Medium-wave infrared camera imaging system and its application

Principles and Characteristics of Mid-Wave Infrared Imaging According to Rayleigh scattering law, when electromagnetic waves pass through the atmosphere, the ability to penetrate fog and haze is related to the wavelength of the electromagnetic wave. The longer the wavelength, the stronger the penetration ability. Therefore, compared with electromagnetic waves in the visible-near-infrared band, the mid-wave infrared has a longer wavelength, can better penetrate the haze, and is less affected by bad weather. On the other hand, the electromagnetic waves applied in remote sensing imaging are divided into two types: electromagnetic waves reflected from the sun by air objects and electromagnetic waves emitted by themselves. The mid-wave infrared band is included in both the emission spectrum of the sun and the emission spectrum of the earth's surface. Therefore, the medium wave infrared image contains both the reflected radiation and the emitted radiation of the ground objects, and more information of the ground objects can be obtained. Unlike remote sensing cameras in the visible-near-infrared band, which use semiconductor photocells as the basic photosensitive elements, mid-infrared detectors require a common indium antimonide (InSb) photosensitive material for imaging, and often require cooling equipment to ensure photosensitive imaging. Effect. The common imaging mechanism makes the manufacturing process of the medium-wave infrared camera very complicated, and the technological development is far behind the camera in the visible-near infrared band, and it is very difficult to manufacture a large-scale and wide medium-wave infrared camera. At the same time, due to the high military value of mid-wave infrared cameras, foreign countries have suspended long-term technical blockades and product bans on my country. At present, the image size of domestic mid-infrared cameras that can be used for civilian use is very small. At present, the widest mid-infrared camera reported in China is the megapixel mid-infrared camera (1024*1024 pixels) carried by the Gaofen-4 satellite. The most common ones on the market are still cameras with 512*512 pixels or even smaller widths. Obviously, it is difficult for such a large-sized camera to be mounted on an airplane to complete continuous coverage of a large area. Certain methods must be used to improve the wide coverage of the camera. competence. Application of Medium Wave Infrared Image in Land Information Extraction The use of medium wave infrared images can extract various land resource information, such as the processing of Daye City image processing to extract various building land correlation information. According to the relationship between the electromagnetic waves radiated by ground objects in the mid-infrared band and the temperature, the mid-infrared image can be used to invert the temperature of each pixel, and then the air temperature field in the entire image range can be obtained. The result is shown in Figure 3(c). It can be seen from the figure that the "heat island effect" is very obvious in urban areas, with higher temperatures, while the temperature in rural areas is lower and the temperature of waters is the lowest. Using the spectral characteristics of different objects in the mid-infrared band and visible light band, the air temperature information and the shape characteristics of artificial objects can be used to obtain the classification results of different objects in the air. As shown in Figure 3(d), the images are classified into residential areas, factories, roads, bare ground, vegetation, water bodies and other objects. From Figure 3(c) and Figure 3(d), it can be further seen that in urban areas, the area with dense factories and workshops has the highest temperature, and the asphalt road is also very hot under the sunlight in summer.