Abstract
The ability to measure elongated structures such as platelets and colonies, is an important step in the microstructural analysis of many materials. Widely used techniques and standards require extensive manual interaction making them slow, laborious, difficult to repeat and prone to human error. Automated approaches have been proposed but often fail when analysing complex microstructures. This paper addresses these challenges by proposing a new, automated image analysis technique, to reliably assess platelet microstructure. Tools from Mathematical Morphology are designed to probe the image and map the response onto a new feature-length orientation space (FLOS). This enables automated measurement of key microstructural features such as platelet width, orientation, globular volume fraction, and colony size. The method has a wide field of view, low dependency on input parameters, and does not require prior thresholding, common in other automated analysis techniques. Multiple datasets of complex Titanium alloys were used to evaluate the new techniques which are shown to match measurements from expert materials scientists using recognized standards, while drastically reducing measurement time and ensuring repeatability. The per-pixel measurement style of the technique also allows for the generation of useful colourmaps, that aid further analysis and provide evidence to increase user confidence in the quantitative measurements.
Highlights
Microstructural analysis is key to understanding material properties and is important for quality assurance and optimization of manufacturing processes
We provide an analysis solution that can automatically measure a wide range of features including, platelet width, orientation, volume fraction of globular alpha, and colony size, where a colony is defined as a set of spatially clustered, parallel platelets
Implemented on a modern laptop with an i7 processor, the feature-length orientation space (FLOS) techniques take from 20 s to 3 min to measure every property depending on image size, while existing standards required at least 15 min to measure only platelet width
Summary
Microstructural analysis is key to understanding material properties and is important for quality assurance and optimization of manufacturing processes. A technique known as the ultimate opening [32] will allow us to find the optimal length and orientation of segments to fit the image at each location, and estimate the size and morphology of microstructural features. This is will not often cause significant problems as both width and orientation measurements would remain accurate at the location of measurement In cases where such features do present a more substantially challenge the ultimate opening in (2) may be replaced by an alternative definition using rank-based morphological filters [33], as shown in (5), where B is an SE of variable length and orientation. Applying Algorithm 1 to this data allows for successful colony segmentation, as shown in Fig. 6d, which there is no obvious way to compute from the original greyscale values
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
