Infrared Imaging Systems Tending towards High Definition and Digitization
向高清化和数字化发展的红外成像系统

High definition infrared imaging systems are those thermal imagers that have higher spatial resolution without sacrificing thermal sensitivity and generate video signals according to the high definition television standards (1280?1024, 1920?1080 or 1280?720). The higher the spatial resolution is, the smaller the detectable target is and the farther the target is from. The improvement of spatial resolution means that the number of detector pixels is increased, the pixel pitch is decreased and the signal-to-noise ratio in each pixel is enhanced. Digitization involves the incorporation of an analog-to-digital converter (ADC) into a readout integrated circuit (ROIC). Analog-to-digital conversion can be implemented with a high speed ADC at the chip level or be implemented with multiple medium speed ADCs at the column level or be implemented with multiple low speed ADCs at the pixel level. Because only digital data need to be transferred, the ADC at the pixel level is helpful to the reduction of system noise and is suited for implementation in the standard digital CMOS process. The recent advances and trends of infrared imaging systems in the aspects of high definition and digitization are presented.