Coverage area and network lifetime are major problems in wireless multimedia sensor networks (WMSNs). In order to optimize the network coverage, we propose a coverage-enhancing algorithm based on overlap-sense ratio. By adjusting the sensing direction of the nodes, the coverage area is increased with the reduction of computational complexity. In addition, a modified strategy is presented to shut off the redundant sensors so that network lifetime is prolonged. Simulation results show that the proposed algorithm achieves more effective enhancement on network coverage compared to the existing algorithm.