The mechanism and application of computer-assisted full facial skin imaging systems

Abstract

Computer-assisted full facial imaging systems are currently among the most widely used skin analysis instruments in dermatology and medical cosmetology. These systems offer objective quantitative evaluation of facial skin conditions, and as they are non-invasive, play an important role in assessing dermatological conditions such as pigmentation, inflammation, vascular diseases, skin texture, the severity of ageing, and therapeutic follow-up. Although computer-assisted full facial imaging systems enable quantitative analysis in the scope of medical treatment and cosmetic evaluation, their results may considerably vary because of the influence of environmental and postural factors for improper operation. Furthermore, manual observation is sometimes necessary for experimental work for more accuracy, and familiarity with the imaging principles and application points is necessary to best apply this technique. This report aims to discuss and interpret these systems' imaging mechanisms and explore the primary issues with their application.

FIGURE 1

Three main light sources: the white light (1, yellow arrow), ultraviolet A and/or Wood's light (2, purple allow) and polarised light (3, orange arrow).

FIGURE 2

In the white light mode, unruly hair may affect the automatic selection of the areas processed as wrinkles (green lines).

FIGURE 3

It is necessary to combine the images in white light mode (a) to differentiate facial acne (white circles) from nevus (black circles) in ultraviolet spot (b), red area (c) and brown spot (d) modes.

FIGURE 4

Erythema segmented automatically by the VISIA^® system (Blue dotted area), with diffuse erythema not thoroughly segmented (yellow arrows) and erythema not automatically fully recognised (blue arrows).

FIGURE 5

Facial exudate scabs shown in white light mode (a) can be fluorescently blue‐green (yellow circle) in ultraviolet‐induced fluorescence mode (b).