Apodization.h

//-*-C++-*-
/***************************************************************************
 *
 *   Copyright (C) 2002 by Willem van Straten
 *   Licensed under the Academic Free License version 2.1
 *
 ***************************************************************************/
 
#ifndef __Apodization_h
#define __Apodization_h
 
#include <map>
#include <string>
 
#include "dsp/Shape.h"
 
namespace dsp {
 
  /* The Apodization class implements apodizing functions that may be used
     in the time domain before performing an FFT, in order to improve
     the spectral leakage characteristics */
  class Apodization : public Shape
  {
 
  public:
 
    enum Type { none, hanning, welch, bartlett, tukey, top_hat };
 
    Apodization();
 
    void set_type (const std::string&);
 
    void set_analytic (bool f = true) { analytic = f; }
    bool get_analytic () const { return analytic; }
 
    void set_size (unsigned);
 
    void set_transition_start (unsigned n) { transition_start = n; }
    void set_transition_end (unsigned n) { transition_end = n; }
    void set_transition (unsigned n) { transition_end = transition_start = n; }
 
    void build ();
 
    void Hanning ();
 
    void Welch ();
 
    void Bartlett ();
 
 
    void Tukey ();
 
    void TopHat ();
 
    void normalize();
 
    Type getType () { return type; };
 
    Type get_type () { return getType(); };
 
    void operate (float* indata, float* outdata = 0) const;
 
    void swap ();
 
    double integrated_product (float* data, unsigned incr=1) const;
 
 
    void dump (const std::string& filename);
 
  private:
 
    static std::map<std::string, Type> type_map;
 
    Type type;
 
    bool analytic;
 
    bool swapped;
 
    unsigned zero_start;
    unsigned zero_end;
 
    unsigned transition_start;
    unsigned transition_end;
 
    static std::map<std::string, Type> init_type_map ()
    {
      static std::map<std::string, Type> _type_map;
      _type_map["no_window"] = none;
      _type_map["none"] = none;
      _type_map["bartlett"] = bartlett;
      _type_map["hanning"] = hanning;
      _type_map["tukey"] = tukey;
      _type_map["welch"] = welch;
      _type_map["top_hat"] = top_hat;
      return _type_map;
    }
 
  };
}
 
#endif