This week, I put my focus more on implementing the comparison algorithm and normalizing body sizes for better results which accounts for difference in body sizes. Abiding our Gantt Chart, here’s my progress:
Progress:
Since our pipeline from OpenPose is still under development, I constructed some datasets myself (purely random) to test my comparison algorithm using cosine similarity. Cosine similarity measures the angular similarity between vectors, making it ideal for assessing body orientations. Additionally, I will explore techniques to normalize body sizes to enhance the accuracy of these posture comparisons in the following week.
To facilitate comparison, each body posture is transformed into a vector within a multi-dimensional space. Each dimension within this space corresponds to a specific key point (in our case, joint) detected by OpenPose. For instance, if I am receiving from OpenPose output consists of 18 absolute positions, each posture is then represented as an 18-dimensional vector.
The implementation requires packages including numpy, normal Python environment and VSC for development. I used 3.11.5 in this case since 3.12 was just released a few days ago which could have compatibility issues with package supports. I’ll make sure to keep targeting the latest version for optimization and support of the packages.
Implementation on absolute position (Planned for next week):
To account for differences in body sizes and variations in the distances between body joints, it is imperative to normalize the posture vectors. The idea I have now is to normalize every person into my body size, which is around 5’10 and 170 lbs (need to be justified next week with other members of the group). This will be an add on to the cosine comparison idea to determine the absolute position of users. The idea of using absolute position eliminates the possibility that the user is doing a completely different posture and scores a high similarity due to the nature of cosine similarity. The normalization process involves dividing the coordinates of key points by reference length, which is typically the distance between two consistent points (two shoulders, the ratio between upper and lower body, the ratio between calf and thigh). This procedure scales all joints proportionally to this reference length, facilitating a relatively standard comparison.