Fig. 3From: Image-based quantitative analysis of tear film lipid layer thickness for meibomian gland evaluationDetailed image processing steps for automatic ROI tracking and background subtraction (Phase 2–3). a–e Finding the pupil (Phase 2). f–j Finding the iris (Phase 2). k–o Extracting the ROI (Phase 3) (see Additional file 1: Movie S1)Back to article page