Demonstration of a cost-effective single-pixel UV camera for flame chemiluminescence imaging

Combustion is the dominant form of energy conversion for a span of power systems such as engines and power plant boilers. It is an extremely complicated process which produces a huge number of intermediate products that usually feature non-uniform spatial distributions. Among those intermediate products, free radicals emitting in the UV band are of special interest because they contain abundant useful information of the target flame. Imaging methods such as planar laser-induced fluorescence or chemiluminescence imaging with UV cameras are of paramount importance to resolve the non-uniformities for a better understanding of combustion. However, a major limitation of UV cameras is that they are usually expensive, especially when multiple cameras are needed, such as in a tomographic system. In this work, we report the attempt of flame imaging with a cost-effective single-pixel UV camera which enables 2D spatial resolution of a single-pixel detector through light modulation to overcome this limitation. Meanwhile, numerical studies were conducted to systematically assess the performance of a few representative reconstruction algorithms. The impact of important factors such as sampling ratio and measurement matrix were also investigated. A validation as well as a demonstrative experiment was also conducted to reconstruct a laminar diffusion flame. The high similarity between the reconstruction and the image taken by a CMOS camera proves the feasibility of flame imaging with a single-pixel camera.