Infrared detection devices
Infrared detection devices are specialized instruments that detect infrared radiation, which is part of the electromagnetic spectrum, encompassing wavelengths longer than visible light but shorter than microwaves. The infrared spectrum is categorized into three types: near infrared, mid-infrared, and far infrared, with far infrared being the longest wavelength and associated with the thermal energy emitted by most objects. These devices are primarily used to identify heat signatures from various sources, including living beings and inanimate objects. They can detect temperature variations ranging from -20 degrees Celsius to 2,000 degrees Celsius, showcasing high sensitivity to even slight temperature differences.
Infrared detectors collect and analyze infrared waves, presenting the data visually, often using color-coded displays to indicate varying temperatures. They come in various forms, from handheld gadgets to larger, stationary units that may require cooling systems. While smaller devices might be less accurate, they are also more portable and durable. Infrared detection devices have critical applications in law enforcement, enabling officers to locate hidden individuals, conduct nighttime searches discreetly, and monitor areas from aerial vehicles. Additionally, they can be utilized to detect the heat of running engines in vehicles, highlighting their versatility in security and surveillance contexts.
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Subject Terms
Infrared detection devices
Definition: Instruments capable of detecting the presence of infrared light.
Significance: Because infrared light is present in the heat given off by the human body, infrared detection devices are useful for law-enforcement and military personnel who need to locate persons who are hidden, whether by darkness or by line of sight. Such devices are also sometimes used to detect other sources of heat that may be of interest to law enforcement, such as the lamps that are often used in the growing of marijuana indoors.
Infrared light is the part of the electromagnetic spectrum that involves wavelengths longer than those that can be seen by the human eye (visible light) but shorter than microwaves. Infrared light is divided into three subcategories: near infrared, mid-infrared, and far infrared. Near infrared has the shortest wavelengths, and far infrared has the longest wavelengths. The heat given off by most objects as thermal energy is far infrared.
Most infrared detection devices are designed to detect the infrared waves given off by an object that is emitting heat, such as a live person or animal. Many such devices can detect objects as cold as –20 degrees Celsius (–4 degrees Fahrenheit) and as hot as 2,000 degrees Celsius (3,200 degrees Fahrenheit). Many are also extremely sensitive and can detect temperature differences of less than a single degree.
Infrared detection devices work by collecting the infrared waves that are emanating from the area in question and then analyzing the data received. The data are then presented in a user-friendly form, usually as a visual display in which different temperatures are represented by different colors. Many infrared detection devices also have complex software to help enhance the images for greater usability. Infrared detection devices are available in many sizes and types, from handheld devices and goggles to large machines that require constant cooling. Generally, smaller, portable devices are less accurate than larger ones, but they also tend to be less fragile. Some infrared detection devices include cameras that allow them to record infrared information.
Infrared detection devices have many different uses that can benefit law-enforcement personnel. Such instruments can be used to find persons who are hidden behind bushes, fences, or walls or who are otherwise obscured from view. They can also be used to search for suspects at night, especially when police officers do not want to give away their own locations by using flashlights and other visible search equipment. Law-enforcement personnel can also use infrared detection devices from helicopters to search the ground below, such as to follow fleeing suspects. These instruments are also sometimes used to scan rows of cars to determine if any of them have recently had their engines running.
Bibliography
Henini, Mohamed, and Manijeh Razeghi, eds. Handbook of Infrared Detection Technologies. New York: Elsevier, 2002.
Rogalski, Antoni, ed. Selected Papers on Infrared Detectors: Developments. Bellingham, Wash.: SPIE Press, 2004.