Height Measurement for Humans in Motion Using a Camera: A Comparison of Different Methods

This paper aims to answer the questions whether human height measurement from video is affected by human motion and how accurately human static height can be measured from a video or from a single image frame that captures a walking subject. In this paper, we present a new approach for measuring human height based on the cross ratio. This approach is performed in parallel with the vanishing point based approach for comparison. The accuracy of each approach is examined by comparing the estimated value to the actual static height value which is measured directly. For the height measurement from video, our analyses show that human height varies significantly during human motion and the highest point in a human stride is the most accurate measurement of the static height. We also model the height variation as a sinusoidal pattern to maximize the accuracy of the estimated height. For the height measurement from a single frame, a correction method is developed in which the length of the human torso with human head and the length of the human leg are separately estimated. We conclude that static human height can be measured accurately, even though the variation of human height is significant during human motion.