function img=grabimage(shutter_time, Naverages)
% This funcion calls the external program which takes an image from camera 
% with apropriate settings.
cmnd_string = horzcat('grabNimages_1394cam.exe', ' -s ',num2str(shutter_time),' -n ',num2str(Naverages));
[status,result] = system(cmnd_string);
% by default our grabber save png image to this file name
image_name = 'test.png';
img=imread(image_name);