Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
OPTIMAL PREPROCESSING FOR PROPER ORTHOGONAL DECOMPOSITION OF THE OSCILLATORY METHANE JET DIFFUSION FLAMES DATASET
Submission Author:
Fernanda Spilotros Costa Cordeiro , RJ
Co-Authors:
Fernanda Spilotros Costa Cordeiro, Leonardo Santos de Brito Alves, Davi Saadi de Almeida Lettieri
Presenter: Davi Saadi de Almeida Lettieri
doi://10.26678/ABCM.COBEM2023.COB2023-1426
Abstract
This study aims to establish an experimental image processing to study oscillatory diffusion flames of the single methane jet, and its impact on the Proper Orthogonal Decomposition (POD). Modal decomposition techniques are widely used to characterize the behavior of unsteady dynamical systems. They provide a systematic way to generate lowdimensional approximations of a large set of high-dimensional dynamical systems. In particular, the POD has numerous applications, among which are experimental image analysis, order reduction in dynamical systems, turbulence modeling and neural network training. Noting the ultimate goal of reducing the order of the dynamical system that models the oscillatory diffusion flames, it is necessary to topologically analyze the trajectories of the POD coefficients through their phase portraits, in order to identify information about the existence of attractors, repulsors and limit cycles. However, since the input data are experimental images, the signal-to-noise ratio can be quite high. Hence, filtering techniques employed on experimental images allow the extraction and identification of essential elements of the images, and improve the visual quality of certain structural aspects, facilitating their computational interpretation. In this paper, we present the image processing technique known as Block-Matching and 3D Filtering (BM3D), which aims to remove as much noise as possible from the original data. The removal of noisy signals through such processing is fundamental for the accurate generation of higher-order POD coefficients. Based on this statement, several filtering parameters of the BM3D processing were tested on experimental images, generating the phase portraits obtained from the POD decomposition. The obtained results were compared with each other to evaluate which parameter provides the highest number of accurate POD coefficients.
Keywords
image processing, Proper orthogonal decomposition (POD), Order reduction, Block-Matching and 3D Filtering (BM3D), Phase Portraits
