Help me out with this C code for histogram equalization

getbiplab's Avatar, Join Date: Sep 2008
Newbie Member
Code:
#include <stdio.h>
#include <stdlib.h>
#include <dos.h>
#include <mem.h>
#include <string.h>
#include <conio.h>
#include <fcntl.h>
#include <io.h>
#include <math.h>

unsigned char r[360],mini,mode;
unsigned char rgb[256][3],rgb2[256][3],**rgb1,t;
char *fullname;
char *fname;
int hist[256],tmp=0,sum=0;
unsigned int screen_width=320;
unsigned int first_row=0,first_column=0,last_row=0,last_column=0;
int handle,i,j,rem,color_bits;
long int file_size,data_offset,size_info_header,width,height,compression,
	      image_size,xpelspermeter,ypelspermeter,colorsused,k,colorsimpt,p,index,max,min,**sum_hist;
float theta,temp;
void drawdot(int x, int y, int pal_index){
		_AX=pal_index;
		_CX=x;
		_DX=y;
		_AH=0x0c;
		_BH=0x00;
		geninterrupt(0x10);
}

void main(){

	gets(fname);
	strcpy(fullname,fname);strcat(fullname,".bmp");
	handle=_open(fullname,O_RDONLY);if (handle==-1) exit(EXIT_FAILURE);
	_read(handle,r,2);if (r[0] !='B' | r[1] !='M') exit(EXIT_FAILURE);
	_read(handle,r,4);file_size=r[0]+0x100*r[1]+0x10000*r[2]+0x1000000*r[3];
	_read(handle,r,2);_read(handle,r,2);
	_read(handle,r,4);data_offset=r[0]+256*r[1]+65536*r[2]+0x1000000*r[3];
	_read(handle,r,4);size_info_header=r[0]+256*r[1]+65536*r[2]+0x1000000*r[3];
	if (size_info_header !=40) exit(EXIT_FAILURE);
	_read(handle,r,4);width=r[0]+0x100*r[1]+0x10000*r[2]+0x1000000*r[3];
	if (width > screen_width) exit(0);
	_read(handle,r,4);height=r[0]+0x100*r[1]+0x10000*r[2]+0x1000000*r[3];
	_read(handle,r,2);if (r[0] != 1) exit(EXIT_FAILURE);
	_read(handle,r,2);
	color_bits=r[0];
	_read(handle,r,4);
	compression=r[0]+0x100*r[1]+0x10000*r[2]+0x1000000*r[3];
	_read(handle,r,4);
	image_size=r[0]+256*r[1]+256*256*r[2]+256*256*256*r[3];
	_read(handle,r,4);
	xpelspermeter=r[0]+0x100*r[1]+0x10000*r[2]+0x1000000*r[3];
	_read(handle,r,4);
	ypelspermeter=r[0]+0x100*r[1]+0x10000*r[2]+0x1000000*r[3];
	_read(handle,r,4);
	colorsused=r[0]+0x100*r[1]+0x10000*r[2]+0x1000000*r[3];
	_read(handle,r,4);
	colorsimpt=r[0]+0x100*r[1]+0x10000*r[2]+0x1000000*r[3];

	_AX=0x1201;_BL=0x33;geninterrupt(0x10);//don't add RGB
	_AX=0x0013;geninterrupt(0x10);//set mode 13 i.e. 320x200x256

	for (i=0;i<256;i++) {
		_read(handle,r,4);
		rgb[i][0]=r[2]>>2;rgb[i][1]=r[1]>>2;rgb[i][2]=r[0]>>2;
	}
	rgb1=calloc(height,sizeof(char*));
	for(i=0;i<height;i++)
	rgb1[i]=calloc(width,sizeof(char));
	for (i=0;i<256;i++) {
		rgb2[i][0]=i;rgb2[i][1]=i;rgb2[i][2]=i;
	}
	_ES=FP_SEG(rgb2);_DX=FP_OFF(rgb2);
	_BX=0;_CX=0x100; _AX=0x1012;
	geninterrupt(0x10);//set DAC from rgb
	first_column=(screen_width-width)/2;
	last_row=first_row+height-1;last_column=first_column+width-1;
	rem=4 - (width % 4);
	for (i=0;i<=height-1;i++) {
		_read(handle,r,width);

		for (j=0;j<=width-1;j++)
		{
		//drawdot(first_column+j,last_row-i,r[j]);
		rgb1[i][j]=(rgb2[r[j]][0]+rgb2[r[j]][1]+rgb2[r[j]][2])/3;
		//printf("%d\n",rgb1[i][j]);
		//delay(100);
		}
		if (rem==1) _read(handle,r,1);
		else if (rem==2) _read(handle,r,2);
		else if (rem==3) _read(handle,r,3);//getch();
	}
	
	for(i=0;i<256;i++)
		{
			hist[i]=0;
		     }
	for(i=0;i<height;i++)
	{
		for(j=0;j<width;j++)
		{
			k=(long int)rgb1[i][j];
			hist[k]=hist[k]+1;
		}
	}

	for(i=0;i<256;i++)
	{
		if(hist[i]!=0)
		tmp++;
		else continue;
	}

	sum_hist=(long int **)calloc(tmp,sizeof(long int*));
	for(i=0;i<tmp;i++)
		sum_hist[i]=(long int *)calloc(2,sizeof(long int));
	
	for(i=0;i<256;i++)
	{
		if(hist[i]!=0)
		{
			sum_hist[sum][0]=(long int)i;
			sum_hist[sum][1]=(long int)hist[i];
			sum++;
		}
		else continue;
	}


	for(i=1;i<tmp;i++)
		sum_hist[i][1]+=sum_hist[i-1][1];


	min=sum_hist[0][1];
	max=sum_hist[0][1];
	for(i=1;i<tmp;i++)
		{
			if(min>sum_hist[i][1])
			min=sum_hist[i][1];
			else continue;
		}
	for(i=1;i<tmp;i++)
		{
			if(max<sum_hist[i][1])
			max=sum_hist[i][1];
			else continue;
		}

	p=((height*width)-min);

	for(i=0;i<height;i++)
	{
		for(j=0;width;j++)
		{
			printf("%d\n",rgb1[i][j]);
			delay(100);
		}
	}	
     	for(i=0;i<height;i++)
	{
		for(j=0;j<width;j++)
		{
			t=rgb1[i][j];
			//printf("%d\n",t);
			//delay(100);
			for(i=0;i<tmp;i++)
			{
			if(sum_hist[i][0]==t)
			index=sum_hist[i][1];
			}
			index=index-min;
			rgb1[i][j]=abs(index*255/p);
			//printf("%d %d\n",t,rgb1[i][j]);
			//delay(100);	
		}
	} 
	/*for(i=0;i<height;i++)
		{
			for(j=0;j<width;j++)
			drawdot(first_column+j,last_row-i,rgb1[i][j]);
		}*/
	
	_close(handle);
	getch();
	_AX=0x1201;_BL=0x33;geninterrupt(0x10);//don't add RGB
	_AX=0x0003;geninterrupt(0x10);//set mode 3 i.e. 16-color text

}
In the above code..I have two problems...
when assining the value of rgb1[][]..thn if i print the values..it is giving correct results..but if i try to print it outside the block..some garbage values are printed..
and no code is running beyond...
Code:
for(i=0;i<height;i++)
	{
		for(j=0;j<width;j++)
		{
			t=rgb1[i][j];
			//printf("%d\n",t);
			//delay(100);
			for(i=0;i<tmp;i++)
			{
			if(sum_hist[i][0]==t)
			index=sum_hist[i][1];
			}
			index=index-min;
			rgb1[i][j]=abs(index*255/p);
			//printf("%d %d\n",t,rgb1[i][j]);
			//delay(100);	
		}

Last edited by shabbir; 14Sep2008 at 13:48.. Reason: Code block
0
hbilling's Avatar, Join Date: Aug 2008
Light Poster
Hi,
I don't think i clearly understand ur issue!. But i see an issue here. You are using(or rather reusing) the variable 'i' in the loop.
Code:
for(i=0;i<height;i++)
	{
		for(j=0;j<width;j++)
		{
			t=rgb1[i][j];
			//printf("%d\n",t);
			//delay(100);
			for(i=0;i<tmp;i++) <<< Here u are using the same variable 'i' as the outer loop.
                                                    // You could use a new variable like 'inner_i' here. I guess thats what u actually intended to..
			{
			if(sum_hist[i][0]==t)
			index=sum_hist[i][1];
			}
			index=index-min;
			rgb1[i][j]=abs(index*255/p);
			//printf("%d %d\n",t,rgb1[i][j]);
			//delay(100);	
		}

Last edited by shabbir; 14Sep2008 at 23:40.. Reason: Code block
0
oogabooga's Avatar
Ambitious contributor
This is obviously an old (16-bit?) piece of code you are trying to resurrect. Rarely a good idea. You should start fresh or at least find a more modern starting point.