ALS intensity correction for a forest area

Abstract

This study applied the relative intensity correction for the ALS data of a subtropical forestry area to evaluate the effectiveness of intensity correction in southern Taiwan Our ALS data contains six flight strips with the altitudes varied from 1403 m to 2745 m which were obtained with two different flying heading A homogeneous road surface with asphalt pavement were used to estimate the parameters of the modified LiDAR equation This study found that the flying heading may affect the recorded intensity and the estimation of the parameters and this phenomenon is called “heading phenomenon” We consider the heading phenomenon spherical loss atmospheric effect topographic effect and non-lambertian characteristic when conducting the intensity correction To evaluate the results of intensity correction in the forestry area the ISODATA unsupervised classification was used The classification of corrected intensity showed that although the forestry area did not fulfill the assumption of the LiDAR equation which assumes the return signal is the ‘only return’ the results of the correction using first and only return are still acceptable After all the intensity correction the classification accuracy achieved a value of 83 32%

Date of Award	2015 Aug 21
Original language	English
Supervisor	Chi-Kuei Wang (Supervisor)