Giáo trình xử lý ảnh y tế Tập 2 P5 pps

150

#include <stdio.h>
#include <math.h>
#include <alloc.h>
#include <stdlib.h>
#include <io.h>
#include <conio.h>
#include <ctype.h>
#include <conio.h>
#include <string.h>

void bit_reversal(unsigned int *, int , int);
void WTS(float *, float *, int, int);
void FFT(float *xr, float *xi, float *, float *,int,
int) ;
void transpose(FILE *, int, int);
void FFT2D(FILE *, FILE *, float *, float *,
unsigned int *,
int,int , int) ;

void main()
{
int M,M1,m,n2,i,j,ii,jj,k;
int Nt,n,M2,M3,N,N1,ind,yt;
unsigned int *L;
float *wr,*wi,Do,winc,Do1,Do2;
float win,T,alpha,beta,sum1,sum2;
float nsq,nsqrt;
FILE *fptri,*fptro,*fptr;
float *buffi,*buffo,R2,H;

float xrm,xim,xrn,xin,zrt,zit,mag,theta;
float *w,**h,r1,im;
unsigned char file_name[14],
ch,ch1,choice,file_name1[14];

clrscr() ;
printf("Freq. response can be calculated using
standard \n");
printf(" functions which you can select from a menu
if your\n");
printf(" reply to the following question is
negative.\n");
printf("Is freq. response provided in a file? (y or
n) >");
while(((ch1=getch())!='y')&&(ch1!='n'));
151

putch(ch1);
switch(ch1)
{
case 'n':
printf("\n Enter # of points to be generated
(e.g. 32x32) >");
scanf("%dx%d",&M1,&M1);
break ;
case 'y':
printf("\nEnter name of file storing magnitude
response >");
scanf("%s",file_name1);
fptr=fopen(file_name1,"r");

fscanf(fptr,"%d %d 11,01,&Mi");
}
M=M1>>1 ;
yt=wherey();
again1 :
gotoxy(1,yt);
printf( "
");
gotoxy(1,yt);
printf("Enter file name for storing impulse
response >");
scanf("%s",file_name);
if(((stricmp("FFT.DAT",file_name))==0)||
((stricmp("TEMP.DAT",file_name))==0)||
((stricmp("IFFT.DAT",file_name))==0))
printf("This is a reserved file name. Use some
other name.");
goto again1;
gotoxy(1,yt);
printf ( "
");
ind=access(file_name,0);
while(!ind)
{
gotoxy(1,yt+1);
printf ( "
");
gotoxy(1,yt+1);
printf("File exists. Wish to overwrite? (y or n)-
->");

while(((ch=tolower(getch()))!='y')&&(ch1='n'));
152

putch(ch);
switch(ch)
{
case 'y' :
ind=1 ;
break;

case 'n' :
gotoxy(1,yt+1);
printf("
");
gotoxy(1,yt);
printf("Enter file name >");
scanf("file_name");
ind=access(file_name,0);
}
}

fptri=fopen("FFT.DAT","wb+");
fptro=fopen("IFFT.DAT","wb+");
buffi=(float *)malloc((M1<<1)*sizeof(float));
switch(ch1)
{
case 'n': /*Generating data for IFFT.*/
printf("\nEnter choice (1,2 etc.):\n");
printf(" 1. Low-pass.\n");
printf(" 2. High-pass.\n");

printf(" 3. Band-pass.\n");
printf(" 4. Band-reject >");

while(((ch=getche())!='1')&&(ch!='2')&&(ch!='3')&&(c
h!='4'));
switch(ch)
{
case '1' :
case '2' :
printf("\nEnter cut-off freq. in
rad./sec.(cut-off <= n.)->");
scanf("%f",&Do);
Do=(Do/pi)*(float)M;
Do*=Do;
printf("Enter choice:\n");
printf(" 1. Abrupt transition.\n");
printf(" 2. Butterworth.\n");
153

printf(" Enter 1 or 2 >");
while(((choice=getche())!='1')&&(choice!='2'));
printf("\n");
break;
case '3':
case '4':
printf
("\nEnter lower cut-off freq. in rad./sec.
(cut-off <=n.");
scanf("%f",&Do1);
Do1=(Do/pi)*(float)M;

Do1*=Do1;
printf
("\nEnter upper cut-off freq. in
rad./sec.cut-off<= n.)->");
scanf("%f",&Do2);
Do2=(Do/pi)*(float)M;
Do2*=Do2;
}

for(i=0;i<M1;i++)
{
ii=(i-M)*(i-M);
for(j=0;j<M1;j++)
{
R2=(float)((j-M)*(j-M)+ii);
switch(ch)
{
case '1': /* low-pass. */
if(choice=='1')
{
if(R2<Do) H=(float)1.0;
else H=(float)0.0;
}
if(choice=='2')
H=0.414*Do/(R2+0.414*Do);
break;

case '2': /* high-pass. */
if(choice=='1')
{

if(R2<Do) H=(float)0.0;
else H=(float)1.0;
}
154

if(choice=='2')
H=R2/(R2+0.414*Do);
break;

case '3': /* Band-pass. */
if(R2<Do1) H=(float)0.0;
else if (R2>Do2) H=(float)0.0;
else H=(float)1.0;
break;

case '4': /* Band-reject. */
if(R2<Do1) H=(float)1.0;
else if (R2>Do2) H=(float)1.0;
else H=(float)0.0;
break;
}
jj=j <<1;
buffi[jj]=H;
buffi[jj+1]=0.0;
}
fwrite(buffi,M1,2*sizeof(float),fptri);
}
break;

case 'y' :

for(i=0;i<M1;i++)
{
for(j=0;j<M1;j++)
{
fscanf(fptr,"%f ",&H);
jj=j<<1 ;
buffi[jj]=H;
buffi[jj+1]=(float)0.0;
}
fwrite(buffi,M1,2*sizeof(float),fptri);
}
fclose(fptr);
}
rewind(fptri);
m=(int)(log10((double)M1)/log10((double)2));

/* Allocating memory for bit reversal LUT. */
L=(unsigned int *)malloc(M1*sizeof(unsigned
int));
155


/* Generate Look-up table for bit reversal. */
bit_reversal(L,m,M1);

/* Allocating memory for twiddle factors. */
n2=M1-1;
wr=(float *)malloc(n2*sizeof(float));
wi=(float *)malloc(n2*sizeof(float));

/* Generating twiddle factor.*/
WTS(wr,wi,M1,1);
clrscr();
FFT2D(fptri,fptro,wr,wi,L,M1,m,1);
clrscr();
fptri=fopen("IFFT.DAT","rb");
fptro=fopen("temp.dat","wb+");
nsq=(float)(M1*M1);
buffo=(float *)malloc(M1*sizeof(float));
for(i=0;i<M1;i++)
{
fread(buffi,M1,2*sizeof(float),fptri);
for(j=0;j<M1;j++)
buffo[j]=(float)(buffi[2*j]/nsq);
fwrite(buffo,M1,sizeof(float),fptro);
}
fclose(fptri);
rewind(fptro);
printf("Enter order of FIR filter (odd
numbers).");
printf(" \n >(e.g. 3x3, 5x5) ");
scanf("%dx%d",&N,&N);
N1=(N-1)/2;
M2=M-N1;
M3=M+N1;

h=(float **)malloc(N*sizeof(float));
for(i=0;i<N;i++)
*(h+i)=(float *)malloc(N*sizeof(float));

/* Reading in the impulse response. */
buffo=(float *)malloc(M1*sizeof(float));

fseek(fptro,(long)(M2)*(long)(M1*sizeof(float)),SEEK
_SET);
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for(i=M2;i<=M3;i++)
{
fread(buffo,M1,sizeof(float),fptro);
for(j=M2;j<=M3;j++)
h[(i-M2)][j-M2]=buffo[j];
}

/* Selection of Window functions. */
printf("\nEnter selection of window function:");
printf("\n 1.Rectangular.");
printf("\n 2.Hann.");
printf("\n 3.Hamming,");
printf("\n 4.Blackmann.");
printf("\n 5.Kaiser.");
printf("\nEnter (1,2 etc.) >");
while(((ch=getche())!='1')&&(ch!='2')
&&(ch!='3')&&(ch!='4')&&(ch!='5'));
yt=wherey();

/* Storing impulse response of FIR filter.*/
again :
gotoxy(1,yt+2);
printf("

");
gotoxy(1,yt+2);
printf("\nEnter file name to store FIR filter
coefficients >");
scanf("%s",file_name);
if(((stricmp("FFT.DAT",file_name))==0)||
((stricmp("temp.DAT",file_name))==0)||
((stricmp("IFFT.DAT",file_name))==0))
{
printf("This is a reserved file name. Use some
other name.");
goto again;
}
gotoxy(1,yt+2);
printf("
");
ind=access(file_name,0);
while(!ind)
{
gotoxy(1,yt+3);
157

printf ( "
");
gotoxy(1,yt+3);
printf("File exists. Wish to overwrite? (y or n)-
->");
while(((ch1=tolower(getch()))!='y')&&(ch1!='n'));
putch(ch1);
switch(ch1)

{
case 'y':
ind=1;
break;

case 'n' :
gotoxy(1,yt+3);
printf("
");
gotoxy(1,yt+2);
printf("
");
gotoxy(1,yt+2);
printf("Enter file name >");
scanf("%s",file_name);
ind=access(file_name,0);
}
}

fptri=fopen(file_name,"w");
theta=pi/((float)N1*sqrt((double)2.0));
for(i=0;i<N;i++)
{
ii=(i-N1)*(i-N1);
for(j=0;j<N;j++)
{
jj=(j-N1)-(j-N1);
nsq=(float)(ii+jj);
nsqrt=sqrt((double)nsq)/sqrt((double)2.0);
switch(ch)

{
case '1':
break;

case '2':
win=0.5+0.5*cos((double)(theta*nsqrt));