Catalysts characterization and discrimination
Collaboration with LISTIC, Univ. Savoie, Annecy, and IFPEN Zhangyun Tan’s PhD thesis, ARC6 region Rhône-Alpes grant
The main objective of this project is the statistical characterization of spatial arrangements of fringes (active phases) in the catalysts imaged by High Resolution Transmission Electron Microscopy (HRTEM).
The contributions proposed are two statistical models for the description of the HRTEM image contents.
The first model involves 2-D isotropic Fractional Brownian Field (FBF) and 2-D Auto Regressive (AR) models, as well as morphological analysis of the spectra associated with these models (ARFBF morphological analysis). We also proposed two methods for estimating the Hurst parameter for an isotropic FBF: Log-RDWP (Log-Regression on Diagonal Wavelet Packet spectrum) and Log-RPWP (Log-Regression on Polar representation of Wavelet Packet spectrum). The morphological method on ARFBF spectrum for detecting and identifying HRTEM texture features allows to obtain a separation between diļ¬erent catalysts.
The second model proposed in this thesis is a generalization of FBF (GFBF) constructed by using convolution and modulation operators of several FBF. The textures synthesized from GFBF model are shown to present some structural similarities with certain fringe structures present in HRTEM images.
ARFBF modeling procedure of HRTEM image.
Line 1, 2 & 3, first column, images in the spatial domain: I1 original image; I2 is I1 after wavelet-based low-pass filtering (Pre-processing WHFR); I3 is I2 after FBF removal.
Line 1, 2 & 3, second column, Power Spectral Densities (PSD) of I1, I2 & I3 respectively, estimated with periodogram: the origin is at the center.
Last line, PSD of I3 estimated in polar and cartesian coordinates with a method based on 2D AutoRegressive (AR) model.
Z. Tan, M. Moreaud, O. Alata & A. Atto, “ARFBF morphological analysis - Application to the discrimination of catalyst active phases”, submitted to “Image Analysis & Stereology” journal.
Zhangyun Tan. "Extensions of Fractional Brownian Fields and Morphological Spectral Analysis for Discrimination of Catalysts". PhD Thesis, Annecy, Dec. 2016. http://perso.univ-st-etienne.fr/ao29170h/PhD_graduates.html
Z. Tan, A. Atto, O. Alata & M. Moreaud, "ARFBF model for non-stationary random fields and application in HRTEM images". IEEE ICIP 2015, Sept. 2015, Québec City, Canada.
Z. Tan, O. Alata, M. Moreaud & A. Atto, "Convolution mixture of FBF and modulated FBF and application to HRTEM images", GRETSI 2015, Lyon, France.
A. M. Atto, Z. Tan, O. Alata and M. Moreaud, “Non-stationary texture synthesis from random field modeling”, IEEE ICIP 2014, Paris, France.