Visual inspection of a combustion process in a thermoelectric plant

Abstract

Infrared images provide useful information to inspect the status of combustion processes. The flame geometry and intensity depend on the combustion status and can be used for control and monitoring purposes. Flame segmentation is difficult since the background intensity is sometimes higher than the flame intensity, therefore requiring the use of sophisticated image analysis algorithms. This paper describes methods to analyze infrared images of industrial flames and to characterize the flame geometry. A segmentation algorithm is proposed to separate the flame region from the background using an image formation model, a background model and the available shape information. Segmentation algorithms (e.g., active contours) usually assume solid objects with sharp boundaries. This is not true in the case of flame images. The flame is nonhomogeneous and it has a fuzzy boundary. To circumvent this difficulty multiple contours are used to characterize the flame geometry. The flame shape is then obtained by robust estimation methods, using a model of the image formation process inside the combustion chamber. The proposed algorithm is evaluated and used to monitor the flame characteristics in a boiler of a thermoelectric plant.