Precision in polymer fiber analysis: Evaluating advanced algorithms for phase map extraction in necking and inclined fiber conditions in dynamic fibers studies

The paper uniquely addresses the challenges of analyzing complex interference patterns of fibers undergoing necking and vibration-induced inclination which are a common issues in real-world dynamic studies. Three advanced fringe pattern analysis algorithms, two-dimensional Fourier transform (2D FT), four-shot phase-shifting interferometry (PSI), and one-dimensional continuous wavelet transform (1D CWT), were employed for extracting phase information and measuring optical characteristics of polypropylene (PP) fibers with these challenges. For necking challenge, the algorithms were evaluated on their ability to accurately demodulate phase maps across different regions of necked fiber using the contour line technique. Results demonstrate that the 1D CWT method significantly outperforms the other techniques, exhibiting superior accuracy in phase extraction for all necked regions. Using the 1D CWT approach, 3D birefringence computations are presented, revealing the molecular orientation in different zones of necked PP fibers. For vibration-induced inclination challenge, the effectiveness of each algorithm was assessed based on how precisely it could extract stable phase information from identical fringe patterns at various inclination angles. Here, Unlike 2D FT and PSI, the 1D CWT algorithm effectively handles non-parallel fringes and is more robust to noise and irregularities. So, the 1D CWT approach is recommended for extracting the phase map data of necked and inclined fibers conditions. The findings have important implications for enhancing the characterization and analysis of polymeric materials in various applications