As no civil infrastructure can escape aging and deterioration, health monitoring can prevent and report serious structural damage. With the rapid evolution of computer vision algorithms, optical-based systems become an increasingly feasible option for automatic monitoring. This paper proposes a cheap and flexible standalone system based on marker tracking to report deflection of structural elements of civil infrastructure. A single marker is placed on tracked objects, which allows unambiguous identification of objects and accurate movement tracking. Accuracy of the system is discussed by presenting a theoretical analysis of the translation error. Additionally, as a proof of concept we extend our work with a low-cost laboratory test implementation.