As for the existing research on coverage of Wireless Multimedia Sensor Networks(WMSNs), applications of sensor being in target region are paid more attention to, and the effect of the whole possible sense area on coverage ratio is not taken into consideration. Aiming at different applications of sensor being higher than target region, a classification taxonomy is presented, in which these applications are fallen into two categories: delayed coverage and non-delayed coverage. Then a Deployment-Controlling Algorithm (IVPDCA) is put forward. Force model of improved virtual potential fields is established, and the sensor's mass is defined to exhibit the overlap between sensors. Redundant sensors are shut off and the coverage of networks can be enhanced by re-deploying sensors. Simulation results are presented for demonstrating the effectiveness of the proposed approach.