In addition to precise 3D coordinates, most light detection and ranging (LIDAR) systems also record “intensity”, loosely defined as the strength of the backscattered echo for each measured point. To date, LIDAR intensity data have proven beneficial in a wide range of applications because they are related to surface parameters, such as reflectance. While numerous procedures have been introduced in the scientific literature, and even commercial software, to enhance the utility of intensity data through a variety of “normalization”, “correction”, or “calibration” techniques, the current situation is complicated by a lack of standardization, as well as confusing, inconsistent use of terminology. In this paper, we first provide an overview of basic principles of LIDAR intensity measurements and applications utilizing intensity information from terrestrial, airborne topographic, and airborne bathymetric LIDAR. Next, we review effective parameters on intensity measurements, basic theory, and current intensity processing methods. We define terminology adopted from the most commonly-used conventions based on a review of current literature. Finally, we identify topics in need of further research. Ultimately, the presented information helps lay the foundation for future standards and specifications for LIDAR radiometric calibration.

Structural fragility models have been developed to provide probabilistic estimates of building component damage states caused by exposure to differing wind speeds. Limitations in taking accurate measurements and gathering quantitative loss information in the aftermath of tornadoes has not allowed for comparing fragility-based information with actual building-loss data. This paper presents a methodology for extracting damaged building geometry and roof sheathing loss information from three-dimensional (3D) point cloud data collected with laser scanning technology. The observed building component damage states are then compared to fragility model predictions to validate the models. The methodology was tested on 3D data collected after the 2013 Moore, Oklahoma tornado. From this initial study, which was performed on 5 houses having 27 damaged roof surfaces, it was shown that fragility models underestimated the loss in the center of roof planes (Zone 1) and overestimated the loss in the corners of roo...