Aerial image mosaicking of an area of interest is the process of combining multiple images, of an area with overlapping regions, into a single comprehensive view. In this process, image registration, i.e., the operation of geometric transformation to align and overlay two or more images of the same scene taken from different viewpoints, starting from their common parts, plays a key role in terms of artifacts reduction. In the current state-of-the-art, image registration of aerial images is usually performed through the use of the homography transformation. This occurs because these images are frequently acquired at high altitudes (more than 100 meters) and the homography has always provided excellent performance. The recent widespread of Unmanned Aerial Vehicles (UAVs) has enabled the development of several applications where mosaics are used as reference images for high precision tasks, including Detection, Recognition, and Identification (hereinafter DRI) of people and objects. These tasks need to acquire images at very low altitudes (below 50 meters), in which the homography tends to introduce artifacts during the registration process. Therefore, a different transformation able to limit how an image can be morphed, i.e., the similarity transformation, is necessary to perform the image registration, thus improving the overall accuracy of the obtained mosaics. In this paper, for the first time in literature, a comparison between the homography and similarity transformations is performed. In particular, the comparison is carried out by using three recently released public datasets, i.e., NPU Drone-Map, senseFly, and UAV Mosaicking and Change Detection (UMCD), containing challenging aerial video sequences acquired at high and low altitudes. The experimental tests have pointed out the direct relationship among best image transformation, UAV altitude, and spatial resolution, required to accomplish the DRI tasks reported above.
Homography vs similarity transformation in aerial mosaicking: which is the best at different altitudes? / Avola, D.; Cinque, L.; Foresti, G. L.; Pannone, D.. - In: MULTIMEDIA TOOLS AND APPLICATIONS. - ISSN 1380-7501. - 79:25-26(2020), pp. 18387-18404. [10.1007/s11042-020-08758-0]
Homography vs similarity transformation in aerial mosaicking: which is the best at different altitudes?
Avola D.Primo
;Cinque L.;Foresti G. L.;Pannone D.
2020
Abstract
Aerial image mosaicking of an area of interest is the process of combining multiple images, of an area with overlapping regions, into a single comprehensive view. In this process, image registration, i.e., the operation of geometric transformation to align and overlay two or more images of the same scene taken from different viewpoints, starting from their common parts, plays a key role in terms of artifacts reduction. In the current state-of-the-art, image registration of aerial images is usually performed through the use of the homography transformation. This occurs because these images are frequently acquired at high altitudes (more than 100 meters) and the homography has always provided excellent performance. The recent widespread of Unmanned Aerial Vehicles (UAVs) has enabled the development of several applications where mosaics are used as reference images for high precision tasks, including Detection, Recognition, and Identification (hereinafter DRI) of people and objects. These tasks need to acquire images at very low altitudes (below 50 meters), in which the homography tends to introduce artifacts during the registration process. Therefore, a different transformation able to limit how an image can be morphed, i.e., the similarity transformation, is necessary to perform the image registration, thus improving the overall accuracy of the obtained mosaics. In this paper, for the first time in literature, a comparison between the homography and similarity transformations is performed. In particular, the comparison is carried out by using three recently released public datasets, i.e., NPU Drone-Map, senseFly, and UAV Mosaicking and Change Detection (UMCD), containing challenging aerial video sequences acquired at high and low altitudes. The experimental tests have pointed out the direct relationship among best image transformation, UAV altitude, and spatial resolution, required to accomplish the DRI tasks reported above.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
