/**************************************************
*
* variance(...
*
* This function replaces the pixel in the center
* of a 3x3 area with the square root of the
* sum of squares of the differences between
* the center pixel and its eight neighbors.
*
**************************************************/
variance(in_name, out_name, the_image, out_image,
il, ie, ll, le, threshold, high)
char in_name[], out_name[];
int il, ie, ll, le, high, threshold;
short the_image[ROWS][COLS],
out_image[ROWS][COLS];
{
int a, b, diff, i, j, length,
max, new_hi, new_low, width;
long sum = 0;
struct tiff_header_struct image_header;
if(does_not_exist(out_name)){
printf("\n\noutput file does not exist %s",
out_name);
read_tiff_header(in_name, &image_header);
round_off_image_size(&image_header,
&length, &width);
image_header.image_length = length*ROWS;
image_header.image_width = width*COLS;
create_allocate_tiff_file(out_name, &image_header,
out_image);
} /* ends if doe_ not_exist */
read_tiff_header(in_name, &image_header);
new_hi = 250;
new_low = 16;
if(image_header.bits_per_pixel == 4){
new_hi = 10;
new_low = 3;
}
max = 255;
if(image_header.bits_per_pixel == 4)
max = 16;
read_tiff_image(in_name, the_image, il, ie, ll, le);
for(i=1; i<ROWS-1; i++){
if( (i%10) == 0) printf("%3d", i);
for(j=1; j<COLS-1; j++){
sum = 0;
for(a=-1; a<=1; a++){
for(b=-1; b<=1; b++){
if( a!=0 && b!=0){
diff = 0;
diff = the_image[i][j] -
the_image[i+a][j+b];
diff = diff*diff;
sum = sum + diff;
}
}
}
sum = sqrt(sum);
if(sum > max) sum = max;
out_image[i][j] = sum;
} /* ends loop over j */
} /* ends loop over i */
/* if desired, threshold the output image */
if(threshold == 1){
for(i=0; i<ROWS; i++){
for(j=0; j<COLS; j++){
if(out_image[i][j] > high){
out_image[i][j] = new_hi;
}
else{
out_image[i][j] = new_low;
}
}
}
} /* ends if threshold == 1 */
fix_edges(out_image, 1);
write_array_into_tiff_image(out_name, out_image,
il, ie, ll, le);
} /* ends variance */
/*******************************************
*
* range(..
*
* This edge detector performs the
* range operation.
* It replaces the pixel at the center of a
* 3x3, 5x5, etc. area with the max - min
* for that area.
*
*******************************************/
range(in_name, out_name, the_image, out_image,
il, ie, ll, le, size, threshold, high)
char in_name[], out_name[];
int il, ie, ll, le,
high, threshold, size;
short the_image[ROWS][COLS],
out_image[ROWS][COLS];
{
int a, b, count, i, j, k,
new_hi, new_low, length,
sd2, sd2p1, ss, width;
short *elements;
struct tiff_header_struct image_header;
sd2 = size/2;
sd2p1 = sd2 + 1;
/**********************************************
*
* Allocate the elements array large enough
* to hold size*size shorts.
*
***********************************************/
ss = size*size;
elements = (short *) malloc(ss * sizeof(short));
if(does_not_exist(out_name)){
printf("\n\n output file does not exist %s",
out_name);
read_tiff_header(in_name, &image_header);
round off_image_size(&image_header,
&length, &width);
image_header.image_length = length*ROWS;
image_header.image_width = width*COLS;
create_allocate_tiff_file(out_name,
&image_header,
out_image);
} /* ends if does_not_exist */
read_tiff_image(in_name, the_image, il, ie, ll, le);
new_hi = 250;
new_low = 16;
if(image_header.bits_per_pixel == 4){
new_hi = 10;
new_low = 3;
}
/***************************
*
* Loop over image array
*
****************************/
printf("\n");
for(i=sd2; i<ROWS-sd2; i++){
if( (i%10) == 0) printf("%d ", i);
for(j=sd2; j<COLS-sd2; j++){
count = 0;
for(a=-sd2; a<sd2p1; a++){
for (b=-sd2; b<sd2p1; b++){
elements[count] = the_image[i+a][j+b];
count++;
}
}
sort_elements(elements, &ss);
out_image[i][j] = elements[ss-1]-elements[0];
} /* ends loop over j */
} /* ends loop over i */
/* if desired, threshold the output image */
if(threshold == 1){
for(i=0; i<ROWS; i++){
for(j=0; j<COLS; j++){
if(out_image[i][j] > high){
out_image[i][j] = new_hi;
}
else{
out_image[i][j] = new_low;
}
}
}
} /* ends if threshold == 1 */
fix_edges(out_image, sd2);
write_array_into_tiff_image(out_name, out_image,
il, ie, ll, le);
free(elements);
} /* ends range */
/* End of File */