The performance of a local maxima method for detecting individual tree tops in aerial photographs

Abstract

Tree locations are needed in image‐based single tree forest inventories. Accurate tree‐top image positions would also be useful in image matching (IM) for the estimation of a canopy surface model. We explored the performance of a local maxima (LM)‐based method for detecting image positions of individual tree tops by using digitized aerial photographs in recently thinned stands in Southern Finland. The accuracy of tree detection at the single tree level was assessed using a novel 3D approach. The results indicate that the LM method works most reliably in the central parts of the aerial images. Small trees are mostly missed by the LM detector and commission errors seem unavoidable. We propose further work that would assess the applicability of the LM method as a feature detector for use in IM.

Acknowledgements

We thank the Finnish Ministry of Agriculture and Forestry, the Graduate School in Forest Sciences, the Metsämiesten Säätiö Foundation and the Finnish Society of Forest Science for funding and Greg Watson for revising the English text.