# Error-Resistant Movement Detection Algorithm for the Elderly with Smart Mirror
## 5 Experimental Results
### Result of Experiment 2  
Table 4 reports the average/standard deviation of the mean displacement of whole points and threshold in the video. The purpose is to show that although it is easy to distinguish between a stationary state and fast movement by comparing adjacent two frames, it is difficult to distinguish between a stationary state and slow movement by comparing two adjacent frames. All units of measure in the table are pixels.  
Joint point displacement is around 10 pixels in FMV scenarios, around 4 pixels in SMV scenarios and around 1.5 pixels in NMV scenarios. However, in the \"Standing-High Error\" scenario, its displacement is around 4 pixels. This means the distinction between the target's slow movement and natural error is difficult in a particular video.  
In the current experiment, the threshold is set to the target's shoulder width and its shown to 7\(\sim\)9 pixel. With this high threshold and method that only compares threshold and displacement between two adjacent frames (AFSM, CGM), the natural error in the NMV scenario is detected as 'not moved' but the target's slow movement is detected as 'not moved' too. If the threshold is set lower (as half of the current threshold), the target's slow movement will be detected as'moved' but a natural error in the NMV scenario would detect as'moved' too. By using VSM, the threshold is set high, natural error in NMV scenario is detected as 'not moved' and target's slow movement is detected as'moved'.  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Scenario**} & \multicolumn{2}{c}{**Joint Displacement (Pixel)**} & \multicolumn{2}{c}{**Threshold (Pixel)**} \\ \cline{2-5}  & **AVG** & **STDEV** & **AVG** & **STDEV** \\ \hline (FMV) Walking & 09.55 & 02.93 & 07.79 & 00.67 \\ (FMV) Freehand Exercise & 13.54 & 03.53 & 06.82 & 00.43 \\ (SMV) Walking & 05.14 & 00.71 & 08.29 & 00.29 \\ (SMV) Freehand Exercise & 03.47 & 01.77 & 07.61 & 00.11 \\ (NMV) Standing-Low Error & 01.86 & 00.42 & 09.45 & 00.71 \\ (NMV) Standing-High Error & 04.47 & 01.22 & 07.52 & 02.59 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Experiment 2 result. Each cell represents (average, standard deviation) of joint displacement and used threshold through prepared 15 video sequences. Each frame has 12 joint points of shoulder, arm, wrist, hip, leg, and ankle. Distance between left shoulder point and right shoulder point is set as a threshold. Each 12 joint displacement is calculated by comparing adjacent two frames. Average joint displacement is the average value of 12 joint displacements and its standard deviation. Units of measure are in pixels.  
\begin{table}
\begin{tabular}{l c c c c c} \hline \hline \multirow{2}{*}{**Scenario**} & \multicolumn{2}{c}{**CGM(\%)**} & \multicolumn{2}{c}{**AFSM(\%)**} & \multicolumn{2}{c}{**VSM(\%)**} \\ \cline{2-6}  & **AVG** & **STDEV** & **AVG** & **STDEV** & **AVG** & **STDEV** \\ \hline (FMV) Walking & 51.15 & 21.05 & 61.27 & 19.92 & 95.31 & 02.82 \\ (FMV) Freehand Exercise & 15.98 & 06.46 & 73.85 & 11.15 & 85.47 & 07.91 \\ (SMV) Walking & 74.83 & 22.05 & 24.13 & 07.51 & 93.43 & 04.24 \\ (SMV) Freehand Exercise & 00.48 & 00.21 & 08.54 & 10.87 & 67.69 & 20.57 \\ (NMV) Standing-Low Error & 01.17 & 02.93 & 00.23 & 00.06 & 01.92 & 03.29 \\ (NMV) Standing-High Error & 40.43 & 38.43 & 06.00 & 08.30 & 04.29 & 02.81 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Experiment 1 result for movement scenarios. Each cell represents (average detection rate, standard deviation) through prepared 15 video sequences. Detection rate is calculated by (number of frame which method returned ’moved’)/(number of total frame) in every single video sequence. Units of measure are percentage.