Image analysis method for multi-phase system with overlapping grayscale intensities

A system for segmenting a scanning electron microscope (SEM) image based on grayscale inflection points, the system comprising:

• an SEM with a backscattered electron detector;
• a processor;
• and
• a computer readable memory containing instructions that, when executed by the processor, cause the system to:
• capture an SEM image of a ceramic matrix composite that includes ceramic fibers coated with first coating layer of a first material and a second coating layer of a second material, the second material different from the first material;
• identify a fiber in the SEM image, the fiber having a substantially circular cross-sectional profile;
• generate a line graph of a gradient of grayscale values as a function of a line scan traverse location, the line scan traversing across the SEM image along a radius of the coated fiber, the line scan extending between a first location in an interior region of the coated fiber to an exterior region outside the coated fiber;
• identify a plurality of inflection points in the line graph of the gradient of grayscale values as a function of the line scan traverse location;
• and
• determine coating thicknesses based on the identified inflection points.