MOESM6 of Image-based quantitative analysis of tear film lipid layer thickness for meibomian gland evaluation

Additional file 6. The relationship between the threshold value and the captured shape of the pupil. The threshold value to identify pupil in our flood-fill algorithm was chosen as 5 out of 256 (8 bit data type.) (i) If we choose a lower threshold, only central sub-region of the pupil could be recognized as a full pupil (see threshold = 3 cases.) (ii) If we choose a higher threshold, then some regions of the iris could be incorrectly recognized as the pupil (see threshold = 7 cases).