ANALYSIS OF THE INFLUENCE OF DISTANCE ON DATA ACQUISITION INTENSITY FORESTRY TARGETS BY A LIDAR TECHNIQUE WITH TERRESTRIAL LASER SCANNER
- 1Graduate Program in Remote Sensing, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- 2State Foundation of Environmental Protection Luiz Henrique Roessler (FEPAM), Porto Alegre, RS, Brazil
- 3Graduate Program in Geology, University of Vale do Rio dos Sinos (UNISINOS), São Leopoldo, RS, Brazil
- 4Civil, Surveying and Cartographic Engineering, University of Vale do Rio dos Sinos (UNISINOS), São Leopoldo, RS, Brazil
Keywords: Remote sensing, Terrestrial laser scanner, k-means algorithm, LIDAR, laser intensity, radiometric calibration
Abstract. The forest sciences as well as other areas of knowledge benefit from technological advances to develop their working methods and increase their knowledge of their specific field of study. New equipment and methods are continually developed to support these applications. In the last decade, laser scanning and profiling systems have been consolidated as one of the most effective technologies for geospatial data acquisition. Based on the time-of-flight and with an electromagnetic spectrum that ranges into the mid-infrared, 1535 nm, the terrestrial laser systems are appropriate for correlating the intensity data with physicochemical properties. Thus, the main objective of this study was to evaluate the influence of the distance to the target in the data acquisition intensity targets forest in order to support future studies of correlation between this variable and the physicochemical characteristics of the targets. In this study we used the Terrestrial Laser Scanner 3D Ilris with Optech operating principle based on flight time and wavelength of 1535 nm spectral range from infrared magnetic medium. The data acquisition targets intensity was assessed at distances (1 m à 50 m) by using a target reference of 99% reflectance. The results were analysed and showed that the distance interferes with the return of intensity. From the results of this research recommend that the intensity data are calibrated in relation to distance before using them as a source for study of the physical-chemical characteristics of the targets.