A webcam-based photogrammetric system for the measurement of facial landmarks on newborns

摘要

A photogrammetric system of four webcams was developed to acquire craniofacial measurements of newborn babies. The errors between a set of photogrammetrically-derived measurements on a clinical mannequin with those made by an experienced nursing sister were found to be negligible (less than 0.5 mm) at the 5 percent level of significance. The four cameras were individually calibrated and the parameters and distortion patterns compared. To assess the impact of camera calibration, the validation imagery was also processed with both average and nominal calibration parameter sets. It was found that the average parameter set produced measurement errors similar to those produced by the individual calibrations, but using the nominal calibration set produced less accurate measurements. The project demonstrates that a low-cost photogrammetric system is as accurate as manual measurements and at the same time provides a safe, non-contact measurement environment and a visual record of the subjects.