Mechanism of AIR

Suppose you inserted data of patient 1 at 10:00:00 just before shooting a photo of the patient at 10:00:30 (photo 1). Also suppose you shot a photo of patient 2 at 10:30:00 and then inserted her data at 10:31:00 (photo 2). You can know which photo belongs to which patient by the procedure as follows.

1. Subtract the time stamp of photo 1 (10:00:30) from every data insertion time (10:00:00 of patient 1 and 10:30:00 of patient 2), resulting in 2#200:00:30 of patient 1 and 00:29:30 of patient 2.
2. Photo 1 is supposed to belong to patient 1 because the absolute value of the difference of patient 1 (1#100:00:30) is less than that of patient 2 (1#100:29:30).
3. In the same way, subtract the time stamp of photo 2 (10:31:00) from every data insertion time (10:00:00 of patient 1 and 10:30:00 of patient 2), resulting in 2#200:31:00 of patient 1 and 2#200:01:00 of patient 2.
4. Photo 2 is supposed to belong to patient 2 because the absolute value of the difference of patient 2 (1#100:01:00) is less than that of patient 2 (1#100:31:00).