3D Anthropometric Scanning based on Pattern Projection

Abstract

In the current global fashion marketplace taking body measurements using scanner technologies is increasingly gaining popularity. This is mainly due to the majority of transactions are now being done online and almost 50% of such purchases are returned annually due to mismatches in size. The time and effort requirement for taking manual measurements is also a contributing factor. Several studies have been carried out in this regard, particularly in the Bio Medical field where anthropometry is an integral part in diagnostics. Several companies are also providing 3D scanning solutions for the fashion industry with various attributes. However the majority of such scanners are based on Laser Triangulation System which is not the most economical in a competitive environment. This study focuses on the feasibility of incorporating a scanner based on pattern projection for the same purpose. The main aspects this study will be covering are achieving a low scanning time and a significant reduction in cost against the conventional method. The Laser Triangulation Scanners that are currently in the market take up to 33 seconds in scanning time while ranging between $25 000 - $85 000 in cost. This study will discuss the possibilities of achieving a scanning time under 5 seconds and designing the physical scanner under $10 000. In the Pattern Technique, a series of stripes/patterns were projected simultaneously on to the object. This contrasts with the Laser technique where scanning is done on a single line of point where independent range profiles are processed. Patterns ranging from simple stripes of white light to complex Moiré patterns were tested out on a Mannequin with a standard erect pose. A camera was used to view the projected pattern from an angle complimenting the projection angle which generated straight equally spaced fringes incident on the surface, producing equally spaced contour intervals. The study indicated that using Moiré pattern projection wasn’t the optimal solution in body scanning, given the constrains. The complex mathematics involved in demodulating the viewed pattern to create fringes required extensive processing. Binary coded pattern was generating the best results as it required a simple low cost projector and simple processing. However the use of incoherent light resulted in a compromise of the depth of view and the resolution of the image compared with its laser technique counterparts, a drawback which can be mitigated during programming.