## 3 Results  
Figure 11 represents the time-course data of foot contact and the foot-off position calculated during walking. The frames on the y-axis signifies the time data from the LiDAR sensor. The distance on the x-axis signifies the location of the single-support leg during walking. If the right leg is in contact with the floor, the opposite left leg must be in mid-air during walking, and vice versa. Both the left-leg and right-leg data were calculated using the moving average over a sliding window of length 2, thus removing the DC offset.  
Figure 12a,b shows the individual results of the average step length from all 10 participants for each of the fast walk and normal walk experiments obtained from both the visual inspection and polynomial methods. From the figure, it can be observed that each participant tends to have a unique or individualistic step length. Since they were instructed to walk on their own pace for both walking speed experiments, it resulted in an individually selected walking pace.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Subjects** & **Height (cm)** & **Weight (kg)** & **Age** \\ \hline
6 males & 172.2 \(\pm\) 4.3 & 74.3 \(\pm\) 7.8 & 28.8 \(\pm\) 6.1 \\
4 females & 153.8 \(\pm\) 4.3 & 51.5 \(\pm\) 11.4 & 26.8 \(\pm\) 2.9 \\ Average & 164.8 \(\pm\) 10.0 & 65.2 \(\pm\) 14.6 & 28 \(\pm\) 5.2 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Number of participants with the corresponding standard deviation.  
Figure 10: Determination of step length from the cloud points data.  
In Figure 13, the average male step length was 0.7439 m and 0.6292 m for fast and normal walk, respectively. This translates to an increase of 11.5% in step length from normal walk to fast walk. The average female step length was 0.6545 m and 0.5856 m for fast and normal walk, respectively. For female participants, normal to fast walking corresponded to an increase of 6.9% in the experiment. Other factors, such as aging or physical complications, might affect the results of step length. In this study, since the subjects consisted of healthy young adults, the trial results for both fast walk and normal walk are observed to be in the same walking gait for young adults, i.e., an increase in distance in step length with an increase in walking speed.  
Figure 11: Foot position during walking.  
Figure 12: Experimental results obtained from both a fast and normal walking speed: (**a**) the differences in step length value between the visual inspection method and polynomial fitting curve method for normal walk; (**b**) the differences in step length value between the visual inspection method and polynomial fitting curve method for fast walk.  
Figure 14 shows the scatter plot between the height of each participant and their represented average step length for normal walk and fast walk, respectively. A linear fit is applied to the data, as shown. The correlation coefficient between the mean step length of normal walk and the subject's height is R = 0.1482. Meanwhile, for fast walk, the correlation coefficient against the subject's height is R = 0.4951.  
Table 3 shows the summary of the step length gait parameter for both normal speed and fast speed using the visualization inspection and the quadratic polynomial method. From the table, the visual inspection method of step length agrees with the proposed  
Figure 14: Correlation of subject’s height and step length for normal walking speed and fast walking speed.  
Figure 13: Comparisons of step length during fast walking speed and normal walking speed between male participants and female participants.  
method. The SD value is taken to represent the accuracy of the measurement. From the data, visual inspection is accurate up to 6%, which translates to 6 cm, while the polynomial method achieves 8 cm in fast walking.