In wireless sensor networks, the purpose of surveillance cannot be fulfilled if coverage holes are generated due to accidental death of the nodes caused due to technical failures, explosions and malicious activities or power exhaustion. Since, sensors are normally deployed randomly over the dense forests and harsh terrains, it is not possible to find out the coverage holes manually. Hence, in this work a computational geometry approach based distributed hole detection protocol is designed to find out the coverage holes in a post deployment scenario. An efficient geometric method with proper theoretical basis is used to detect the coverage holes of the wireless sensor network, where communication and sensing range of the nodes are same. Performance evaluation of our protocol shows that the hole detection time and energy consumption due to hole detection outperforms over similar hole detection protocols.