Automated Split-End Closure Measurement

TRI NOTES ON RESEARCH #563: FREE TO ALL TRI MEMBER COMPANIES

Split-ends, also known as trichoptilosis, is a common condition and a key sign that hair has suffered from physical damage. Split ends are formed as a result of chemical processing, heat styling and combing, and arise from the loss of the hair cuticle, or the external ‘jacket’ that keeps hair fibers intact. 

The split-end problem

For customers, formation of split-ends is problematic and can lead to hair feeling and looking unhealthy; not characteristics that customers find desirable. However, formation of split ends is a natural outcome from daily grooming habits and difficult to avoid, resulting from a combination of bending, torsion, and inter-fiber friction can result in localized stresses, leading to fiber weakening or breakage, and, ultimately, split-ends. And it’s because the hair fiber has been damaged that hair tangles easily, is dry and frizzy, or looks dull – not desirable traits for hair. 

To address this, many hair treatments have been designed to ‘heal’ his common consumer complaint, and TRI has particular expertise with claims substantiation and support around split-end treatment products. 

Claims substantiation for split-end treatments: an opportunity for an update

When it comes to claims substantiation for these hair treatments, TRI’s repeated grooming apparatus is a stalwart. This instrument can be used to create new split-ends and then measure the effectiveness of hair treatments in their closure, with closure measured through the assessment of microscope images by trained assessors. However, while this technique is tried-and-tested, there can be some variation based on operator perceptions. For example, features such as fiber curvature, orientation, or the length of the split can influence how the opening appears, which occasionally introduces small inconsistencies in how closure is judged across samples.

To address this potential source of error or inaccuracy, TRI has developed the use of an automated image-analysis method that can quantify split end geometry directly from microscope images. Through using the TRI Split end Evaluation Protocol (SOP HME 101.8V2), opening angles of the splits can be measured using consistent geometric criteria. Classification of the split ends was through use of a five-level scale, aligned with the framework traditionally used at TRI. When data from manual grading and automated grading were compared, the automated split end analysis was shown to reproduce the manual decision within ~3 percentage points, providing a valuable, reliable method for quantification of split-end formation and closure. 

The development of an automated test for monitoring split-end closure enables TRI to continue to provide excellent, reliable support for customers – especially those working within hair repair. In addition, more granular data generation means that split-end closure across a range of categories, for example hair type, enabling probing of treatments designed for different international markets or differing consumer hair profiles. 

Further information about the techniques used and analysis undertaken is available in the Note on Research published in the TRI library

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