sample bgfg_segm.cpp don't display background in 2.1.0 version

The following function fills model->background image when model is MOG (cvCreateGaussianBGModel). I hope this helps those who encounter this problem in the meanwhile

typedef struct MyCvGaussBGValues{    float match_sum;    float weight;    float mean[3];    float variance[3];}MyCvGaussBGValues;static void updateBackground(CvGaussBGModel* bg_model){        int K = bg_model->params.n_gauss;        int nchannels = bg_model->background->nChannels;        int height = bg_model->background->height;        int width = bg_model->background->width;        MyCvGaussBGValues *g_point = (MyCvGaussBGValues *) ((CvMat*)(bg_model->g_point))->data.ptr;        MyCvGaussBGValues *mptr = g_point;    for(int y=0; y
     
      background->widthStep*y + x*nchannels;                        float mean[3] = {
   0.0, 0.0, 0.0};                                                for(int k=0; k
      
       background->imageData[pos+m] = (uchar) (mean[m]+0.5);                        }                }        }}
      
     

Call just after cvUpdateBGStatModel(), as this:

cvUpdateBGStatModel( tmp_frame, bg_model, update_bg_model ? -1 : 0 );updateBackground((CvGaussBGModel*)bg_model);

Improved previous version：

typedef struct MixData1{        float match_sum;        float weight;        float mean;        float variance;}MixData1;typedef struct MixData3{        float match_sum;        float weight;        float mean[3];        float variance[3];}MixData3;void BackgroundThread::update8uC1(CvGaussBGModel* bg_model){        int K = bg_model->params.n_gauss;        float T = bg_model->params.bg_threshold;        int height = bg_model->background->height;        int width = bg_model->background->width;        MixData1 *g_point = (MixData1 *) ((CvMat*)(bg_model->g_point))->data.ptr;        MixData1 *mptr = g_point;        for(int y=0; y
     
      background->widthStep*y + x;                        float mean = 0.0;                        float wsum = 0.0;                        int kForeground = K;                        for(int k=0; k
      
        T)                                {                                        kForeground = k+1;                                        break;                                }                        }                        for(int k=0; k
       
        background->imageData[pos] = (uchar) (mean/wsum);                }        }}void BackgroundThread::update8uC3(CvGaussBGModel* bg_model){        int K = bg_model->params.n_gauss;        float T = bg_model->params.bg_threshold;        int nchannels = bg_model->background->nChannels;        int height = bg_model->background->height;        int width = bg_model->background->width;        MixData3 *g_point = (MixData3 *) ((CvMat*)(bg_model->g_point))->data.ptr;        MixData3 *mptr = g_point;        for(int y=0; y
        
         background->widthStep*y + x*nchannels;                        float mean[3] = {
   0.0, 0.0, 0.0};                        float wsum = 0.0;                        int kForeground = K;                        for(int k=0; k
         
           T)                                {                                        kForeground = k+1;                                        break;                                }                        }                        for(int k=0; k
          
           background->imageData[pos+m] = (uchar) (mean[m]/wsum); //+0.5 } } }}
          
         
        
       
      
     

Call just after cvUpdateBGStatModel(), as this:

cvUpdateBGStatModel(image, model, -1);update8uC3((CvGaussBGModel*)model);

文章摘自上面链接，本人测试还没有通过，程序编译没问题，但运行时会崩溃。可能是内存或指针的问题吧，检查中.....