3D Scene Angles Using UL Decomposition of Planar Homography

Pinak Paliwal, Vikas Paliwal; Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV) Workshops, 2021, pp. 2031-2038

Proctoring during online exams often requires students to be under surveillance from a side pose and there is a strong need to estimate the side camera's relative position with respect to student's computer screen. This work uses edge and line detectors to extract the computer screen's boundaries and estimates homography with respect to rectangular shape with corresponding aspect ratio as in a normal view. A novel Upper-Lower Decomposition of Homography (ULDH) algorithm is proposed that calculates the polar and azimuthal angles with less than 5^o mean errors and can help distinguish bad camera placements from good ones with good precision. A purpose-built dataset is created and validated for this purpose and the software for key parts of image processing pipeline is made available for remote proctoring purposes