Background Monitoring infant growth is essential for evaluation of development and is an important indicator of health and illness. Length is an essential indicator of infant growth, however, length measurement methods suffer from limitations which restrict their use.

Objective To improve infant length measurement by development of a novel, accurate, precise and practical measurement technique.

Methods A new system based on stereoscopic vision was developed. The system is comprised of two digital still cameras combined with software that calculates the infant's length from two simultaneously taken pictures. Length measurements of 54 healthy newborns were performed using a standard length board and the stereoscopic system. The two measurement methods were compared.

Results Mean infant length was 473.1 (SD=29.1) mm versus 473.3 (SD=29.3) mm by length board and by the stereoscopic system, respectively. The mean difference between measurements was 0.2 (SD=2.5) mm and the mean of the absolute values of differences was 2.0 (SD=1.4) mm. Bland–Altman analysis showed good agreement between the two measurement methods. Precision of the new technique was demonstrated by a technical error of measurement of 2.57 mm.

Conclusions The stereoscopic system is accurate, reliable, easy to use, and involves less handling and discomfort to the newborns. It has the potential to measure premature infants or sick neonates through incubators.