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Título del libro: American Society For Photogrammetry And Remote Sensing - 20th Biennial Workshop On Aerial Photography, Videography, And High Resolution Digital Imagery For Resource Assessment 2005
Título del capítulo: A comparison of small-format digital vs. metric aerial cameras for medium to large-scale mapping

Autores UNAM:
ARMANDO PERALTA HIGUERA; JORGE PRADO MOLINA; ENRIQUE CABRAL CANO; OSCAR DIAZ MOLINA;

Autores externos:

Idioma:

Año de publicación:
2006

Palabras clave:

Aerial camera; Aerial triangulation; Camera images; Cost advantages; Digital photographs; Dual-band GPS receiver; Dynamic range; Feature identification; Ground control; High quality; Image source; Interpretability; Pixel count; Pixel size; Positional accuracy; Post processing; Reliable measurement; RMS errors; Technical work; Thematic information; Three models; Aerial photography; Digital cameras; Information management; Natural resources management; Photogrammetry; Photographic equipment; Pixels; Remote sensing; Video cameras; Video recording; Global positioning system

Resumen:

Aerial digital photographs are now widely used in the study and management of natural resources, mainly because they provide accurate thematic information and have clear cost advantages when compared with other image sources. However, some applications also require positional accuracy, be it to provide reliable measurements for technical work or to deal with socially sensitive issues. It is desirable to take advantage of all the characteristics that small-format digital cameras do offer, among which there is the potential to obtain reliable, high quality maps and mosaics from proven photogrammetric methods. To assess these possibilities, an experiment was conducted to compare the performance of images obtained with a calibrated aerial metric camera (scale 1:4,500), with those obtained with three models of small-format digital cameras, with medium to very high pixel counts. The images were obtained over a small, well characterized area (700 hectares) from different altitudes, with pixel sizes varying from 0.2 to 2 meters. All the images were processed with the same methods and software for aerial triangulation and ortho-correction, and RMS errors were determined. A net of 135 ground control/check points was obtained from a survey with dual-band GPS receivers, working in static mode with post-processing, to an average accuracy of 15mm. Besides positional accuracy, the interpretability of the images was also compared, by assessing the effect of relief displacements, grain, blurring, dynamic range and color contents on feature identification. The results show that small-format camera images provide adequate and even equivalent products as those from metric cameras, as long as good ground-control and careful processing are satisfied.

Entidades citadas de la UNAM: