AR.Drone is a remote-controlled quad-rotor helicopter that is operated by computer instruction. Because communications between AR. Drone and a computer are complex, it is difficult to program AR. Drone software. Existing software development kits (SDKs) reduce those complexities; however, SDKs have many limitations. They can be difficult to use because the structure is too complex to understand, or their extensibility is too minimal for making a multifunctional application. To address these problems, we developed the new DronePilot.NET SDK. The DronePilot.NET SDK supports managed code, and it enables creation of user application programs using C# and Visual Basic. Moreover, because the proposed SDK includes code written in C++/CLI, it supports unmanaged code and enables direct access to native libraries. In addition, the DronePilot.NET SDK supports high-definition video data, image analysis by OpenCV, marker recognition by ARToolkit, and 3D object display by OpenGL. We measured the performance of our proposed SDK for processing video images and have verified its satisfactory performance.