Intensity Correction of Multispectral Airborne Laser Scanning Data

Correction of the range and angle effects has been proven to be viable to improve the radiometric quality of laser scanning data, regardless of the data collection platform. Existing range normalization (RN) method usually adopts the range to the power of two as a correction factor. Nevertheless, such a setting cannot always guarantee the best improvement of intensity homogeneity, particularly on the recently invented multispectral airborne laser scanner. Therefore, this study aims to propose and intensity correction model for the world's first multispectral airborne laser scanner, Optech Titan. The correction model is built upon the iteratively reweighted least squares, and is able to estimate the correction parameters for the range, scan angle and atmospheric attenuation through using a number of paired closest points from the overlapping data strips. Experimental results show that the correction parameters estimated yielded better than the traditional RN approach with a reduction of coefficient of variation ranging from 2.03–18.35% in channel 1 (1550 nm), 15.56–58.42% in channel 2 (1064 nm), and 2.53–29.8% in channel 3 (532 nm) in six land cover classes. Therefore, intensity correction parameters should be estimated from the overlapping laser scanning data strips, regardless of the laser channel being used.