The appearance of coverage holes in wireless sensor networks has an adverse effect on network performance. Consequently, the early detection and correction of such holes is a sine qua non-condition for maintaining network reliability. Our objective in this chapter is to propose a new method for detecting coverage holes. On the one hand, our method makes it possible to take the heterogeneity of sensors into account, and on the other hand, it enables a more accurate calculation of coverage hole size whatever their shape. This solution is made up of three phases: (1) a network scan using a virtual straight line to find uncovered segments, (2) precise coverage hole detection, and (3) analysis of holes generated and merging of adjacent holes. The simulation and the comparative study performed have shown that our method is extremely competitive as it reduces average detection error while increasing precision and execution time.