GrabCut.h

#ifndef GRAB_CUT_H
#define GRAB_CUT_H

#include "graph.h"

#include "Image.h"
#include "Color.h"
#include "GMM.h"

namespace GrabCutNS {

class GrabCut
{
public:

	GrabCut( Image<Color> *image );

	~GrabCut();

	// Initialize Trimap, inside rectangle is TrimapUnknown, outside is TrimapBackground
	void initialize(unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2);
	void initializeWithMask(Image<Color>* mask);

	// Edit Trimap
	void setTrimap(int x1, int y1, int x2, int y2, const TrimapValue& t);
    //	显示GMM组件分配
	void fitGMMs();

	// Run Grabcut refinement on the hard segmentation

//    运行Grabcut细化算法收敛。
	void refine();
//    运行一步Grabcut细化算法
    int refineOnce();	// returns the number of pixels that have changed from foreground to background or vice versa

	const Image<Real>*	getAlphaImage() const	{ return m_AlphaImage; }
	const Image<Real>*	getNLinksImage() const	{ return m_NLinksImage; }
	const Image<Color>* getTLinksImage() const	{ return m_TLinksImage; }
	const Image<Color>* getGMMsImage() const	{ return m_GMMImage; }
	const Image<Color>* getImage() const		{ return m_image; }

	void buildImages();

private:

	unsigned int m_w, m_h;				// All the following Image<*> variables will be the same width and height.
										// Store them here so we don't have to keep asking for them.
	Image<Color> *m_image;
	Image<TrimapValue> *m_trimap;
	Image<unsigned int> *m_GMMcomponent;
	Image<SegmentationValue> *m_hardSegmentation;

	Image<Real> *m_softSegmentation;	// Not yet implemented (this would be interpreted as alpha)

	GMM *m_backgroundGMM, *m_foregroundGMM;

	int updateHardSegmentation();		// Update hard segmentation after running GraphCut, 
										// Returns the number of pixels that have changed from foreground to background or vice versa.

	// Variables used in formulas from the paper.
	Real m_lambda;		// lambda = 50. This value was suggested the GrabCut paper.
	Real m_beta;		// beta = 1 / ( 2 * average of the squared color distances between all pairs of neighboring pixels (8-neighborhood) )
	Real m_L;			// L = a large value to force a pixel to be foreground or background

	void computeBeta();
	void computeL();

	// Precomputed N-link weights
	Image<NLinks> *m_NLinks;

	void computeNLinks();
	Real computeNLink(unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2);

	// Graph for Graphcut
	Graph *m_graph;
	Image<Graph::node_id> *m_nodes;

	void initGraph();	// builds the graph for GraphCut

	// Images of various variables that can be displayed for debugging.
	Image<Real> *m_NLinksImage;
	Image<Color> *m_TLinksImage;
	Image<Color> *m_GMMImage;
	Image<Real> *m_AlphaImage;
};

}
#endif //GRAB_CUT_H