Inefficient SkeletonPose TensorFlow model loading

[Spiess]

Models used for pose detection in images are loaded every time a SkeletonPose class is instantiated, even for similarity queries not using pose extraction.

The following steps should be taken to avoid this:

• The model should be loaded lazily right before being used.
• The model should persist between instances of SkeletonPose.

[sauterl]

Even though the commit bfb6fb1 does not address this issue properly, @Spiess please have a look at this on the branch and report your findings with respect to speedup.

[Spiess]

Do you know if it is necessary to use thread-level caching?
The example you are referencing only uses OpenCV functions and models, if I understand correctly, and there this might be necessary, but for TensorFlow models this may even cause problems depending on if the default session is global or thread local.

[lucaro]

Yes, in this case, it might make sense to explicitly avoid parallelism since tensorflow already uses all compute resources it can get (at least in CPU mode).