%0 Research article
%T Geometrically accurate time series of archived aerial images and airborne lidar data in a forest environment
%A Korpela, Ilkka
%D 2006
%J Silva Fennica
%V 40
%N 1
%R doi:10.14214/sf.355
%U https://silvafennica.fi/article/355
%X Reconstructing three-dimensional structural changes in the forest over  time is possible using archived aerial photographs and photogrammetric  techniques, which have recently been introduced to a larger audience  with the advent of digital photogrammetry. This paper explores the  feasibility of constructing an accurate time-series of archived aerial  photographs spanning 42 years using different types of geometric data  and estimation methods for image orientation. A recent airborne laser  scanning (lidar) data set was combined with the image block and assessed  for geometric match. The results suggest that it is possible to  establish the multitemporal geometry of an image block to an accuracy  that is better than 0.5 m in 3D and constant over time. Even geodetic  ground control points can be omitted from the estimation if the most  recent images have accurate direct sensor orientation, which is becoming  a standard technique in aerial photography. This greatly reduces the  costs and facilitates the work. An accurate multitemporal image block  combined with recent lidar scanning for the estimation of topography  allows accurate monitoring and retrospective analysis of forest  vegetation and management operations.