Research On HgCdTe Long-wave IRFPA Readout Post-processing Technology

To realize the long-wave infrared focal plane detector readout signal post-processing, has important significance for enhancing long-wave IRFPA experimental system’s signal to noise ratio. This paper dedicated to the research for the HgCdTe LWIR Long-Wave IRFPA readout post-processing technology,research on the methods to solve the problem of the HgCdTe Long-Wave IRFPA dark current to limit the system for the long integration time required.In the new generation of three-axis stabilized geosynchronous orbit satellite platform remote sensing instrument development requirements, it is still an urgent demand for the HgCdTe long-wave IRFPA detector. However, due to the longer wavelength background radiation is strong, long-wave infrared focal plane arrays dark current is relatively large, the long-wave IRFPA detector has not yet reached the integration time the system requirements, the integrating capacitor has reached saturation. Therefore, to meet the requirements of the system long integration times, research HgCdTe Long-Wave IRFPA readout post-processing technology is important.Since the dark current of the HgCdTe long-wave IRFPA detector will limit the integration time of long-wave IRFPA detector, this paper established the appropriate model about the current mechanisms, for generating the dark current of four physical mechanism. To investigate the existence of proportional relationship between long-wave IRFPA output signal to noise ratio and the square root of the integration time.For experimental system architecture of long-wave IRFPA detector, it gives the corresponding information processing programs and processes. By discussing the different technologies to extend the equivalent integration time of the long-wave infrared focal plane experimental system, illustrating the multi-frame accumulated technology in the long-wave IRFPA readout post-processing technology is feasibility, establishing the mathematical model of multi-frame cumulative average technology to improve the focal plane experimental system signal-to-noise ratio, analyzes influence of the different noise to multi-frame accumulated improve SNR.From the perspective of the needs of low-noise, completed to design a set of the information acquisition circuitry to match HgCdTe long-wave IRFPA detector, including the driving pulse of long-wave IRFPA detector design, analog signal conditioning circuit design, data processing on-chip design, signal transmission and storage module design, and a corresponding noise model is established, and through the experiment to complete the information acquisition circuit noise test.Built experiment platform for the HgCdTe long-wave IRFPA experimental system, complete long-wave IRFPA performance parameters testing for dark current, time noise and signal to noise ratio and so on. To achieve the long-wave infrared focal plane of readout signal post-processing with multi-frame accumulation, verify that the different states of effect for the multi-frame accumulating technology to improve the signal to noise ratio of the focal plane system and reduce of noise equivalent temperature difference.