Fourier optics for polymeric substrates and coating textures analysis

TL;DR

This paper explores the application of optical Fourier spectrum analysis to identify and characterize textures in polymer films and coatings, offering a vibration-insensitive alternative to traditional image processing methods.

Contribution

It introduces a Fourier optics-based approach for texture analysis of polymer substrates and coatings, emphasizing its advantages over image processing techniques.

Findings

Fourier spectrum reveals texture heterogeneity in polymer films.

Surface and bulk conditions significantly influence the optical texture signatures.

The method can detect changes in refractive index and surface conditions.

Abstract

Several devices for substrate texture detection based on diffractive optics, for paper, textiles and non-wovens have been proposed in the past for direct inspection during the production processes. In spite of the presence of devices totally based on image processing, the use of diffractive optics cannot be considered surpassed for many reasons. Compared with image processing procedures, it is less sensitive to vibrations and does not suffer from the presence of ambient light. Based on transmitted light, it can give information on changes in refractive indexes, thickness variation and surface conditions. We study the use of optical Fourier spectrum to identify textures of polymer films. As the power spectrum reveals, the texture is seldom homogeneous. Here we report investigation on several substrates and on thin ink coatings on substrate. Role of bulk and surface conditions is analysed.