Figure 8.

Calculation of the maximum length of contour presenting no significant discontinuity on the right side of range reading i (t_f [i]): (a) Part of the laser scan and point i; (b) scan data acquired by the laser range sensor; and (c) evolution of the area delimited by the arc and the chord ( ${\sum }_{j=i}^{i+t_f [i]-1}|t_j^a|-({\sum }_{j=i}^{i+t_f [i]-1}|t_j^a|\cap {\sum }_{j=i}^{i+t_f [i]-1}|t_j^c|)$). It can be noted that this area suffers a sharp increasing when t_f [i] ≥ 8. This change allows to estimate the correct t_f [i] value and it will be detected in our approach using the Equation 12 (in this case, t_f [i] = 8).