Calibration of Two 3D Sensors with Perpendicular Scanning Directions by using a Piece of Paper Topics: Device Calibration, Characterization and Modeling; Image Enhancement and Restoration; Image-Based Modeling and 3D Reconstruction In Proceedings of the 14th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications - Volume 4 VISAPP: VISAPP, 162-168, 2019 , Prague, Czech Republic