微量气体泄漏红外差分成像与探测性能理论研究

Great damage to safety production and environment will be induced if the leakage of inflammable, explosive, toxic and harmful industrial gases not be detected in time. Gas leakage infrared imaging can present spatial distribution and diffusion tendency of gas, locate leakage spot, and own advantages of long monitoring distance and detecting multiple gases simultaneously. Towards the needs of high sensitivity, high signal-to-noise (SNR) ratio and fast response, a kind of Archimedes' spiral cord push-broom broad-band long-pass filtering infrared differential imaging method is proposed. Broad-band long-pass filter can transmit high infrared radiance, high SNR is guaranteed. Differential calculation between two broad-band long-pass filters plays same role as narrow-band filter, and the area of leakage gas can acquire good contrast. When the square filter plane constructed by Archimedes' spiral cord filters rotate continuously, it push broom infrared focal plane array (FPA) uniformly and realize fast imaging. Aiming at the characteristics of gas of dynamic diffusion and weak signal, quantification of mean concentration and absorption path length of leakage gas is researched. The Johnson target detection criterion is modified or a novel gas leakage infrared imaging detection criterion is proposed. At last, the detecting theory of gas leakage infrared imaging is established. Moreover, the method and setup of measuring the least detectable gas concentration is worked on.

易燃易爆、有毒有害工业气体的泄漏如果探测不及时，将对安全生产和环境造成极大损害。泄漏气体红外成像技术能够快速、大视场成像泄漏气体的空间分布和扩散趋势，准确定位泄漏点，并具有监测距离远、成像多种气体的优点。针对高灵敏度、高信噪比、快速成像微量气体泄漏的需求，提出阿基米德螺旋线推扫宽带长通滤光的差分成像方法。宽带长通滤光片透过的光能量高，保证较高的图像信噪比；多片宽带长通滤光片图像之间的差分计算起到窄带滤光和运动信息检测的作用，保证高灵敏度的泄漏气体红外成像；阿基米德螺旋线形滤光片构成的圆形滤光盘连续转动，逐行对红外焦平面探测器均匀推扫，保证泄漏气体的快速成像。针对泄漏气体动态扩散、信号微弱的特点，研究泄漏气体平均浓度和吸收路径长度非线性变化的定量化，修正目标探测约翰逊准则或提出一种新的泄漏气体红外成像探测准则，建立泄漏气体红外成像的探测理论模型，并研究泄漏气体最小可探测浓度的测量方法和装置。

泄漏气体红外成像技术能够快速、大视场成像泄漏气体的空间分布和扩散趋势，准确定位泄漏点，并具有监测距离远、成像多种气体的优点。非制冷红外焦平面探测器在成本方面具有优势，但其用于多波段红外成像时受限于低帧率和低灵敏度。本项目针对高灵敏度、高信噪比、快速成像微量气体泄漏的需求，提出阿基米德螺旋线形滤光盘的概念，其能近似直线地逐行对红外焦平面探测器均匀推扫，保证泄漏气体的快速成像。 以阿基米德螺旋线形滤光盘为基础提出阿基米德螺旋线推扫宽带长通滤光的差分成像方法，宽带长通滤光片透过的光能量高，保证较高的图像信噪比；多片宽带长通滤光片图像之间的差分计算起到窄带滤光和运动信息检测的作用，保证高灵敏度的泄漏气体红外成像；研究了阿基米德螺旋线推扫非制冷红外焦平面探测器的数学模型及其参数优化方法；提出了针对待探测泄漏气体红外吸收峰优化选择差分波段的方法，建立权衡图像信噪比和对比度的F1因子，通过最大化F1因子选择最佳的气体滤光片和背景滤光片起始波长；本项目最后研制了双波段四区域阿盘推扫系统样机。室内和外场实验结果表明：样机可探测到泄漏速率为11ml/min的乙烯气体，成像帧频为8Hz。.发表SCI论文5篇，其中顶级期刊论文1篇；发表EI论文5篇，发表国内核心期刊论文3篇；授权4项国家发明专利。.共培养研究生13名，其中毕业博士生3名、毕业硕士生6名、在读博士生3名、在读硕士生1名。