Local texture (pore / fine-line proxy)
Mean local standard deviation of lightness in small windows across the cheeks and forehead.
How to read it
Dominated by lighting geometry: grazing side-light exaggerates texture, flat front flash erases it. Clinical systems (VISIA, Antera) solve this with enclosed calibrated illumination, which a phone cannot. Compare only under matched lighting.
Why every value has an error bar
Every value Canthion reports carries a 1σ uncertainty propagated from MediaPipe Face Mesh's published accuracy (3.96% of inter-ocular distance mean absolute error per landmark, Kartynnik 2019). For a typical 300 px inter-pupil photo that is ≈12 px per landmark, which is why small ratios and angles get wide intervals. A number without an interval is a number pretending to be more precise than it is.
Related: how bone-level measurements are taken from a photo · methodology · all insights