Non-contact 3D measurement techniques applied to the skin

In recent decades there has been a significant incorporation of three-dimensional (3D) information in many applications related to the sectors of cinema and computer games, fashion, surgery plastic surgery, dermatology, forensic medicine, the ophthalmology, orthopedics, dentistry, etc. Hand in hand with this boom in demand, have been developed new 3D body scanning systems human, as well as new methods and tools to make efficient use of data in terms of of each application. Optical equipment offers important advantages, such as non-contact 3D scanning, greater speed and precision, resulting in digital format which allows its display, storage and processing posterior, etc. The main optical techniques used are classified in three main groups: - Those of scanning by point or laser line. - Those based on pattern projection of structured light. - The photogrammetric type based on multiple images captured at different views. All of them have advantages and disadvantages that must be taken into account when selecting the most appropriate technique for each application. However, most commercial solutions use structured light pattern projection.The principle of measurement consists of projecting a series of black and white stripes over the area to be scanned and, from their deformation, obtaining the 3D shape. Figure 1 shows an example of a 3D measurement of a person's face using the structured light pattern projection technique. In recent years, the Centre for the Development of Sensors, Instrumentation and Systems (CD6) at the Technical University of Catalonia (UPC) has been actively working on the development of this type of instrumentation for applications in the cosmetic and dermatological sectors.