#ifndef _ETF_H_
#define _ETF_H_
typedef struct Vect {
double tx, ty, mag;
} Vect;
typedef struct ETF {
int Nr, Nc;
Vect **p;
double max_grad;
} ETF;
extern ETF *New_ETF(int i, int j);
extern void ETF_copy(ETF *this, ETF *s);
extern double ETF_crc(ETF *e);
#ifdef NEVER
extern void set(ETF *this, imatrix *image);
#endif
extern void set2(ETF *this, imatrix *image);
extern void Smooth(ETF *this, int half_w, int M);
extern void normalize(ETF *ETF);
#endif