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/*
* itrans-zaefferer.c
*
* Zaefferer peak search
*
* (c) 2007 Thomas White <taw27@cam.ac.uk>
*
* dtr - Diffraction Tomography Reconstruction
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdint.h>
#include <assert.h>
#include "utils.h"
#include "image.h"
#define PEAK_WINDOW_SIZE 20
ImageFeatureList *itrans_peaksearch_zaefferer(ImageRecord *imagerecord) {
int x, y;
int width, height;
uint16_t *image;
ImageFeatureList *flist;
flist = image_feature_list_new();
image = imagerecord->image;
width = imagerecord->width;
height = imagerecord->height;
for ( x=1; x<width-1; x++ ) {
for ( y=1; y<height-1; y++ ) {
double dx1, dx2, dy1, dy2;
double dxs, dys;
double grad;
/* Get gradients */
dx1 = image[x+width*y] - image[(x+1)+width*y];
dx2 = image[(x-1)+width*y] - image[x+width*y];
dy1 = image[x+width*y] - image[(x+1)+width*(y+1)];
dy2 = image[x+width*(y-1)] - image[x+width*y];
/* Average gradient measurements from both sides */
dxs = ((dx1*dx1) + (dx2*dx2)) / 2;
dys = ((dy1*dy1) + (dy2*dy2)) / 2;
/* Calculate overall gradient */
grad = dxs + dys;
if ( grad > 400 ) {
int mask_x, mask_y;
int sx, sy;
double max;
unsigned int did_something = 1;
mask_x = x;
mask_y = y;
while ( (did_something) && (distance(mask_x, mask_y, x, y)<50) ) {
max = image[mask_x+width*mask_y];
did_something = 0;
for ( sy=biggest(mask_y-PEAK_WINDOW_SIZE/2, 0); sy<smallest(mask_y+PEAK_WINDOW_SIZE/2, height); sy++ ) {
for ( sx=biggest(mask_x-PEAK_WINDOW_SIZE/2, 0); sx<smallest(mask_x+PEAK_WINDOW_SIZE/2, width); sx++ ) {
if ( image[sx+width*sy] > max ) {
max = image[sx+width*sy];
mask_x = sx;
mask_y = sy;
did_something = 1;
}
}
}
}
if ( !did_something ) {
assert(mask_x<width);
assert(mask_y<height);
assert(mask_x>=0);
assert(mask_y>=0);
image_add_feature(flist, mask_x, mask_y, imagerecord, image[mask_x + width*mask_y]);
}
}
}
}
return flist;
}
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