The infrared system is the most widely used term, followed by the infrared imaging system. Infrared systems can be classified in a variety of ways.
According to whether the detected target is a point heat source target or an extended source target classification: point target infrared detection system; imaging detection system; sub-imaging detection system.
For any infrared imaging system, when the target distance is far enough, all the detected points are points. The advantage of using the infrared focal plane detector to develop the point source infrared detection system is that a sufficiently large field of view can be obtained in at least one direction, reducing The complexity of the optical system in this direction. At present, the sub-imaging detection system is mainly used for the terminal guidance of precision guided munitions. A simple scanning method and a detector array with a small number of detecting elements, such as a rose line scanning mechanism and a quaternary infrared detector, can be used to obtain the characteristics of the target from the generated thermal image to minimize the cost.
Thermal imaging systems can be divided into passive infrared imaging systems and active infrared imaging systems by active imaging or passive imaging.
The thermal imaging system refers to the real-time passive imaging of the room temperature target by using the long-wave infrared and medium-wave infrared bands of the atmospheric window. It is imaged by the long-wave infrared and medium-wave infrared radiation of the target's own radiation. A device for real-time infrared imaging using target reflection moonlight, atmospheric glow, and short-wave infrared radiation in night sky light is a passive infrared imaging system. Devices that rely on artificial infrared light sources to illuminate targets to achieve infrared imaging, including those operating in the long-wave, medium-wave, and short-wave infrared bands, are called active infrared imaging systems.
According to whether the infrared imaging system requires optomechanical scanner classification: scanning infrared imaging system; gaze-type infrared imaging system.
Line-column focal plane detectors with TDI functions such as 288×4, 480×6, 768×8 are currently the mainstream of long-wave infrared focal plane detectors, taking into account key factors such as thermal sensitivity, spatial resolution and price, especially suitable for For a variety of viewing-type thermal imaging cameras, infrared search and tracking systems, infrared scanning devices.
To improve spatial resolution, some gaze-type infrared imaging systems (including uncooled thermal imaging cameras) also use micro-scanning mechanisms. Such infrared imaging systems are also classified as scanning infrared imaging systems. In general, uncooled thermal imaging cameras use a gaze-type infrared focal plane detector that does not scan. However, some special uncooled thermal imaging systems use uncooled line-column focal plane detectors, instead of using optical mechanical scanners, instead use the target's own motion to achieve thermal imaging. This is applied in industrial capitals such as quality control. For example, the monitoring of the axle of a train is to achieve thermal imaging using the motion of the train.
According to whether the system has a refrigeration device, it is divided into a cooling type thermal imager and an uncooled type thermal imager.
The performance of the cooling type thermal imager is high, but the price is high, the volume and weight are relatively large, and the reliability is not high. The uncooled thermal imager is not as cool as the refrigeration type, but the price is small, the volume is small, and the weight is light. In particular, the refrigeration device is omitted, so the reliability is very high, and it has broad application prospects in the low-end application and civil use of the military city.
According to the working band of the system, it is divided into long-wave infrared thermal imager, medium-wave infrared thermal imager, short-wave infrared thermal imager, dual-band infrared thermal imager and multi-band infrared thermal imager.
According to the purpose and technical characteristics of the system, it is divided into platform view type thermal imager, portable thermal imager, guided thermal imager, infrared search and tracking system, and infrared line scanter.