Improved Accuracy for Measurement of Filament Diameter Based on Image-Based Fitting Method

Laser diffraction (LD) has many obvious advantages for measuring. However, the measurement accuracy is limited by a number of factors, such as imaging noise, sensor threshold, and fitting methods. In this paper, we present novel method measuring filament diameter based on image-based fitting, which maintains more information. Before image, image processing applied to solve problem noise non-linear response charge-coupled device (CCD). Then, formula established distribution laser intensity fitted results are solved with Levenberg–Marquardt (LM) algorithm. Finally, initial parameters fit obtained calculation, speeds up calculation improves fitting. The verified experimental theoretical analysis. experiments, diameters 125 125.2 μm measured relative error approximately 0.12%, Furthermore, superiority demonstrated comparing measurements other To verify stability measurements, 110–180 chosen be standard deviation less than 0.14%.