Taking a step back in time, the characteristics of infrared radiation from the human body were employed by the security industry and used as a base for the development of PIRs (passive infrared detectors). Infrared waves radiate from the human body at 3~50μm, amongst them, the 8~14μm spectrum occupies 46 percent, and the peak radiation is reflected at around 9.5μm. At the same time, the body emission rate is as high as 0.95, much higher than that of the emission levels of the general  environment.  This means that even if the human body and the environment temperature are exactly the same, then the human body can still be easily distinguished from its surroundings.

The infrared detector output of a visual processing image is called " infrared thermal imaging ".  The visualised processed image emitted by an infrared detector is referred to as thermography. Radiating capacity of different objects, even different parts from the same object is diverse, as well as their reflection to radiation. Utilising radiation differentiates objects from their environment, and also differentiates from each part of a scene. Thermography can present each scene as part of a radiating fluctuation to display the thermal energy distribution of the scenario. It is like a third human eye being able to visualise the imperceptible world beyond human recognition.

Sunell has recently released its latest thermal bullet network camera, SN-TPC4200K, which includes features such as a non-refrigeration IRFPA sensor, infrared long-waves 8~14um, at 420×315 pixels, high thermal sensitivity up to 50mK, with an 8 / 15 / 25 / 35 / 50 mm parfocal prime lens (optional),  pseudo colour mode shift (black hot/white heat/iron red), and  DVE image enhancement.

As one of the mainstream CCTV providers in China, Sunell is presenting the market with this latest cutting-edge thermal IP camera, aimed at providing industrial professionals with a complete solution for large project applications, such as forest fire prevention, security monitoring and control for airports, breeding industry monitoring, important cultural relic monitoring, red tide monitoring, border monitoring, coastal defense monitoring, individual combat systems for public security and armed police, flood control monitoring at nuclear power plants, transformer substations, hydropower stations, reservoirs, dams and lakes, maritime ports and piers, marine environmental protection, maritime petroleum detection, overhead lookout in cities, night viewing in oil fields, night viewing in large factories and the monitoring of petroleum transport pipelines, natural gas pipelines, ship dispatch systems, uninhabited islands and ancient tombs etc.

Featuring some of the latest and advanced technologies, Sunell is planning for their thermal network camera to take leading position among others in the global market.