Automated Analysis of Diffraction Patterns for Hair Characterization

Hair has an interesting structure that affects its curliness. However, being only on the order of 100 micrometers wide, this structure cannot be seen and can even be challenging to measure. A technique called laser diffraction can be used to measure super small items such as hair. This is a common process, but it takes a long time if you want to take several measurements. To see a complete picture of the structure of a hair, numerous measurements need to be taken from different angles. This project revolves around creating an apparatus to automate this process, allowing numerous measurements to be taken quickly and easily. In 2023, the device used to mount and rotate the hair was constructed. As a continuation of that project, a program was written to automate the process of analyzing the diffraction patterns using image processing. The program analyzed an image of the diffraction pattern using a free Python library called Sci-kit Image and output the width of the object that produced the pattern. The program does not rely on the pattern being in a particular location in the image but instead can find the pattern using minimal assumptions. Key features are then extracted from the pattern to calculate the hair's width.