int
motion_count(Mat I) {

	const int size = motion_mask_size;
	resize(I, I, Size(size, size), 0, 0, INTER_NEAREST);

	int i = 0;

	int count = 0;

	for (
		MatConstIterator_<uchar>

		it  = I.begin<uchar>(),
		end = I.end<uchar>();

		it != end;
		it++
	) {

		const bool b = *it == 0 ? false : true;

		if (b) {
			count++;
		}
	}

	return count;
}