期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2006
卷号：XXXVI Part 1
出版社：Copernicus Publications
摘要：In this paper the calibration of Optech ALTM 3100 laser scanner intensity is reported using airborne experiments and known brightness targets. The Finnish Geodetic Institute has had a permanent photogrammetric test field in Sj.kulla Kirkkonummi since 1994. This test field contains permanent and transportable test targets for radiometric calibration, permanent ground control points for small, medium and large-scale geometric calibration and also test bar targets for spatial analysis of analogue and digital aerial cameras. Since 2000 LIDAR testing has also been carried out, the latest being Optech ALTM 3100 campaign in 12-14 July 2005. Eight portable brightness targets with nominal reflectance of 5 %, 10 %, 20 %, 25 %, 30 %, 45 %, 50 % and 70 % were in use for LIDAR testing. Flying heights were about 200, 1000 and 3000 m above ground level. Intensity values need to be corrected with respect to range, incidence angle (both BRDF and range correction), atmospheric transmittance, attenuation using dark object addition and transmitted power (because difference in PRF will lead to different transmitter power values). After these corrections, the intensity values were directly relative to target reflectance. Flight heights of 200 m and 1000 m are suitable for intensity calibration using artificial test targets due to the practical aspects of the calibration (size of the calibrator). With the 3000 m altitude signals with reflectance of less or equal of 10% could not be recorded most probably due to insufficient signal-to-noise ratio. Thus, the test target reflectance should exceed 10% to give a reliable distance measurement from 3000 m altitude
