Potential of the incidence angle effect on the radiometric calibration of full-waveform airborne laser scanning in urban areas

摘要

Full-waveform airborne laser scanning has shown potential to better describe land cover features through the additional physical information it can provide alongside the standard geometric information. To fully utilize full-waveform for enhanced object recognition and feature extraction, it is essential to calibrate the backscattered energy of the received signal. The backscatter signal is affected by many variables during the travel between the sensor and the target. To eliminate these effects and deliver more reliable physical information for land cover features, the incidence angle effect was considered following the RSN method which was introduced in previous work. Following the radar equation, a comprehensive radiometric calibration routine was applied in this paper where the backscatter coefficient utilized to deliver the calibration constant. The calibrated results were achieved by means of backscatter cross-section and coefficient parameters in addition to the normalized parameters with respect to the incidence angle effect. The backscatter signals from overlapping flight lines were investigated and analyzed over various land cover types before and after calibration in the study site. Results show the potential of using the backscatter coefficient to deliver the calibration constant for the radiometric calibration purposes. It was also proven that the normalized backscatter coefficient with respect to incidence angle provides the greatest potential amongst the other backscatter parameters by delivering the optimal match between flight lines.