EE4206/EE5806 Digital Image Processing

/*************************************************************************
Sample C Programs for Computer Project of Digital Image Processing.
These programs provide image reading and writing functions.

You should modify, extend and optimize these programs for your project.
Hong Yan, July 2011
*************************************************************************/

#include
#include
#include

unsigned char *bmpread(char *imname, int *n_row, int *n_col);
void bmpsave(char *imname, unsigned char *ima, int n_row, int n_col);



int main(int argc, char *argv[])
{
int i, j, n_row, n_col;
unsigned char *ima;

/* Read image */

ima = bmpread("image01.bmp", &n_row, &n_col);

/* Show the image size */

printf("Number of rows = %d, Number of columns = %d\n", n_row, n_col);

/* Reduce pixel intensity by a factor of 2. This is just a simple example
and you you need to do things much more complicated than this. */

for (i=0; i< n_row; i++) {
for (j=0; j< n_col; j++) {
ima[i*n_col+j] /= 2;
}
}

/* Save output */

bmpsave("image01_tmp.bmp", ima, n_row, n_col);

return 0;
}




unsigned char *bmpread(char *imname, int *n_row, int *n_col)
{
int i, ncols, nrows, n_bit, n_tab, inv;
short word1;
unsigned int uint1;
unsigned char byte1, byte2, *ima;
FILE *imdata;

imdata = fopen(imname, "rb");
if (imdata == NULL) {
printf("%s open error.\n", imname); exit(0);
}

fread(&byte1, 1, 1, imdata); fread(&byte2, 1, 1, imdata);
if (byte1 != 'B' || byte2 != 'M') {
printf("Not a BMP file.\n"); exit(0);
}

fseek(imdata, 18, 0);

fread(&ncols, 4, 1, imdata); fread(&nrows, 4, 1, imdata);
if (nrows < 0) {nrows = -nrows; inv = 1;} else inv = 0;

fseek(imdata, 2, 1);
fread(&word1, 2, 1, imdata); n_bit = word1;
if (n_bit != 8) {
printf("n_bit = %d not supported.\n", n_bit); exit(0);
}

fread(&uint1, 4, 1, imdata);
if (uint1 != 0) {
printf("Compression not supported.\n"); exit(0);
}

fseek(imdata, 12, 1);
fread(&uint1, 4, 1, imdata); n_tab = uint1;
fread(&uint1, 4, 1, imdata);
fseek(imdata, 4*n_tab, 1);

ima = (unsigned char *)malloc(nrows*ncols*sizeof(unsigned char));
if (ima == NULL) {
printf("Not enough memory\n"); exit(1);
}

if (inv == 1) {
for (i=0; i }
else {
for (i=nrows-1; i>=0; i--) fread(&(ima[i*ncols]), 1, ncols, imdata);
}

fclose(imdata);

*n_col = ncols; *n_row = nrows;

return ima;
}




void bmpsave(char *imname, unsigned char *ima, int n_row, int n_col)
{
int i, j;
unsigned int uint1;
short word1;
unsigned char byte1, byte2;
FILE *imdata;

imdata = fopen(imname, "wb");
if (imdata == NULL) {
printf("%s open error.\n", imname); exit(0);
}

byte1 = 'B'; byte2 = 'M';
fwrite(&byte1, 1, 1, imdata); fwrite(&byte2, 1, 1, imdata);
uint1 = 54 + 4*256 + n_col*n_row; fwrite(&uint1, 4, 1, imdata);
word1 = 0; fwrite(&word1, 2, 1, imdata); fwrite(&word1, 2, 1, imdata);
uint1 = 54 + 4*256; fwrite(&uint1, 4, 1, imdata);
uint1 = 40; fwrite(&uint1, 4, 1, imdata);
fwrite(&n_col, 4, 1, imdata); fwrite(&n_row, 4, 1, imdata);
word1 = 1; fwrite(&word1, 2, 1, imdata);
word1 = 8; fwrite(&word1, 2, 1, imdata);
uint1 = 0; fwrite(&uint1, 4, 1, imdata);
uint1 = n_col*n_row; fwrite(&uint1, 4, 1, imdata);
j = 11811; fwrite(&j, 4, 1, imdata); fwrite(&j, 4, 1, imdata);
uint1 = 256; fwrite(&uint1, 4, 1, imdata);
uint1 = 0; fwrite(&uint1, 4, 1, imdata);

for (i=0; i<256; i++) {
byte1 = i;
fwrite(&byte1, 1, 1, imdata); fwrite(&byte1, 1, 1, imdata);
fwrite(&byte1, 1, 1, imdata); fwrite(&byte1, 1, 1, imdata);
}

for (i=n_row-1; i>=0; i--) fwrite(&(ima[i*n_col]), 1, n_col, imdata);

fclose(imdata);
}