ABSTRACT
Recently, a special type of non-optical skin surface imaging was designed under the heading of skin capacitance imaging (SCI). This method is an application of the silicon image sensor (SIS) technology, which was primarily developed for recording fingerprints for security reasons (1)]. The sensor is composed of 92160 microcapacitors dispersed on a 18 12.8-mm sensor plate measuring skin capacitance every 50 mm. These microcapacitors are protected by a thin silicon oxide layer. SkinChip1 (ST Microelectronics, Geneva and L’Ore´al, Paris, France) is not yet commercially available. It represents a dedicated device for computer recordings of the skin’s surface hydration and microrelief (1-3). The device must be closely applied to the skin surface for five seconds at the most not to interfere with the water flux and content inside the stratum corneum (SC). SCI images are acquired and displayed in real time on a computer screen where the capacitance values are transformed into a range of 256 gray levels to form a non-optical image. On a flat surface, the darker pixels represent high capacitance spots, and the clear ones, the lower capacitance values. Besides the regular software providing images, other softwares were developed for routinely characterizing some other specific skin parameters (3). The mean gray level (MGL) of the image represents the average skin surface hydration. The so-called corner density (CD) parameter corresponds to the number of crossings between the primary lines per centimeter square (4). The main orientations of the primary lines of the skin microrelief can also be assessed.
