Design, construction, and testing of a stereo-photogrammetric tool for the diagnosis of fetal alcohol syndrome in infants.

Stereo-photogrammetry provides a low cost, easy to use, and noninvasive alternative to traditional facial anthropometry for the diagnosis of fetal alcohol syndrome (FAS). We describe such a system for use in obtaining 3-D facial information in infants. The infant is photographed using three high resolution digital cameras simultaneously while seated in a car seat. The subject's head is enclosed in a control frame during imaging. Technical system tests, namely control frame interpolation, camera calibration reliability, and camera synchronization delay assessments were performed. Direct and stereo-photogrammetric measurements of a doll were compared. Of 275 inter-landmark distances, 100% were within a 1.5 mm error range and 92.36% within a 1 mm error range when the two modalities were compared. Stereo-photogrammetry proved to be highly precise with submillimeter error in landmark placement for all landmarks on the doll. An intra-modality comparison of inter-landmark distances using two sets of images of five subjects showed the stereo-photogrammetric system to be highly reliable, with an average 72.25% of distances within a 1 mm error range. The system has potential for large scale screening and surveillance studies for FAS.