制冷探測器積分時(shí)間與SNR分析

劉寧，陳錢。顧國華，隋修寶

(南京理工大學(xué)光電工程國防重點(diǎn)實(shí)驗(yàn)室，江蘇南京210094)

摘要：對國產(chǎn)640x512中波凝視型制冷焦平面探測器的積分時(shí)間與信噪比(SNR)之間的關(guān)系進(jìn)行了研究，以積分時(shí)間與探測器輸出信號(hào)和噪聲關(guān)系的原理為基礎(chǔ)。分別對探測器正常工作時(shí)的輸出信號(hào)情況以及輸出噪聲情況做了仔細(xì)的分析。文中分析了隨著積分時(shí)間的增加，實(shí)際測器輸出信號(hào)和噪聲信號(hào)各自的增長關(guān)系，并通過大量的數(shù)據(jù)和圖表印證了這種關(guān)系的正確性，并z*終得出了積分時(shí)間對探測器信噪比的影響程度，給出了z*佳工作積分時(shí)間。

關(guān)鍵詞：制冷探測器; 積分時(shí)間; 信噪比

中圖分類號(hào)：TN216 文獻(xiàn)標(biāo)志碼：A 文章編號(hào)：1007-2276(2012)01-0043-06

Analysis on the integration time and SNR of

640×512 cooled IR detector’

Liu Ning，Chen Qian，Gu Guohua，Sui Xiubao

(National Defense Key Laboratory of Optoelectronic Engineering，Nanjmg University of Science and

Technology Nanjing.210094.China)Abstract：SNR is a crucial parameter of the detector.In this paper，it was mainly concenffated on theanalysis on the relationship between the integration time and the SNR of the domestic 640x512 MWIRcooled detector.Based on the theory of the fact that the integration time is corresponding to the signaland the noise，a lot of work was done which focused on these two aspects in the separate way when thedetector was working under the normal condition.A large number of experimental data was analyzedwhich demonstrated the increasing relationship between the detector’S output signal and the noise signalwhile the integration time was changed.The experimental and the theoretical analyzed results bothconcluded the impact of the integration time to the SNR.Finally，the most optimal integration time WaSsubmitted.

Key words：cooled detector; integration time; SNR

O引言

信噪比(SNR)是評價(jià)探測器性能的一項(xiàng)重要指標(biāo)，對于直接注入式的制冷型探測器，焦平面本身就是主要的噪聲源。焦平面由探測器象元陣列和讀出電路組成，象元陣列將光輻射通量轉(zhuǎn)化為光電流，進(jìn)而經(jīng)過讀出電路的積分放大后被輸出，這種輸出電流就是z*主要的信號(hào)源和噪聲源¨1。一些已知的方法可以用來提高SNR值：帶寬限制，增大光學(xué)系統(tǒng)孔徑，加長積分時(shí)間和使用噪聲更低以及對光輻射更加敏感的探測器12l。

文中以與國內(nèi)某著名研究所合作國產(chǎn)640x512凝視型中波制冷熱像儀整機(jī)項(xiàng)目為基礎(chǔ)，分析了探測器原始輸出響應(yīng)以及總噪聲與有效積分時(shí)間的關(guān)系，并在帶寬、光學(xué)系統(tǒng)孔徑和探測器對光輻射的敏感程度都固定的情況下，通過調(diào)整積分時(shí)間來對探測器原始輸出信號(hào)的SNR進(jìn)行分析，并通過實(shí)驗(yàn)數(shù)據(jù)的結(jié)果得出使用該國產(chǎn)探測器的z*佳積分時(shí)間。

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