Figure 10.

Results for the second harmonic generation image of collagen fibres of chicken cartilage (figure 2c): (a) shows the mean angle and the median angle for increasing dividing steps n, and (b) shows the weighted error entropy, E_w. In (a) we observe a lower cut-off point for both angles and at n = 4, below which both measures yield unstable values owing to artefacts and different collagen fibre orientations at the perimeter of the cartilage. Both measures show a stable behaviour up to n = 25 (upper cut-off point), though the values for are approximately 6° higher than . The behaviour of the weighted error entropy, E_w up to around n = 6 in (b) confirms the existence of an initially unstable domain (highlighted in (a)), followed by a stable and low E_w regime up to about n = 21.