Distance Effect Correction on TLS Intensity Data Using Naturally Homogeneous Targets

The intensity data recorded by a terrestrial laser scanner (TLS) are significantly influenced by the distance between the scanned point and the scanner center. In this letter, we propose a new method to estimate the TLS distance-intensity relationship by using naturally homogeneous targets (NHT). Since the original intensity data of the NHT are simultaneously influenced by the incidence angle and distance, the incidence angle effect is first eliminated to obtain a corrected intensity that merely depends on distance. Then, the distance-intensity relationship is derived by analyzing the incidence angle corrected intensity data of the NHT. Results indicate that compared with existing methods the proposed method is accurate and easily implementable. The coefficient of variation for the intensity data can be reduced by 52% after correction by the proposed method.