Teager-Kaiser Energy and Higher-Order Operators in White-Light Interference Microscopy for Surface Shape Measurement

Fabien Salzenstein,Abdel-Ouahab Boudraa,Paul C Montgomery,Denis Montaner

doi:10.1155/asp.2005.2804

Abstract

In white-light interference microscopy, measurement of surface shape generally requires peak extraction of the fringe function envelope. In this paper the Teager-Kaiser energy and higher-order energy operators are proposed for efficient extraction of the fringe envelope. These energy operators are compared in terms of precision, robustness to noise, and subsampling. Flexible energy operators, depending on order and lag parameters, can be obtained. Results show that smoothing and interpolation of envelope approximation using spline model performs better than Gaussian-based approach.

Highlights

Different signal processing methods have been proposed in coherence probe microscopy (CPM), known as whitelight scanning interference microscopy (WLSI), for roughness surface measurement [1, 2]
Most of the methods are based on an AM-modulated signal model, which represents the variation in light intensity measured along the optical axis of an interference microscope
The proposed algorithms have been first applied to the profiling of a step etched in silicon (Figure 2a) using the interference microscopy system described in [22]

Summary

Introduction

Different signal processing methods have been proposed in coherence probe microscopy (CPM), known as whitelight scanning interference microscopy (WLSI), for roughness surface measurement [1, 2]. The Demodulation method [2] requires carrier frequency information, while the five sample adaptive (FSA) method, proposed by Larkin [4], detects the peak by using only five adjacent samples along the optical axis. The TKEO (Teager-Kaiser energy operator) has found applications in speech processing [9], image processing [10], and pattern recognition [11]. This operator is an energy-tracking operator which does not measure the signal energy but the energy of the source or the system that produces this signal. Some highorder methods were applied in the signal processing field

Objectives

Results

Conclusion