source: GTP/trunk/Lib/Vis/Preprocessing/src/DifferenceSampling.h @ 2546

#ifndef _DifferenceSampling_H__
#define _DifferenceSampling_H__

#include <vector>
//

#include "common.h"
#include "Halton.h"

namespace GtpVisibilityPreprocessor {



/** This sampling strategy utilizes the spatial filter to find 
        areas that are likely to be visible.

        First the filter is applied. The difference set of objects (filtered pvs - unfiltered pvs) gives you the objects 
        which are not found visible yet but have a good probability that they are in fact visible, based on the current 
        state of the sampling and the size of the filter. In fact the difference set is a probably visible set.
    
        Idea:
        We apply the filter for n times, each time with a higher filter radius. The difference set gives you the probable visible set. 
        Then we use a certain #random samples for sampling the view cell border + the object border. 
        We can use different filter sizes to estimate the probablility distribution. The objects shouldreceived samples 
        roughly according to their probability of becoming invisible.
*/      
class DifferenceSampling: public SamplingStrategy
{
public:
        DifferenceSampling(Preprocessor &preprocessor);
        /** Compute the difference set between filtered and unfiltered pvs.
        */
        void ComputeDifferenceSet(ViewCell *vc, ObjectContainer &differenceSet);

private:

  virtual bool GenerateSample(SimpleRay &ray);
  
};


}

#endif