ABSTRACT

The work proposes a novel method for sensitivity modelling of uncooled thermal cameras for optical gas imaging purposes. Such cameras use warm interference filters for better gas leak contrast at the cost of decreased sensitivity. With the presented method, it is possible to estimate this sensitivity without the need for physically installing a filter inside the camera. It can be done for any chosen background temperature and an arbitrary filter with known spectral transmission characteristic, which is often found in the filter manufacturer’s documentation. The proposed method requires prior measurement of the camera calibration curve before filter installation. In addition, this method may be used for estimating, how camera noise equivalent temperature difference will change after filter installation. With the aid of new parameter gas equivalent blackbody digital level difference, one may also verify, whether in particular measurement scenario gas leak will be visible or not. The performance of the proposed method is validated with five different filters and broadband uncooled thermal imaging camera.

摘要

这项工作提出了一种用于光学气体成像目的的非制冷热像仪灵敏度建模的新方法。这种相机使用暖干涉滤光片来获得更好的气体泄漏对比度，但会降低灵敏度。使用所提出的方法，可以估计这种灵敏度，而无需在相机内物理安装过滤器。它可以针对任何选定的背景温度和具有已知光谱透射特性的任意滤光片进行，这通常在滤光片制造商的文档中找到。所提出的方法需要在安装过滤器之前预先测量相机校准曲线。此外，该方法还可用于估计安装滤波器后相机噪声等效温差将如何变化。借助新参数气体当量黑体数字电平差，还可以验证在特定测量场景中气体泄漏是否可见。所提出的方法的性能通过五种不同的滤波器和宽带非制冷热像仪进行了验证。