| Full text | |
| Author(s): |
Total Authors: 2
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| Affiliation: | [1] Univ Estadual Paulista Unesp, Dept Cartog, Presidente Prudente, SP - Brazil
Total Affiliations: 1
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| Document type: | Journal article |
| Source: | Bol. Ciênc. Geod.; v. 24, n. 2, p. 171-185, APR-JUN 2018. |
| Web of Science Citations: | 0 |
| Abstract | |
This paper presents an experimental assessment of photogrammetric targets and subpixel location techniques to be used with low contrast images such as images acquired by hyperspectral frame cameras. Eight different target patterns of varying shape, background, and size were tested. The aim was to identify an optimum distinctive pattern to serve as control point in aerial surveys of small areas using hyperspectral cameras when natural points are difficult to find in suitable areas. Three automatic techniques to identify the target point of interest were compared, which were weighted centroid, template matching, and line intersection. For assessment, hyperspectral images of the set of targets were collected in an outdoor 3D terrestrial calibration field. RGB images were also acquired for reference and comparison. Experiments were conducted to assess the accuracy at the sub-pixel level. Bundle adjustment with several images was used, and vertical and horizontal distances were directly measured in the field for verification. An experiment with aerial flight was also performed to validate the chosen target. The analysis of residuals and discrepancies indicated that a circular target is best suited as the ground control in aerial surveys, considering the condition in which the target appears with few pixels in the image. (AU) | |
| FAPESP's process: | 13/50426-4 - Unmanned airborne vehicle-based 4D remote sensing for mapping Rain Forest biodiversity and its change in Brazil (UAV_4D_Bio) |
| Grantee: | Antonio Maria Garcia Tommaselli |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 14/05033-7 - Integrated Orientation of Hyperspectral Images Collected with UAV |
| Grantee: | Adilson Berveglieri |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |