main.c

eye tracking source code. used for hci.

/*
 * EyeTracking 1.0 - Display video from webcam and track user's eye with
 * manually selected template.
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 * @author 	  Nashruddin Amin <[e-mail]>
 * @copyright Nashruddin Amin 2008
 * @license	  GNU General Public License 3.0
 * @version   1.0
 * @website	  http://www.nashruddin.com
 */

 #include "main.h"

int main( int argc, char** argv )
{
	CvCapture	*capture;
	int			key;

	display_info();
	
	/* initialize webcam */
	capture = cvCaptureFromCAM( 0 );

	/* always check */
	if( !capture ) {
		fprintf( stderr, "Cannot initialize webcam!\n" );
		return 1;
	}
	
	/* test camera */
	if( !cvGrabFrame( capture ) ) {
		fprintf( stderr, "Could not grab a frame!\n" );
		return 1; 
	}

	/* get a frame to get video properties, needed by template image */
	frame = cvRetrieveFrame( capture );
	
	/* create template image */
	tpl = cvCreateImage( cvSize( TPL_WIDTH, TPL_HEIGHT ), 
						 frame->depth, frame->nChannels );

	/* image for template matching result */
	match_res = cvCreateImage( cvSize( 2 * SEARCH_RANGE_X + 1,
									   2 * SEARCH_RANGE_Y + 1 ),
							   IPL_DEPTH_32F, 1 );

	/* create GUI */
	cvNamedWindow( "video", CV_WINDOW_AUTOSIZE );
	cvShowImage( "video", frame );

	/* install mouse hander */
	cvSetMouseCallback( "video", mouse_handler, NULL );

	while( TRUE ) {	/* display forever */
		if( !cvGrabFrame( capture ) ) {
			fprintf( stderr, "Could not grab a frame!\n" );
			return 1; 
		}

		/* get a frame */
		frame = cvRetrieveFrame( capture );

		/* 'fix' frame */
		cvFlip( frame, frame, -1 );
		frame->origin = 0;

		/* track object if template has been selected */
		if( state == STATE_TRACKING ) {
			track_object();
		}
		
		/* display video */
		cvShowImage( "video", frame );

		/* exit if user press a key */
		if( ( key = cvWaitKey( 1 ) ) >= 0 ) {
			goto done;
		}
	}

done:
	/* free memory */
	cvDestroyWindow( "video" );
	cvReleaseCapture( &capture );

	return 0;
}

/**
 * mouse handler
 */
void mouse_handler( int event, int x, int y, int flags, void *param )
{
	if( event == CV_EVENT_LBUTTONUP ) {
		object_x0	  = x - ( TPL_WIDTH / 2 );
		object_y0     = y - ( TPL_HEIGHT / 2 );	
		object_x0_ini = object_x0;
		object_y0_ini = object_y0;

		/* extract template from frame */
		cvSetImageROI( frame, cvRect( object_x0, 
									  object_y0, 
									  TPL_WIDTH, 
									  TPL_HEIGHT ) );
		cvCopy( frame, tpl, NULL );
		cvResetImageROI( frame );

		/* template has been extracted, start tracking! */
		state = STATE_TRACKING;
	}
}

/**
 * function to track object
 */
void track_object()
{
	int		win_x0, win_y0, win_x1, win_y1;
	CvPoint	minloc, maxloc;
	double	minval, maxval;

	/* setup search window */
	win_x0 = object_x0 - SEARCH_RANGE_X;
	win_y0 = object_y0 - SEARCH_RANGE_Y;
	win_x1 = win_x0 + TPL_WIDTH  + ( 2 * SEARCH_RANGE_X );
	win_y1 = win_y0 + TPL_HEIGHT + ( 2 * SEARCH_RANGE_Y );

	/* make sure the window still inside the frame */
	if( win_x0 < 0 ) {
		win_x0 = 0;
		win_x1 = TPL_WIDTH + ( 2 * SEARCH_RANGE_X );
	}
	
	if( win_y0 < 0 ) {
		win_y0 = 0;
		win_y1 = TPL_HEIGHT + ( 2 * SEARCH_RANGE_Y );
	}

	if( win_x1 > frame->width ) {
		win_x1 = frame->width;
		win_x0 = frame->width - TPL_WIDTH - ( 2 * SEARCH_RANGE_X );
	}

	if( win_y1 > frame->height ) {
		win_y1 = frame->height;
		win_y0 = frame->height - TPL_HEIGHT - ( 2 * SEARCH_RANGE_Y );
	}

	/* draw window */
	/*
	cvRectangle( frame,
				 cvPoint( win_x0, win_y0 ),
				 cvPoint( win_x1, win_y1 ),
				 cvScalar( 0, 255, 0, 0 ), 
				 1, 0, 0 );
	*/
	
	/* apply window to frame */
	cvSetImageROI( frame, cvRect( win_x0, 
								  win_y0, 
								  win_x1 - win_x0, 
								  win_y1 - win_y0 ) );

	/* search for matching object */
	cvMatchTemplate( frame, tpl, match_res, CV_TM_SQDIFF_NORMED );
	cvMinMaxLoc( match_res, &minval, &maxval, &minloc, &maxloc, 0 );

	/* clear window */
	cvResetImageROI( frame );

	/* if object found... */
	if( minval <= THRESHOLD ) {
		/* save object's current location */
		object_x0 = object_x0 - SEARCH_RANGE_X + minloc.x;
		object_y0 = object_y0 - SEARCH_RANGE_Y + minloc.y;

		/* and draw a box there */
		cvRectangle( frame,
					 cvPoint( object_x0, object_y0 ),
					 cvPoint( object_x0 + TPL_WIDTH, object_y0 + TPL_HEIGHT ),
					 cvScalar( 0, 0, 255, 0 ), 1, 0, 0 );
	}
	/* if not found... */
	else {
		/* search around initialization area */
		object_x0 = object_x0_ini;
		object_y0 = object_y0_ini;
	}
}

void display_info()
{
	fprintf( stdout, "EyeTracking 1.0 - Track user's eye with manually selected template\n" );
	fprintf( stdout, "Author:  Nashruddin Amin ([e-mail])\n" );
	fprintf( stdout, "Website: http://www.nashruddin.com\n\n" );
	fprintf( stdout, "Enjoy!\n" );
}