Mums: a Measure of hUman Motion Similarity by

4.33D ChainCode and FastDTW Comparison Results – Shoulder Elevation and Rotation Key Rehabilitation Exercise

Shoulder Elevation and Rotation – this is one of the key rehabilitation exercises used in our experiments. A picture of the motion capture session for this exercise is shown in Figure 4.20

Figure 4.20 – Motion Capture Session for Shoulder Elevation and Rotation Exercise

Three sessions were captured for this exercise. The following figures show the similarity values when comparing those three sessions among each other, using 3D ChainCode algorithm. Values for the comparison of human motion similarity for the full body and for both arms are shown in the following figures. Each session was compared with each other.

Figure 4.21 – Session 1 vs. Session 2 – 3D ChainCode

Figure 4.22 – Session 1 vs Session 3 – 3D ChainCode

Figure 4.23 – Session 2 vs. Session 3 – 3D ChainCode

Figure 4.24 shows that when performing the analysis of similarity in the whole body, i.e., using all 34 sensors, Session 1 vs. 3 turns out to be the most similar. However, when using only the sensors for the arms, Sessions 2 vs. 3 are more similar than the rest of the comparisons.

Figure 4.24 – Comparison of All Motion Sessions for Full Body and Arms – 3D ChainCode

The following figures show the similarity values when comparing those three sessions among each other, using FastDTW algorithm. Values for the comparison of human motion similarity for the full body and for both arms are shown in the following figures. Each session was compared with each other.

Figure 4.25 - Session 1 vs. Session 2 – FastDTW

Figure 4.26 - Session 1 vs. Session 3 – FastDTW

Figure 4.27 – Session 2 vs. Session 3 – FastDTW

FastDTW algorithm shows that for the analysis of both the whole body and only the arms, Session 2 vs. 3 are the more similar, as shown in Figure 4.28

Figure 4.28 – Comparison of All Motion Sessions for Full Body and Arms - FastDTW

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  Our implementation of 3D ChainCode technique cannot be used for real time analysis due to the time spent when performing the analysis of human motion. The current implementation takes time to perform the analysis of human motion similarity. Potential ways to improve execution time are reducing accuracy in terms of speed, when searching for common strings in the analysis of similarity, or using different approach when implementing the algorithm that performs the similarity step, i.e., using CUDA tools for nVidia GPUs.
  
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  [This section will be updated once data is collected for the other 3 key rehabilitation exercises]
  

4.4Contribution

In this Chapter, we have compared results from FastDTW algorithm, and our 3D ChainCode implementation. Lack of movement has been detected when generating chain code, and it has been removed so it won’t add to the similarity value when performing the analysis of human motion similarity. LABANotation was also utilized so we can compare similarity values when analyzing the whole body for this particular key rehabilitation exercise, or just the arms.

Chapter 5Enhancing Laban Notation for Rehabilitation Specification

We observed that some potential requirements in the suggested key exercises cannot be fulfilled using current LABANotation.

5.1Proposed Enhancements Based on Mini-Squats Exercise

Figure 5.1 shows a picture of this key exercise.

Figure 5.1 – Mini-Squat Key Rehabilitation Exercise

Exercise a. Mini-squats: muscle group – hips
Description

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  Start standing with equal weight distributed between right and left legs.
  
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  Place feet shoulder width apart.
  
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  Keep torso upright, avoid bending at the waist.
  
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  Slowly lower yourself by bending the ankles, knees, and hips.
  
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  Return to standing.
  

LABANotation has ways to describe positions based on several parts of the body, previous positions, and the scenario. While this requirement could be interpreted with the following symbols shown in Figure 5.2

Figure 5.2 – LABANotation for ‘feet apart, equal distribution in both legs’
There is no way to prove that those symbols actually mean “place feet shoulder width apart”. What we propose is an enhancement to the current LABANotation set of symbols, or the use of existing symbols in LABANotation to create a new meaning. For example, in order to fulfill the requirement “place feet shoulder width apart”, we could use the following symbols shown in Figure 5.3

Figure 5.3 – Proposed LABANotation for ‘feet shoulder width apart, equal weight distribution in both legs’

The added symbols already exist in LABANotation, and they are used to describe both shoulders: the left and the right one. By placing shoulder symbols before the symbols “feet apart, equal weight distribution in both legs,” we want the meaning of such position as “feet shoulder width apart, equal weight distribution in both legs.”