With the advancement of light detection and ranging (LiDAR) technology, the mobile laser scanner (MLS) has been regarded as an important technology to collect geometric representations of the indoor environment. In particular, methods for detecting indoor objects from indoor point cloud data (PCD) captured through MLS have thus far been developed based on the trajectory of MLS. However, the existing methods have a limitation on applying to an indoor environment where the building components made by concrete impede obtaining the information of trajectory. Thus, this study aims to propose a building component detection algorithm for MLS-based indoor PCD without trajectory using random sample consensus (RANSAC)-based region growth. The proposed algorithm used the RANSAC and region growing to overcome the low accuracy and uniformity of MLS caused by the movement of LiDAR. This study ensures over 90% precision, recall, and proper segmentation rate of building component detection by testing the algorithm using the indoor PCD. The result of the case study shows that the proposed algorithm opens the possibility of accurately detecting interior objects from indoor PCD without trajectory information of MLS.

Video analysis and understanding play a central role in visual intelligence. In this paper, we aim to analyze unconstrained videos, by designing features and approaches to represent and analyze videography styles in the videos. Videography denotes the process of making videos. The unconstrained videos are defined as the long duration consumer videos that usually have diverse editing artifacts and significant complexity of contents. We propose to construct a videography dictionary , which can be utilized to represent every video clip as a sequence of videography words. In addition to semantic features, such as foreground object motion and camera motion, we also incorporate two novel interpretable features to characterize videography, including the scale information and the motion correlations. We then demonstrate that, by using statistical analysis methods, the unique videography signatures extracted from different events can be automatically identified. For real-world applications, we explore the use of videography analysis for three types of applications, including content-based video retrieval, video summarization (both visual and textual), and videography-based feature pooling. In the experiments, we evaluate the performance of our approach and other methods on a large-scale unconstrained video dataset, and show that the proposed approach significantly benefits video analysis in various ways.

This study proposes a new method to generate a three-dimensional (3D) geometric representation of an indoor environment by refining and processing an indoor point cloud data (PCD) captured through backpack laser scanners. The proposed algorithm comprises two parts to generate the 3D geometric representation: data refinement and data processing. In the refinement section, the inputted indoor PCD are roughly segmented by applying random sample consensus (RANSAC) to raw data based on an estimated normal vector. Next, the 3D geometric representation is generated by calculating and separating tangent points on segmented PCD. This study proposes a robust algorithm that utilizes the topological feature of the indoor PCD created by a hierarchical data process. The algorithm minimizes the size and the uncertainty of raw PCD caused by the absence of a global navigation satellite system and equipment errors. The result of this study shows that the indoor environment can be converted into 3D geometric representation by applying the proposed algorithm to the indoor PCD.