A self-developed microscope image capturing system is established to digitalise the cross-sectional images of polyester/cotton blended yarn. 
self-developed microscope image capturing system
One set of image preprocessing algorithm is developed to conduct greyscale inversion, median filtering denoising and binarisation. 
image preprocessing algorithm
The specially designed edge detection algorithm is used to identify the continuous profile of fibres. 
edge detection algorithm
Finally, the roundness value of the cross-sectional fibre is calculated based on the proposed roundness algorithm, it can be used to identify the polyester/cotton fibres and calculate the blending ratio of them. 
roundness algorithm