Rapid in vivo measurement of the topography of human skin by active image triangulation using a digital micromirror device

Abstract

Background/aims: Topometry is one of the most relevant methods for biophysical research on skin in dermatologic and cosmetic science, because it relates very closely to the perceived quality of skin. Taking silicon replicas of skin sites under investigation and measuring those imprints with mechanical or optical profilometers is still the most frequently used method. Direct measurement of the topography of human skin in vivo by active image triangulation avoids the need to make replicas and seems to be a promising alternative. Methods: The introduction of active image triangulation in conjunction with phase‐shift techniques in skin topometry enables a fast and non‐invasive measurement of the skin surface in vivo. The main attribute of the proposed system is the projection of a regular sinusoidal intensity pattern with a sophisticated digital projection device onto the surface of skin under a certain angle of incidence. The height information of the structured surface is coded in the distorted intensity pattern, which is recorded by an appropriate video technique. Results: Successful in vivo measurements of selected body sites and measurements on scar, nevus, wound and wrinkles are presented in this paper. Furthermore, irritation of skin, influence of hydration of skin, and differences between youthful and elderly skin can be detected in the measurement results of the new optical system. Conclusions: For measuring the topog raphy of human skin, active image triangulation is appropriate both for macrotopometry (nevus, scar, wound) and for microtopometry (casts, selected body sites). This new non‐contact technique allows dynamic measurements of alterations in skin topography as a consequence of certain treatments (e.g., application of ingredient, hydration of skin) without removal of corneocytes or scales. Optical three‐dimensional (3D) topometry using active image triangulation appears to offer a significant improvement in speed and flexibility, providing a fast and accurate analysis of skin surface topography.

Ablative fractional lasers (CO2 and Er:YAG): A randomized controlled double‐blind split‐face trial of the treatment of peri‐orbital rhytides

“…The wrinkle profile recording was performed by using the optical 3D in vivo measurement system PRIMOS (Phaseshift Rapid In vivo Measurement Of Skin) (GFMesstechnik GmbH, Teltow, Germany). The system is based on the digital fringe projection technique as described by Jaspers et al [29], and has been validated for rhytide assessment in several clinical studies [30][31][32]. Briefly, a parallel stripe pattern is projected onto the skin surface by using micro-mirrors and recorded by a CCD camera.…”

In vivo measurement of skin microrelief using photometric stereo in the presence of interreflections

“…Its acquisition time is <100ms with a lateral and vertical resolution of 28µm and 2µm respectively. The PRIMOS device has also proven to give comparable results to a mechanical profilometer [42], and unlike photometric stereo its accuracy is not dependent on the reflectance properties of replica or skin as it uses the variation in projected pattern to recover height information. Hence the measurements from this device were used to verify the in vivo measurements produced by our photometric stereo device.…”

Multidimensional imaging for skin tissue surface characterization

“…In contrast to mechanical techniques, the 'stylus' used in optical various methods take the form of spots, lines or patterns of structured lights. For example, a time multiplexing optical system frequently used in dermatology projects a series of parallel white stripes with a constant phase shift onto the tissue surface from which the 3D topography is calculated based on the observed deflection of the stripes [6]. There is no direct contact pressure on the skin in the case of optical measurement techniques and this is an important consideration that serves to make optical measurement techniques more appealing.…”