Matlab function that can tell when no person is present
function result = person_present(img_string)
% Determines if a person is present in the frame or not
%
% Return values:
% 1 - person present
% 0 - person not present
[name, frame] = parse_frame_name(img_string);
zero_frame = make_frame_name(name, 0);
zero_image = read_gray(zero_frame);
image = read_gray(img_string);
diff = abs(zero_image - image);
threshold = 10;
t = (diff > threshold);
[labels, number] = bwlabel(t, 4);
counters = zeros(1, number);
for i = 1:number
component_image = (labels == i);
counters(i) = sum(component_image(:));
end
[area, id] = max(counters);
if area > 1000
result = 1;
else
result = 0;
end