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#ifndef __OPENCV_BACKGROUND_SEGM_HPP__
#define __OPENCV_BACKGROUND_SEGM_HPP__

#include "opencv2/core/core.hpp"

#ifdef __cplusplus
extern "C" {
#endif

/****************************************************************************************\
*                           Background/foreground segmentation                           *
\****************************************************************************************/

/* We discriminate between foreground and background pixels
 * by building and maintaining a model of the background.
 * Any pixel which does not fit this model is then deemed
 * to be foreground.
 *
 * At present we support two core background models,
 * one of which has two variations:
 *
 *  o CV_BG_MODEL_FGD: latest and greatest algorithm, described in
 *    
 *	 Foreground Object Detection from Videos Containing Complex Background.
 *	 Liyuan Li, Weimin Huang, Irene Y.H. Gu, and Qi Tian. 
 *	 ACM MM2003 9p
 *
 *  o CV_BG_MODEL_FGD_SIMPLE:
 *       A code comment describes this as a simplified version of the above,
 *       but the code is in fact currently identical
 *
 *  o CV_BG_MODEL_MOG: "Mixture of Gaussians", older algorithm, described in
 *
 *       Moving target classification and tracking from real-time video.
 *       A Lipton, H Fujijoshi, R Patil
 *       Proceedings IEEE Workshop on Application of Computer Vision pp 8-14 1998
 *
 *       Learning patterns of activity using real-time tracking
 *       C Stauffer and W Grimson  August 2000
 *       IEEE Transactions on Pattern Analysis and Machine Intelligence 22(8):747-757
 */


#define CV_BG_MODEL_FGD		0
#define CV_BG_MODEL_MOG		1			/* "Mixture of Gaussians".	*/
#define CV_BG_MODEL_FGD_SIMPLE	2

struct CvBGStatModel;

typedef void (CV_CDECL * CvReleaseBGStatModel)( struct CvBGStatModel** bg_model );
typedef int (CV_CDECL * CvUpdateBGStatModel)( IplImage* curr_frame, struct CvBGStatModel* bg_model,
                                              double learningRate );

#define CV_BG_STAT_MODEL_FIELDS()                                                   \
    int             type; /*type of BG model*/                                      \
    CvReleaseBGStatModel release;                                                   \
    CvUpdateBGStatModel update;                                                     \
    IplImage*       background;   /*8UC3 reference background image*/               \
    IplImage*       foreground;   /*8UC1 foreground image*/                         \
    IplImage**      layers;       /*8UC3 reference background image, can be null */ \
    int             layer_count;  /* can be zero */                                 \
    CvMemStorage*   storage;      /*storage for foreground_regions*/                \
    CvSeq*          foreground_regions /*foreground object contours*/

typedef struct CvBGStatModel
{
    CV_BG_STAT_MODEL_FIELDS();
} CvBGStatModel;

// 

// Releases memory used by BGStatModel
CVAPI(void) cvReleaseBGStatModel( CvBGStatModel** bg_model );

// Updates statistical model and returns number of found foreground regions
CVAPI(int) cvUpdateBGStatModel( IplImage* current_frame, CvBGStatModel*  bg_model,
                                double learningRate CV_DEFAULT(-1));

// Performs FG post-processing using segmentation
// (all pixels of a region will be classified as foreground if majority of pixels of the region are FG).
// parameters:
//      segments - pointer to result of segmentation (for example MeanShiftSegmentation)
//      bg_model - pointer to CvBGStatModel structure
CVAPI(void) cvRefineForegroundMaskBySegm( CvSeq* segments, CvBGStatModel*  bg_model );

/* Common use change detection function */
CVAPI(int)  cvChangeDetection( IplImage*  prev_frame,
                               IplImage*  curr_frame,
                               IplImage*  change_mask );

/*
  Interface of ACM MM2003 algorithm
*/

/* Default parameters of foreground detection algorithm: */
#define  CV_BGFG_FGD_LC              128
#define  CV_BGFG_FGD_N1C             15
#define  CV_BGFG_FGD_N2C             25

#define  CV_BGFG_FGD_LCC             64
#define  CV_BGFG_FGD_N1CC            25
#define  CV_BGFG_FGD_N2CC            40

/* Background reference image update parameter: */
#define  CV_BGFG_FGD_ALPHA_1         0.1f

/* stat model update parameter
 * 0.002f ~ 1K frame(~45sec), 0.005 ~ 18sec (if 25fps and absolutely static BG)
 */
#define  CV_BGFG_FGD_ALPHA_2         0.005f

/* start value for alpha parameter (to fast initiate statistic model) */
#define  CV_BGFG_FGD_ALPHA_3         0.1f

#define  CV_BGFG_FGD_DELTA           2

#define  CV_BGFG_FGD_T               0.9f

#define  CV_BGFG_FGD_MINAREA         15.f

#define  CV_BGFG_FGD_BG_UPDATE_TRESH 0.5f

/* See the above-referenced Li/Huang/Gu/Tian paper
 * for a full description of these background-model
 * tuning parameters.
 *
 * Nomenclature:  'c'  == "color", a three-component red/green/blue vector.
 *                         We use histograms of these to model the range of
 *                         colors we've seen at a given background pixel.
 *
 *                'cc' == "color co-occurrence", a six-component vector giving
 *                         RGB color for both this frame and preceding frame.
 *                             We use histograms of these to model the range of
 *                         color CHANGES we've seen at a given background pixel.
 */
typedef struct CvFGDStatModelParams
{
    int    Lc;			/* Quantized levels per 'color' component. Power of two, typically 32, 64 or 128.				*/
    int    N1c;			/* Number of color vectors used to model normal background color variation at a given pixel.			*/
    int    N2c;			/* Number of color vectors retained at given pixel.  Must be > N1c, typically ~ 5/3 of N1c.			*/
				/* Used to allow the first N1c vectors to adapt over time to changing background.				*/

    int    Lcc;			/* Quantized levels per 'color co-occurrence' component.  Power of two, typically 16, 32 or 64.			*/
    int    N1cc;		/* Number of color co-occurrence vectors used to model normal background color variation at a given pixel.	*/
    int    N2cc;		/* Number of color co-occurrence vectors retained at given pixel.  Must be > N1cc, typically ~ 5/3 of N1cc.	*/
				/* Used to allow the first N1cc vectors to adapt over time to changing background.				*/

    int    is_obj_without_holes;/* If TRUE we ignore holes within foreground blobs. Defaults to TRUE.						*/
    int    perform_morphing;	/* Number of erode-dilate-erode foreground-blob cleanup iterations.						*/
				/* These erase one-pixel junk blobs and merge almost-touching blobs. Default value is 1.			*/

    float  alpha1;		/* How quickly we forget old background pixel values seen.  Typically set to 0.1  				*/
    float  alpha2;		/* "Controls speed of feature learning". Depends on T. Typical value circa 0.005. 				*/
    float  alpha3;		/* Alternate to alpha2, used (e.g.) for quicker initial convergence. Typical value 0.1.				*/

    float  delta;		/* Affects color and color co-occurrence quantization, typically set to 2.					*/
    float  T;			/* "A percentage value which determines when new features can be recognized as new background." (Typically 0.9).*/
    float  minArea;		/* Discard foreground blobs whose bounding box is smaller than this threshold.					*/
} CvFGDStatModelParams;

typedef struct CvBGPixelCStatTable
{
    float          Pv, Pvb;
    uchar          v[3];
} CvBGPixelCStatTable;

typedef struct CvBGPixelCCStatTable
{
    float          Pv, Pvb;
    uchar          v[6];
} CvBGPixelCCStatTable;

typedef struct CvBGPixelStat
{
    float                 Pbc;
    float                 Pbcc;
    CvBGPixelCStatTable*  ctable;
    CvBGPixelCCStatTable* cctable;
    uchar                 is_trained_st_model;
    uchar                 is_trained_dyn_model;
} CvBGPixelStat;


typedef struct CvFGDStatModel
{
    CV_BG_STAT_MODEL_FIELDS();
    CvBGPixelStat*         pixel_stat;
    IplImage*              Ftd;
    IplImage*              Fbd;
    IplImage*              prev_frame;
    CvFGDStatModelParams   params;
} CvFGDStatModel;

/* Creates FGD model */
CVAPI(CvBGStatModel*) cvCreateFGDStatModel( IplImage* first_frame,
                    CvFGDStatModelParams* parameters CV_DEFAULT(NULL));

/* 
   Interface of Gaussian mixture algorithm

   "An improved adaptive background mixture model for real-time tracking with shadow detection"
   P. KadewTraKuPong and R. Bowden,
   Proc. 2nd European Workshp on Advanced Video-Based Surveillance Systems, 2001."
   http://personal.ee.surrey.ac.uk/Personal/R.Bowden/publications/avbs01/avbs01.pdf
*/

/* Note:  "MOG" == "Mixture Of Gaussians": */

#define CV_BGFG_MOG_MAX_NGAUSSIANS 500

/* default parameters of gaussian background detection algorithm */
#define CV_BGFG_MOG_BACKGROUND_THRESHOLD     0.7     /* threshold sum of weights for background test */
#define CV_BGFG_MOG_STD_THRESHOLD            2.5     /* lambda=2.5 is 99% */
#define CV_BGFG_MOG_WINDOW_SIZE              200     /* Learning rate; alpha = 1/CV_GBG_WINDOW_SIZE */
#define CV_BGFG_MOG_NGAUSSIANS               5       /* = K = number of Gaussians in mixture */
#define CV_BGFG_MOG_WEIGHT_INIT              0.05
#define CV_BGFG_MOG_SIGMA_INIT               30
#define CV_BGFG_MOG_MINAREA                  15.f


#define CV_BGFG_MOG_NCOLORS                  3

typedef struct CvGaussBGStatModelParams
{    
    int     win_size;               /* = 1/alpha */
    int     n_gauss;
    double  bg_threshold, std_threshold, minArea;
    double  weight_init, variance_init;
}CvGaussBGStatModelParams;

typedef struct CvGaussBGValues
{
    int         match_sum;
    double      weight;
    double      variance[CV_BGFG_MOG_NCOLORS];
    double      mean[CV_BGFG_MOG_NCOLORS];
} CvGaussBGValues;

typedef struct CvGaussBGPoint
{
    CvGaussBGValues* g_values;
} CvGaussBGPoint;


typedef struct CvGaussBGModel
{
    CV_BG_STAT_MODEL_FIELDS();
    CvGaussBGStatModelParams   params;    
    CvGaussBGPoint*            g_point;    
    int                        countFrames;
} CvGaussBGModel;


/* Creates Gaussian mixture background model */
CVAPI(CvBGStatModel*) cvCreateGaussianBGModel( IplImage* first_frame,
                CvGaussBGStatModelParams* parameters CV_DEFAULT(NULL));


typedef struct CvBGCodeBookElem
{
    struct CvBGCodeBookElem* next;
    int tLastUpdate;
    int stale;
    uchar boxMin[3];
    uchar boxMax[3];
    uchar learnMin[3];
    uchar learnMax[3];
} CvBGCodeBookElem;

typedef struct CvBGCodeBookModel
{
    CvSize size;
    int t;
    uchar cbBounds[3];
    uchar modMin[3];
    uchar modMax[3];
    CvBGCodeBookElem** cbmap;
    CvMemStorage* storage;
    CvBGCodeBookElem* freeList;
} CvBGCodeBookModel;

CVAPI(CvBGCodeBookModel*) cvCreateBGCodeBookModel();
CVAPI(void) cvReleaseBGCodeBookModel( CvBGCodeBookModel** model );

CVAPI(void) cvBGCodeBookUpdate( CvBGCodeBookModel* model, const CvArr* image,
                                CvRect roi CV_DEFAULT(cvRect(0,0,0,0)),
                                const CvArr* mask CV_DEFAULT(0) );

CVAPI(int) cvBGCodeBookDiff( const CvBGCodeBookModel* model, const CvArr* image,
                             CvArr* fgmask, CvRect roi CV_DEFAULT(cvRect(0,0,0,0)) );

CVAPI(void) cvBGCodeBookClearStale( CvBGCodeBookModel* model, int staleThresh,
                                    CvRect roi CV_DEFAULT(cvRect(0,0,0,0)),
                                    const CvArr* mask CV_DEFAULT(0) );

CVAPI(CvSeq*) cvSegmentFGMask( CvArr *fgmask, int poly1Hull0 CV_DEFAULT(1),
                               float perimScale CV_DEFAULT(4.f),
                               CvMemStorage* storage CV_DEFAULT(0),
                               CvPoint offset CV_DEFAULT(cvPoint(0,0)));

#ifdef __cplusplus
}

namespace cv
{

/*!
 The Base Class for Background/Foreground Segmentation
 
 The class is only used to define the common interface for
 the whole family of background/foreground segmentation algorithms.
*/
class CV_EXPORTS_W BackgroundSubtractor
{
public:
    //! the virtual destructor
    virtual ~BackgroundSubtractor();
    //! the update operator that takes the next video frame and returns the current foreground mask as 8-bit binary image.
    CV_WRAP_AS(apply) virtual void operator()(const Mat& image, CV_OUT Mat& fgmask,
                                              double learningRate=0);
};


/*!
 Gaussian Mixture-based Backbround/Foreground Segmentation Algorithm
 
 The class implements the following algorithm:
 "An improved adaptive background mixture model for real-time tracking with shadow detection"
 P. KadewTraKuPong and R. Bowden,
 Proc. 2nd European Workshp on Advanced Video-Based Surveillance Systems, 2001."
 http://personal.ee.surrey.ac.uk/Personal/R.Bowden/publications/avbs01/avbs01.pdf
 
*/
class CV_EXPORTS_W BackgroundSubtractorMOG : public BackgroundSubtractor
{
public:
    //! the default constructor
    CV_WRAP BackgroundSubtractorMOG();
    //! the full constructor that takes the length of the history, the number of gaussian mixtures, the background ratio parameter and the noise strength
    CV_WRAP BackgroundSubtractorMOG(int history, int nmixtures, double backgroundRatio, double noiseSigma=0);
    //! the destructor
    virtual ~BackgroundSubtractorMOG();
    //! the update operator
    virtual void operator()(const Mat& image, Mat& fgmask, double learningRate=0);
    
    //! re-initiaization method
    virtual void initialize(Size frameSize, int frameType);
    
    Size frameSize;
    int frameType;
    Mat bgmodel;
    int nframes;
    int history;
    int nmixtures;
    double varThreshold;
    double backgroundRatio;
    double noiseSigma;
};	

}
#endif

#endif
