBackgroundOU++;
369     }
370     pOUNeighbours[2]      = pBackgroundOU - iPicWidthInOU;
371     pVaaBackgroundMbFlag += OU_SIZE_IN_MB * iPicWidthInMb;
372   }
373 }
374 
BackgroundDetection(vBGDParam * pBgdParam)375 void CBackgroundDetection::BackgroundDetection (vBGDParam* pBgdParam) {
376   // 1st step: foreground/background coarse division
377   ForegroundBackgroundDivision (pBgdParam);
378 
379   // 2nd step: foreground dilation and background erosion
380   ForegroundDilationAndBackgroundErosion (pBgdParam);
381 }
382 
383 WELSVP_NAMESPACE_END
384