2017 |
Kossieris, S; Kourounioti, O; Agrafiotis, P; Georgopoulos, A Developing a low-cost system for 3d data acquisition Journal Article In: Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci. - ISPRS Arch., 42 (2W8), pp. 119–126, 2017, ISSN: 16821750. Abstract | Links | BibTeX | Tags: 360° camera, Action camera, Facades, Low-cost 3D, Narrow streets, Orthoimage @article{Kossieris2017, In this paper, a developed low-cost system is described, which aims to facilitate 3D documentation fast and reliably by acquiring the necessary data in outdoor environment for the 3D documentation of facades especially in the case of very narrow streets. In particular, it provides a viable solution for buildings up to 8-10m high and streets as narrow as 2m or even less. In cases like that, it is practically impossible or highly time-consuming to acquire images in a conventional way. This practice would lead to a huge number of images and long processing times. The developed system was tested in the narrow streets of a medieval village on the Greek island of Chios. There, in order to by-pass the problem of short taking distances, it was thought to use high definition action cameras together with a 360¢camera, which are usually provided with very wide-angle lenses and are capable of acquiring images, of high definition, are rather cheap and, most importantly, extremely light. Results suggest that the system can perform fast 3D data acquisition adequate for deliverables of high quality. |
2016 |
Agrafiotis, P; Georgopoulos, A; Karantzalos, K The effect of pansharpening algorithms on the resulting orthoimagery Journal Article In: Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci. - ISPRS Arch., 41 , pp. 625–630, 2016, ISSN: 16821750. Abstract | Links | BibTeX | Tags: Accuracy, Digital surface model (DSM), Orthoimage, Pansharpening, Pleiades-1B @article{Agrafiotis2016a, This paper evaluates the geometric effects of pansharpening algorithms on automatically generated DSMs and thus on the resulting orthoimagery through a quantitative assessment of the accuracy on the end products. The main motivation was based on the fact that for automatically generated Digital Surface Models, an image correlation step is employed for extracting correspondences between the overlapping images. Thus their accuracy and reliability is strictly related to image quality, while pansharpening may result into lower image quality which may affect the DSM generation and the resulting orthoimage accuracy. To this direction, an iterative methodology was applied in order to combine the process described by Agrafiotis and Georgopoulos (2015) with different pansharpening algorithms and check the accuracy of orthoimagery resulting from pansharpened data. Results are thoroughly examined and statistically analysed. The overall evaluation indicated that the pansharpening process didn't affect the geometric accuracy of the resulting DSM with a 10m interval, as well as the resulting orthoimagery. Although some residuals in the orthoimages were observed, their magnitude cannot adversely affect the accuracy of the final orthoimagery. |
2017 |
Developing a low-cost system for 3d data acquisition Journal Article In: Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci. - ISPRS Arch., 42 (2W8), pp. 119–126, 2017, ISSN: 16821750. |
2016 |
The effect of pansharpening algorithms on the resulting orthoimagery Journal Article In: Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci. - ISPRS Arch., 41 , pp. 625–630, 2016, ISSN: 16821750. |