Hardware Design And Implement Of Highly Sensitive320×256Cooled Infrared Imaging System

Infrared imaging technology developes rapidly and wide range of applications beginadopt this technology. Accordingly,the applications puts forward higher requirements ofinfrared imaging system performance.The imaging sensitivity which is one of mostperformance indicator determines the ability to distinguish details of temperature. Thisindicator is evaluated by noise equivalent temperature difference(NETD) and is improvedas main index in infrared imaging system all the time. Aimed at improving the imagingsensitivity,this article designs and implements a set of infrared imaging hardware circuitof infrared imaging system.Firstly, from the perspective of infrared detector and the hardware circuit,the articleanalyzes the noise of infrared imaging system hardware. Due to manufacturing materials,production processes and other factors, the infrared detector will bring in noise. Similarly,processing circuit will reduce signal noise ratio, because of the circuit device, circuitconfiguration, environmental factors and other reasons. After analysis, the detector biasvoltage and the disruption of output pixel signal will seriously affect the system’s imagingsensitivity. Therefore, in the infrared imaging system, stable detector bias and a reasonablepixel signal conditioning circuit will be an important technical means to improve thesensitivity of the system.Based on the ideas above, this article proposes a set of differential analog processingscheme to suppress common mode noise in analog conditioning and acquisitionprocessing. After analyzing functional requirements of infrared imaging,the articlecompletes the hardware architecture design. In order to reduce system noise equivalenttemperature difference, the power supply circuit, detector bias circuit and conditioningacquisition circuit are introduced in detail. At last, the article presents the PCB design andfinished320×256cooled infrared imaging system debugging and implementation.In the actual test, the imaging system output frame rate is100Hz and the NETD is24.4mK.Compared to most of the infrared imaging systems’s NETD of30mK,which workat output frame rate of100Hz, the system introduced in the article achieved a betterimaging sensitivity and verifed the performance of the system hardware.