In infrared (IR) conditions, which characteristic can be used to identify someone?

• A. Arm swing
• B. Foot splay
• C. Relative height and build
• D. Mannerisms

Answer: (C)

In infrared imaging, identification relies on stable physical traits that appear in the thermal silhouette rather than on fine appearance details or movement cues. Height and overall body build are the most reliable of these, because they reflect a person’s typical size and proportions and tend to remain consistent across different conditions and clothing. The other cues—arm movements, foot placement, and general mannerisms—are dynamic and can change with pace, stance, footwear, or masking, making them less dependable in IR. So the most dependable identifying trait in infrared conditions is a person’s relative height and build.