The CTCR is incentivized by the concept of Shapley Value. The r-function in the above equation is the accuracy of the triangulated human pose. In essence, CTCR measures the average weighted marginal contribution of a camera agent to every valid sub-formation that contains this agent. A sub-formation needs to have at least two cameras to be considered valid, since the problem definition requires at least two cameras to form a valid multi-view 3D triangulation.
The main idea is that achieving the overall optimality needs to also account for the optimality of every possible sub-formation (S). In order for a camera agent to receive the highest reward possible, its current position and view must be optimal both in terms of its current formation and any sub-formation possible.
The figure below shows an example of calculating CTCR for every camera agent in a three-cameras team.