Improvement of automatic coregistration of multisensor orthophotos generated from unmanned aerial vehicle using edge sharpening

The images acquired by multi-sensor on the Unmanned Aerial Vehicles (UAVs) have very high resolution (VHR) and are utilized as basic data in various fields. To utilize these images together, orthophoto should be generated based on the acquired UAVs images, and ground control points (GCPs) data acquired through the global navigation satellite system (GNSS) survey should be collected. However, it takes a lot of manpower and time to obtain GCP data every time it is acquired. Also, since sensors mounted on UAV have different properties of acquired images and there are limitations on collecting GCPs. Therefore, in this paper, we propose a methodology to improve the accuracy of automatic co-registration by improving the quality of multi-sensor orthophotos generated based on images acquired from UAVs using unsharp masking method. The image quality affects the extraction of matching points (MPs) used for automatic co-registration. Accordingly, we extracted MPs using phase correction after improving the quality of the reference and input images by utilizing unsharp masking method. And then, co-registration was performed using MPs extracted by proposed method, and the efficiency of the proposed method was verified through visual and quantitative analysis. As a result, we confirmed that the accuracy of automatic co-registration can be improved by using the proposed method.