Dynamic scene rendering and reconstruction play a crucial role in computer vision and augmented reality. Recent methods based on 3D Gaussian Splatting (3DGS), have enabled accurate modeling of dynamic urban scenes, but for urban scenes they require both camera and LiDAR data, ground-truth 3D segmentations and motion data in the form of tracklets or pre-defined object templates such as SMPL. In this work, we explore whether a combination of 2D object agnostic priors in the form of depth and point tracking coupled with a signed distance function (SDF) representation for dynamic objects can be used to relax some of these requirements. We present a novel approach that integrates Signed Distance Functions (SDFs) with 3D Gaussian Splatting (3DGS) to create a more robust object representation by harnessing the strengths of both methods. Our unified optimization framework enhances the geometric accuracy of 3D Gaussian splatting and improves deformation modeling within the SDF, resulting in a more adaptable and precise representation. We demonstrate that our method achieves state-of-the-art performance in rendering metrics even without LiDAR data on urban scenes. When incorporating LiDAR, our approach improved further in reconstructing and generating novel views across diverse object categories, without ground-truth 3D motion annotation. Additionally, our method enables various scene editing tasks, including scene decomposition, and scene composition.

Human action recognition (HAR) in untrimmed videos can make insightful predictions of human behaviour. Previous work on HAR-included models trained on spatial and temporal annotations and could classify limited actions from trimmed videos. These methods reported limitations such as (1) performance degradation due to the lack of precision temporal regions proposal and (2) poor adaptability of the models in the clinical domain because of unrelated actions of interest. We propose an innovative method that could analyse untrimmed behavioural videos to recommend actions of interest leading to diagnostic and functional assessments for children with Autism Spectrum Disorder (ASD). Our method entails end-to-end behaviour action recognition (BAR) pipeline, including child detection, temporal action localization, and actions of interest identification and classification. The model trained on the data of 400 ASD children and 125 with other developmental delays (ODD) accurately identified ASD, ODD, and Neurotypical children with 79.7, 77.2, and 80.8 accuracy, respectively. The model's performance on an independent benchmark Self-Stimulatory Behaviour Dataset (SSBD) reported top-1 accuracy of 78.57 for combined localization with action recognition, significantly higher than the earlier reported outcomes. © 2023 John Wiley & Sons Ltd.