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biohistogram.cpp
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biohistogram.cpp
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/***************************************************************************
* Copyright (C) 2008-2009 by evilsocket *
* *
* evilsocket@gmail.com *
* http://www.evilsocket.net/ *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
***************************************************************************/
#include "biohistogram.h"
bio_error_t bio_histogram_compute( bio_image_t *image, bio_histogram_t *histogram ){
int x, y, offset;
memset( histogram, 0x00, sizeof(bio_histogram_t) );
histogram->mean = -1;
histogram->variance = -1;
for( y = 0; y < image->height; y++ ){
offset = image->width * y;
for( x = 0; x < image->width; x++ ){
histogram->table[ (*image)[offset++] ]++;
}
}
histogram->size = image->width * image->height;
return BIOERR_SUCCESS;
}
byte_t bio_histogram_compute_mean( bio_histogram_t *histogram ){
int i;
if( histogram->mean == -1 ){
histogram->mean = 0;
for( i = 1; i < 255; i++ ){
histogram->mean += i * histogram->table[i];
}
histogram->mean /= histogram->size;
}
return (byte_t)histogram->mean;
}
uint_t bio_histogram_compute_variance( bio_histogram_t *histogram ){
int i;
byte_t mean;
if( histogram->variance == -1 ){
histogram->variance = 0;
mean = bio_histogram_compute_mean(histogram);
for( i = 0; i < 255; i++ ){
histogram->variance += histogram->table[i] * (i - mean) * (i - mean);
}
histogram->variance /= histogram->size;
}
return (uint_t)histogram->variance;
}