605 CvBackgroundData* cvbgdata = NULL;  variable
1144     if( cvbgdata == NULL && filename != NULL )  in icvInitBackgroundReaders()
1146         cvbgdata = icvCreateBackgroundData( filename, winsize );  in icvInitBackgroundReaders()
1149     if( cvbgdata )  in icvInitBackgroundReaders()
1169     return (cvbgdata != NULL);  in icvInitBackgroundReaders()
1197     if( cvbgdata != NULL )  in icvDestroyBackgroundReaders()
1199         icvReleaseBackgroundData( &cvbgdata );  in icvDestroyBackgroundReaders()
1200         cvbgdata = NULL;  in icvDestroyBackgroundReaders()
1253                     icvGetBackgroundImage( cvbgdata, cvbgreader, &sample );  in cvCreateTrainingSamples()
1364             count = MIN( count, cvbgdata->count );  in cvCreateTestSamples()
1368                 icvGetNextFromBackgroundData( cvbgdata, cvbgreader );  in cvCreateTestSamples()