Understanding and Modeling Motion-Induced Point Cloud Distortions in Mobile Laser Scanning (Thesis Defense Presentation)

Slides from my thesis oral examination at IIT Kanpur (Department of Civil Engineering), presented on 21 May 2025. Supervisor: Prof. Bharat Lohani. Co-supervisor: Prof. Gaurav Pandey. What it is about: A mobile mapping vehicle uses laser scanners to build a 3D “point cloud” of the road and its surroundings. The laser measures an object bit by bit, so if the object (for example, a passing car) is also moving, its scanned shape comes out wrong: stretched, squashed, front and back swapped, or tilted like a leaning box. The talk explains why this happens, shows real examples from mobile-mapping data, and derives simple equations that predict these distortions from the speeds and directions of the vehicle and the object. The equations are checked against computer-simulated LiDAR data (length error about 0.17 m, angle errors under 0.6°). The equations assume constant-speed straight-line motion and flat ground. Not peer reviewed. The peer-reviewed paper: Singh, A. K., and B. Lohani (2026), J. Surv. Eng. 152(3): 04026006, https://doi.org/10.1061/JSUED2.SUENG-1663.