AdaptiveMedianBGS.hpp

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/****************************************************************************
*
* AdaptiveMedianBGS.hpp
*
* Purpose: Implementation of the simple adaptive median background 
*		  		 subtraction algorithm described in:
*	  			 "Segmentation and tracking of piglets in images"
* 						by McFarlane and Schofield
*
* Author: Donovan Parks, September 2007

Example:
		Algorithms::BackgroundSubtraction::AdaptiveMedianParams params;
		params.SetFrameSize(width, height);
		params.LowThreshold() = 40;
		params.HighThreshold() = 2*params.LowThreshold();
		params.SamplingRate() = 7;
		params.LearningFrames() = 30;

		Algorithms::BackgroundSubtraction::AdaptiveMedianBGS bgs;
		bgs.Initalize(params);
******************************************************************************/
#ifndef _ADAPTIVE_MEDIAN_BGS_H_		
#define _ADAPTIVE_MEDIAN_BGS_H_		

#include "Bgs.hpp"

namespace Algorithms
{
namespace BackgroundSubtraction
{

// --- Parameters used by the Adaptive Median BGS algorithm ---
class AdaptiveMedianParams : public BgsParams
{
public:
	unsigned char &LowThreshold() { return m_low_threshold; }
	unsigned char &HighThreshold() { return m_high_threshold; }

	int &SamplingRate() { return m_samplingRate; }
	int &LearningFrames() { return m_learning_frames; }

private:
	unsigned char m_low_threshold;
	unsigned char m_high_threshold;

	int m_samplingRate;
	int m_learning_frames;
};


// --- Adaptive Median BGS algorithm ---
class AdaptiveMedianBGS : public Bgs 
{
public:
	virtual ~AdaptiveMedianBGS() {}

	void Initalize(const BgsParams& param);

	void InitModel(const RgbImage& data);
	void Subtract(int frame_num, const RgbImage& data,  
									BwImage& low_threshold_mask, BwImage& high_threshold_mask);	
	void Update(int frame_num, const RgbImage& data,  const BwImage& update_mask);

	RgbImage* Background();

private:	
	void SubtractPixel(int r, int c, const RgbPixel& pixel, 
											unsigned char& low_threshold, unsigned char& high_threshold);

	AdaptiveMedianParams m_params;

	RgbImage m_median;
};

};
};

#endif