<title>Real-time optical scanning system for measurement of chest volume changes during anesthesia</title>

A low cost real time method of measuring the movement of the ribcage and abdomen during anaesthesia is described. The equipment comprises a scanning light stripe system video pre-processing electronics and a personal computer. Selected chest surface contours are measured at the rate of 2Oms per contour. Linear interpolation is used to provide contour area estimates between contour sample periods to allow chest volume to be calculated at 2Oms intervals. Results using test objects show that the equipment is able to measure volume to an accuracy of beuer than 1 with reproducibility to within 0. 3