Robots cooperation means also to define the commune task. In order to understand their cooperation the robots must have complete knowledge about all possible states of the work or to understand the context by extract useful information from observation. Present paper focus on the second possibility. We propose a strategy of information extraction and context understanding based on an original data structure, the fuzzy signature and on a priori knowledge, the robot codebook. The paper starts by presenting the concept of the fuzzy signature and exemplify the idea of cooperation by context understanding.