Fig 7. Preprocessing piepline.

A. Quality control, videos with less than 70% of body points labelled on average were excluded from further analysis. B. Outlier removal, outlier body points were removed (denoted by x) when outside of ellipical envelope for the whole body or each body point indiviudally. C. Gap filling using linear interpolation for gaps less than 5 frames, or a multivariate imputer for gaps larger than 5 frames. D. Body points were rotated on a frame by frame basis ensuring midline of body is aligned to the vertical. E. Body point position was scaled to unit length based on infant size, unit length distance crown to mid hip. F. For each frame x- and y-coordiates and additional features consisting of joint angles from the left and right shoulder, elbow, hip, knee and ankle were extracted.