PREFACE – ISPRS WORKSHOP INDOOR 3D 2019 - Z. Kang; K. Khoshelham; L. Díaz-Vilariño; C. Wang; S. Nebiker; V. Lehtola; K. W. Chiang; K.-J. Li; B. De Lathouwer; S. Dalyot (ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2019)