iffilter.h

A tutorial and open source code for finding edges and corners based on the filters used in primary v

// IFFilter.h

/*
** Copyright (C) 1994, 2003 Tyler C. Folsom
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation.  This software is provided "as is" without express or
** implied warranty.
*/
#ifndef IFFILTER_H
#define IFFILTER_H

const MAX_COEFS = 4;

// A set of cortical filters at several orientations.
// Each filter within a given CFilter has the same size.
// Each CFilter consists of all even or all odd filters.
// There must be pairs of even and odd CFilters.
class CFilter
{
    friend class CProcessFeatures; 

public:
    // Use positive diameters for even filters,
    // negative diameters for odd.
    CFilter( int diameter = 0, int spacing = 1);  // constructor
    ~CFilter( );  // destructor
    // copy constructor
    CFilter(const CFilter &right);
    // assignment
    const CFilter &operator=( const CFilter &right );
    // correlate two kernels
    void fl_correlate (CFilter& other);

private:
    inline void Copy(const CFilter &right);
    // construct the kernels
    void setKernel();
    // windowing function
    inline float bump( float x);
    
    int m_diam;  // diameter of receptive field (pixels)
    int m_sampleSpacing;  // 1 unless if subsampled
    int m_orientations; 	// Number of  filters
    bool m_isEven;
    float *kern;      /* the kernel */
    // had been kern[orientation][row][col]
    // coefficients of polynomials used to produce kernels
    float m_coef[MAX_COEFS];
    // overlap of kernels at different orientations
    float m_self_ovlap[MAX_COEFS];
    // overlap between even and odd kernels at orientations
    float m_cross_ovlap[MAX_COEFS];
    // width of the center lobe of the even filter.
    float m_center_lobe;
	// The maximum possible response from correlating an image with this filter size.
	float m_maxResponse;

};
#endif // IFFILTER_H